text: /* build: `node build.js modules=ALL exclude=gestures,accessors requirejs minifier=uglifyjs` */
  /*! Fabric.js Copyright 2008-2015, Printio (Juriy Zaytsev, Maxim Chernyak) */
  
  var fabric = fabric || { version: '3.5.1' };
  if (typeof exports !== 'undefined') {
    exports.fabric = fabric;
  }
  /* _AMD_START_ */
  else if (typeof define === 'function' && define.amd) {
    define([], function() { return fabric; });
  }
  /* _AMD_END_ */
  if (typeof document !== 'undefined' && typeof window !== 'undefined') {
    if (document instanceof (typeof HTMLDocument !== 'undefined' ? HTMLDocument : Document)) {
      fabric.document = document;
    }
    else {
      fabric.document = document.implementation.createHTMLDocument('');
    }
    fabric.window = window;
  }
  else {
    // assume we're running under node.js when document/window are not present
    var jsdom = require('jsdom');
    var virtualWindow = new jsdom.JSDOM(
      decodeURIComponent('%3C!DOCTYPE%20html%3E%3Chtml%3E%3Chead%3E%3C%2Fhead%3E%3Cbody%3E%3C%2Fbody%3E%3C%2Fhtml%3E'),
      {
        features: {
          FetchExternalResources: ['img']
        },
        resources: 'usable'
      }).window;
    fabric.document = virtualWindow.document;
    fabric.jsdomImplForWrapper = require('jsdom/lib/jsdom/living/generated/utils').implForWrapper;
    fabric.nodeCanvas = require('jsdom/lib/jsdom/utils').Canvas;
    fabric.window = virtualWindow;
    DOMParser = fabric.window.DOMParser;
  }
  
  /**
   * True when in environment that supports touch events
   * @type boolean
   */
  fabric.isTouchSupported = 'ontouchstart' in fabric.window || 'ontouchstart' in fabric.document ||
    (fabric.window && fabric.window.navigator && fabric.window.navigator.maxTouchPoints > 0);
  
  /**
   * True when in environment that's probably Node.js
   * @type boolean
   */
  fabric.isLikelyNode = typeof Buffer !== 'undefined' &&
                        typeof window === 'undefined';
  
  /* _FROM_SVG_START_ */
  /**
   * Attributes parsed from all SVG elements
   * @type array
   */
  fabric.SHARED_ATTRIBUTES = [
    'display',
    'transform',
    'fill', 'fill-opacity', 'fill-rule',
    'opacity',
    'stroke', 'stroke-dasharray', 'stroke-linecap', 'stroke-dashoffset',
    'stroke-linejoin', 'stroke-miterlimit',
    'stroke-opacity', 'stroke-width',
    'id', 'paint-order', 'vector-effect',
    'instantiated_by_use', 'clip-path'
  ];
  /* _FROM_SVG_END_ */
  
  /**
   * Pixel per Inch as a default value set to 96. Can be changed for more realistic conversion.
   */
  fabric.DPI = 96;
  fabric.reNum = '(?:[-+]?(?:\\d+|\\d*\\.\\d+)(?:[eE][-+]?\\d+)?)';
  fabric.fontPaths = { };
  fabric.iMatrix = [1, 0, 0, 1, 0, 0];
  
  /**
   * Pixel limit for cache canvases. 1Mpx , 4Mpx should be fine.
   * @since 1.7.14
   * @type Number
   * @default
   */
  fabric.perfLimitSizeTotal = 2097152;
  
  /**
   * Pixel limit for cache canvases width or height. IE fixes the maximum at 5000
   * @since 1.7.14
   * @type Number
   * @default
   */
  fabric.maxCacheSideLimit = 4096;
  
  /**
   * Lowest pixel limit for cache canvases, set at 256PX
   * @since 1.7.14
   * @type Number
   * @default
   */
  fabric.minCacheSideLimit = 256;
  
  /**
   * Cache Object for widths of chars in text rendering.
   */
  fabric.charWidthsCache = { };
  
  /**
   * if webgl is enabled and available, textureSize will determine the size
   * of the canvas backend
   * @since 2.0.0
   * @type Number
   * @default
   */
  fabric.textureSize = 2048;
  
  /**
   * When 'true', style information is not retained when copy/pasting text, making
   * pasted text use destination style.
   * Defaults to 'false'.
   * @type Boolean
   * @default
   */
  fabric.disableStyleCopyPaste = false;
  
  /**
   * Enable webgl for filtering picture is available
   * A filtering backend will be initialized, this will both take memory and
   * time since a default 2048x2048 canvas will be created for the gl context
   * @since 2.0.0
   * @type Boolean
   * @default
   */
  fabric.enableGLFiltering = true;
  
  /**
   * Device Pixel Ratio
   * @see https://developer.apple.com/library/safari/documentation/AudioVideo/Conceptual/HTML-canvas-guide/SettingUptheCanvas/SettingUptheCanvas.html
   */
  fabric.devicePixelRatio = fabric.window.devicePixelRatio ||
                            fabric.window.webkitDevicePixelRatio ||
                            fabric.window.mozDevicePixelRatio ||
                            1;
  /**
   * Browser-specific constant to adjust CanvasRenderingContext2D.shadowBlur value,
   * which is unitless and not rendered equally across browsers.
   *
   * Values that work quite well (as of October 2017) are:
   * - Chrome: 1.5
   * - Edge: 1.75
   * - Firefox: 0.9
   * - Safari: 0.95
   *
   * @since 2.0.0
   * @type Number
   * @default 1
   */
  fabric.browserShadowBlurConstant = 1;
  
  /**
   * This object contains the result of arc to beizer conversion for faster retrieving if the same arc needs to be converted again.
   * It was an internal variable, is accessible since version 2.3.4
   */
  fabric.arcToSegmentsCache = { };
  
  /**
   * This object keeps the results of the boundsOfCurve calculation mapped by the joined arguments necessary to calculate it.
   * It does speed up calculation, if you parse and add always the same paths, but in case of heavy usage of freedrawing
   * you do not get any speed benefit and you get a big object in memory.
   * The object was a private variable before, while now is appended to the lib so that you have access to it and you
   * can eventually clear it.
   * It was an internal variable, is accessible since version 2.3.4
   */
  fabric.boundsOfCurveCache = { };
  
  /**
   * If disabled boundsOfCurveCache is not used. For apps that make heavy usage of pencil drawing probably disabling it is better
   * @default true
   */
  fabric.cachesBoundsOfCurve = true;
  
  /**
   * Skip performance testing of setupGLContext and force the use of putImageData that seems to be the one that works best on
   * Chrome + old hardware. if your users are experiencing empty images after filtering you may try to force this to true
   * this has to be set before instantiating the filtering backend ( before filtering the first image )
   * @type Boolean
   * @default false
   */
  fabric.forceGLPutImageData = false;
  
  fabric.initFilterBackend = function() {
    if (fabric.enableGLFiltering && fabric.isWebglSupported && fabric.isWebglSupported(fabric.textureSize)) {
      console.log('max texture size: ' + fabric.maxTextureSize);
      return (new fabric.WebglFilterBackend({ tileSize: fabric.textureSize }));
    }
    else if (fabric.Canvas2dFilterBackend) {
      return (new fabric.Canvas2dFilterBackend());
    }
  };
  
  
  if (typeof document !== 'undefined' && typeof window !== 'undefined') {
    // ensure globality even if entire library were function wrapped (as in Meteor.js packaging system)
    window.fabric = fabric;
  }
  
  
  (function() {
  
    /**
     * @private
     * @param {String} eventName
     * @param {Function} handler
     */
    function _removeEventListener(eventName, handler) {
      if (!this.__eventListeners[eventName]) {
        return;
      }
      var eventListener = this.__eventListeners[eventName];
      if (handler) {
        eventListener[eventListener.indexOf(handler)] = false;
      }
      else {
        fabric.util.array.fill(eventListener, false);
      }
    }
  
    /**
     * Observes specified event
     * @deprecated `observe` deprecated since 0.8.34 (use `on` instead)
     * @memberOf fabric.Observable
     * @alias on
     * @param {String|Object} eventName Event name (eg. 'after:render') or object with key/value pairs (eg. {'after:render': handler, 'selection:cleared': handler})
     * @param {Function} handler Function that receives a notification when an event of the specified type occurs
     * @return {Self} thisArg
     * @chainable
     */
    function observe(eventName, handler) {
      if (!this.__eventListeners) {
        this.__eventListeners = { };
      }
      // one object with key/value pairs was passed
      if (arguments.length === 1) {
        for (var prop in eventName) {
          this.on(prop, eventName[prop]);
        }
      }
      else {
        if (!this.__eventListeners[eventName]) {
          this.__eventListeners[eventName] = [];
        }
        this.__eventListeners[eventName].push(handler);
      }
      return this;
    }
  
    /**
     * Stops event observing for a particular event handler. Calling this method
     * without arguments removes all handlers for all events
     * @deprecated `stopObserving` deprecated since 0.8.34 (use `off` instead)
     * @memberOf fabric.Observable
     * @alias off
     * @param {String|Object} eventName Event name (eg. 'after:render') or object with key/value pairs (eg. {'after:render': handler, 'selection:cleared': handler})
     * @param {Function} handler Function to be deleted from EventListeners
     * @return {Self} thisArg
     * @chainable
     */
    function stopObserving(eventName, handler) {
      if (!this.__eventListeners) {
        return this;
      }
  
      // remove all key/value pairs (event name -> event handler)
      if (arguments.length === 0) {
        for (eventName in this.__eventListeners) {
          _removeEventListener.call(this, eventName);
        }
      }
      // one object with key/value pairs was passed
      else if (arguments.length === 1 && typeof arguments[0] === 'object') {
        for (var prop in eventName) {
          _removeEventListener.call(this, prop, eventName[prop]);
        }
      }
      else {
        _removeEventListener.call(this, eventName, handler);
      }
      return this;
    }
  
    /**
     * Fires event with an optional options object
     * @deprecated `fire` deprecated since 1.0.7 (use `trigger` instead)
     * @memberOf fabric.Observable
     * @alias trigger
     * @param {String} eventName Event name to fire
     * @param {Object} [options] Options object
     * @return {Self} thisArg
     * @chainable
     */
    function fire(eventName, options) {
      if (!this.__eventListeners) {
        return this;
      }
  
      var listenersForEvent = this.__eventListeners[eventName];
      if (!listenersForEvent) {
        return this;
      }
  
      for (var i = 0, len = listenersForEvent.length; i < len; i++) {
        listenersForEvent[i] && listenersForEvent[i].call(this, options || { });
      }
      this.__eventListeners[eventName] = listenersForEvent.filter(function(value) {
        return value !== false;
      });
      return this;
    }
  
    /**
     * @namespace fabric.Observable
     * @tutorial {@link http://fabricjs.com/fabric-intro-part-2#events}
     * @see {@link http://fabricjs.com/events|Events demo}
     */
    fabric.Observable = {
      observe: observe,
      stopObserving: stopObserving,
      fire: fire,
  
      on: observe,
      off: stopObserving,
      trigger: fire
    };
  })();
  
  
  /**
   * @namespace fabric.Collection
   */
  fabric.Collection = {
  
    _objects: [],
  
    /**
     * Adds objects to collection, Canvas or Group, then renders canvas
     * (if `renderOnAddRemove` is not `false`).
     * in case of Group no changes to bounding box are made.
     * Objects should be instances of (or inherit from) fabric.Object
     * Use of this function is highly discouraged for groups.
     * you can add a bunch of objects with the add method but then you NEED
     * to run a addWithUpdate call for the Group class or position/bbox will be wrong.
     * @param {...fabric.Object} object Zero or more fabric instances
     * @return {Self} thisArg
     * @chainable
     */
    add: function () {
      this._objects.push.apply(this._objects, arguments);
      if (this._onObjectAdded) {
        for (var i = 0, length = arguments.length; i < length; i++) {
          this._onObjectAdded(arguments[i]);
        }
      }
      this.renderOnAddRemove && this.requestRenderAll();
      return this;
    },
  
    /**
     * Inserts an object into collection at specified index, then renders canvas (if `renderOnAddRemove` is not `false`)
     * An object should be an instance of (or inherit from) fabric.Object
     * Use of this function is highly discouraged for groups.
     * you can add a bunch of objects with the insertAt method but then you NEED
     * to run a addWithUpdate call for the Group class or position/bbox will be wrong.
     * @param {Object} object Object to insert
     * @param {Number} index Index to insert object at
     * @param {Boolean} nonSplicing When `true`, no splicing (shifting) of objects occurs
     * @return {Self} thisArg
     * @chainable
     */
    insertAt: function (object, index, nonSplicing) {
      var objects = this._objects;
      if (nonSplicing) {
        objects[index] = object;
      }
      else {
        objects.splice(index, 0, object);
      }
      this._onObjectAdded && this._onObjectAdded(object);
      this.renderOnAddRemove && this.requestRenderAll();
      return this;
    },
  
    /**
     * Removes objects from a collection, then renders canvas (if `renderOnAddRemove` is not `false`)
     * @param {...fabric.Object} object Zero or more fabric instances
     * @return {Self} thisArg
     * @chainable
     */
    remove: function() {
      var objects = this._objects,
          index, somethingRemoved = false;
  
      for (var i = 0, length = arguments.length; i < length; i++) {
        index = objects.indexOf(arguments[i]);
  
        // only call onObjectRemoved if an object was actually removed
        if (index !== -1) {
          somethingRemoved = true;
          objects.splice(index, 1);
          this._onObjectRemoved && this._onObjectRemoved(arguments[i]);
        }
      }
  
      this.renderOnAddRemove && somethingRemoved && this.requestRenderAll();
      return this;
    },
  
    /**
     * Executes given function for each object in this group
     * @param {Function} callback
     *                   Callback invoked with current object as first argument,
     *                   index - as second and an array of all objects - as third.
     *                   Callback is invoked in a context of Global Object (e.g. `window`)
     *                   when no `context` argument is given
     *
     * @param {Object} context Context (aka thisObject)
     * @return {Self} thisArg
     * @chainable
     */
    forEachObject: function(callback, context) {
      var objects = this.getObjects();
      for (var i = 0, len = objects.length; i < len; i++) {
        callback.call(context, objects[i], i, objects);
      }
      return this;
    },
  
    /**
     * Returns an array of children objects of this instance
     * Type parameter introduced in 1.3.10
     * since 2.3.5 this method return always a COPY of the array;
     * @param {String} [type] When specified, only objects of this type are returned
     * @return {Array}
     */
    getObjects: function(type) {
      if (typeof type === 'undefined') {
        return this._objects.concat();
      }
      return this._objects.filter(function(o) {
        return o.type === type;
      });
    },
  
    /**
     * Returns object at specified index
     * @param {Number} index
     * @return {Self} thisArg
     */
    item: function (index) {
      return this._objects[index];
    },
  
    /**
     * Returns true if collection contains no objects
     * @return {Boolean} true if collection is empty
     */
    isEmpty: function () {
      return this._objects.length === 0;
    },
  
    /**
     * Returns a size of a collection (i.e: length of an array containing its objects)
     * @return {Number} Collection size
     */
    size: function() {
      return this._objects.length;
    },
  
    /**
     * Returns true if collection contains an object
     * @param {Object} object Object to check against
     * @return {Boolean} `true` if collection contains an object
     */
    contains: function(object) {
      return this._objects.indexOf(object) > -1;
    },
  
    /**
     * Returns number representation of a collection complexity
     * @return {Number} complexity
     */
    complexity: function () {
      return this._objects.reduce(function (memo, current) {
        memo += current.complexity ? current.complexity() : 0;
        return memo;
      }, 0);
    }
  };
  
  
  /**
   * @namespace fabric.CommonMethods
   */
  fabric.CommonMethods = {
  
    /**
     * Sets object's properties from options
     * @param {Object} [options] Options object
     */
    _setOptions: function(options) {
      for (var prop in options) {
        this.set(prop, options[prop]);
      }
    },
  
    /**
     * @private
     * @param {Object} [filler] Options object
     * @param {String} [property] property to set the Gradient to
     */
    _initGradient: function(filler, property) {
      if (filler && filler.colorStops && !(filler instanceof fabric.Gradient)) {
        this.set(property, new fabric.Gradient(filler));
      }
    },
  
    /**
     * @private
     * @param {Object} [filler] Options object
     * @param {String} [property] property to set the Pattern to
     * @param {Function} [callback] callback to invoke after pattern load
     */
    _initPattern: function(filler, property, callback) {
      if (filler && filler.source && !(filler instanceof fabric.Pattern)) {
        this.set(property, new fabric.Pattern(filler, callback));
      }
      else {
        callback && callback();
      }
    },
  
    /**
     * @private
     * @param {Object} [options] Options object
     */
    _initClipping: function(options) {
      if (!options.clipTo || typeof options.clipTo !== 'string') {
        return;
      }
  
      var functionBody = fabric.util.getFunctionBody(options.clipTo);
      if (typeof functionBody !== 'undefined') {
        this.clipTo = new Function('ctx', functionBody);
      }
    },
  
    /**
     * @private
     */
    _setObject: function(obj) {
      for (var prop in obj) {
        this._set(prop, obj[prop]);
      }
    },
  
    /**
     * Sets property to a given value. When changing position/dimension -related properties (left, top, scale, angle, etc.) `set` does not update position of object's borders/controls. If you need to update those, call `setCoords()`.
     * @param {String|Object} key Property name or object (if object, iterate over the object properties)
     * @param {Object|Function} value Property value (if function, the value is passed into it and its return value is used as a new one)
     * @return {fabric.Object} thisArg
     * @chainable
     */
    set: function(key, value) {
      if (typeof key === 'object') {
        this._setObject(key);
      }
      else {
        if (typeof value === 'function' && key !== 'clipTo') {
          this._set(key, value(this.get(key)));
        }
        else {
          this._set(key, value);
        }
      }
      return this;
    },
  
    _set: function(key, value) {
      this[key] = value;
    },
  
    /**
     * Toggles specified property from `true` to `false` or from `false` to `true`
     * @param {String} property Property to toggle
     * @return {fabric.Object} thisArg
     * @chainable
     */
    toggle: function(property) {
      var value = this.get(property);
      if (typeof value === 'boolean') {
        this.set(property, !value);
      }
      return this;
    },
  
    /**
     * Basic getter
     * @param {String} property Property name
     * @return {*} value of a property
     */
    get: function(property) {
      return this[property];
    }
  };
  
  
  (function(global) {
  
    var sqrt = Math.sqrt,
        atan2 = Math.atan2,
        pow = Math.pow,
        PiBy180 = Math.PI / 180,
        PiBy2 = Math.PI / 2;
  
    /**
     * @namespace fabric.util
     */
    fabric.util = {
  
      /**
       * Calculate the cos of an angle, avoiding returning floats for known results
       * @static
       * @memberOf fabric.util
       * @param {Number} angle the angle in radians or in degree
       * @return {Number}
       */
      cos: function(angle) {
        if (angle === 0) { return 1; }
        if (angle < 0) {
          // cos(a) = cos(-a)
          angle = -angle;
        }
        var angleSlice = angle / PiBy2;
        switch (angleSlice) {
          case 1: case 3: return 0;
          case 2: return -1;
        }
        return Math.cos(angle);
      },
  
      /**
       * Calculate the sin of an angle, avoiding returning floats for known results
       * @static
       * @memberOf fabric.util
       * @param {Number} angle the angle in radians or in degree
       * @return {Number}
       */
      sin: function(angle) {
        if (angle === 0) { return 0; }
        var angleSlice = angle / PiBy2, sign = 1;
        if (angle < 0) {
          // sin(-a) = -sin(a)
          sign = -1;
        }
        switch (angleSlice) {
          case 1: return sign;
          case 2: return 0;
          case 3: return -sign;
        }
        return Math.sin(angle);
      },
  
      /**
       * Removes value from an array.
       * Presence of value (and its position in an array) is determined via `Array.prototype.indexOf`
       * @static
       * @memberOf fabric.util
       * @param {Array} array
       * @param {*} value
       * @return {Array} original array
       */
      removeFromArray: function(array, value) {
        var idx = array.indexOf(value);
        if (idx !== -1) {
          array.splice(idx, 1);
        }
        return array;
      },
  
      /**
       * Returns random number between 2 specified ones.
       * @static
       * @memberOf fabric.util
       * @param {Number} min lower limit
       * @param {Number} max upper limit
       * @return {Number} random value (between min and max)
       */
      getRandomInt: function(min, max) {
        return Math.floor(Math.random() * (max - min + 1)) + min;
      },
  
      /**
       * Transforms degrees to radians.
       * @static
       * @memberOf fabric.util
       * @param {Number} degrees value in degrees
       * @return {Number} value in radians
       */
      degreesToRadians: function(degrees) {
        return degrees * PiBy180;
      },
  
      /**
       * Transforms radians to degrees.
       * @static
       * @memberOf fabric.util
       * @param {Number} radians value in radians
       * @return {Number} value in degrees
       */
      radiansToDegrees: function(radians) {
        return radians / PiBy180;
      },
  
      /**
       * Rotates `point` around `origin` with `radians`
       * @static
       * @memberOf fabric.util
       * @param {fabric.Point} point The point to rotate
       * @param {fabric.Point} origin The origin of the rotation
       * @param {Number} radians The radians of the angle for the rotation
       * @return {fabric.Point} The new rotated point
       */
      rotatePoint: function(point, origin, radians) {
        point.subtractEquals(origin);
        var v = fabric.util.rotateVector(point, radians);
        return new fabric.Point(v.x, v.y).addEquals(origin);
      },
  
      /**
       * Rotates `vector` with `radians`
       * @static
       * @memberOf fabric.util
       * @param {Object} vector The vector to rotate (x and y)
       * @param {Number} radians The radians of the angle for the rotation
       * @return {Object} The new rotated point
       */
      rotateVector: function(vector, radians) {
        var sin = fabric.util.sin(radians),
            cos = fabric.util.cos(radians),
            rx = vector.x * cos - vector.y * sin,
            ry = vector.x * sin + vector.y * cos;
        return {
          x: rx,
          y: ry
        };
      },
  
      /**
       * Apply transform t to point p
       * @static
       * @memberOf fabric.util
       * @param  {fabric.Point} p The point to transform
       * @param  {Array} t The transform
       * @param  {Boolean} [ignoreOffset] Indicates that the offset should not be applied
       * @return {fabric.Point} The transformed point
       */
      transformPoint: function(p, t, ignoreOffset) {
        if (ignoreOffset) {
          return new fabric.Point(
            t[0] * p.x + t[2] * p.y,
            t[1] * p.x + t[3] * p.y
          );
        }
        return new fabric.Point(
          t[0] * p.x + t[2] * p.y + t[4],
          t[1] * p.x + t[3] * p.y + t[5]
        );
      },
  
      /**
       * Returns coordinates of points's bounding rectangle (left, top, width, height)
       * @param {Array} points 4 points array
       * @param {Array} [transform] an array of 6 numbers representing a 2x3 transform matrix
       * @return {Object} Object with left, top, width, height properties
       */
      makeBoundingBoxFromPoints: function(points, transform) {
        if (transform) {
          for (var i = 0; i < points.length; i++) {
            points[i] = fabric.util.transformPoint(points[i], transform);
          }
        }
        var xPoints = [points[0].x, points[1].x, points[2].x, points[3].x],
            minX = fabric.util.array.min(xPoints),
            maxX = fabric.util.array.max(xPoints),
            width = maxX - minX,
            yPoints = [points[0].y, points[1].y, points[2].y, points[3].y],
            minY = fabric.util.array.min(yPoints),
            maxY = fabric.util.array.max(yPoints),
            height = maxY - minY;
  
        return {
          left: minX,
          top: minY,
          width: width,
          height: height
        };
      },
  
      /**
       * Invert transformation t
       * @static
       * @memberOf fabric.util
       * @param {Array} t The transform
       * @return {Array} The inverted transform
       */
      invertTransform: function(t) {
        var a = 1 / (t[0] * t[3] - t[1] * t[2]),
            r = [a * t[3], -a * t[1], -a * t[2], a * t[0]],
            o = fabric.util.transformPoint({ x: t[4], y: t[5] }, r, true);
        r[4] = -o.x;
        r[5] = -o.y;
        return r;
      },
  
      /**
       * A wrapper around Number#toFixed, which contrary to native method returns number, not string.
       * @static
       * @memberOf fabric.util
       * @param {Number|String} number number to operate on
       * @param {Number} fractionDigits number of fraction digits to "leave"
       * @return {Number}
       */
      toFixed: function(number, fractionDigits) {
        return parseFloat(Number(number).toFixed(fractionDigits));
      },
  
      /**
       * Converts from attribute value to pixel value if applicable.
       * Returns converted pixels or original value not converted.
       * @param {Number|String} value number to operate on
       * @param {Number} fontSize
       * @return {Number|String}
       */
      parseUnit: function(value, fontSize) {
        var unit = /\D{0,2}$/.exec(value),
            number = parseFloat(value);
        if (!fontSize) {
          fontSize = fabric.Text.DEFAULT_SVG_FONT_SIZE;
        }
        switch (unit[0]) {
          case 'mm':
            return number * fabric.DPI / 25.4;
  
          case 'cm':
            return number * fabric.DPI / 2.54;
  
          case 'in':
            return number * fabric.DPI;
  
          case 'pt':
            return number * fabric.DPI / 72; // or * 4 / 3
  
          case 'pc':
            return number * fabric.DPI / 72 * 12; // or * 16
  
          case 'em':
            return number * fontSize;
  
          default:
            return number;
        }
      },
  
      /**
       * Function which always returns `false`.
       * @static
       * @memberOf fabric.util
       * @return {Boolean}
       */
      falseFunction: function() {
        return false;
      },
  
      /**
       * Returns klass "Class" object of given namespace
       * @memberOf fabric.util
       * @param {String} type Type of object (eg. 'circle')
       * @param {String} namespace Namespace to get klass "Class" object from
       * @return {Object} klass "Class"
       */
      getKlass: function(type, namespace) {
        // capitalize first letter only
        type = fabric.util.string.camelize(type.charAt(0).toUpperCase() + type.slice(1));
        return fabric.util.resolveNamespace(namespace)[type];
      },
  
      /**
       * Returns array of attributes for given svg that fabric parses
       * @memberOf fabric.util
       * @param {String} type Type of svg element (eg. 'circle')
       * @return {Array} string names of supported attributes
       */
      getSvgAttributes: function(type) {
        var attributes = [
          'instantiated_by_use',
          'style',
          'id',
          'class'
        ];
        switch (type) {
          case 'linearGradient':
            attributes = attributes.concat(['x1', 'y1', 'x2', 'y2', 'gradientUnits', 'gradientTransform']);
            break;
          case 'radialGradient':
            attributes = attributes.concat(['gradientUnits', 'gradientTransform', 'cx', 'cy', 'r', 'fx', 'fy', 'fr']);
            break;
          case 'stop':
            attributes = attributes.concat(['offset', 'stop-color', 'stop-opacity']);
            break;
        }
        return attributes;
      },
  
      /**
       * Returns object of given namespace
       * @memberOf fabric.util
       * @param {String} namespace Namespace string e.g. 'fabric.Image.filter' or 'fabric'
       * @return {Object} Object for given namespace (default fabric)
       */
      resolveNamespace: function(namespace) {
        if (!namespace) {
          return fabric;
        }
  
        var parts = namespace.split('.'),
            len = parts.length, i,
            obj = global || fabric.window;
  
        for (i = 0; i < len; ++i) {
          obj = obj[parts[i]];
        }
  
        return obj;
      },
  
      /**
       * Loads image element from given url and passes it to a callback
       * @memberOf fabric.util
       * @param {String} url URL representing an image
       * @param {Function} callback Callback; invoked with loaded image
       * @param {*} [context] Context to invoke callback in
       * @param {Object} [crossOrigin] crossOrigin value to set image element to
       */
      loadImage: function(url, callback, context, crossOrigin) {
        if (!url) {
          callback && callback.call(context, url);
          return;
        }
  
        var img = fabric.util.createImage();
  
        /** @ignore */
        var onLoadCallback = function () {
          callback && callback.call(context, img);
          img = img.onload = img.onerror = null;
        };
  
        img.onload = onLoadCallback;
        /** @ignore */
        img.onerror = function() {
          fabric.log('Error loading ' + img.src);
          callback && callback.call(context, null, true);
          img = img.onload = img.onerror = null;
        };
  
        // data-urls appear to be buggy with crossOrigin
        // https://github.com/kangax/fabric.js/commit/d0abb90f1cd5c5ef9d2a94d3fb21a22330da3e0a#commitcomment-4513767
        // see https://code.google.com/p/chromium/issues/detail?id=315152
        //     https://bugzilla.mozilla.org/show_bug.cgi?id=935069
        if (url.indexOf('data') !== 0 && crossOrigin) {
          img.crossOrigin = crossOrigin;
        }
  
        // IE10 / IE11-Fix: SVG contents from data: URI
        // will only be available if the IMG is present
        // in the DOM (and visible)
        if (url.substring(0,14) === 'data:image/svg') {
          img.onload = null;
          fabric.util.loadImageInDom(img, onLoadCallback);
        }
  
        img.src = url;
      },
  
      /**
       * Attaches SVG image with data: URL to the dom
       * @memberOf fabric.util
       * @param {Object} img Image object with data:image/svg src
       * @param {Function} callback Callback; invoked with loaded image
       * @return {Object} DOM element (div containing the SVG image)
       */
      loadImageInDom: function(img, onLoadCallback) {
        var div = fabric.document.createElement('div');
        div.style.width = div.style.height = '1px';
        div.style.left = div.style.top = '-100%';
        div.style.position = 'absolute';
        div.appendChild(img);
        fabric.document.querySelector('body').appendChild(div);
        /**
         * Wrap in function to:
         *   1. Call existing callback
         *   2. Cleanup DOM
         */
        img.onload = function () {
          onLoadCallback();
          div.parentNode.removeChild(div);
          div = null;
        };
      },
  
      /**
       * Creates corresponding fabric instances from their object representations
       * @static
       * @memberOf fabric.util
       * @param {Array} objects Objects to enliven
       * @param {Function} callback Callback to invoke when all objects are created
       * @param {String} namespace Namespace to get klass "Class" object from
       * @param {Function} reviver Method for further parsing of object elements,
       * called after each fabric object created.
       */
      enlivenObjects: function(objects, callback, namespace, reviver) {
        objects = objects || [];
  
        var enlivenedObjects = [],
            numLoadedObjects = 0,
            numTotalObjects = objects.length;
  
        function onLoaded() {
          if (++numLoadedObjects === numTotalObjects) {
            callback && callback(enlivenedObjects.filter(function(obj) {
              // filter out undefined objects (objects that gave error)
              return obj;
            }));
          }
        }
  
        if (!numTotalObjects) {
          callback && callback(enlivenedObjects);
          return;
        }
  
        objects.forEach(function (o, index) {
          // if sparse array
          if (!o || !o.type) {
            onLoaded();
            return;
          }
          var klass = fabric.util.getKlass(o.type, namespace);
          klass.fromObject(o, function (obj, error) {
            error || (enlivenedObjects[index] = obj);
            reviver && reviver(o, obj, error);
            onLoaded();
          });
        });
      },
  
      /**
       * Create and wait for loading of patterns
       * @static
       * @memberOf fabric.util
       * @param {Array} patterns Objects to enliven
       * @param {Function} callback Callback to invoke when all objects are created
       * called after each fabric object created.
       */
      enlivenPatterns: function(patterns, callback) {
        patterns = patterns || [];
  
        function onLoaded() {
          if (++numLoadedPatterns === numPatterns) {
            callback && callback(enlivenedPatterns);
          }
        }
  
        var enlivenedPatterns = [],
            numLoadedPatterns = 0,
            numPatterns = patterns.length;
  
        if (!numPatterns) {
          callback && callback(enlivenedPatterns);
          return;
        }
  
        patterns.forEach(function (p, index) {
          if (p && p.source) {
            new fabric.Pattern(p, function(pattern) {
              enlivenedPatterns[index] = pattern;
              onLoaded();
            });
          }
          else {
            enlivenedPatterns[index] = p;
            onLoaded();
          }
        });
      },
  
      /**
       * Groups SVG elements (usually those retrieved from SVG document)
       * @static
       * @memberOf fabric.util
       * @param {Array} elements SVG elements to group
       * @param {Object} [options] Options object
       * @param {String} path Value to set sourcePath to
       * @return {fabric.Object|fabric.Group}
       */
      groupSVGElements: function(elements, options, path) {
        var object;
        if (elements && elements.length === 1) {
          return elements[0];
        }
        if (options) {
          if (options.width && options.height) {
            options.centerPoint = {
              x: options.width / 2,
              y: options.height / 2
            };
          }
          else {
            delete options.width;
            delete options.height;
          }
        }
        object = new fabric.Group(elements, options);
        if (typeof path !== 'undefined') {
          object.sourcePath = path;
        }
        return object;
      },
  
      /**
       * Populates an object with properties of another object
       * @static
       * @memberOf fabric.util
       * @param {Object} source Source object
       * @param {Object} destination Destination object
       * @return {Array} properties Properties names to include
       */
      populateWithProperties: function(source, destination, properties) {
        if (properties && Object.prototype.toString.call(properties) === '[object Array]') {
          for (var i = 0, len = properties.length; i < len; i++) {
            if (properties[i] in source) {
              destination[properties[i]] = source[properties[i]];
            }
          }
        }
      },
  
      /**
       * Draws a dashed line between two points
       *
       * This method is used to draw dashed line around selection area.
       * See <a href="http://stackoverflow.com/questions/4576724/dotted-stroke-in-canvas">dotted stroke in canvas</a>
       *
       * @param {CanvasRenderingContext2D} ctx context
       * @param {Number} x  start x coordinate
       * @param {Number} y start y coordinate
       * @param {Number} x2 end x coordinate
       * @param {Number} y2 end y coordinate
       * @param {Array} da dash array pattern
       */
      drawDashedLine: function(ctx, x, y, x2, y2, da) {
        var dx = x2 - x,
            dy = y2 - y,
            len = sqrt(dx * dx + dy * dy),
            rot = atan2(dy, dx),
            dc = da.length,
            di = 0,
            draw = true;
  
        ctx.save();
        ctx.translate(x, y);
        ctx.moveTo(0, 0);
        ctx.rotate(rot);
  
        x = 0;
        while (len > x) {
          x += da[di++ % dc];
          if (x > len) {
            x = len;
          }
          ctx[draw ? 'lineTo' : 'moveTo'](x, 0);
          draw = !draw;
        }
  
        ctx.restore();
      },
  
      /**
       * Creates canvas element
       * @static
       * @memberOf fabric.util
       * @return {CanvasElement} initialized canvas element
       */
      createCanvasElement: function() {
        return fabric.document.createElement('canvas');
      },
  
      /**
       * Creates a canvas element that is a copy of another and is also painted
       * @param {CanvasElement} canvas to copy size and content of
       * @static
       * @memberOf fabric.util
       * @return {CanvasElement} initialized canvas element
       */
      copyCanvasElement: function(canvas) {
        var newCanvas = fabric.util.createCanvasElement();
        newCanvas.width = canvas.width;
        newCanvas.height = canvas.height;
        newCanvas.getContext('2d').drawImage(canvas, 0, 0);
        return newCanvas;
      },
  
      /**
       * since 2.6.0 moved from canvas instance to utility.
       * @param {CanvasElement} canvasEl to copy size and content of
       * @param {String} format 'jpeg' or 'png', in some browsers 'webp' is ok too
       * @param {Number} quality <= 1 and > 0
       * @static
       * @memberOf fabric.util
       * @return {String} data url
       */
      toDataURL: function(canvasEl, format, quality) {
        return canvasEl.toDataURL('image/' + format, quality);
      },
  
      /**
       * Creates image element (works on client and node)
       * @static
       * @memberOf fabric.util
       * @return {HTMLImageElement} HTML image element
       */
      createImage: function() {
        return fabric.document.createElement('img');
      },
  
      /**
       * @static
       * @memberOf fabric.util
       * @deprecated since 2.0.0
       * @param {fabric.Object} receiver Object implementing `clipTo` method
       * @param {CanvasRenderingContext2D} ctx Context to clip
       */
      clipContext: function(receiver, ctx) {
        ctx.save();
        ctx.beginPath();
        receiver.clipTo(ctx);
        ctx.clip();
      },
  
      /**
       * Multiply matrix A by matrix B to nest transformations
       * @static
       * @memberOf fabric.util
       * @param  {Array} a First transformMatrix
       * @param  {Array} b Second transformMatrix
       * @param  {Boolean} is2x2 flag to multiply matrices as 2x2 matrices
       * @return {Array} The product of the two transform matrices
       */
      multiplyTransformMatrices: function(a, b, is2x2) {
        // Matrix multiply a * b
        return [
          a[0] * b[0] + a[2] * b[1],
          a[1] * b[0] + a[3] * b[1],
          a[0] * b[2] + a[2] * b[3],
          a[1] * b[2] + a[3] * b[3],
          is2x2 ? 0 : a[0] * b[4] + a[2] * b[5] + a[4],
          is2x2 ? 0 : a[1] * b[4] + a[3] * b[5] + a[5]
        ];
      },
  
      /**
       * Decomposes standard 2x3 matrix into transform components
       * @static
       * @memberOf fabric.util
       * @param  {Array} a transformMatrix
       * @return {Object} Components of transform
       */
      qrDecompose: function(a) {
        var angle = atan2(a[1], a[0]),
            denom = pow(a[0], 2) + pow(a[1], 2),
            scaleX = sqrt(denom),
            scaleY = (a[0] * a[3] - a[2] * a [1]) / scaleX,
            skewX = atan2(a[0] * a[2] + a[1] * a [3], denom);
        return {
          angle: angle  / PiBy180,
          scaleX: scaleX,
          scaleY: scaleY,
          skewX: skewX / PiBy180,
          skewY: 0,
          translateX: a[4],
          translateY: a[5]
        };
      },
  
      /**
       * Returns a transform matrix starting from an object of the same kind of
       * the one returned from qrDecompose, useful also if you want to calculate some
       * transformations from an object that is not enlived yet
       * @static
       * @memberOf fabric.util
       * @param  {Object} options
       * @param  {Number} [options.angle] angle in degrees
       * @return {Number[]} transform matrix
       */
      calcRotateMatrix: function(options) {
        if (!options.angle) {
          return fabric.iMatrix.concat();
        }
        var theta = fabric.util.degreesToRadians(options.angle),
            cos = fabric.util.cos(theta),
            sin = fabric.util.sin(theta);
        return [cos, sin, -sin, cos, 0, 0];
      },
  
      /**
       * Returns a transform matrix starting from an object of the same kind of
       * the one returned from qrDecompose, useful also if you want to calculate some
       * transformations from an object that is not enlived yet.
       * is called DimensionsTransformMatrix because those properties are the one that influence
       * the size of the resulting box of the object.
       * @static
       * @memberOf fabric.util
       * @param  {Object} options
       * @param  {Number} [options.scaleX]
       * @param  {Number} [options.scaleY]
       * @param  {Boolean} [options.flipX]
       * @param  {Boolean} [options.flipY]
       * @param  {Number} [options.skewX]
       * @param  {Number} [options.skewX]
       * @return {Number[]} transform matrix
       */
      calcDimensionsMatrix: function(options) {
        var scaleX = typeof options.scaleX === 'undefined' ? 1 : options.scaleX,
            scaleY = typeof options.scaleY === 'undefined' ? 1 : options.scaleY,
            scaleMatrix = [
              options.flipX ? -scaleX : scaleX,
              0,
              0,
              options.flipY ? -scaleY : scaleY,
              0,
              0],
            multiply = fabric.util.multiplyTransformMatrices,
            degreesToRadians = fabric.util.degreesToRadians;
        if (options.skewX) {
          scaleMatrix = multiply(
            scaleMatrix,
            [1, 0, Math.tan(degreesToRadians(options.skewX)), 1],
            true);
        }
        if (options.skewY) {
          scaleMatrix = multiply(
            scaleMatrix,
            [1, Math.tan(degreesToRadians(options.skewY)), 0, 1],
            true);
        }
        return scaleMatrix;
      },
  
      /**
       * Returns a transform matrix starting from an object of the same kind of
       * the one returned from qrDecompose, useful also if you want to calculate some
       * transformations from an object that is not enlived yet
       * @static
       * @memberOf fabric.util
       * @param  {Object} options
       * @param  {Number} [options.angle]
       * @param  {Number} [options.scaleX]
       * @param  {Number} [options.scaleY]
       * @param  {Boolean} [options.flipX]
       * @param  {Boolean} [options.flipY]
       * @param  {Number} [options.skewX]
       * @param  {Number} [options.skewX]
       * @param  {Number} [options.translateX]
       * @param  {Number} [options.translateY]
       * @return {Number[]} transform matrix
       */
      composeMatrix: function(options) {
        var matrix = [1, 0, 0, 1, options.translateX || 0, options.translateY || 0],
            multiply = fabric.util.multiplyTransformMatrices;
        if (options.angle) {
          matrix = multiply(matrix, fabric.util.calcRotateMatrix(options));
        }
        if (options.scaleX || options.scaleY || options.skewX || options.skewY || options.flipX || options.flipY) {
          matrix = multiply(matrix, fabric.util.calcDimensionsMatrix(options));
        }
        return matrix;
      },
  
      /**
       * Returns a transform matrix that has the same effect of scaleX, scaleY and skewX.
       * Is deprecated for composeMatrix. Please do not use it.
       * @static
       * @deprecated since 3.4.0
       * @memberOf fabric.util
       * @param  {Number} scaleX
       * @param  {Number} scaleY
       * @param  {Number} skewX
       * @return {Number[]} transform matrix
       */
      customTransformMatrix: function(scaleX, scaleY, skewX) {
        return fabric.util.composeMatrix({ scaleX: scaleX, scaleY: scaleY, skewX: skewX });
      },
  
      /**
       * reset an object transform state to neutral. Top and left are not accounted for
       * @static
       * @memberOf fabric.util
       * @param  {fabric.Object} target object to transform
       */
      resetObjectTransform: function (target) {
        target.scaleX = 1;
        target.scaleY = 1;
        target.skewX = 0;
        target.skewY = 0;
        target.flipX = false;
        target.flipY = false;
        target.rotate(0);
      },
  
      /**
       * Extract Object transform values
       * @static
       * @memberOf fabric.util
       * @param  {fabric.Object} target object to read from
       * @return {Object} Components of transform
       */
      saveObjectTransform: function (target) {
        return {
          scaleX: target.scaleX,
          scaleY: target.scaleY,
          skewX: target.skewX,
          skewY: target.skewY,
          angle: target.angle,
          left: target.left,
          flipX: target.flipX,
          flipY: target.flipY,
          top: target.top
        };
      },
  
      /**
       * Returns string representation of function body
       * @param {Function} fn Function to get body of
       * @return {String} Function body
       */
      getFunctionBody: function(fn) {
        return (String(fn).match(/function[^{]*\{([\s\S]*)\}/) || {})[1];
      },
  
      /**
       * Returns true if context has transparent pixel
       * at specified location (taking tolerance into account)
       * @param {CanvasRenderingContext2D} ctx context
       * @param {Number} x x coordinate
       * @param {Number} y y coordinate
       * @param {Number} tolerance Tolerance
       */
      isTransparent: function(ctx, x, y, tolerance) {
  
        // If tolerance is > 0 adjust start coords to take into account.
        // If moves off Canvas fix to 0
        if (tolerance > 0) {
          if (x > tolerance) {
            x -= tolerance;
          }
          else {
            x = 0;
          }
          if (y > tolerance) {
            y -= tolerance;
          }
          else {
            y = 0;
          }
        }
  
        var _isTransparent = true, i, temp,
            imageData = ctx.getImageData(x, y, (tolerance * 2) || 1, (tolerance * 2) || 1),
            l = imageData.data.length;
  
        // Split image data - for tolerance > 1, pixelDataSize = 4;
        for (i = 3; i < l; i += 4) {
          temp = imageData.data[i];
          _isTransparent = temp <= 0;
          if (_isTransparent === false) {
            break; // Stop if colour found
          }
        }
  
        imageData = null;
  
        return _isTransparent;
      },
  
      /**
       * Parse preserveAspectRatio attribute from element
       * @param {string} attribute to be parsed
       * @return {Object} an object containing align and meetOrSlice attribute
       */
      parsePreserveAspectRatioAttribute: function(attribute) {
        var meetOrSlice = 'meet', alignX = 'Mid', alignY = 'Mid',
            aspectRatioAttrs = attribute.split(' '), align;
  
        if (aspectRatioAttrs && aspectRatioAttrs.length) {
          meetOrSlice = aspectRatioAttrs.pop();
          if (meetOrSlice !== 'meet' && meetOrSlice !== 'slice') {
            align = meetOrSlice;
            meetOrSlice = 'meet';
          }
          else if (aspectRatioAttrs.length) {
            align = aspectRatioAttrs.pop();
          }
        }
        //divide align in alignX and alignY
        alignX = align !== 'none' ? align.slice(1, 4) : 'none';
        alignY = align !== 'none' ? align.slice(5, 8) : 'none';
        return {
          meetOrSlice: meetOrSlice,
          alignX: alignX,
          alignY: alignY
        };
      },
  
      /**
       * Clear char widths cache for the given font family or all the cache if no
       * fontFamily is specified.
       * Use it if you know you are loading fonts in a lazy way and you are not waiting
       * for custom fonts to load properly when adding text objects to the canvas.
       * If a text object is added when its own font is not loaded yet, you will get wrong
       * measurement and so wrong bounding boxes.
       * After the font cache is cleared, either change the textObject text content or call
       * initDimensions() to trigger a recalculation
       * @memberOf fabric.util
       * @param {String} [fontFamily] font family to clear
       */
      clearFabricFontCache: function(fontFamily) {
        fontFamily = (fontFamily || '').toLowerCase();
        if (!fontFamily) {
          fabric.charWidthsCache = { };
        }
        else if (fabric.charWidthsCache[fontFamily]) {
          delete fabric.charWidthsCache[fontFamily];
        }
      },
  
      /**
       * Given current aspect ratio, determines the max width and height that can
       * respect the total allowed area for the cache.
       * @memberOf fabric.util
       * @param {Number} ar aspect ratio
       * @param {Number} maximumArea Maximum area you want to achieve
       * @return {Object.x} Limited dimensions by X
       * @return {Object.y} Limited dimensions by Y
       */
      limitDimsByArea: function(ar, maximumArea) {
        var roughWidth = Math.sqrt(maximumArea * ar),
            perfLimitSizeY = Math.floor(maximumArea / roughWidth);
        return { x: Math.floor(roughWidth), y: perfLimitSizeY };
      },
  
      capValue: function(min, value, max) {
        return Math.max(min, Math.min(value, max));
      },
  
      findScaleToFit: function(source, destination) {
        return Math.min(destination.width / source.width, destination.height / source.height);
      },
  
      findScaleToCover: function(source, destination) {
        return Math.max(destination.width / source.width, destination.height / source.height);
      },
  
      /**
       * given an array of 6 number returns something like `"matrix(...numbers)"`
       * @memberOf fabric.util
       * @param {Array} trasnform an array with 6 numbers
       * @return {String} transform matrix for svg
       * @return {Object.y} Limited dimensions by Y
       */
      matrixToSVG: function(transform) {
        return 'matrix(' + transform.map(function(value) {
          return fabric.util.toFixed(value, fabric.Object.NUM_FRACTION_DIGITS);
        }).join(' ') + ')';
      }
    };
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function() {
  
    var _join = Array.prototype.join;
  
    /* Adapted from http://dxr.mozilla.org/mozilla-central/source/content/svg/content/src/nsSVGPathDataParser.cpp
     * by Andrea Bogazzi code is under MPL. if you don't have a copy of the license you can take it here
     * http://mozilla.org/MPL/2.0/
     */
    function arcToSegments(toX, toY, rx, ry, large, sweep, rotateX) {
      var argsString = _join.call(arguments);
      if (fabric.arcToSegmentsCache[argsString]) {
        return fabric.arcToSegmentsCache[argsString];
      }
  
      var PI = Math.PI, th = rotateX * PI / 180,
          sinTh = fabric.util.sin(th),
          cosTh = fabric.util.cos(th),
          fromX = 0, fromY = 0;
  
      rx = Math.abs(rx);
      ry = Math.abs(ry);
  
      var px = -cosTh * toX * 0.5 - sinTh * toY * 0.5,
          py = -cosTh * toY * 0.5 + sinTh * toX * 0.5,
          rx2 = rx * rx, ry2 = ry * ry, py2 = py * py, px2 = px * px,
          pl = rx2 * ry2 - rx2 * py2 - ry2 * px2,
          root = 0;
  
      if (pl < 0) {
        var s = Math.sqrt(1 - pl / (rx2 * ry2));
        rx *= s;
        ry *= s;
      }
      else {
        root = (large === sweep ? -1.0 : 1.0) *
                Math.sqrt( pl / (rx2 * py2 + ry2 * px2));
      }
  
      var cx = root * rx * py / ry,
          cy = -root * ry * px / rx,
          cx1 = cosTh * cx - sinTh * cy + toX * 0.5,
          cy1 = sinTh * cx + cosTh * cy + toY * 0.5,
          mTheta = calcVectorAngle(1, 0, (px - cx) / rx, (py - cy) / ry),
          dtheta = calcVectorAngle((px - cx) / rx, (py - cy) / ry, (-px - cx) / rx, (-py - cy) / ry);
  
      if (sweep === 0 && dtheta > 0) {
        dtheta -= 2 * PI;
      }
      else if (sweep === 1 && dtheta < 0) {
        dtheta += 2 * PI;
      }
  
      // Convert into cubic bezier segments <= 90deg
      var segments = Math.ceil(Math.abs(dtheta / PI * 2)),
          result = [], mDelta = dtheta / segments,
          mT = 8 / 3 * Math.sin(mDelta / 4) * Math.sin(mDelta / 4) / Math.sin(mDelta / 2),
          th3 = mTheta + mDelta;
  
      for (var i = 0; i < segments; i++) {
        result[i] = segmentToBezier(mTheta, th3, cosTh, sinTh, rx, ry, cx1, cy1, mT, fromX, fromY);
        fromX = result[i][4];
        fromY = result[i][5];
        mTheta = th3;
        th3 += mDelta;
      }
      fabric.arcToSegmentsCache[argsString] = result;
      return result;
    }
  
    function segmentToBezier(th2, th3, cosTh, sinTh, rx, ry, cx1, cy1, mT, fromX, fromY) {
      var costh2 = fabric.util.cos(th2),
          sinth2 = fabric.util.sin(th2),
          costh3 = fabric.util.cos(th3),
          sinth3 = fabric.util.sin(th3),
          toX = cosTh * rx * costh3 - sinTh * ry * sinth3 + cx1,
          toY = sinTh * rx * costh3 + cosTh * ry * sinth3 + cy1,
          cp1X = fromX + mT * ( -cosTh * rx * sinth2 - sinTh * ry * costh2),
          cp1Y = fromY + mT * ( -sinTh * rx * sinth2 + cosTh * ry * costh2),
          cp2X = toX + mT * ( cosTh * rx * sinth3 + sinTh * ry * costh3),
          cp2Y = toY + mT * ( sinTh * rx * sinth3 - cosTh * ry * costh3);
  
      return [
        cp1X, cp1Y,
        cp2X, cp2Y,
        toX, toY
      ];
    }
  
    /*
     * Private
     */
    function calcVectorAngle(ux, uy, vx, vy) {
      var ta = Math.atan2(uy, ux),
          tb = Math.atan2(vy, vx);
      if (tb >= ta) {
        return tb - ta;
      }
      else {
        return 2 * Math.PI - (ta - tb);
      }
    }
  
    /**
     * Draws arc
     * @param {CanvasRenderingContext2D} ctx
     * @param {Number} fx
     * @param {Number} fy
     * @param {Array} coords
     */
    fabric.util.drawArc = function(ctx, fx, fy, coords) {
      var rx = coords[0],
          ry = coords[1],
          rot = coords[2],
          large = coords[3],
          sweep = coords[4],
          tx = coords[5],
          ty = coords[6],
          segs = [[], [], [], []],
          segsNorm = arcToSegments(tx - fx, ty - fy, rx, ry, large, sweep, rot);
  
      for (var i = 0, len = segsNorm.length; i < len; i++) {
        segs[i][0] = segsNorm[i][0] + fx;
        segs[i][1] = segsNorm[i][1] + fy;
        segs[i][2] = segsNorm[i][2] + fx;
        segs[i][3] = segsNorm[i][3] + fy;
        segs[i][4] = segsNorm[i][4] + fx;
        segs[i][5] = segsNorm[i][5] + fy;
        ctx.bezierCurveTo.apply(ctx, segs[i]);
      }
    };
  
    /**
     * Calculate bounding box of a elliptic-arc
     * @param {Number} fx start point of arc
     * @param {Number} fy
     * @param {Number} rx horizontal radius
     * @param {Number} ry vertical radius
     * @param {Number} rot angle of horizontal axe
     * @param {Number} large 1 or 0, whatever the arc is the big or the small on the 2 points
     * @param {Number} sweep 1 or 0, 1 clockwise or counterclockwise direction
     * @param {Number} tx end point of arc
     * @param {Number} ty
     */
    fabric.util.getBoundsOfArc = function(fx, fy, rx, ry, rot, large, sweep, tx, ty) {
  
      var fromX = 0, fromY = 0, bound, bounds = [],
          segs = arcToSegments(tx - fx, ty - fy, rx, ry, large, sweep, rot);
  
      for (var i = 0, len = segs.length; i < len; i++) {
        bound = getBoundsOfCurve(fromX, fromY, segs[i][0], segs[i][1], segs[i][2], segs[i][3], segs[i][4], segs[i][5]);
        bounds.push({ x: bound[0].x + fx, y: bound[0].y + fy });
        bounds.push({ x: bound[1].x + fx, y: bound[1].y + fy });
        fromX = segs[i][4];
        fromY = segs[i][5];
      }
      return bounds;
    };
  
    /**
     * Calculate bounding box of a beziercurve
     * @param {Number} x0 starting point
     * @param {Number} y0
     * @param {Number} x1 first control point
     * @param {Number} y1
     * @param {Number} x2 secondo control point
     * @param {Number} y2
     * @param {Number} x3 end of beizer
     * @param {Number} y3
     */
    // taken from http://jsbin.com/ivomiq/56/edit  no credits available for that.
    function getBoundsOfCurve(x0, y0, x1, y1, x2, y2, x3, y3) {
      var argsString;
      if (fabric.cachesBoundsOfCurve) {
        argsString = _join.call(arguments);
        if (fabric.boundsOfCurveCache[argsString]) {
          return fabric.boundsOfCurveCache[argsString];
        }
      }
  
      var sqrt = Math.sqrt,
          min = Math.min, max = Math.max,
          abs = Math.abs, tvalues = [],
          bounds = [[], []],
          a, b, c, t, t1, t2, b2ac, sqrtb2ac;
  
      b = 6 * x0 - 12 * x1 + 6 * x2;
      a = -3 * x0 + 9 * x1 - 9 * x2 + 3 * x3;
      c = 3 * x1 - 3 * x0;
  
      for (var i = 0; i < 2; ++i) {
        if (i > 0) {
          b = 6 * y0 - 12 * y1 + 6 * y2;
          a = -3 * y0 + 9 * y1 - 9 * y2 + 3 * y3;
          c = 3 * y1 - 3 * y0;
        }
  
        if (abs(a) < 1e-12) {
          if (abs(b) < 1e-12) {
            continue;
          }
          t = -c / b;
          if (0 < t && t < 1) {
            tvalues.push(t);
          }
          continue;
        }
        b2ac = b * b - 4 * c * a;
        if (b2ac < 0) {
          continue;
        }
        sqrtb2ac = sqrt(b2ac);
        t1 = (-b + sqrtb2ac) / (2 * a);
        if (0 < t1 && t1 < 1) {
          tvalues.push(t1);
        }
        t2 = (-b - sqrtb2ac) / (2 * a);
        if (0 < t2 && t2 < 1) {
          tvalues.push(t2);
        }
      }
  
      var x, y, j = tvalues.length, jlen = j, mt;
      while (j--) {
        t = tvalues[j];
        mt = 1 - t;
        x = (mt * mt * mt * x0) + (3 * mt * mt * t * x1) + (3 * mt * t * t * x2) + (t * t * t * x3);
        bounds[0][j] = x;
  
        y = (mt * mt * mt * y0) + (3 * mt * mt * t * y1) + (3 * mt * t * t * y2) + (t * t * t * y3);
        bounds[1][j] = y;
      }
  
      bounds[0][jlen] = x0;
      bounds[1][jlen] = y0;
      bounds[0][jlen + 1] = x3;
      bounds[1][jlen + 1] = y3;
      var result = [
        {
          x: min.apply(null, bounds[0]),
          y: min.apply(null, bounds[1])
        },
        {
          x: max.apply(null, bounds[0]),
          y: max.apply(null, bounds[1])
        }
      ];
      if (fabric.cachesBoundsOfCurve) {
        fabric.boundsOfCurveCache[argsString] = result;
      }
      return result;
    }
  
    fabric.util.getBoundsOfCurve = getBoundsOfCurve;
  
  })();
  
  
  (function() {
  
    var slice = Array.prototype.slice;
  
    /**
     * Invokes method on all items in a given array
     * @memberOf fabric.util.array
     * @param {Array} array Array to iterate over
     * @param {String} method Name of a method to invoke
     * @return {Array}
     */
    function invoke(array, method) {
      var args = slice.call(arguments, 2), result = [];
      for (var i = 0, len = array.length; i < len; i++) {
        result[i] = args.length ? array[i][method].apply(array[i], args) : array[i][method].call(array[i]);
      }
      return result;
    }
  
    /**
     * Finds maximum value in array (not necessarily "first" one)
     * @memberOf fabric.util.array
     * @param {Array} array Array to iterate over
     * @param {String} byProperty
     * @return {*}
     */
    function max(array, byProperty) {
      return find(array, byProperty, function(value1, value2) {
        return value1 >= value2;
      });
    }
  
    /**
     * Finds minimum value in array (not necessarily "first" one)
     * @memberOf fabric.util.array
     * @param {Array} array Array to iterate over
     * @param {String} byProperty
     * @return {*}
     */
    function min(array, byProperty) {
      return find(array, byProperty, function(value1, value2) {
        return value1 < value2;
      });
    }
  
    /**
     * @private
     */
    function fill(array, value) {
      var k = array.length;
      while (k--) {
        array[k] = value;
      }
      return array;
    }
  
    /**
     * @private
     */
    function find(array, byProperty, condition) {
      if (!array || array.length === 0) {
        return;
      }
  
      var i = array.length - 1,
          result = byProperty ? array[i][byProperty] : array[i];
      if (byProperty) {
        while (i--) {
          if (condition(array[i][byProperty], result)) {
            result = array[i][byProperty];
          }
        }
      }
      else {
        while (i--) {
          if (condition(array[i], result)) {
            result = array[i];
          }
        }
      }
      return result;
    }
  
    /**
     * @namespace fabric.util.array
     */
    fabric.util.array = {
      fill: fill,
      invoke: invoke,
      min: min,
      max: max
    };
  
  })();
  
  
  (function() {
    /**
     * Copies all enumerable properties of one js object to another
     * this does not and cannot compete with generic utils.
     * Does not clone or extend fabric.Object subclasses.
     * This is mostly for internal use and has extra handling for fabricJS objects
     * it skips the canvas property in deep cloning.
     * @memberOf fabric.util.object
     * @param {Object} destination Where to copy to
     * @param {Object} source Where to copy from
     * @return {Object}
     */
  
    function extend(destination, source, deep) {
      // JScript DontEnum bug is not taken care of
      // the deep clone is for internal use, is not meant to avoid
      // javascript traps or cloning html element or self referenced objects.
      if (deep) {
        if (!fabric.isLikelyNode && source instanceof Element) {
          // avoid cloning deep images, canvases,
          destination = source;
        }
        else if (source instanceof Array) {
          destination = [];
          for (var i = 0, len = source.length; i < len; i++) {
            destination[i] = extend({ }, source[i], deep);
          }
        }
        else if (source && typeof source === 'object') {
          for (var property in source) {
            if (property === 'canvas') {
              destination[property] = extend({ }, source[property]);
            }
            else if (source.hasOwnProperty(property)) {
              destination[property] = extend({ }, source[property], deep);
            }
          }
        }
        else {
          // this sounds odd for an extend but is ok for recursive use
          destination = source;
        }
      }
      else {
        for (var property in source) {
          destination[property] = source[property];
        }
      }
      return destination;
    }
  
    /**
     * Creates an empty object and copies all enumerable properties of another object to it
     * @memberOf fabric.util.object
     * TODO: this function return an empty object if you try to clone null
     * @param {Object} object Object to clone
     * @return {Object}
     */
    function clone(object, deep) {
      return extend({ }, object, deep);
    }
  
    /** @namespace fabric.util.object */
    fabric.util.object = {
      extend: extend,
      clone: clone
    };
    fabric.util.object.extend(fabric.util, fabric.Observable);
  })();
  
  
  (function() {
  
    /**
     * Camelizes a string
     * @memberOf fabric.util.string
     * @param {String} string String to camelize
     * @return {String} Camelized version of a string
     */
    function camelize(string) {
      return string.replace(/-+(.)?/g, function(match, character) {
        return character ? character.toUpperCase() : '';
      });
    }
  
    /**
     * Capitalizes a string
     * @memberOf fabric.util.string
     * @param {String} string String to capitalize
     * @param {Boolean} [firstLetterOnly] If true only first letter is capitalized
     * and other letters stay untouched, if false first letter is capitalized
     * and other letters are converted to lowercase.
     * @return {String} Capitalized version of a string
     */
    function capitalize(string, firstLetterOnly) {
      return string.charAt(0).toUpperCase() +
        (firstLetterOnly ? string.slice(1) : string.slice(1).toLowerCase());
    }
  
    /**
     * Escapes XML in a string
     * @memberOf fabric.util.string
     * @param {String} string String to escape
     * @return {String} Escaped version of a string
     */
    function escapeXml(string) {
      return string.replace(/&/g, '&amp;')
        .replace(/"/g, '&quot;')
        .replace(/'/g, '&apos;')
        .replace(/</g, '&lt;')
        .replace(/>/g, '&gt;');
    }
  
    /**
     * Divide a string in the user perceived single units
     * @memberOf fabric.util.string
     * @param {String} textstring String to escape
     * @return {Array} array containing the graphemes
     */
    function graphemeSplit(textstring) {
      var i = 0, chr, graphemes = [];
      for (i = 0, chr; i < textstring.length; i++) {
        if ((chr = getWholeChar(textstring, i)) === false) {
          continue;
        }
        graphemes.push(chr);
      }
      return graphemes;
    }
  
    // taken from mdn in the charAt doc page.
    function getWholeChar(str, i) {
      var code = str.charCodeAt(i);
  
      if (isNaN(code)) {
        return ''; // Position not found
      }
      if (code < 0xD800 || code > 0xDFFF) {
        return str.charAt(i);
      }
  
      // High surrogate (could change last hex to 0xDB7F to treat high private
      // surrogates as single characters)
      if (0xD800 <= code && code <= 0xDBFF) {
        if (str.length <= (i + 1)) {
          throw 'High surrogate without following low surrogate';
        }
        var next = str.charCodeAt(i + 1);
        if (0xDC00 > next || next > 0xDFFF) {
          throw 'High surrogate without following low surrogate';
        }
        return str.charAt(i) + str.charAt(i + 1);
      }
      // Low surrogate (0xDC00 <= code && code <= 0xDFFF)
      if (i === 0) {
        throw 'Low surrogate without preceding high surrogate';
      }
      var prev = str.charCodeAt(i - 1);
  
      // (could change last hex to 0xDB7F to treat high private
      // surrogates as single characters)
      if (0xD800 > prev || prev > 0xDBFF) {
        throw 'Low surrogate without preceding high surrogate';
      }
      // We can pass over low surrogates now as the second component
      // in a pair which we have already processed
      return false;
    }
  
  
    /**
     * String utilities
     * @namespace fabric.util.string
     */
    fabric.util.string = {
      camelize: camelize,
      capitalize: capitalize,
      escapeXml: escapeXml,
      graphemeSplit: graphemeSplit
    };
  })();
  
  
  (function() {
  
    var slice = Array.prototype.slice, emptyFunction = function() { },
  
        IS_DONTENUM_BUGGY = (function() {
          for (var p in { toString: 1 }) {
            if (p === 'toString') {
              return false;
            }
          }
          return true;
        })(),
  
        /** @ignore */
        addMethods = function(klass, source, parent) {
          for (var property in source) {
  
            if (property in klass.prototype &&
                typeof klass.prototype[property] === 'function' &&
                (source[property] + '').indexOf('callSuper') > -1) {
  
              klass.prototype[property] = (function(property) {
                return function() {
  
                  var superclass = this.constructor.superclass;
                  this.constructor.superclass = parent;
                  var returnValue = source[property].apply(this, arguments);
                  this.constructor.superclass = superclass;
  
                  if (property !== 'initialize') {
                    return returnValue;
                  }
                };
              })(property);
            }
            else {
              klass.prototype[property] = source[property];
            }
  
            if (IS_DONTENUM_BUGGY) {
              if (source.toString !== Object.prototype.toString) {
                klass.prototype.toString = source.toString;
              }
              if (source.valueOf !== Object.prototype.valueOf) {
                klass.prototype.valueOf = source.valueOf;
              }
            }
          }
        };
  
    function Subclass() { }
  
    function callSuper(methodName) {
      var parentMethod = null,
          _this = this;
  
      // climb prototype chain to find method not equal to callee's method
      while (_this.constructor.superclass) {
        var superClassMethod = _this.constructor.superclass.prototype[methodName];
        if (_this[methodName] !== superClassMethod) {
          parentMethod = superClassMethod;
          break;
        }
        // eslint-disable-next-line
        _this = _this.constructor.superclass.prototype;
      }
  
      if (!parentMethod) {
        return console.log('tried to callSuper ' + methodName + ', method not found in prototype chain', this);
      }
  
      return (arguments.length > 1)
        ? parentMethod.apply(this, slice.call(arguments, 1))
        : parentMethod.call(this);
    }
  
    /**
     * Helper for creation of "classes".
     * @memberOf fabric.util
     * @param {Function} [parent] optional "Class" to inherit from
     * @param {Object} [properties] Properties shared by all instances of this class
     *                  (be careful modifying objects defined here as this would affect all instances)
     */
    function createClass() {
      var parent = null,
          properties = slice.call(arguments, 0);
  
      if (typeof properties[0] === 'function') {
        parent = properties.shift();
      }
      function klass() {
        this.initialize.apply(this, arguments);
      }
  
      klass.superclass = parent;
      klass.subclasses = [];
  
      if (parent) {
        Subclass.prototype = parent.prototype;
        klass.prototype = new Subclass();
        parent.subclasses.push(klass);
      }
      for (var i = 0, length = properties.length; i < length; i++) {
        addMethods(klass, properties[i], parent);
      }
      if (!klass.prototype.initialize) {
        klass.prototype.initialize = emptyFunction;
      }
      klass.prototype.constructor = klass;
      klass.prototype.callSuper = callSuper;
      return klass;
    }
  
    fabric.util.createClass = createClass;
  })();
  
  
  (function () {
    // since ie10 or ie9 can use addEventListener but they do not support options, i need to check
    var couldUseAttachEvent = !!fabric.document.createElement('div').attachEvent;
    /**
     * Adds an event listener to an element
     * @function
     * @memberOf fabric.util
     * @param {HTMLElement} element
     * @param {String} eventName
     * @param {Function} handler
     */
    fabric.util.addListener = function(element, eventName, handler, options) {
      element && element.addEventListener(eventName, handler, couldUseAttachEvent ? false : options);
    };
  
    /**
     * Removes an event listener from an element
     * @function
     * @memberOf fabric.util
     * @param {HTMLElement} element
     * @param {String} eventName
     * @param {Function} handler
     */
    fabric.util.removeListener = function(element, eventName, handler, options) {
      element && element.removeEventListener(eventName, handler, couldUseAttachEvent ? false : options);
    };
  
    function getTouchInfo(event) {
      var touchProp = event.changedTouches;
      if (touchProp && touchProp[0]) {
        return touchProp[0];
      }
      return event;
    }
  
    fabric.util.getPointer = function(event) {
      var element = event.target,
          scroll = fabric.util.getScrollLeftTop(element),
          _evt = getTouchInfo(event);
      return {
        x: _evt.clientX + scroll.left,
        y: _evt.clientY + scroll.top
      };
    };
  })();
  
  
  (function () {
  
    /**
     * Cross-browser wrapper for setting element's style
     * @memberOf fabric.util
     * @param {HTMLElement} element
     * @param {Object} styles
     * @return {HTMLElement} Element that was passed as a first argument
     */
    function setStyle(element, styles) {
      var elementStyle = element.style;
      if (!elementStyle) {
        return element;
      }
      if (typeof styles === 'string') {
        element.style.cssText += ';' + styles;
        return styles.indexOf('opacity') > -1
          ? setOpacity(element, styles.match(/opacity:\s*(\d?\.?\d*)/)[1])
          : element;
      }
      for (var property in styles) {
        if (property === 'opacity') {
          setOpacity(element, styles[property]);
        }
        else {
          var normalizedProperty = (property === 'float' || property === 'cssFloat')
            ? (typeof elementStyle.styleFloat === 'undefined' ? 'cssFloat' : 'styleFloat')
            : property;
          elementStyle[normalizedProperty] = styles[property];
        }
      }
      return element;
    }
  
    var parseEl = fabric.document.createElement('div'),
        supportsOpacity = typeof parseEl.style.opacity === 'string',
        supportsFilters = typeof parseEl.style.filter === 'string',
        reOpacity = /alpha\s*\(\s*opacity\s*=\s*([^\)]+)\)/,
  
        /** @ignore */
        setOpacity = function (element) { return element; };
  
    if (supportsOpacity) {
      /** @ignore */
      setOpacity = function(element, value) {
        element.style.opacity = value;
        return element;
      };
    }
    else if (supportsFilters) {
      /** @ignore */
      setOpacity = function(element, value) {
        var es = element.style;
        if (element.currentStyle && !element.currentStyle.hasLayout) {
          es.zoom = 1;
        }
        if (reOpacity.test(es.filter)) {
          value = value >= 0.9999 ? '' : ('alpha(opacity=' + (value * 100) + ')');
          es.filter = es.filter.replace(reOpacity, value);
        }
        else {
          es.filter += ' alpha(opacity=' + (value * 100) + ')';
        }
        return element;
      };
    }
  
    fabric.util.setStyle = setStyle;
  
  })();
  
  
  (function() {
  
    var _slice = Array.prototype.slice;
  
    /**
     * Takes id and returns an element with that id (if one exists in a document)
     * @memberOf fabric.util
     * @param {String|HTMLElement} id
     * @return {HTMLElement|null}
     */
    function getById(id) {
      return typeof id === 'string' ? fabric.document.getElementById(id) : id;
    }
  
    var sliceCanConvertNodelists,
        /**
         * Converts an array-like object (e.g. arguments or NodeList) to an array
         * @memberOf fabric.util
         * @param {Object} arrayLike
         * @return {Array}
         */
        toArray = function(arrayLike) {
          return _slice.call(arrayLike, 0);
        };
  
    try {
      sliceCanConvertNodelists = toArray(fabric.document.childNodes) instanceof Array;
    }
    catch (err) { }
  
    if (!sliceCanConvertNodelists) {
      toArray = function(arrayLike) {
        var arr = new Array(arrayLike.length), i = arrayLike.length;
        while (i--) {
          arr[i] = arrayLike[i];
        }
        return arr;
      };
    }
  
    /**
     * Creates specified element with specified attributes
     * @memberOf fabric.util
     * @param {String} tagName Type of an element to create
     * @param {Object} [attributes] Attributes to set on an element
     * @return {HTMLElement} Newly created element
     */
    function makeElement(tagName, attributes) {
      var el = fabric.document.createElement(tagName);
      for (var prop in attributes) {
        if (prop === 'class') {
          el.className = attributes[prop];
        }
        else if (prop === 'for') {
          el.htmlFor = attributes[prop];
        }
        else {
          el.setAttribute(prop, attributes[prop]);
        }
      }
      return el;
    }
  
    /**
     * Adds class to an element
     * @memberOf fabric.util
     * @param {HTMLElement} element Element to add class to
     * @param {String} className Class to add to an element
     */
    function addClass(element, className) {
      if (element && (' ' + element.className + ' ').indexOf(' ' + className + ' ') === -1) {
        element.className += (element.className ? ' ' : '') + className;
      }
    }
  
    /**
     * Wraps element with another element
     * @memberOf fabric.util
     * @param {HTMLElement} element Element to wrap
     * @param {HTMLElement|String} wrapper Element to wrap with
     * @param {Object} [attributes] Attributes to set on a wrapper
     * @return {HTMLElement} wrapper
     */
    function wrapElement(element, wrapper, attributes) {
      if (typeof wrapper === 'string') {
        wrapper = makeElement(wrapper, attributes);
      }
      if (element.parentNode) {
        element.parentNode.replaceChild(wrapper, element);
      }
      wrapper.appendChild(element);
      return wrapper;
    }
  
    /**
     * Returns element scroll offsets
     * @memberOf fabric.util
     * @param {HTMLElement} element Element to operate on
     * @return {Object} Object with left/top values
     */
    function getScrollLeftTop(element) {
  
      var left = 0,
          top = 0,
          docElement = fabric.document.documentElement,
          body = fabric.document.body || {
            scrollLeft: 0, scrollTop: 0
          };
  
      // While loop checks (and then sets element to) .parentNode OR .host
      //  to account for ShadowDOM. We still want to traverse up out of ShadowDOM,
      //  but the .parentNode of a root ShadowDOM node will always be null, instead
      //  it should be accessed through .host. See http://stackoverflow.com/a/24765528/4383938
      while (element && (element.parentNode || element.host)) {
  
        // Set element to element parent, or 'host' in case of ShadowDOM
        element = element.parentNode || element.host;
  
        if (element === fabric.document) {
          left = body.scrollLeft || docElement.scrollLeft || 0;
          top = body.scrollTop ||  docElement.scrollTop || 0;
        }
        else {
          left += element.scrollLeft || 0;
          top += element.scrollTop || 0;
        }
  
        if (element.nodeType === 1 && element.style.position === 'fixed') {
          break;
        }
      }
  
      return { left: left, top: top };
    }
  
    /**
     * Returns offset for a given element
     * @function
     * @memberOf fabric.util
     * @param {HTMLElement} element Element to get offset for
     * @return {Object} Object with "left" and "top" properties
     */
    function getElementOffset(element) {
      var docElem,
          doc = element && element.ownerDocument,
          box = { left: 0, top: 0 },
          offset = { left: 0, top: 0 },
          scrollLeftTop,
          offsetAttributes = {
            borderLeftWidth: 'left',
            borderTopWidth:  'top',
            paddingLeft:     'left',
            paddingTop:      'top'
          };
  
      if (!doc) {
        return offset;
      }
  
      for (var attr in offsetAttributes) {
        offset[offsetAttributes[attr]] += parseInt(getElementStyle(element, attr), 10) || 0;
      }
  
      docElem = doc.documentElement;
      if ( typeof element.getBoundingClientRect !== 'undefined' ) {
        box = element.getBoundingClientRect();
      }
  
      scrollLeftTop = getScrollLeftTop(element);
  
      return {
        left: box.left + scrollLeftTop.left - (docElem.clientLeft || 0) + offset.left,
        top: box.top + scrollLeftTop.top - (docElem.clientTop || 0)  + offset.top
      };
    }
  
    /**
     * Returns style attribute value of a given element
     * @memberOf fabric.util
     * @param {HTMLElement} element Element to get style attribute for
     * @param {String} attr Style attribute to get for element
     * @return {String} Style attribute value of the given element.
     */
    var getElementStyle;
    if (fabric.document.defaultView && fabric.document.defaultView.getComputedStyle) {
      getElementStyle = function(element, attr) {
        var style = fabric.document.defaultView.getComputedStyle(element, null);
        return style ? style[attr] : undefined;
      };
    }
    else {
      getElementStyle = function(element, attr) {
        var value = element.style[attr];
        if (!value && element.currentStyle) {
          value = element.currentStyle[attr];
        }
        return value;
      };
    }
  
    (function () {
      var style = fabric.document.documentElement.style,
          selectProp = 'userSelect' in style
            ? 'userSelect'
            : 'MozUserSelect' in style
              ? 'MozUserSelect'
              : 'WebkitUserSelect' in style
                ? 'WebkitUserSelect'
                : 'KhtmlUserSelect' in style
                  ? 'KhtmlUserSelect'
                  : '';
  
      /**
       * Makes element unselectable
       * @memberOf fabric.util
       * @param {HTMLElement} element Element to make unselectable
       * @return {HTMLElement} Element that was passed in
       */
      function makeElementUnselectable(element) {
        if (typeof element.onselectstart !== 'undefined') {
          element.onselectstart = fabric.util.falseFunction;
        }
        if (selectProp) {
          element.style[selectProp] = 'none';
        }
        else if (typeof element.unselectable === 'string') {
          element.unselectable = 'on';
        }
        return element;
      }
  
      /**
       * Makes element selectable
       * @memberOf fabric.util
       * @param {HTMLElement} element Element to make selectable
       * @return {HTMLElement} Element that was passed in
       */
      function makeElementSelectable(element) {
        if (typeof element.onselectstart !== 'undefined') {
          element.onselectstart = null;
        }
        if (selectProp) {
          element.style[selectProp] = '';
        }
        else if (typeof element.unselectable === 'string') {
          element.unselectable = '';
        }
        return element;
      }
  
      fabric.util.makeElementUnselectable = makeElementUnselectable;
      fabric.util.makeElementSelectable = makeElementSelectable;
    })();
  
    (function() {
  
      /**
       * Inserts a script element with a given url into a document; invokes callback, when that script is finished loading
       * @memberOf fabric.util
       * @param {String} url URL of a script to load
       * @param {Function} callback Callback to execute when script is finished loading
       */
      function getScript(url, callback) {
        var headEl = fabric.document.getElementsByTagName('head')[0],
            scriptEl = fabric.document.createElement('script'),
            loading = true;
  
        /** @ignore */
        scriptEl.onload = /** @ignore */ scriptEl.onreadystatechange = function(e) {
          if (loading) {
            if (typeof this.readyState === 'string' &&
                this.readyState !== 'loaded' &&
                this.readyState !== 'complete') {
              return;
            }
            loading = false;
            callback(e || fabric.window.event);
            scriptEl = scriptEl.onload = scriptEl.onreadystatechange = null;
          }
        };
        scriptEl.src = url;
        headEl.appendChild(scriptEl);
        // causes issue in Opera
        // headEl.removeChild(scriptEl);
      }
  
      fabric.util.getScript = getScript;
    })();
  
    function getNodeCanvas(element) {
      var impl = fabric.jsdomImplForWrapper(element);
      return impl._canvas || impl._image;
    };
  
    function cleanUpJsdomNode(element) {
      if (!fabric.isLikelyNode) {
        return;
      }
      var impl = fabric.jsdomImplForWrapper(element);
      if (impl) {
        impl._image = null;
        impl._canvas = null;
        // unsure if necessary
        impl._currentSrc = null;
        impl._attributes = null;
        impl._classList = null;
      }
    }
  
    fabric.util.getById = getById;
    fabric.util.toArray = toArray;
    fabric.util.makeElement = makeElement;
    fabric.util.addClass = addClass;
    fabric.util.wrapElement = wrapElement;
    fabric.util.getScrollLeftTop = getScrollLeftTop;
    fabric.util.getElementOffset = getElementOffset;
    fabric.util.getElementStyle = getElementStyle;
    fabric.util.getNodeCanvas = getNodeCanvas;
    fabric.util.cleanUpJsdomNode = cleanUpJsdomNode;
  
  })();
  
  
  (function() {
  
    function addParamToUrl(url, param) {
      return url + (/\?/.test(url) ? '&' : '?') + param;
    }
  
    function emptyFn() { }
  
    /**
     * Cross-browser abstraction for sending XMLHttpRequest
     * @memberOf fabric.util
     * @param {String} url URL to send XMLHttpRequest to
     * @param {Object} [options] Options object
     * @param {String} [options.method="GET"]
     * @param {String} [options.parameters] parameters to append to url in GET or in body
     * @param {String} [options.body] body to send with POST or PUT request
     * @param {Function} options.onComplete Callback to invoke when request is completed
     * @return {XMLHttpRequest} request
     */
    function request(url, options) {
      options || (options = { });
  
      var method = options.method ? options.method.toUpperCase() : 'GET',
          onComplete = options.onComplete || function() { },
          xhr = new fabric.window.XMLHttpRequest(),
          body = options.body || options.parameters;
  
      /** @ignore */
      xhr.onreadystatechange = function() {
        if (xhr.readyState === 4) {
          onComplete(xhr);
          xhr.onreadystatechange = emptyFn;
        }
      };
  
      if (method === 'GET') {
        body = null;
        if (typeof options.parameters === 'string') {
          url = addParamToUrl(url, options.parameters);
        }
      }
  
      xhr.open(method, url, true);
  
      if (method === 'POST' || method === 'PUT') {
        xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
      }
  
      xhr.send(body);
      return xhr;
    }
  
    fabric.util.request = request;
  })();
  
  
  /**
   * Wrapper around `console.log` (when available)
   * @param {*} [values] Values to log
   */
  fabric.log = function() { };
  
  /**
   * Wrapper around `console.warn` (when available)
   * @param {*} [values] Values to log as a warning
   */
  fabric.warn = function() { };
  
  /* eslint-disable */
  if (typeof console !== 'undefined') {
  
    ['log', 'warn'].forEach(function(methodName) {
  
      if (typeof console[methodName] !== 'undefined' &&
          typeof console[methodName].apply === 'function') {
  
        fabric[methodName] = function() {
          return console[methodName].apply(console, arguments);
        };
      }
    });
  }
  /* eslint-enable */
  
  
  (function() {
  
    function noop() {
      return false;
    }
  
    function defaultEasing(t, b, c, d) {
      return -c * Math.cos(t / d * (Math.PI / 2)) + c + b;
    }
  
    /**
     * Changes value from one to another within certain period of time, invoking callbacks as value is being changed.
     * @memberOf fabric.util
     * @param {Object} [options] Animation options
     * @param {Function} [options.onChange] Callback; invoked on every value change
     * @param {Function} [options.onComplete] Callback; invoked when value change is completed
     * @param {Number} [options.startValue=0] Starting value
     * @param {Number} [options.endValue=100] Ending value
     * @param {Number} [options.byValue=100] Value to modify the property by
     * @param {Function} [options.easing] Easing function
     * @param {Number} [options.duration=500] Duration of change (in ms)
     * @param {Function} [options.abort] Additional function with logic. If returns true, onComplete is called.
     */
    function animate(options) {
  
      requestAnimFrame(function(timestamp) {
        options || (options = { });
  
        var start = timestamp || +new Date(),
            duration = options.duration || 500,
            finish = start + duration, time,
            onChange = options.onChange || noop,
            abort = options.abort || noop,
            onComplete = options.onComplete || noop,
            easing = options.easing || defaultEasing,
            startValue = 'startValue' in options ? options.startValue : 0,
            endValue = 'endValue' in options ? options.endValue : 100,
            byValue = options.byValue || endValue - startValue;
  
        options.onStart && options.onStart();
  
        (function tick(ticktime) {
          // TODO: move abort call after calculation
          // and pass (current,valuePerc, timePerc) as arguments
          time = ticktime || +new Date();
          var currentTime = time > finish ? duration : (time - start),
              timePerc = currentTime / duration,
              current = easing(currentTime, startValue, byValue, duration),
              valuePerc = Math.abs((current - startValue) / byValue);
          if (abort()) {
            onComplete(endValue, 1, 1);
            return;
          }
          if (time > finish) {
            onChange(endValue, 1, 1);
            onComplete(endValue, 1, 1);
            return;
          }
          else {
            onChange(current, valuePerc, timePerc);
            requestAnimFrame(tick);
          }
        })(start);
      });
    }
  
    var _requestAnimFrame = fabric.window.requestAnimationFrame       ||
                            fabric.window.webkitRequestAnimationFrame ||
                            fabric.window.mozRequestAnimationFrame    ||
                            fabric.window.oRequestAnimationFrame      ||
                            fabric.window.msRequestAnimationFrame     ||
                            function(callback) {
                              return fabric.window.setTimeout(callback, 1000 / 60);
                            };
  
    var _cancelAnimFrame = fabric.window.cancelAnimationFrame || fabric.window.clearTimeout;
  
    /**
     * requestAnimationFrame polyfill based on http://paulirish.com/2011/requestanimationframe-for-smart-animating/
     * In order to get a precise start time, `requestAnimFrame` should be called as an entry into the method
     * @memberOf fabric.util
     * @param {Function} callback Callback to invoke
     * @param {DOMElement} element optional Element to associate with animation
     */
    function requestAnimFrame() {
      return _requestAnimFrame.apply(fabric.window, arguments);
    }
  
    function cancelAnimFrame() {
      return _cancelAnimFrame.apply(fabric.window, arguments);
    }
  
    fabric.util.animate = animate;
    fabric.util.requestAnimFrame = requestAnimFrame;
    fabric.util.cancelAnimFrame = cancelAnimFrame;
  })();
  
  
  (function() {
    // Calculate an in-between color. Returns a "rgba()" string.
    // Credit: Edwin Martin <edwin@bitstorm.org>
    //         http://www.bitstorm.org/jquery/color-animation/jquery.animate-colors.js
    function calculateColor(begin, end, pos) {
      var color = 'rgba('
          + parseInt((begin[0] + pos * (end[0] - begin[0])), 10) + ','
          + parseInt((begin[1] + pos * (end[1] - begin[1])), 10) + ','
          + parseInt((begin[2] + pos * (end[2] - begin[2])), 10);
  
      color += ',' + (begin && end ? parseFloat(begin[3] + pos * (end[3] - begin[3])) : 1);
      color += ')';
      return color;
    }
  
    /**
     * Changes the color from one to another within certain period of time, invoking callbacks as value is being changed.
     * @memberOf fabric.util
     * @param {String} fromColor The starting color in hex or rgb(a) format.
     * @param {String} toColor The starting color in hex or rgb(a) format.
     * @param {Number} [duration] Duration of change (in ms).
     * @param {Object} [options] Animation options
     * @param {Function} [options.onChange] Callback; invoked on every value change
     * @param {Function} [options.onComplete] Callback; invoked when value change is completed
     * @param {Function} [options.colorEasing] Easing function. Note that this function only take two arguments (currentTime, duration). Thus the regular animation easing functions cannot be used.
     * @param {Function} [options.abort] Additional function with logic. If returns true, onComplete is called.
     */
    function animateColor(fromColor, toColor, duration, options) {
      var startColor = new fabric.Color(fromColor).getSource(),
          endColor = new fabric.Color(toColor).getSource();
  
      options = options || {};
  
      fabric.util.animate(fabric.util.object.extend(options, {
        duration: duration || 500,
        startValue: startColor,
        endValue: endColor,
        byValue: endColor,
        easing: function (currentTime, startValue, byValue, duration) {
          var posValue = options.colorEasing
            ? options.colorEasing(currentTime, duration)
            : 1 - Math.cos(currentTime / duration * (Math.PI / 2));
          return calculateColor(startValue, byValue, posValue);
        }
      }));
    }
  
    fabric.util.animateColor = animateColor;
  
  })();
  
  
  (function() {
  
    function normalize(a, c, p, s) {
      if (a < Math.abs(c)) {
        a = c;
        s = p / 4;
      }
      else {
        //handle the 0/0 case:
        if (c === 0 && a === 0) {
          s = p / (2 * Math.PI) * Math.asin(1);
        }
        else {
          s = p / (2 * Math.PI) * Math.asin(c / a);
        }
      }
      return { a: a, c: c, p: p, s: s };
    }
  
    function elastic(opts, t, d) {
      return opts.a *
        Math.pow(2, 10 * (t -= 1)) *
        Math.sin( (t * d - opts.s) * (2 * Math.PI) / opts.p );
    }
  
    /**
     * Cubic easing out
     * @memberOf fabric.util.ease
     */
    function easeOutCubic(t, b, c, d) {
      return c * ((t = t / d - 1) * t * t + 1) + b;
    }
  
    /**
     * Cubic easing in and out
     * @memberOf fabric.util.ease
     */
    function easeInOutCubic(t, b, c, d) {
      t /= d / 2;
      if (t < 1) {
        return c / 2 * t * t * t + b;
      }
      return c / 2 * ((t -= 2) * t * t + 2) + b;
    }
  
    /**
     * Quartic easing in
     * @memberOf fabric.util.ease
     */
    function easeInQuart(t, b, c, d) {
      return c * (t /= d) * t * t * t + b;
    }
  
    /**
     * Quartic easing out
     * @memberOf fabric.util.ease
     */
    function easeOutQuart(t, b, c, d) {
      return -c * ((t = t / d - 1) * t * t * t - 1) + b;
    }
  
    /**
     * Quartic easing in and out
     * @memberOf fabric.util.ease
     */
    function easeInOutQuart(t, b, c, d) {
      t /= d / 2;
      if (t < 1) {
        return c / 2 * t * t * t * t + b;
      }
      return -c / 2 * ((t -= 2) * t * t * t - 2) + b;
    }
  
    /**
     * Quintic easing in
     * @memberOf fabric.util.ease
     */
    function easeInQuint(t, b, c, d) {
      return c * (t /= d) * t * t * t * t + b;
    }
  
    /**
     * Quintic easing out
     * @memberOf fabric.util.ease
     */
    function easeOutQuint(t, b, c, d) {
      return c * ((t = t / d - 1) * t * t * t * t + 1) + b;
    }
  
    /**
     * Quintic easing in and out
     * @memberOf fabric.util.ease
     */
    function easeInOutQuint(t, b, c, d) {
      t /= d / 2;
      if (t < 1) {
        return c / 2 * t * t * t * t * t + b;
      }
      return c / 2 * ((t -= 2) * t * t * t * t + 2) + b;
    }
  
    /**
     * Sinusoidal easing in
     * @memberOf fabric.util.ease
     */
    function easeInSine(t, b, c, d) {
      return -c * Math.cos(t / d * (Math.PI / 2)) + c + b;
    }
  
    /**
     * Sinusoidal easing out
     * @memberOf fabric.util.ease
     */
    function easeOutSine(t, b, c, d) {
      return c * Math.sin(t / d * (Math.PI / 2)) + b;
    }
  
    /**
     * Sinusoidal easing in and out
     * @memberOf fabric.util.ease
     */
    function easeInOutSine(t, b, c, d) {
      return -c / 2 * (Math.cos(Math.PI * t / d) - 1) + b;
    }
  
    /**
     * Exponential easing in
     * @memberOf fabric.util.ease
     */
    function easeInExpo(t, b, c, d) {
      return (t === 0) ? b : c * Math.pow(2, 10 * (t / d - 1)) + b;
    }
  
    /**
     * Exponential easing out
     * @memberOf fabric.util.ease
     */
    function easeOutExpo(t, b, c, d) {
      return (t === d) ? b + c : c * (-Math.pow(2, -10 * t / d) + 1) + b;
    }
  
    /**
     * Exponential easing in and out
     * @memberOf fabric.util.ease
     */
    function easeInOutExpo(t, b, c, d) {
      if (t === 0) {
        return b;
      }
      if (t === d) {
        return b + c;
      }
      t /= d / 2;
      if (t < 1) {
        return c / 2 * Math.pow(2, 10 * (t - 1)) + b;
      }
      return c / 2 * (-Math.pow(2, -10 * --t) + 2) + b;
    }
  
    /**
     * Circular easing in
     * @memberOf fabric.util.ease
     */
    function easeInCirc(t, b, c, d) {
      return -c * (Math.sqrt(1 - (t /= d) * t) - 1) + b;
    }
  
    /**
     * Circular easing out
     * @memberOf fabric.util.ease
     */
    function easeOutCirc(t, b, c, d) {
      return c * Math.sqrt(1 - (t = t / d - 1) * t) + b;
    }
  
    /**
     * Circular easing in and out
     * @memberOf fabric.util.ease
     */
    function easeInOutCirc(t, b, c, d) {
      t /= d / 2;
      if (t < 1) {
        return -c / 2 * (Math.sqrt(1 - t * t) - 1) + b;
      }
      return c / 2 * (Math.sqrt(1 - (t -= 2) * t) + 1) + b;
    }
  
    /**
     * Elastic easing in
     * @memberOf fabric.util.ease
     */
    function easeInElastic(t, b, c, d) {
      var s = 1.70158, p = 0, a = c;
      if (t === 0) {
        return b;
      }
      t /= d;
      if (t === 1) {
        return b + c;
      }
      if (!p) {
        p = d * 0.3;
      }
      var opts = normalize(a, c, p, s);
      return -elastic(opts, t, d) + b;
    }
  
    /**
     * Elastic easing out
     * @memberOf fabric.util.ease
     */
    function easeOutElastic(t, b, c, d) {
      var s = 1.70158, p = 0, a = c;
      if (t === 0) {
        return b;
      }
      t /= d;
      if (t === 1) {
        return b + c;
      }
      if (!p) {
        p = d * 0.3;
      }
      var opts = normalize(a, c, p, s);
      return opts.a * Math.pow(2, -10 * t) * Math.sin((t * d - opts.s) * (2 * Math.PI) / opts.p ) + opts.c + b;
    }
  
    /**
     * Elastic easing in and out
     * @memberOf fabric.util.ease
     */
    function easeInOutElastic(t, b, c, d) {
      var s = 1.70158, p = 0, a = c;
      if (t === 0) {
        return b;
      }
      t /= d / 2;
      if (t === 2) {
        return b + c;
      }
      if (!p) {
        p = d * (0.3 * 1.5);
      }
      var opts = normalize(a, c, p, s);
      if (t < 1) {
        return -0.5 * elastic(opts, t, d) + b;
      }
      return opts.a * Math.pow(2, -10 * (t -= 1)) *
        Math.sin((t * d - opts.s) * (2 * Math.PI) / opts.p ) * 0.5 + opts.c + b;
    }
  
    /**
     * Backwards easing in
     * @memberOf fabric.util.ease
     */
    function easeInBack(t, b, c, d, s) {
      if (s === undefined) {
        s = 1.70158;
      }
      return c * (t /= d) * t * ((s + 1) * t - s) + b;
    }
  
    /**
     * Backwards easing out
     * @memberOf fabric.util.ease
     */
    function easeOutBack(t, b, c, d, s) {
      if (s === undefined) {
        s = 1.70158;
      }
      return c * ((t = t / d - 1) * t * ((s + 1) * t + s) + 1) + b;
    }
  
    /**
     * Backwards easing in and out
     * @memberOf fabric.util.ease
     */
    function easeInOutBack(t, b, c, d, s) {
      if (s === undefined) {
        s = 1.70158;
      }
      t /= d / 2;
      if (t < 1) {
        return c / 2 * (t * t * (((s *= (1.525)) + 1) * t - s)) + b;
      }
      return c / 2 * ((t -= 2) * t * (((s *= (1.525)) + 1) * t + s) + 2) + b;
    }
  
    /**
     * Bouncing easing in
     * @memberOf fabric.util.ease
     */
    function easeInBounce(t, b, c, d) {
      return c - easeOutBounce (d - t, 0, c, d) + b;
    }
  
    /**
     * Bouncing easing out
     * @memberOf fabric.util.ease
     */
    function easeOutBounce(t, b, c, d) {
      if ((t /= d) < (1 / 2.75)) {
        return c * (7.5625 * t * t) + b;
      }
      else if (t < (2 / 2.75)) {
        return c * (7.5625 * (t -= (1.5 / 2.75)) * t + 0.75) + b;
      }
      else if (t < (2.5 / 2.75)) {
        return c * (7.5625 * (t -= (2.25 / 2.75)) * t + 0.9375) + b;
      }
      else {
        return c * (7.5625 * (t -= (2.625 / 2.75)) * t + 0.984375) + b;
      }
    }
  
    /**
     * Bouncing easing in and out
     * @memberOf fabric.util.ease
     */
    function easeInOutBounce(t, b, c, d) {
      if (t < d / 2) {
        return easeInBounce (t * 2, 0, c, d) * 0.5 + b;
      }
      return easeOutBounce(t * 2 - d, 0, c, d) * 0.5 + c * 0.5 + b;
    }
  
    /**
     * Easing functions
     * See <a href="http://gizma.com/easing/">Easing Equations by Robert Penner</a>
     * @namespace fabric.util.ease
     */
    fabric.util.ease = {
  
      /**
       * Quadratic easing in
       * @memberOf fabric.util.ease
       */
      easeInQuad: function(t, b, c, d) {
        return c * (t /= d) * t + b;
      },
  
      /**
       * Quadratic easing out
       * @memberOf fabric.util.ease
       */
      easeOutQuad: function(t, b, c, d) {
        return -c * (t /= d) * (t - 2) + b;
      },
  
      /**
       * Quadratic easing in and out
       * @memberOf fabric.util.ease
       */
      easeInOutQuad: function(t, b, c, d) {
        t /= (d / 2);
        if (t < 1) {
          return c / 2 * t * t + b;
        }
        return -c / 2 * ((--t) * (t - 2) - 1) + b;
      },
  
      /**
       * Cubic easing in
       * @memberOf fabric.util.ease
       */
      easeInCubic: function(t, b, c, d) {
        return c * (t /= d) * t * t + b;
      },
  
      easeOutCubic: easeOutCubic,
      easeInOutCubic: easeInOutCubic,
      easeInQuart: easeInQuart,
      easeOutQuart: easeOutQuart,
      easeInOutQuart: easeInOutQuart,
      easeInQuint: easeInQuint,
      easeOutQuint: easeOutQuint,
      easeInOutQuint: easeInOutQuint,
      easeInSine: easeInSine,
      easeOutSine: easeOutSine,
      easeInOutSine: easeInOutSine,
      easeInExpo: easeInExpo,
      easeOutExpo: easeOutExpo,
      easeInOutExpo: easeInOutExpo,
      easeInCirc: easeInCirc,
      easeOutCirc: easeOutCirc,
      easeInOutCirc: easeInOutCirc,
      easeInElastic: easeInElastic,
      easeOutElastic: easeOutElastic,
      easeInOutElastic: easeInOutElastic,
      easeInBack: easeInBack,
      easeOutBack: easeOutBack,
      easeInOutBack: easeInOutBack,
      easeInBounce: easeInBounce,
      easeOutBounce: easeOutBounce,
      easeInOutBounce: easeInOutBounce
    };
  
  })();
  
  
  (function(global) {
  
    'use strict';
  
    /**
     * @name fabric
     * @namespace
     */
  
    var fabric = global.fabric || (global.fabric = { }),
        extend = fabric.util.object.extend,
        clone = fabric.util.object.clone,
        toFixed = fabric.util.toFixed,
        parseUnit = fabric.util.parseUnit,
        multiplyTransformMatrices = fabric.util.multiplyTransformMatrices,
  
        svgValidTagNames = ['path', 'circle', 'polygon', 'polyline', 'ellipse', 'rect', 'line',
          'image', 'text'],
        svgViewBoxElements = ['symbol', 'image', 'marker', 'pattern', 'view', 'svg'],
        svgInvalidAncestors = ['pattern', 'defs', 'symbol', 'metadata', 'clipPath', 'mask', 'desc'],
        svgValidParents = ['symbol', 'g', 'a', 'svg', 'clipPath', 'defs'],
  
        attributesMap = {
          cx:                   'left',
          x:                    'left',
          r:                    'radius',
          cy:                   'top',
          y:                    'top',
          display:              'visible',
          visibility:           'visible',
          transform:            'transformMatrix',
          'fill-opacity':       'fillOpacity',
          'fill-rule':          'fillRule',
          'font-family':        'fontFamily',
          'font-size':          'fontSize',
          'font-style':         'fontStyle',
          'font-weight':        'fontWeight',
          'letter-spacing':     'charSpacing',
          'paint-order':        'paintFirst',
          'stroke-dasharray':   'strokeDashArray',
          'stroke-dashoffset':  'strokeDashOffset',
          'stroke-linecap':     'strokeLineCap',
          'stroke-linejoin':    'strokeLineJoin',
          'stroke-miterlimit':  'strokeMiterLimit',
          'stroke-opacity':     'strokeOpacity',
          'stroke-width':       'strokeWidth',
          'text-decoration':    'textDecoration',
          'text-anchor':        'textAnchor',
          opacity:              'opacity',
          'clip-path':          'clipPath',
          'clip-rule':          'clipRule',
          'vector-effect':      'strokeUniform'
        },
  
        colorAttributes = {
          stroke: 'strokeOpacity',
          fill:   'fillOpacity'
        };
  
    fabric.svgValidTagNamesRegEx = getSvgRegex(svgValidTagNames);
    fabric.svgViewBoxElementsRegEx = getSvgRegex(svgViewBoxElements);
    fabric.svgInvalidAncestorsRegEx = getSvgRegex(svgInvalidAncestors);
    fabric.svgValidParentsRegEx = getSvgRegex(svgValidParents);
  
    fabric.cssRules = { };
    fabric.gradientDefs = { };
    fabric.clipPaths = { };
  
    function normalizeAttr(attr) {
      // transform attribute names
      if (attr in attributesMap) {
        return attributesMap[attr];
      }
      return attr;
    }
  
    function normalizeValue(attr, value, parentAttributes, fontSize) {
      var isArray = Object.prototype.toString.call(value) === '[object Array]',
          parsed;
  
      if ((attr === 'fill' || attr === 'stroke') && value === 'none') {
        value = '';
      }
      else if (attr === 'vector-effect') {
        value = value === 'non-scaling-stroke';
      }
      else if (attr === 'strokeDashArray') {
        if (value === 'none') {
          value = null;
        }
        else {
          value = value.replace(/,/g, ' ').split(/\s+/).map(parseFloat);
        }
      }
      else if (attr === 'transformMatrix') {
        if (parentAttributes && parentAttributes.transformMatrix) {
          value = multiplyTransformMatrices(
            parentAttributes.transformMatrix, fabric.parseTransformAttribute(value));
        }
        else {
          value = fabric.parseTransformAttribute(value);
        }
      }
      else if (attr === 'visible') {
        value = value !== 'none' && value !== 'hidden';
        // display=none on parent element always takes precedence over child element
        if (parentAttributes && parentAttributes.visible === false) {
          value = false;
        }
      }
      else if (attr === 'opacity') {
        value = parseFloat(value);
        if (parentAttributes && typeof parentAttributes.opacity !== 'undefined') {
          value *= parentAttributes.opacity;
        }
      }
      else if (attr === 'textAnchor' /* text-anchor */) {
        value = value === 'start' ? 'left' : value === 'end' ? 'right' : 'center';
      }
      else if (attr === 'charSpacing') {
        // parseUnit returns px and we convert it to em
        parsed = parseUnit(value, fontSize) / fontSize * 1000;
      }
      else if (attr === 'paintFirst') {
        var fillIndex = value.indexOf('fill');
        var strokeIndex = value.indexOf('stroke');
        var value = 'fill';
        if (fillIndex > -1 && strokeIndex > -1 && strokeIndex < fillIndex) {
          value = 'stroke';
        }
        else if (fillIndex === -1 && strokeIndex > -1) {
          value = 'stroke';
        }
      }
      else if (attr === 'href' || attr === 'xlink:href') {
        return value;
      }
      else {
        parsed = isArray ? value.map(parseUnit) : parseUnit(value, fontSize);
      }
  
      return (!isArray && isNaN(parsed) ? value : parsed);
    }
  
    /**
      * @private
      */
    function getSvgRegex(arr) {
      return new RegExp('^(' + arr.join('|') + ')\\b', 'i');
    }
  
    /**
     * @private
     * @param {Object} attributes Array of attributes to parse
     */
    function _setStrokeFillOpacity(attributes) {
      for (var attr in colorAttributes) {
  
        if (typeof attributes[colorAttributes[attr]] === 'undefined' || attributes[attr] === '') {
          continue;
        }
  
        if (typeof attributes[attr] === 'undefined') {
          if (!fabric.Object.prototype[attr]) {
            continue;
          }
          attributes[attr] = fabric.Object.prototype[attr];
        }
  
        if (attributes[attr].indexOf('url(') === 0) {
          continue;
        }
  
        var color = new fabric.Color(attributes[attr]);
        attributes[attr] = color.setAlpha(toFixed(color.getAlpha() * attributes[colorAttributes[attr]], 2)).toRgba();
      }
      return attributes;
    }
  
    /**
     * @private
     */
    function _getMultipleNodes(doc, nodeNames) {
      var nodeName, nodeArray = [], nodeList, i, len;
      for (i = 0, len = nodeNames.length; i < len; i++) {
        nodeName = nodeNames[i];
        nodeList = doc.getElementsByTagName(nodeName);
        nodeArray = nodeArray.concat(Array.prototype.slice.call(nodeList));
      }
      return nodeArray;
    }
  
    /**
     * Parses "transform" attribute, returning an array of values
     * @static
     * @function
     * @memberOf fabric
     * @param {String} attributeValue String containing attribute value
     * @return {Array} Array of 6 elements representing transformation matrix
     */
    fabric.parseTransformAttribute = (function() {
      function rotateMatrix(matrix, args) {
        var cos = fabric.util.cos(args[0]), sin = fabric.util.sin(args[0]),
            x = 0, y = 0;
        if (args.length === 3) {
          x = args[1];
          y = args[2];
        }
  
        matrix[0] = cos;
        matrix[1] = sin;
        matrix[2] = -sin;
        matrix[3] = cos;
        matrix[4] = x - (cos * x - sin * y);
        matrix[5] = y - (sin * x + cos * y);
      }
  
      function scaleMatrix(matrix, args) {
        var multiplierX = args[0],
            multiplierY = (args.length === 2) ? args[1] : args[0];
  
        matrix[0] = multiplierX;
        matrix[3] = multiplierY;
      }
  
      function skewMatrix(matrix, args, pos) {
        matrix[pos] = Math.tan(fabric.util.degreesToRadians(args[0]));
      }
  
      function translateMatrix(matrix, args) {
        matrix[4] = args[0];
        if (args.length === 2) {
          matrix[5] = args[1];
        }
      }
  
      // identity matrix
      var iMatrix = fabric.iMatrix,
  
          // == begin transform regexp
          number = fabric.reNum,
  
          commaWsp = '(?:\\s+,?\\s*|,\\s*)',
  
          skewX = '(?:(skewX)\\s*\\(\\s*(' + number + ')\\s*\\))',
  
          skewY = '(?:(skewY)\\s*\\(\\s*(' + number + ')\\s*\\))',
  
          rotate = '(?:(rotate)\\s*\\(\\s*(' + number + ')(?:' +
                      commaWsp + '(' + number + ')' +
                      commaWsp + '(' + number + '))?\\s*\\))',
  
          scale = '(?:(scale)\\s*\\(\\s*(' + number + ')(?:' +
                      commaWsp + '(' + number + '))?\\s*\\))',
  
          translate = '(?:(translate)\\s*\\(\\s*(' + number + ')(?:' +
                      commaWsp + '(' + number + '))?\\s*\\))',
  
          matrix = '(?:(matrix)\\s*\\(\\s*' +
                    '(' + number + ')' + commaWsp +
                    '(' + number + ')' + commaWsp +
                    '(' + number + ')' + commaWsp +
                    '(' + number + ')' + commaWsp +
                    '(' + number + ')' + commaWsp +
                    '(' + number + ')' +
                    '\\s*\\))',
  
          transform = '(?:' +
                      matrix + '|' +
                      translate + '|' +
                      scale + '|' +
                      rotate + '|' +
                      skewX + '|' +
                      skewY +
                      ')',
  
          transforms = '(?:' + transform + '(?:' + commaWsp + '*' + transform + ')*' + ')',
  
          transformList = '^\\s*(?:' + transforms + '?)\\s*$',
  
          // http://www.w3.org/TR/SVG/coords.html#TransformAttribute
          reTransformList = new RegExp(transformList),
          // == end transform regexp
  
          reTransform = new RegExp(transform, 'g');
  
      return function(attributeValue) {
  
        // start with identity matrix
        var matrix = iMatrix.concat(),
            matrices = [];
  
        // return if no argument was given or
        // an argument does not match transform attribute regexp
        if (!attributeValue || (attributeValue && !reTransformList.test(attributeValue))) {
          return matrix;
        }
  
        attributeValue.replace(reTransform, function(match) {
  
          var m = new RegExp(transform).exec(match).filter(function (match) {
                // match !== '' && match != null
                return (!!match);
              }),
              operation = m[1],
              args = m.slice(2).map(parseFloat);
  
          switch (operation) {
            case 'translate':
              translateMatrix(matrix, args);
              break;
            case 'rotate':
              args[0] = fabric.util.degreesToRadians(args[0]);
              rotateMatrix(matrix, args);
              break;
            case 'scale':
              scaleMatrix(matrix, args);
              break;
            case 'skewX':
              skewMatrix(matrix, args, 2);
              break;
            case 'skewY':
              skewMatrix(matrix, args, 1);
              break;
            case 'matrix':
              matrix = args;
              break;
          }
  
          // snapshot current matrix into matrices array
          matrices.push(matrix.concat());
          // reset
          matrix = iMatrix.concat();
        });
  
        var combinedMatrix = matrices[0];
        while (matrices.length > 1) {
          matrices.shift();
          combinedMatrix = fabric.util.multiplyTransformMatrices(combinedMatrix, matrices[0]);
        }
        return combinedMatrix;
      };
    })();
  
    /**
     * @private
     */
    function parseStyleString(style, oStyle) {
      var attr, value;
      style.replace(/;\s*$/, '').split(';').forEach(function (chunk) {
        var pair = chunk.split(':');
  
        attr = pair[0].trim().toLowerCase();
        value =  pair[1].trim();
  
        oStyle[attr] = value;
      });
    }
  
    /**
     * @private
     */
    function parseStyleObject(style, oStyle) {
      var attr, value;
      for (var prop in style) {
        if (typeof style[prop] === 'undefined') {
          continue;
        }
  
        attr = prop.toLowerCase();
        value = style[prop];
  
        oStyle[attr] = value;
      }
    }
  
    /**
     * @private
     */
    function getGlobalStylesForElement(element, svgUid) {
      var styles = { };
      for (var rule in fabric.cssRules[svgUid]) {
        if (elementMatchesRule(element, rule.split(' '))) {
          for (var property in fabric.cssRules[svgUid][rule]) {
            styles[property] = fabric.cssRules[svgUid][rule][property];
          }
        }
      }
      return styles;
    }
  
    /**
     * @private
     */
    function elementMatchesRule(element, selectors) {
      var firstMatching, parentMatching = true;
      //start from rightmost selector.
      firstMatching = selectorMatches(element, selectors.pop());
      if (firstMatching && selectors.length) {
        parentMatching = doesSomeParentMatch(element, selectors);
      }
      return firstMatching && parentMatching && (selectors.length === 0);
    }
  
    function doesSomeParentMatch(element, selectors) {
      var selector, parentMatching = true;
      while (element.parentNode && element.parentNode.nodeType === 1 && selectors.length) {
        if (parentMatching) {
          selector = selectors.pop();
        }
        element = element.parentNode;
        parentMatching = selectorMatches(element, selector);
      }
      return selectors.length === 0;
    }
  
    /**
     * @private
     */
    function selectorMatches(element, selector) {
      var nodeName = element.nodeName,
          classNames = element.getAttribute('class'),
          id = element.getAttribute('id'), matcher, i;
      // i check if a selector matches slicing away part from it.
      // if i get empty string i should match
      matcher = new RegExp('^' + nodeName, 'i');
      selector = selector.replace(matcher, '');
      if (id && selector.length) {
        matcher = new RegExp('#' + id + '(?![a-zA-Z\\-]+)', 'i');
        selector = selector.replace(matcher, '');
      }
      if (classNames && selector.length) {
        classNames = classNames.split(' ');
        for (i = classNames.length; i--;) {
          matcher = new RegExp('\\.' + classNames[i] + '(?![a-zA-Z\\-]+)', 'i');
          selector = selector.replace(matcher, '');
        }
      }
      return selector.length === 0;
    }
  
    /**
     * @private
     * to support IE8 missing getElementById on SVGdocument and on node xmlDOM
     */
    function elementById(doc, id) {
      var el;
      doc.getElementById && (el = doc.getElementById(id));
      if (el) {
        return el;
      }
      var node, i, len, nodelist = doc.getElementsByTagName('*');
      for (i = 0, len = nodelist.length; i < len; i++) {
        node = nodelist[i];
        if (id === node.getAttribute('id')) {
          return node;
        }
      }
    }
  
    /**
     * @private
     */
    function parseUseDirectives(doc) {
      var nodelist = _getMultipleNodes(doc, ['use', 'svg:use']), i = 0;
      while (nodelist.length && i < nodelist.length) {
        var el = nodelist[i],
            xlink = (el.getAttribute('xlink:href') || el.getAttribute('href')).substr(1),
            x = el.getAttribute('x') || 0,
            y = el.getAttribute('y') || 0,
            el2 = elementById(doc, xlink).cloneNode(true),
            currentTrans = (el2.getAttribute('transform') || '') + ' translate(' + x + ', ' + y + ')',
            parentNode, oldLength = nodelist.length, attr, j, attrs, len;
  
        applyViewboxTransform(el2);
        if (/^svg$/i.test(el2.nodeName)) {
          var el3 = el2.ownerDocument.createElement('g');
          for (j = 0, attrs = el2.attributes, len = attrs.length; j < len; j++) {
            attr = attrs.item(j);
            el3.setAttribute(attr.nodeName, attr.nodeValue);
          }
          // el2.firstChild != null
          while (el2.firstChild) {
            el3.appendChild(el2.firstChild);
          }
          el2 = el3;
        }
  
        for (j = 0, attrs = el.attributes, len = attrs.length; j < len; j++) {
          attr = attrs.item(j);
          if (attr.nodeName === 'x' || attr.nodeName === 'y' ||
            attr.nodeName === 'xlink:href' || attr.nodeName === 'href') {
            continue;
          }
  
          if (attr.nodeName === 'transform') {
            currentTrans = attr.nodeValue + ' ' + currentTrans;
          }
          else {
            el2.setAttribute(attr.nodeName, attr.nodeValue);
          }
        }
  
        el2.setAttribute('transform', currentTrans);
        el2.setAttribute('instantiated_by_use', '1');
        el2.removeAttribute('id');
        parentNode = el.parentNode;
        parentNode.replaceChild(el2, el);
        // some browsers do not shorten nodelist after replaceChild (IE8)
        if (nodelist.length === oldLength) {
          i++;
        }
      }
    }
  
    // http://www.w3.org/TR/SVG/coords.html#ViewBoxAttribute
    // matches, e.g.: +14.56e-12, etc.
    var reViewBoxAttrValue = new RegExp(
      '^' +
      '\\s*(' + fabric.reNum + '+)\\s*,?' +
      '\\s*(' + fabric.reNum + '+)\\s*,?' +
      '\\s*(' + fabric.reNum + '+)\\s*,?' +
      '\\s*(' + fabric.reNum + '+)\\s*' +
      '$'
    );
  
    /**
     * Add a <g> element that envelop all child elements and makes the viewbox transformMatrix descend on all elements
     */
    function applyViewboxTransform(element) {
  
      var viewBoxAttr = element.getAttribute('viewBox'),
          scaleX = 1,
          scaleY = 1,
          minX = 0,
          minY = 0,
          viewBoxWidth, viewBoxHeight, matrix, el,
          widthAttr = element.getAttribute('width'),
          heightAttr = element.getAttribute('height'),
          x = element.getAttribute('x') || 0,
          y = element.getAttribute('y') || 0,
          preserveAspectRatio = element.getAttribute('preserveAspectRatio') || '',
          missingViewBox = (!viewBoxAttr || !fabric.svgViewBoxElementsRegEx.test(element.nodeName)
                             || !(viewBoxAttr = viewBoxAttr.match(reViewBoxAttrValue))),
          missingDimAttr = (!widthAttr || !heightAttr || widthAttr === '100%' || heightAttr === '100%'),
          toBeParsed = missingViewBox && missingDimAttr,
          parsedDim = { }, translateMatrix = '', widthDiff = 0, heightDiff = 0;
  
      parsedDim.width = 0;
      parsedDim.height = 0;
      parsedDim.toBeParsed = toBeParsed;
  
      if (toBeParsed) {
        return parsedDim;
      }
  
      if (missingViewBox) {
        parsedDim.width = parseUnit(widthAttr);
        parsedDim.height = parseUnit(heightAttr);
        return parsedDim;
      }
      minX = -parseFloat(viewBoxAttr[1]);
      minY = -parseFloat(viewBoxAttr[2]);
      viewBoxWidth = parseFloat(viewBoxAttr[3]);
      viewBoxHeight = parseFloat(viewBoxAttr[4]);
      parsedDim.minX = minX;
      parsedDim.minY = minY;
      parsedDim.viewBoxWidth = viewBoxWidth;
      parsedDim.viewBoxHeight = viewBoxHeight;
      if (!missingDimAttr) {
        parsedDim.width = parseUnit(widthAttr);
        parsedDim.height = parseUnit(heightAttr);
        scaleX = parsedDim.width / viewBoxWidth;
        scaleY = parsedDim.height / viewBoxHeight;
      }
      else {
        parsedDim.width = viewBoxWidth;
        parsedDim.height = viewBoxHeight;
      }
  
      // default is to preserve aspect ratio
      preserveAspectRatio = fabric.util.parsePreserveAspectRatioAttribute(preserveAspectRatio);
      if (preserveAspectRatio.alignX !== 'none') {
        //translate all container for the effect of Mid, Min, Max
        if (preserveAspectRatio.meetOrSlice === 'meet') {
          scaleY = scaleX = (scaleX > scaleY ? scaleY : scaleX);
          // calculate additional translation to move the viewbox
        }
        if (preserveAspectRatio.meetOrSlice === 'slice') {
          scaleY = scaleX = (scaleX > scaleY ? scaleX : scaleY);
          // calculate additional translation to move the viewbox
        }
        widthDiff = parsedDim.width - viewBoxWidth * scaleX;
        heightDiff = parsedDim.height - viewBoxHeight * scaleX;
        if (preserveAspectRatio.alignX === 'Mid') {
          widthDiff /= 2;
        }
        if (preserveAspectRatio.alignY === 'Mid') {
          heightDiff /= 2;
        }
        if (preserveAspectRatio.alignX === 'Min') {
          widthDiff = 0;
        }
        if (preserveAspectRatio.alignY === 'Min') {
          heightDiff = 0;
        }
      }
  
      if (scaleX === 1 && scaleY === 1 && minX === 0 && minY === 0 && x === 0 && y === 0) {
        return parsedDim;
      }
  
      if (x || y) {
        translateMatrix = ' translate(' + parseUnit(x) + ' ' + parseUnit(y) + ') ';
      }
  
      matrix = translateMatrix + ' matrix(' + scaleX +
                    ' 0' +
                    ' 0 ' +
                    scaleY + ' ' +
                    (minX * scaleX + widthDiff) + ' ' +
                    (minY * scaleY + heightDiff) + ') ';
      parsedDim.viewboxTransform = fabric.parseTransformAttribute(matrix);
      if (element.nodeName === 'svg') {
        el = element.ownerDocument.createElement('g');
        // element.firstChild != null
        while (element.firstChild) {
          el.appendChild(element.firstChild);
        }
        element.appendChild(el);
      }
      else {
        el = element;
        matrix = el.getAttribute('transform') + matrix;
      }
      el.setAttribute('transform', matrix);
      return parsedDim;
    }
  
    function hasAncestorWithNodeName(element, nodeName) {
      while (element && (element = element.parentNode)) {
        if (element.nodeName && nodeName.test(element.nodeName.replace('svg:', ''))
          && !element.getAttribute('instantiated_by_use')) {
          return true;
        }
      }
      return false;
    }
  
    /**
     * Parses an SVG document, converts it to an array of corresponding fabric.* instances and passes them to a callback
     * @static
     * @function
     * @memberOf fabric
     * @param {SVGDocument} doc SVG document to parse
     * @param {Function} callback Callback to call when parsing is finished;
     * It's being passed an array of elements (parsed from a document).
     * @param {Function} [reviver] Method for further parsing of SVG elements, called after each fabric object created.
     * @param {Object} [parsingOptions] options for parsing document
     * @param {String} [parsingOptions.crossOrigin] crossOrigin settings
     */
    fabric.parseSVGDocument = function(doc, callback, reviver, parsingOptions) {
      if (!doc) {
        return;
      }
  
      parseUseDirectives(doc);
  
      var svgUid =  fabric.Object.__uid++, i, len,
          options = applyViewboxTransform(doc),
          descendants = fabric.util.toArray(doc.getElementsByTagName('*'));
      options.crossOrigin = parsingOptions && parsingOptions.crossOrigin;
      options.svgUid = svgUid;
  
      if (descendants.length === 0 && fabric.isLikelyNode) {
        // we're likely in node, where "o3-xml" library fails to gEBTN("*")
        // https://github.com/ajaxorg/node-o3-xml/issues/21
        descendants = doc.selectNodes('//*[name(.)!="svg"]');
        var arr = [];
        for (i = 0, len = descendants.length; i < len; i++) {
          arr[i] = descendants[i];
        }
        descendants = arr;
      }
  
      var elements = descendants.filter(function(el) {
        applyViewboxTransform(el);
        return fabric.svgValidTagNamesRegEx.test(el.nodeName.replace('svg:', '')) &&
              !hasAncestorWithNodeName(el, fabric.svgInvalidAncestorsRegEx); // http://www.w3.org/TR/SVG/struct.html#DefsElement
      });
  
      if (!elements || (elements && !elements.length)) {
        callback && callback([], {});
        return;
      }
      var clipPaths = { };
      descendants.filter(function(el) {
        return el.nodeName.replace('svg:', '') === 'clipPath';
      }).forEach(function(el) {
        var id = el.getAttribute('id');
        clipPaths[id] = fabric.util.toArray(el.getElementsByTagName('*')).filter(function(el) {
          return fabric.svgValidTagNamesRegEx.test(el.nodeName.replace('svg:', ''));
        });
      });
      fabric.gradientDefs[svgUid] = fabric.getGradientDefs(doc);
      fabric.cssRules[svgUid] = fabric.getCSSRules(doc);
      fabric.clipPaths[svgUid] = clipPaths;
      // Precedence of rules:   style > class > attribute
      fabric.parseElements(elements, function(instances, elements) {
        if (callback) {
          callback(instances, options, elements, descendants);
          delete fabric.gradientDefs[svgUid];
          delete fabric.cssRules[svgUid];
          delete fabric.clipPaths[svgUid];
        }
      }, clone(options), reviver, parsingOptions);
    };
  
    function recursivelyParseGradientsXlink(doc, gradient) {
      var gradientsAttrs = ['gradientTransform', 'x1', 'x2', 'y1', 'y2', 'gradientUnits', 'cx', 'cy', 'r', 'fx', 'fy'],
          xlinkAttr = 'xlink:href',
          xLink = gradient.getAttribute(xlinkAttr).substr(1),
          referencedGradient = elementById(doc, xLink);
      if (referencedGradient && referencedGradient.getAttribute(xlinkAttr)) {
        recursivelyParseGradientsXlink(doc, referencedGradient);
      }
      gradientsAttrs.forEach(function(attr) {
        if (referencedGradient && !gradient.hasAttribute(attr) && referencedGradient.hasAttribute(attr)) {
          gradient.setAttribute(attr, referencedGradient.getAttribute(attr));
        }
      });
      if (!gradient.children.length) {
        var referenceClone = referencedGradient.cloneNode(true);
        while (referenceClone.firstChild) {
          gradient.appendChild(referenceClone.firstChild);
        }
      }
      gradient.removeAttribute(xlinkAttr);
    }
  
    var reFontDeclaration = new RegExp(
      '(normal|italic)?\\s*(normal|small-caps)?\\s*' +
      '(normal|bold|bolder|lighter|100|200|300|400|500|600|700|800|900)?\\s*(' +
        fabric.reNum +
      '(?:px|cm|mm|em|pt|pc|in)*)(?:\\/(normal|' + fabric.reNum + '))?\\s+(.*)');
  
    extend(fabric, {
      /**
       * Parses a short font declaration, building adding its properties to a style object
       * @static
       * @function
       * @memberOf fabric
       * @param {String} value font declaration
       * @param {Object} oStyle definition
       */
      parseFontDeclaration: function(value, oStyle) {
        var match = value.match(reFontDeclaration);
  
        if (!match) {
          return;
        }
        var fontStyle = match[1],
            // font variant is not used
            // fontVariant = match[2],
            fontWeight = match[3],
            fontSize = match[4],
            lineHeight = match[5],
            fontFamily = match[6];
  
        if (fontStyle) {
          oStyle.fontStyle = fontStyle;
        }
        if (fontWeight) {
          oStyle.fontWeight = isNaN(parseFloat(fontWeight)) ? fontWeight : parseFloat(fontWeight);
        }
        if (fontSize) {
          oStyle.fontSize = parseUnit(fontSize);
        }
        if (fontFamily) {
          oStyle.fontFamily = fontFamily;
        }
        if (lineHeight) {
          oStyle.lineHeight = lineHeight === 'normal' ? 1 : lineHeight;
        }
      },
  
      /**
       * Parses an SVG document, returning all of the gradient declarations found in it
       * @static
       * @function
       * @memberOf fabric
       * @param {SVGDocument} doc SVG document to parse
       * @return {Object} Gradient definitions; key corresponds to element id, value -- to gradient definition element
       */
      getGradientDefs: function(doc) {
        var tagArray = [
              'linearGradient',
              'radialGradient',
              'svg:linearGradient',
              'svg:radialGradient'],
            elList = _getMultipleNodes(doc, tagArray),
            el, j = 0, gradientDefs = { };
        j = elList.length;
        while (j--) {
          el = elList[j];
          if (el.getAttribute('xlink:href')) {
            recursivelyParseGradientsXlink(doc, el);
          }
          gradientDefs[el.getAttribute('id')] = el;
        }
        return gradientDefs;
      },
  
      /**
       * Returns an object of attributes' name/value, given element and an array of attribute names;
       * Parses parent "g" nodes recursively upwards.
       * @static
       * @memberOf fabric
       * @param {DOMElement} element Element to parse
       * @param {Array} attributes Array of attributes to parse
       * @return {Object} object containing parsed attributes' names/values
       */
      parseAttributes: function(element, attributes, svgUid) {
  
        if (!element) {
          return;
        }
  
        var value,
            parentAttributes = { },
            fontSize, parentFontSize;
  
        if (typeof svgUid === 'undefined') {
          svgUid = element.getAttribute('svgUid');
        }
        // if there's a parent container (`g` or `a` or `symbol` node), parse its attributes recursively upwards
        if (element.parentNode && fabric.svgValidParentsRegEx.test(element.parentNode.nodeName)) {
          parentAttributes = fabric.parseAttributes(element.parentNode, attributes, svgUid);
        }
  
        var ownAttributes = attributes.reduce(function(memo, attr) {
          value = element.getAttribute(attr);
          if (value) { // eslint-disable-line
            memo[attr] = value;
          }
          return memo;
        }, { });
        // add values parsed from style, which take precedence over attributes
        // (see: http://www.w3.org/TR/SVG/styling.html#UsingPresentationAttributes)
        ownAttributes = extend(ownAttributes,
          extend(getGlobalStylesForElement(element, svgUid), fabric.parseStyleAttribute(element)));
  
        fontSize = parentFontSize = parentAttributes.fontSize || fabric.Text.DEFAULT_SVG_FONT_SIZE;
        if (ownAttributes['font-size']) {
          // looks like the minimum should be 9px when dealing with ems. this is what looks like in browsers.
          ownAttributes['font-size'] = fontSize = parseUnit(ownAttributes['font-size'], parentFontSize);
        }
  
        var normalizedAttr, normalizedValue, normalizedStyle = {};
        for (var attr in ownAttributes) {
          normalizedAttr = normalizeAttr(attr);
          normalizedValue = normalizeValue(normalizedAttr, ownAttributes[attr], parentAttributes, fontSize);
          normalizedStyle[normalizedAttr] = normalizedValue;
        }
        if (normalizedStyle && normalizedStyle.font) {
          fabric.parseFontDeclaration(normalizedStyle.font, normalizedStyle);
        }
        var mergedAttrs = extend(parentAttributes, normalizedStyle);
        return fabric.svgValidParentsRegEx.test(element.nodeName) ? mergedAttrs : _setStrokeFillOpacity(mergedAttrs);
      },
  
      /**
       * Transforms an array of svg elements to corresponding fabric.* instances
       * @static
       * @memberOf fabric
       * @param {Array} elements Array of elements to parse
       * @param {Function} callback Being passed an array of fabric instances (transformed from SVG elements)
       * @param {Object} [options] Options object
       * @param {Function} [reviver] Method for further parsing of SVG elements, called after each fabric object created.
       */
      parseElements: function(elements, callback, options, reviver, parsingOptions) {
        new fabric.ElementsParser(elements, callback, options, reviver, parsingOptions).parse();
      },
  
      /**
       * Parses "style" attribute, retuning an object with values
       * @static
       * @memberOf fabric
       * @param {SVGElement} element Element to parse
       * @return {Object} Objects with values parsed from style attribute of an element
       */
      parseStyleAttribute: function(element) {
        var oStyle = { },
            style = element.getAttribute('style');
  
        if (!style) {
          return oStyle;
        }
  
        if (typeof style === 'string') {
          parseStyleString(style, oStyle);
        }
        else {
          parseStyleObject(style, oStyle);
        }
  
        return oStyle;
      },
  
      /**
       * Parses "points" attribute, returning an array of values
       * @static
       * @memberOf fabric
       * @param {String} points points attribute string
       * @return {Array} array of points
       */
      parsePointsAttribute: function(points) {
  
        // points attribute is required and must not be empty
        if (!points) {
          return null;
        }
  
        // replace commas with whitespace and remove bookending whitespace
        points = points.replace(/,/g, ' ').trim();
  
        points = points.split(/\s+/);
        var parsedPoints = [], i, len;
  
        for (i = 0, len = points.length; i < len; i += 2) {
          parsedPoints.push({
            x: parseFloat(points[i]),
            y: parseFloat(points[i + 1])
          });
        }
  
        // odd number of points is an error
        // if (parsedPoints.length % 2 !== 0) {
        //   return null;
        // }
  
        return parsedPoints;
      },
  
      /**
       * Returns CSS rules for a given SVG document
       * @static
       * @function
       * @memberOf fabric
       * @param {SVGDocument} doc SVG document to parse
       * @return {Object} CSS rules of this document
       */
      getCSSRules: function(doc) {
        var styles = doc.getElementsByTagName('style'), i, len,
            allRules = { }, rules;
  
        // very crude parsing of style contents
        for (i = 0, len = styles.length; i < len; i++) {
          // IE9 doesn't support textContent, but provides text instead.
          var styleContents = styles[i].textContent || styles[i].text;
  
          // remove comments
          styleContents = styleContents.replace(/\/\*[\s\S]*?\*\//g, '');
          if (styleContents.trim() === '') {
            continue;
          }
          rules = styleContents.match(/[^{]*\{[\s\S]*?\}/g);
          rules = rules.map(function(rule) { return rule.trim(); });
          // eslint-disable-next-line no-loop-func
          rules.forEach(function(rule) {
  
            var match = rule.match(/([\s\S]*?)\s*\{([^}]*)\}/),
                ruleObj = { }, declaration = match[2].trim(),
                propertyValuePairs = declaration.replace(/;$/, '').split(/\s*;\s*/);
  
            for (i = 0, len = propertyValuePairs.length; i < len; i++) {
              var pair = propertyValuePairs[i].split(/\s*:\s*/),
                  property = pair[0],
                  value = pair[1];
              ruleObj[property] = value;
            }
            rule = match[1];
            rule.split(',').forEach(function(_rule) {
              _rule = _rule.replace(/^svg/i, '').trim();
              if (_rule === '') {
                return;
              }
              if (allRules[_rule]) {
                fabric.util.object.extend(allRules[_rule], ruleObj);
              }
              else {
                allRules[_rule] = fabric.util.object.clone(ruleObj);
              }
            });
          });
        }
        return allRules;
      },
  
      /**
       * Takes url corresponding to an SVG document, and parses it into a set of fabric objects.
       * Note that SVG is fetched via XMLHttpRequest, so it needs to conform to SOP (Same Origin Policy)
       * @memberOf fabric
       * @param {String} url
       * @param {Function} callback
       * @param {Function} [reviver] Method for further parsing of SVG elements, called after each fabric object created.
       * @param {Object} [options] Object containing options for parsing
       * @param {String} [options.crossOrigin] crossOrigin crossOrigin setting to use for external resources
       */
      loadSVGFromURL: function(url, callback, reviver, options) {
  
        url = url.replace(/^\n\s*/, '').trim();
        new fabric.util.request(url, {
          method: 'get',
          onComplete: onComplete
        });
  
        function onComplete(r) {
  
          var xml = r.responseXML;
          if (xml && !xml.documentElement && fabric.window.ActiveXObject && r.responseText) {
            xml = new ActiveXObject('Microsoft.XMLDOM');
            xml.async = 'false';
            //IE chokes on DOCTYPE
            xml.loadXML(r.responseText.replace(/<!DOCTYPE[\s\S]*?(\[[\s\S]*\])*?>/i, ''));
          }
          if (!xml || !xml.documentElement) {
            callback && callback(null);
            return false;
          }
  
          fabric.parseSVGDocument(xml.documentElement, function (results, _options, elements, allElements) {
            callback && callback(results, _options, elements, allElements);
          }, reviver, options);
        }
      },
  
      /**
       * Takes string corresponding to an SVG document, and parses it into a set of fabric objects
       * @memberOf fabric
       * @param {String} string
       * @param {Function} callback
       * @param {Function} [reviver] Method for further parsing of SVG elements, called after each fabric object created.
       * @param {Object} [options] Object containing options for parsing
       * @param {String} [options.crossOrigin] crossOrigin crossOrigin setting to use for external resources
       */
      loadSVGFromString: function(string, callback, reviver, options) {
        string = string.trim();
        var doc;
        if (typeof fabric.window.DOMParser !== 'undefined') {
          var parser = new fabric.window.DOMParser();
          if (parser && parser.parseFromString) {
            doc = parser.parseFromString(string, 'text/xml');
          }
        }
        else if (fabric.window.ActiveXObject) {
          doc = new ActiveXObject('Microsoft.XMLDOM');
          doc.async = 'false';
          // IE chokes on DOCTYPE
          doc.loadXML(string.replace(/<!DOCTYPE[\s\S]*?(\[[\s\S]*\])*?>/i, ''));
        }
  
        fabric.parseSVGDocument(doc.documentElement, function (results, _options, elements, allElements) {
          callback(results, _options, elements, allElements);
        }, reviver, options);
      }
    });
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  fabric.ElementsParser = function(elements, callback, options, reviver, parsingOptions) {
    this.elements = elements;
    this.callback = callback;
    this.options = options;
    this.reviver = reviver;
    this.svgUid = (options && options.svgUid) || 0;
    this.parsingOptions = parsingOptions;
    this.regexUrl = /^url\(['"]?#([^'"]+)['"]?\)/g;
  };
  
  (function(proto) {
    proto.parse = function() {
      this.instances = new Array(this.elements.length);
      this.numElements = this.elements.length;
      this.createObjects();
    };
  
    proto.createObjects = function() {
      var _this = this;
      this.elements.forEach(function(element, i) {
        element.setAttribute('svgUid', _this.svgUid);
        _this.createObject(element, i);
      });
    };
  
    proto.findTag = function(el) {
      return fabric[fabric.util.string.capitalize(el.tagName.replace('svg:', ''))];
    };
  
    proto.createObject = function(el, index) {
      var klass = this.findTag(el);
      if (klass && klass.fromElement) {
        try {
          klass.fromElement(el, this.createCallback(index, el), this.options);
        }
        catch (err) {
          fabric.log(err);
        }
      }
      else {
        this.checkIfDone();
      }
    };
  
    proto.createCallback = function(index, el) {
      var _this = this;
      return function(obj) {
        var _options;
        _this.resolveGradient(obj, el, 'fill');
        _this.resolveGradient(obj, el, 'stroke');
        if (obj instanceof fabric.Image && obj._originalElement) {
          _options = obj.parsePreserveAspectRatioAttribute(el);
        }
        obj._removeTransformMatrix(_options);
        _this.resolveClipPath(obj);
        _this.reviver && _this.reviver(el, obj);
        _this.instances[index] = obj;
        _this.checkIfDone();
      };
    };
  
    proto.extractPropertyDefinition = function(obj, property, storage) {
      var value = obj[property];
      if (!(/^url\(/).test(value)) {
        return;
      }
      var id = this.regexUrl.exec(value)[1];
      this.regexUrl.lastIndex = 0;
      return fabric[storage][this.svgUid][id];
    };
  
    proto.resolveGradient = function(obj, el, property) {
      var gradientDef = this.extractPropertyDefinition(obj, property, 'gradientDefs');
      if (gradientDef) {
        var opacityAttr = el.getAttribute(property + '-opacity');
        var gradient = fabric.Gradient.fromElement(gradientDef, obj, opacityAttr, this.options);
        obj.set(property, gradient);
      }
    };
  
    proto.createClipPathCallback = function(obj, container) {
      return function(_newObj) {
        _newObj._removeTransformMatrix();
        _newObj.fillRule = _newObj.clipRule;
        container.push(_newObj);
      };
    };
  
    proto.resolveClipPath = function(obj) {
      var clipPath = this.extractPropertyDefinition(obj, 'clipPath', 'clipPaths'),
          element, klass, objTransformInv, container, gTransform, options;
      if (clipPath) {
        container = [];
        objTransformInv = fabric.util.invertTransform(obj.calcTransformMatrix());
        for (var i = 0; i < clipPath.length; i++) {
          element = clipPath[i];
          klass = this.findTag(element);
          klass.fromElement(
            element,
            this.createClipPathCallback(obj, container),
            this.options
          );
        }
        if (container.length === 1) {
          clipPath = container[0];
        }
        else {
          clipPath = new fabric.Group(container);
        }
        gTransform = fabric.util.multiplyTransformMatrices(
          objTransformInv,
          clipPath.calcTransformMatrix()
        );
        if (clipPath.clipPath) {
          this.resolveClipPath(clipPath);
        }
        var options = fabric.util.qrDecompose(gTransform);
        clipPath.flipX = false;
        clipPath.flipY = false;
        clipPath.set('scaleX', options.scaleX);
        clipPath.set('scaleY', options.scaleY);
        clipPath.angle = options.angle;
        clipPath.skewX = options.skewX;
        clipPath.skewY = 0;
        clipPath.setPositionByOrigin({ x: options.translateX, y: options.translateY }, 'center', 'center');
        obj.clipPath = clipPath;
      }
    };
  
    proto.checkIfDone = function() {
      if (--this.numElements === 0) {
        this.instances = this.instances.filter(function(el) {
          // eslint-disable-next-line no-eq-null, eqeqeq
          return el != null;
        });
        this.callback(this.instances, this.elements);
      }
    };
  })(fabric.ElementsParser.prototype);
  
  
  (function(global) {
  
    'use strict';
  
    /* Adaptation of work of Kevin Lindsey (kevin@kevlindev.com) */
  
    var fabric = global.fabric || (global.fabric = { });
  
    if (fabric.Point) {
      fabric.warn('fabric.Point is already defined');
      return;
    }
  
    fabric.Point = Point;
  
    /**
     * Point class
     * @class fabric.Point
     * @memberOf fabric
     * @constructor
     * @param {Number} x
     * @param {Number} y
     * @return {fabric.Point} thisArg
     */
    function Point(x, y) {
      this.x = x;
      this.y = y;
    }
  
    Point.prototype = /** @lends fabric.Point.prototype */ {
  
      type: 'point',
  
      constructor: Point,
  
      /**
       * Adds another point to this one and returns another one
       * @param {fabric.Point} that
       * @return {fabric.Point} new Point instance with added values
       */
      add: function (that) {
        return new Point(this.x + that.x, this.y + that.y);
      },
  
      /**
       * Adds another point to this one
       * @param {fabric.Point} that
       * @return {fabric.Point} thisArg
       * @chainable
       */
      addEquals: function (that) {
        this.x += that.x;
        this.y += that.y;
        return this;
      },
  
      /**
       * Adds value to this point and returns a new one
       * @param {Number} scalar
       * @return {fabric.Point} new Point with added value
       */
      scalarAdd: function (scalar) {
        return new Point(this.x + scalar, this.y + scalar);
      },
  
      /**
       * Adds value to this point
       * @param {Number} scalar
       * @return {fabric.Point} thisArg
       * @chainable
       */
      scalarAddEquals: function (scalar) {
        this.x += scalar;
        this.y += scalar;
        return this;
      },
  
      /**
       * Subtracts another point from this point and returns a new one
       * @param {fabric.Point} that
       * @return {fabric.Point} new Point object with subtracted values
       */
      subtract: function (that) {
        return new Point(this.x - that.x, this.y - that.y);
      },
  
      /**
       * Subtracts another point from this point
       * @param {fabric.Point} that
       * @return {fabric.Point} thisArg
       * @chainable
       */
      subtractEquals: function (that) {
        this.x -= that.x;
        this.y -= that.y;
        return this;
      },
  
      /**
       * Subtracts value from this point and returns a new one
       * @param {Number} scalar
       * @return {fabric.Point}
       */
      scalarSubtract: function (scalar) {
        return new Point(this.x - scalar, this.y - scalar);
      },
  
      /**
       * Subtracts value from this point
       * @param {Number} scalar
       * @return {fabric.Point} thisArg
       * @chainable
       */
      scalarSubtractEquals: function (scalar) {
        this.x -= scalar;
        this.y -= scalar;
        return this;
      },
  
      /**
       * Multiplies this point by a value and returns a new one
       * TODO: rename in scalarMultiply in 2.0
       * @param {Number} scalar
       * @return {fabric.Point}
       */
      multiply: function (scalar) {
        return new Point(this.x * scalar, this.y * scalar);
      },
  
      /**
       * Multiplies this point by a value
       * TODO: rename in scalarMultiplyEquals in 2.0
       * @param {Number} scalar
       * @return {fabric.Point} thisArg
       * @chainable
       */
      multiplyEquals: function (scalar) {
        this.x *= scalar;
        this.y *= scalar;
        return this;
      },
  
      /**
       * Divides this point by a value and returns a new one
       * TODO: rename in scalarDivide in 2.0
       * @param {Number} scalar
       * @return {fabric.Point}
       */
      divide: function (scalar) {
        return new Point(this.x / scalar, this.y / scalar);
      },
  
      /**
       * Divides this point by a value
       * TODO: rename in scalarDivideEquals in 2.0
       * @param {Number} scalar
       * @return {fabric.Point} thisArg
       * @chainable
       */
      divideEquals: function (scalar) {
        this.x /= scalar;
        this.y /= scalar;
        return this;
      },
  
      /**
       * Returns true if this point is equal to another one
       * @param {fabric.Point} that
       * @return {Boolean}
       */
      eq: function (that) {
        return (this.x === that.x && this.y === that.y);
      },
  
      /**
       * Returns true if this point is less than another one
       * @param {fabric.Point} that
       * @return {Boolean}
       */
      lt: function (that) {
        return (this.x < that.x && this.y < that.y);
      },
  
      /**
       * Returns true if this point is less than or equal to another one
       * @param {fabric.Point} that
       * @return {Boolean}
       */
      lte: function (that) {
        return (this.x <= that.x && this.y <= that.y);
      },
  
      /**
  
       * Returns true if this point is greater another one
       * @param {fabric.Point} that
       * @return {Boolean}
       */
      gt: function (that) {
        return (this.x > that.x && this.y > that.y);
      },
  
      /**
       * Returns true if this point is greater than or equal to another one
       * @param {fabric.Point} that
       * @return {Boolean}
       */
      gte: function (that) {
        return (this.x >= that.x && this.y >= that.y);
      },
  
      /**
       * Returns new point which is the result of linear interpolation with this one and another one
       * @param {fabric.Point} that
       * @param {Number} t , position of interpolation, between 0 and 1 default 0.5
       * @return {fabric.Point}
       */
      lerp: function (that, t) {
        if (typeof t === 'undefined') {
          t = 0.5;
        }
        t = Math.max(Math.min(1, t), 0);
        return new Point(this.x + (that.x - this.x) * t, this.y + (that.y - this.y) * t);
      },
  
      /**
       * Returns distance from this point and another one
       * @param {fabric.Point} that
       * @return {Number}
       */
      distanceFrom: function (that) {
        var dx = this.x - that.x,
            dy = this.y - that.y;
        return Math.sqrt(dx * dx + dy * dy);
      },
  
      /**
       * Returns the point between this point and another one
       * @param {fabric.Point} that
       * @return {fabric.Point}
       */
      midPointFrom: function (that) {
        return this.lerp(that);
      },
  
      /**
       * Returns a new point which is the min of this and another one
       * @param {fabric.Point} that
       * @return {fabric.Point}
       */
      min: function (that) {
        return new Point(Math.min(this.x, that.x), Math.min(this.y, that.y));
      },
  
      /**
       * Returns a new point which is the max of this and another one
       * @param {fabric.Point} that
       * @return {fabric.Point}
       */
      max: function (that) {
        return new Point(Math.max(this.x, that.x), Math.max(this.y, that.y));
      },
  
      /**
       * Returns string representation of this point
       * @return {String}
       */
      toString: function () {
        return this.x + ',' + this.y;
      },
  
      /**
       * Sets x/y of this point
       * @param {Number} x
       * @param {Number} y
       * @chainable
       */
      setXY: function (x, y) {
        this.x = x;
        this.y = y;
        return this;
      },
  
      /**
       * Sets x of this point
       * @param {Number} x
       * @chainable
       */
      setX: function (x) {
        this.x = x;
        return this;
      },
  
      /**
       * Sets y of this point
       * @param {Number} y
       * @chainable
       */
      setY: function (y) {
        this.y = y;
        return this;
      },
  
      /**
       * Sets x/y of this point from another point
       * @param {fabric.Point} that
       * @chainable
       */
      setFromPoint: function (that) {
        this.x = that.x;
        this.y = that.y;
        return this;
      },
  
      /**
       * Swaps x/y of this point and another point
       * @param {fabric.Point} that
       */
      swap: function (that) {
        var x = this.x,
            y = this.y;
        this.x = that.x;
        this.y = that.y;
        that.x = x;
        that.y = y;
      },
  
      /**
       * return a cloned instance of the point
       * @return {fabric.Point}
       */
      clone: function () {
        return new Point(this.x, this.y);
      }
    };
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    /* Adaptation of work of Kevin Lindsey (kevin@kevlindev.com) */
    var fabric = global.fabric || (global.fabric = { });
  
    if (fabric.Intersection) {
      fabric.warn('fabric.Intersection is already defined');
      return;
    }
  
    /**
     * Intersection class
     * @class fabric.Intersection
     * @memberOf fabric
     * @constructor
     */
    function Intersection(status) {
      this.status = status;
      this.points = [];
    }
  
    fabric.Intersection = Intersection;
  
    fabric.Intersection.prototype = /** @lends fabric.Intersection.prototype */ {
  
      constructor: Intersection,
  
      /**
       * Appends a point to intersection
       * @param {fabric.Point} point
       * @return {fabric.Intersection} thisArg
       * @chainable
       */
      appendPoint: function (point) {
        this.points.push(point);
        return this;
      },
  
      /**
       * Appends points to intersection
       * @param {Array} points
       * @return {fabric.Intersection} thisArg
       * @chainable
       */
      appendPoints: function (points) {
        this.points = this.points.concat(points);
        return this;
      }
    };
  
    /**
     * Checks if one line intersects another
     * TODO: rename in intersectSegmentSegment
     * @static
     * @param {fabric.Point} a1
     * @param {fabric.Point} a2
     * @param {fabric.Point} b1
     * @param {fabric.Point} b2
     * @return {fabric.Intersection}
     */
    fabric.Intersection.intersectLineLine = function (a1, a2, b1, b2) {
      var result,
          uaT = (b2.x - b1.x) * (a1.y - b1.y) - (b2.y - b1.y) * (a1.x - b1.x),
          ubT = (a2.x - a1.x) * (a1.y - b1.y) - (a2.y - a1.y) * (a1.x - b1.x),
          uB = (b2.y - b1.y) * (a2.x - a1.x) - (b2.x - b1.x) * (a2.y - a1.y);
      if (uB !== 0) {
        var ua = uaT / uB,
            ub = ubT / uB;
        if (0 <= ua && ua <= 1 && 0 <= ub && ub <= 1) {
          result = new Intersection('Intersection');
          result.appendPoint(new fabric.Point(a1.x + ua * (a2.x - a1.x), a1.y + ua * (a2.y - a1.y)));
        }
        else {
          result = new Intersection();
        }
      }
      else {
        if (uaT === 0 || ubT === 0) {
          result = new Intersection('Coincident');
        }
        else {
          result = new Intersection('Parallel');
        }
      }
      return result;
    };
  
    /**
     * Checks if line intersects polygon
     * TODO: rename in intersectSegmentPolygon
     * fix detection of coincident
     * @static
     * @param {fabric.Point} a1
     * @param {fabric.Point} a2
     * @param {Array} points
     * @return {fabric.Intersection}
     */
    fabric.Intersection.intersectLinePolygon = function(a1, a2, points) {
      var result = new Intersection(),
          length = points.length,
          b1, b2, inter, i;
  
      for (i = 0; i < length; i++) {
        b1 = points[i];
        b2 = points[(i + 1) % length];
        inter = Intersection.intersectLineLine(a1, a2, b1, b2);
  
        result.appendPoints(inter.points);
      }
      if (result.points.length > 0) {
        result.status = 'Intersection';
      }
      return result;
    };
  
    /**
     * Checks if polygon intersects another polygon
     * @static
     * @param {Array} points1
     * @param {Array} points2
     * @return {fabric.Intersection}
     */
    fabric.Intersection.intersectPolygonPolygon = function (points1, points2) {
      var result = new Intersection(),
          length = points1.length, i;
  
      for (i = 0; i < length; i++) {
        var a1 = points1[i],
            a2 = points1[(i + 1) % length],
            inter = Intersection.intersectLinePolygon(a1, a2, points2);
  
        result.appendPoints(inter.points);
      }
      if (result.points.length > 0) {
        result.status = 'Intersection';
      }
      return result;
    };
  
    /**
     * Checks if polygon intersects rectangle
     * @static
     * @param {Array} points
     * @param {fabric.Point} r1
     * @param {fabric.Point} r2
     * @return {fabric.Intersection}
     */
    fabric.Intersection.intersectPolygonRectangle = function (points, r1, r2) {
      var min = r1.min(r2),
          max = r1.max(r2),
          topRight = new fabric.Point(max.x, min.y),
          bottomLeft = new fabric.Point(min.x, max.y),
          inter1 = Intersection.intersectLinePolygon(min, topRight, points),
          inter2 = Intersection.intersectLinePolygon(topRight, max, points),
          inter3 = Intersection.intersectLinePolygon(max, bottomLeft, points),
          inter4 = Intersection.intersectLinePolygon(bottomLeft, min, points),
          result = new Intersection();
  
      result.appendPoints(inter1.points);
      result.appendPoints(inter2.points);
      result.appendPoints(inter3.points);
      result.appendPoints(inter4.points);
  
      if (result.points.length > 0) {
        result.status = 'Intersection';
      }
      return result;
    };
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric = global.fabric || (global.fabric = { });
  
    if (fabric.Color) {
      fabric.warn('fabric.Color is already defined.');
      return;
    }
  
    /**
     * Color class
     * The purpose of {@link fabric.Color} is to abstract and encapsulate common color operations;
     * {@link fabric.Color} is a constructor and creates instances of {@link fabric.Color} objects.
     *
     * @class fabric.Color
     * @param {String} color optional in hex or rgb(a) or hsl format or from known color list
     * @return {fabric.Color} thisArg
     * @tutorial {@link http://fabricjs.com/fabric-intro-part-2/#colors}
     */
    function Color(color) {
      if (!color) {
        this.setSource([0, 0, 0, 1]);
      }
      else {
        this._tryParsingColor(color);
      }
    }
  
    fabric.Color = Color;
  
    fabric.Color.prototype = /** @lends fabric.Color.prototype */ {
  
      /**
       * @private
       * @param {String|Array} color Color value to parse
       */
      _tryParsingColor: function(color) {
        var source;
  
        if (color in Color.colorNameMap) {
          color = Color.colorNameMap[color];
        }
  
        if (color === 'transparent') {
          source = [255, 255, 255, 0];
        }
  
        if (!source) {
          source = Color.sourceFromHex(color);
        }
        if (!source) {
          source = Color.sourceFromRgb(color);
        }
        if (!source) {
          source = Color.sourceFromHsl(color);
        }
        if (!source) {
          //if color is not recognize let's make black as canvas does
          source = [0, 0, 0, 1];
        }
        if (source) {
          this.setSource(source);
        }
      },
  
      /**
       * Adapted from <a href="https://rawgithub.com/mjijackson/mjijackson.github.com/master/2008/02/rgb-to-hsl-and-rgb-to-hsv-color-model-conversion-algorithms-in-javascript.html">https://github.com/mjijackson</a>
       * @private
       * @param {Number} r Red color value
       * @param {Number} g Green color value
       * @param {Number} b Blue color value
       * @return {Array} Hsl color
       */
      _rgbToHsl: function(r, g, b) {
        r /= 255; g /= 255; b /= 255;
  
        var h, s, l,
            max = fabric.util.array.max([r, g, b]),
            min = fabric.util.array.min([r, g, b]);
  
        l = (max + min) / 2;
  
        if (max === min) {
          h = s = 0; // achromatic
        }
        else {
          var d = max - min;
          s = l > 0.5 ? d / (2 - max - min) : d / (max + min);
          switch (max) {
            case r:
              h = (g - b) / d + (g < b ? 6 : 0);
              break;
            case g:
              h = (b - r) / d + 2;
              break;
            case b:
              h = (r - g) / d + 4;
              break;
          }
          h /= 6;
        }
  
        return [
          Math.round(h * 360),
          Math.round(s * 100),
          Math.round(l * 100)
        ];
      },
  
      /**
       * Returns source of this color (where source is an array representation; ex: [200, 200, 100, 1])
       * @return {Array}
       */
      getSource: function() {
        return this._source;
      },
  
      /**
       * Sets source of this color (where source is an array representation; ex: [200, 200, 100, 1])
       * @param {Array} source
       */
      setSource: function(source) {
        this._source = source;
      },
  
      /**
       * Returns color representation in RGB format
       * @return {String} ex: rgb(0-255,0-255,0-255)
       */
      toRgb: function() {
        var source = this.getSource();
        return 'rgb(' + source[0] + ',' + source[1] + ',' + source[2] + ')';
      },
  
      /**
       * Returns color representation in RGBA format
       * @return {String} ex: rgba(0-255,0-255,0-255,0-1)
       */
      toRgba: function() {
        var source = this.getSource();
        return 'rgba(' + source[0] + ',' + source[1] + ',' + source[2] + ',' + source[3] + ')';
      },
  
      /**
       * Returns color representation in HSL format
       * @return {String} ex: hsl(0-360,0%-100%,0%-100%)
       */
      toHsl: function() {
        var source = this.getSource(),
            hsl = this._rgbToHsl(source[0], source[1], source[2]);
  
        return 'hsl(' + hsl[0] + ',' + hsl[1] + '%,' + hsl[2] + '%)';
      },
  
      /**
       * Returns color representation in HSLA format
       * @return {String} ex: hsla(0-360,0%-100%,0%-100%,0-1)
       */
      toHsla: function() {
        var source = this.getSource(),
            hsl = this._rgbToHsl(source[0], source[1], source[2]);
  
        return 'hsla(' + hsl[0] + ',' + hsl[1] + '%,' + hsl[2] + '%,' + source[3] + ')';
      },
  
      /**
       * Returns color representation in HEX format
       * @return {String} ex: FF5555
       */
      toHex: function() {
        var source = this.getSource(), r, g, b;
  
        r = source[0].toString(16);
        r = (r.length === 1) ? ('0' + r) : r;
  
        g = source[1].toString(16);
        g = (g.length === 1) ? ('0' + g) : g;
  
        b = source[2].toString(16);
        b = (b.length === 1) ? ('0' + b) : b;
  
        return r.toUpperCase() + g.toUpperCase() + b.toUpperCase();
      },
  
      /**
       * Returns color representation in HEXA format
       * @return {String} ex: FF5555CC
       */
      toHexa: function() {
        var source = this.getSource(), a;
  
        a = Math.round(source[3] * 255);
        a = a.toString(16);
        a = (a.length === 1) ? ('0' + a) : a;
  
        return this.toHex() + a.toUpperCase();
      },
  
      /**
       * Gets value of alpha channel for this color
       * @return {Number} 0-1
       */
      getAlpha: function() {
        return this.getSource()[3];
      },
  
      /**
       * Sets value of alpha channel for this color
       * @param {Number} alpha Alpha value 0-1
       * @return {fabric.Color} thisArg
       */
      setAlpha: function(alpha) {
        var source = this.getSource();
        source[3] = alpha;
        this.setSource(source);
        return this;
      },
  
      /**
       * Transforms color to its grayscale representation
       * @return {fabric.Color} thisArg
       */
      toGrayscale: function() {
        var source = this.getSource(),
            average = parseInt((source[0] * 0.3 + source[1] * 0.59 + source[2] * 0.11).toFixed(0), 10),
            currentAlpha = source[3];
        this.setSource([average, average, average, currentAlpha]);
        return this;
      },
  
      /**
       * Transforms color to its black and white representation
       * @param {Number} threshold
       * @return {fabric.Color} thisArg
       */
      toBlackWhite: function(threshold) {
        var source = this.getSource(),
            average = (source[0] * 0.3 + source[1] * 0.59 + source[2] * 0.11).toFixed(0),
            currentAlpha = source[3];
  
        threshold = threshold || 127;
  
        average = (Number(average) < Number(threshold)) ? 0 : 255;
        this.setSource([average, average, average, currentAlpha]);
        return this;
      },
  
      /**
       * Overlays color with another color
       * @param {String|fabric.Color} otherColor
       * @return {fabric.Color} thisArg
       */
      overlayWith: function(otherColor) {
        if (!(otherColor instanceof Color)) {
          otherColor = new Color(otherColor);
        }
  
        var result = [],
            alpha = this.getAlpha(),
            otherAlpha = 0.5,
            source = this.getSource(),
            otherSource = otherColor.getSource(), i;
  
        for (i = 0; i < 3; i++) {
          result.push(Math.round((source[i] * (1 - otherAlpha)) + (otherSource[i] * otherAlpha)));
        }
  
        result[3] = alpha;
        this.setSource(result);
        return this;
      }
    };
  
    /**
     * Regex matching color in RGB or RGBA formats (ex: rgb(0, 0, 0), rgba(255, 100, 10, 0.5), rgba( 255 , 100 , 10 , 0.5 ), rgb(1,1,1), rgba(100%, 60%, 10%, 0.5))
     * @static
     * @field
     * @memberOf fabric.Color
     */
    // eslint-disable-next-line max-len
    fabric.Color.reRGBa = /^rgba?\(\s*(\d{1,3}(?:\.\d+)?\%?)\s*,\s*(\d{1,3}(?:\.\d+)?\%?)\s*,\s*(\d{1,3}(?:\.\d+)?\%?)\s*(?:\s*,\s*((?:\d*\.?\d+)?)\s*)?\)$/i;
  
    /**
     * Regex matching color in HSL or HSLA formats (ex: hsl(200, 80%, 10%), hsla(300, 50%, 80%, 0.5), hsla( 300 , 50% , 80% , 0.5 ))
     * @static
     * @field
     * @memberOf fabric.Color
     */
    fabric.Color.reHSLa = /^hsla?\(\s*(\d{1,3})\s*,\s*(\d{1,3}\%)\s*,\s*(\d{1,3}\%)\s*(?:\s*,\s*(\d+(?:\.\d+)?)\s*)?\)$/i;
  
    /**
     * Regex matching color in HEX format (ex: #FF5544CC, #FF5555, 010155, aff)
     * @static
     * @field
     * @memberOf fabric.Color
     */
    fabric.Color.reHex = /^#?([0-9a-f]{8}|[0-9a-f]{6}|[0-9a-f]{4}|[0-9a-f]{3})$/i;
  
    /**
     * Map of the 148 color names with HEX code
     * @static
     * @field
     * @memberOf fabric.Color
     * @see: https://www.w3.org/TR/css3-color/#svg-color
     */
    fabric.Color.colorNameMap = {
      aliceblue:            '#F0F8FF',
      antiquewhite:         '#FAEBD7',
      aqua:                 '#00FFFF',
      aquamarine:           '#7FFFD4',
      azure:                '#F0FFFF',
      beige:                '#F5F5DC',
      bisque:               '#FFE4C4',
      black:                '#000000',
      blanchedalmond:       '#FFEBCD',
      blue:                 '#0000FF',
      blueviolet:           '#8A2BE2',
      brown:                '#A52A2A',
      burlywood:            '#DEB887',
      cadetblue:            '#5F9EA0',
      chartreuse:           '#7FFF00',
      chocolate:            '#D2691E',
      coral:                '#FF7F50',
      cornflowerblue:       '#6495ED',
      cornsilk:             '#FFF8DC',
      crimson:              '#DC143C',
      cyan:                 '#00FFFF',
      darkblue:             '#00008B',
      darkcyan:             '#008B8B',
      darkgoldenrod:        '#B8860B',
      darkgray:             '#A9A9A9',
      darkgrey:             '#A9A9A9',
      darkgreen:            '#006400',
      darkkhaki:            '#BDB76B',
      darkmagenta:          '#8B008B',
      darkolivegreen:       '#556B2F',
      darkorange:           '#FF8C00',
      darkorchid:           '#9932CC',
      darkred:              '#8B0000',
      darksalmon:           '#E9967A',
      darkseagreen:         '#8FBC8F',
      darkslateblue:        '#483D8B',
      darkslategray:        '#2F4F4F',
      darkslategrey:        '#2F4F4F',
      darkturquoise:        '#00CED1',
      darkviolet:           '#9400D3',
      deeppink:             '#FF1493',
      deepskyblue:          '#00BFFF',
      dimgray:              '#696969',
      dimgrey:              '#696969',
      dodgerblue:           '#1E90FF',
      firebrick:            '#B22222',
      floralwhite:          '#FFFAF0',
      forestgreen:          '#228B22',
      fuchsia:              '#FF00FF',
      gainsboro:            '#DCDCDC',
      ghostwhite:           '#F8F8FF',
      gold:                 '#FFD700',
      goldenrod:            '#DAA520',
      gray:                 '#808080',
      grey:                 '#808080',
      green:                '#008000',
      greenyellow:          '#ADFF2F',
      honeydew:             '#F0FFF0',
      hotpink:              '#FF69B4',
      indianred:            '#CD5C5C',
      indigo:               '#4B0082',
      ivory:                '#FFFFF0',
      khaki:                '#F0E68C',
      lavender:             '#E6E6FA',
      lavenderblush:        '#FFF0F5',
      lawngreen:            '#7CFC00',
      lemonchiffon:         '#FFFACD',
      lightblue:            '#ADD8E6',
      lightcoral:           '#F08080',
      lightcyan:            '#E0FFFF',
      lightgoldenrodyellow: '#FAFAD2',
      lightgray:            '#D3D3D3',
      lightgrey:            '#D3D3D3',
      lightgreen:           '#90EE90',
      lightpink:            '#FFB6C1',
      lightsalmon:          '#FFA07A',
      lightseagreen:        '#20B2AA',
      lightskyblue:         '#87CEFA',
      lightslategray:       '#778899',
      lightslategrey:       '#778899',
      lightsteelblue:       '#B0C4DE',
      lightyellow:          '#FFFFE0',
      lime:                 '#00FF00',
      limegreen:            '#32CD32',
      linen:                '#FAF0E6',
      magenta:              '#FF00FF',
      maroon:               '#800000',
      mediumaquamarine:     '#66CDAA',
      mediumblue:           '#0000CD',
      mediumorchid:         '#BA55D3',
      mediumpurple:         '#9370DB',
      mediumseagreen:       '#3CB371',
      mediumslateblue:      '#7B68EE',
      mediumspringgreen:    '#00FA9A',
      mediumturquoise:      '#48D1CC',
      mediumvioletred:      '#C71585',
      midnightblue:         '#191970',
      mintcream:            '#F5FFFA',
      mistyrose:            '#FFE4E1',
      moccasin:             '#FFE4B5',
      navajowhite:          '#FFDEAD',
      navy:                 '#000080',
      oldlace:              '#FDF5E6',
      olive:                '#808000',
      olivedrab:            '#6B8E23',
      orange:               '#FFA500',
      orangered:            '#FF4500',
      orchid:               '#DA70D6',
      palegoldenrod:        '#EEE8AA',
      palegreen:            '#98FB98',
      paleturquoise:        '#AFEEEE',
      palevioletred:        '#DB7093',
      papayawhip:           '#FFEFD5',
      peachpuff:            '#FFDAB9',
      peru:                 '#CD853F',
      pink:                 '#FFC0CB',
      plum:                 '#DDA0DD',
      powderblue:           '#B0E0E6',
      purple:               '#800080',
      rebeccapurple:        '#663399',
      red:                  '#FF0000',
      rosybrown:            '#BC8F8F',
      royalblue:            '#4169E1',
      saddlebrown:          '#8B4513',
      salmon:               '#FA8072',
      sandybrown:           '#F4A460',
      seagreen:             '#2E8B57',
      seashell:             '#FFF5EE',
      sienna:               '#A0522D',
      silver:               '#C0C0C0',
      skyblue:              '#87CEEB',
      slateblue:            '#6A5ACD',
      slategray:            '#708090',
      slategrey:            '#708090',
      snow:                 '#FFFAFA',
      springgreen:          '#00FF7F',
      steelblue:            '#4682B4',
      tan:                  '#D2B48C',
      teal:                 '#008080',
      thistle:              '#D8BFD8',
      tomato:               '#FF6347',
      turquoise:            '#40E0D0',
      violet:               '#EE82EE',
      wheat:                '#F5DEB3',
      white:                '#FFFFFF',
      whitesmoke:           '#F5F5F5',
      yellow:               '#FFFF00',
      yellowgreen:          '#9ACD32'
    };
  
    /**
     * @private
     * @param {Number} p
     * @param {Number} q
     * @param {Number} t
     * @return {Number}
     */
    function hue2rgb(p, q, t) {
      if (t < 0) {
        t += 1;
      }
      if (t > 1) {
        t -= 1;
      }
      if (t < 1 / 6) {
        return p + (q - p) * 6 * t;
      }
      if (t < 1 / 2) {
        return q;
      }
      if (t < 2 / 3) {
        return p + (q - p) * (2 / 3 - t) * 6;
      }
      return p;
    }
  
    /**
     * Returns new color object, when given a color in RGB format
     * @memberOf fabric.Color
     * @param {String} color Color value ex: rgb(0-255,0-255,0-255)
     * @return {fabric.Color}
     */
    fabric.Color.fromRgb = function(color) {
      return Color.fromSource(Color.sourceFromRgb(color));
    };
  
    /**
     * Returns array representation (ex: [100, 100, 200, 1]) of a color that's in RGB or RGBA format
     * @memberOf fabric.Color
     * @param {String} color Color value ex: rgb(0-255,0-255,0-255), rgb(0%-100%,0%-100%,0%-100%)
     * @return {Array} source
     */
    fabric.Color.sourceFromRgb = function(color) {
      var match = color.match(Color.reRGBa);
      if (match) {
        var r = parseInt(match[1], 10) / (/%$/.test(match[1]) ? 100 : 1) * (/%$/.test(match[1]) ? 255 : 1),
            g = parseInt(match[2], 10) / (/%$/.test(match[2]) ? 100 : 1) * (/%$/.test(match[2]) ? 255 : 1),
            b = parseInt(match[3], 10) / (/%$/.test(match[3]) ? 100 : 1) * (/%$/.test(match[3]) ? 255 : 1);
  
        return [
          parseInt(r, 10),
          parseInt(g, 10),
          parseInt(b, 10),
          match[4] ? parseFloat(match[4]) : 1
        ];
      }
    };
  
    /**
     * Returns new color object, when given a color in RGBA format
     * @static
     * @function
     * @memberOf fabric.Color
     * @param {String} color
     * @return {fabric.Color}
     */
    fabric.Color.fromRgba = Color.fromRgb;
  
    /**
     * Returns new color object, when given a color in HSL format
     * @param {String} color Color value ex: hsl(0-260,0%-100%,0%-100%)
     * @memberOf fabric.Color
     * @return {fabric.Color}
     */
    fabric.Color.fromHsl = function(color) {
      return Color.fromSource(Color.sourceFromHsl(color));
    };
  
    /**
     * Returns array representation (ex: [100, 100, 200, 1]) of a color that's in HSL or HSLA format.
     * Adapted from <a href="https://rawgithub.com/mjijackson/mjijackson.github.com/master/2008/02/rgb-to-hsl-and-rgb-to-hsv-color-model-conversion-algorithms-in-javascript.html">https://github.com/mjijackson</a>
     * @memberOf fabric.Color
     * @param {String} color Color value ex: hsl(0-360,0%-100%,0%-100%) or hsla(0-360,0%-100%,0%-100%, 0-1)
     * @return {Array} source
     * @see http://http://www.w3.org/TR/css3-color/#hsl-color
     */
    fabric.Color.sourceFromHsl = function(color) {
      var match = color.match(Color.reHSLa);
      if (!match) {
        return;
      }
  
      var h = (((parseFloat(match[1]) % 360) + 360) % 360) / 360,
          s = parseFloat(match[2]) / (/%$/.test(match[2]) ? 100 : 1),
          l = parseFloat(match[3]) / (/%$/.test(match[3]) ? 100 : 1),
          r, g, b;
  
      if (s === 0) {
        r = g = b = l;
      }
      else {
        var q = l <= 0.5 ? l * (s + 1) : l + s - l * s,
            p = l * 2 - q;
  
        r = hue2rgb(p, q, h + 1 / 3);
        g = hue2rgb(p, q, h);
        b = hue2rgb(p, q, h - 1 / 3);
      }
  
      return [
        Math.round(r * 255),
        Math.round(g * 255),
        Math.round(b * 255),
        match[4] ? parseFloat(match[4]) : 1
      ];
    };
  
    /**
     * Returns new color object, when given a color in HSLA format
     * @static
     * @function
     * @memberOf fabric.Color
     * @param {String} color
     * @return {fabric.Color}
     */
    fabric.Color.fromHsla = Color.fromHsl;
  
    /**
     * Returns new color object, when given a color in HEX format
     * @static
     * @memberOf fabric.Color
     * @param {String} color Color value ex: FF5555
     * @return {fabric.Color}
     */
    fabric.Color.fromHex = function(color) {
      return Color.fromSource(Color.sourceFromHex(color));
    };
  
    /**
     * Returns array representation (ex: [100, 100, 200, 1]) of a color that's in HEX format
     * @static
     * @memberOf fabric.Color
     * @param {String} color ex: FF5555 or FF5544CC (RGBa)
     * @return {Array} source
     */
    fabric.Color.sourceFromHex = function(color) {
      if (color.match(Color.reHex)) {
        var value = color.slice(color.indexOf('#') + 1),
            isShortNotation = (value.length === 3 || value.length === 4),
            isRGBa = (value.length === 8 || value.length === 4),
            r = isShortNotation ? (value.charAt(0) + value.charAt(0)) : value.substring(0, 2),
            g = isShortNotation ? (value.charAt(1) + value.charAt(1)) : value.substring(2, 4),
            b = isShortNotation ? (value.charAt(2) + value.charAt(2)) : value.substring(4, 6),
            a = isRGBa ? (isShortNotation ? (value.charAt(3) + value.charAt(3)) : value.substring(6, 8)) : 'FF';
  
        return [
          parseInt(r, 16),
          parseInt(g, 16),
          parseInt(b, 16),
          parseFloat((parseInt(a, 16) / 255).toFixed(2))
        ];
      }
    };
  
    /**
     * Returns new color object, when given color in array representation (ex: [200, 100, 100, 0.5])
     * @static
     * @memberOf fabric.Color
     * @param {Array} source
     * @return {fabric.Color}
     */
    fabric.Color.fromSource = function(source) {
      var oColor = new Color();
      oColor.setSource(source);
      return oColor;
    };
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function() {
  
    /* _FROM_SVG_START_ */
    function getColorStop(el, multiplier) {
      var style = el.getAttribute('style'),
          offset = el.getAttribute('offset') || 0,
          color, colorAlpha, opacity, i;
  
      // convert percents to absolute values
      offset = parseFloat(offset) / (/%$/.test(offset) ? 100 : 1);
      offset = offset < 0 ? 0 : offset > 1 ? 1 : offset;
      if (style) {
        var keyValuePairs = style.split(/\s*;\s*/);
  
        if (keyValuePairs[keyValuePairs.length - 1] === '') {
          keyValuePairs.pop();
        }
  
        for (i = keyValuePairs.length; i--; ) {
  
          var split = keyValuePairs[i].split(/\s*:\s*/),
              key = split[0].trim(),
              value = split[1].trim();
  
          if (key === 'stop-color') {
            color = value;
          }
          else if (key === 'stop-opacity') {
            opacity = value;
          }
        }
      }
  
      if (!color) {
        color = el.getAttribute('stop-color') || 'rgb(0,0,0)';
      }
      if (!opacity) {
        opacity = el.getAttribute('stop-opacity');
      }
  
      color = new fabric.Color(color);
      colorAlpha = color.getAlpha();
      opacity = isNaN(parseFloat(opacity)) ? 1 : parseFloat(opacity);
      opacity *= colorAlpha * multiplier;
  
      return {
        offset: offset,
        color: color.toRgb(),
        opacity: opacity
      };
    }
  
    function getLinearCoords(el) {
      return {
        x1: el.getAttribute('x1') || 0,
        y1: el.getAttribute('y1') || 0,
        x2: el.getAttribute('x2') || '100%',
        y2: el.getAttribute('y2') || 0
      };
    }
  
    function getRadialCoords(el) {
      return {
        x1: el.getAttribute('fx') || el.getAttribute('cx') || '50%',
        y1: el.getAttribute('fy') || el.getAttribute('cy') || '50%',
        r1: 0,
        x2: el.getAttribute('cx') || '50%',
        y2: el.getAttribute('cy') || '50%',
        r2: el.getAttribute('r') || '50%'
      };
    }
    /* _FROM_SVG_END_ */
  
    var clone = fabric.util.object.clone;
  
    /**
     * Gradient class
     * @class fabric.Gradient
     * @tutorial {@link http://fabricjs.com/fabric-intro-part-2#gradients}
     * @see {@link fabric.Gradient#initialize} for constructor definition
     */
    fabric.Gradient = fabric.util.createClass(/** @lends fabric.Gradient.prototype */ {
  
      /**
       * Horizontal offset for aligning gradients coming from SVG when outside pathgroups
       * @type Number
       * @default 0
       */
      offsetX: 0,
  
      /**
       * Vertical offset for aligning gradients coming from SVG when outside pathgroups
       * @type Number
       * @default 0
       */
      offsetY: 0,
  
      /**
       * A transform matrix to apply to the gradient before painting.
       * Imported from svg gradients, is not applied with the current transform in the center.
       * Before this transform is applied, the origin point is at the top left corner of the object
       * plus the addition of offsetY and offsetX.
       * @type Number[]
       * @default null
       */
      gradientTransform: null,
  
      /**
       * coordinates units for coords.
       * If `pixels`, the number of coords are in the same unit of width / height.
       * If set as `percentage` the coords are still a number, but 1 means 100% of width
       * for the X and 100% of the height for the y. It can be bigger than 1 and negative.
       * allowed values pixels or percentage.
       * @type String
       * @default 'pixels'
       */
      gradientUnits: 'pixels',
  
      /**
       * Gradient type linear or radial
       * @type String
       * @default 'pixels'
       */
      type: 'linear',
  
      /**
       * Constructor
       * @param {Object} options Options object with type, coords, gradientUnits and colorStops
       * @param {Object} [options.type] gradient type linear or radial
       * @param {Object} [options.gradientUnits] gradient units
       * @param {Object} [options.offsetX] SVG import compatibility
       * @param {Object} [options.offsetY] SVG import compatibility
       * @param {Object[]} options.colorStops contains the colorstops.
       * @param {Object} options.coords contains the coords of the gradient
       * @param {Number} [options.coords.x1] X coordiante of the first point for linear or of the focal point for radial
       * @param {Number} [options.coords.y1] Y coordiante of the first point for linear or of the focal point for radial
       * @param {Number} [options.coords.x2] X coordiante of the second point for linear or of the center point for radial
       * @param {Number} [options.coords.y2] Y coordiante of the second point for linear or of the center point for radial
       * @param {Number} [options.coords.r1] only for radial gradient, radius of the inner circle
       * @param {Number} [options.coords.r2] only for radial gradient, radius of the external circle
       * @return {fabric.Gradient} thisArg
       */
      initialize: function(options) {
        options || (options = { });
        options.coords || (options.coords = { });
  
        var coords, _this = this;
  
        // sets everything, then coords and colorstops get sets again
        Object.keys(options).forEach(function(option) {
          _this[option] = options[option];
        });
  
        if (this.id) {
          this.id += '_' + fabric.Object.__uid++;
        }
        else {
          this.id = fabric.Object.__uid++;
        }
  
        coords = {
          x1: options.coords.x1 || 0,
          y1: options.coords.y1 || 0,
          x2: options.coords.x2 || 0,
          y2: options.coords.y2 || 0
        };
  
        if (this.type === 'radial') {
          coords.r1 = options.coords.r1 || 0;
          coords.r2 = options.coords.r2 || 0;
        }
  
        this.coords = coords;
        this.colorStops = options.colorStops.slice();
      },
  
      /**
       * Adds another colorStop
       * @param {Object} colorStop Object with offset and color
       * @return {fabric.Gradient} thisArg
       */
      addColorStop: function(colorStops) {
        for (var position in colorStops) {
          var color = new fabric.Color(colorStops[position]);
          this.colorStops.push({
            offset: parseFloat(position),
            color: color.toRgb(),
            opacity: color.getAlpha()
          });
        }
        return this;
      },
  
      /**
       * Returns object representation of a gradient
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object}
       */
      toObject: function(propertiesToInclude) {
        var object = {
          type: this.type,
          coords: this.coords,
          colorStops: this.colorStops,
          offsetX: this.offsetX,
          offsetY: this.offsetY,
          gradientUnits: this.gradientUnits,
          gradientTransform: this.gradientTransform ? this.gradientTransform.concat() : this.gradientTransform
        };
        fabric.util.populateWithProperties(this, object, propertiesToInclude);
  
        return object;
      },
  
      /* _TO_SVG_START_ */
      /**
       * Returns SVG representation of an gradient
       * @param {Object} object Object to create a gradient for
       * @return {String} SVG representation of an gradient (linear/radial)
       */
      toSVG: function(object, options) {
        var coords = clone(this.coords, true), i, len, options = options || {},
            markup, commonAttributes, colorStops = clone(this.colorStops, true),
            needsSwap = coords.r1 > coords.r2,
            transform = this.gradientTransform ? this.gradientTransform.concat() : fabric.iMatrix.concat(),
            offsetX = -this.offsetX, offsetY = -this.offsetY,
            withViewport = !!options.additionalTransform,
            gradientUnits = this.gradientUnits === 'pixels' ? 'userSpaceOnUse' : 'objectBoundingBox';
        // colorStops must be sorted ascending
        colorStops.sort(function(a, b) {
          return a.offset - b.offset;
        });
  
        if (gradientUnits === 'objectBoundingBox') {
          offsetX /= object.width;
          offsetY /= object.height;
        }
        else {
          offsetX += object.width / 2;
          offsetY += object.height / 2;
        }
        if (object.type === 'path') {
          offsetX -= object.pathOffset.x;
          offsetY -= object.pathOffset.y;
        }
  
  
        transform[4] -= offsetX;
        transform[5] -= offsetY;
  
        commonAttributes = 'id="SVGID_' + this.id +
                       '" gradientUnits="' + gradientUnits + '"';
        commonAttributes += ' gradientTransform="' + (withViewport ?
          options.additionalTransform + ' ' : '') + fabric.util.matrixToSVG(transform) + '" ';
  
        if (this.type === 'linear') {
          markup = [
            '<linearGradient ',
            commonAttributes,
            ' x1="', coords.x1,
            '" y1="', coords.y1,
            '" x2="', coords.x2,
            '" y2="', coords.y2,
            '">\n'
          ];
        }
        else if (this.type === 'radial') {
          // svg radial gradient has just 1 radius. the biggest.
          markup = [
            '<radialGradient ',
            commonAttributes,
            ' cx="', needsSwap ? coords.x1 : coords.x2,
            '" cy="', needsSwap ? coords.y1 : coords.y2,
            '" r="', needsSwap ? coords.r1 : coords.r2,
            '" fx="', needsSwap ? coords.x2 : coords.x1,
            '" fy="', needsSwap ? coords.y2 : coords.y1,
            '">\n'
          ];
        }
  
        if (this.type === 'radial') {
          if (needsSwap) {
            // svg goes from internal to external radius. if radius are inverted, swap color stops.
            colorStops = colorStops.concat();
            colorStops.reverse();
            for (i = 0, len = colorStops.length; i < len; i++) {
              colorStops[i].offset = 1 - colorStops[i].offset;
            }
          }
          var minRadius = Math.min(coords.r1, coords.r2);
          if (minRadius > 0) {
            // i have to shift all colorStops and add new one in 0.
            var maxRadius = Math.max(coords.r1, coords.r2),
                percentageShift = minRadius / maxRadius;
            for (i = 0, len = colorStops.length; i < len; i++) {
              colorStops[i].offset += percentageShift * (1 - colorStops[i].offset);
            }
          }
        }
  
        for (i = 0, len = colorStops.length; i < len; i++) {
          var colorStop = colorStops[i];
          markup.push(
            '<stop ',
            'offset="', (colorStop.offset * 100) + '%',
            '" style="stop-color:', colorStop.color,
            (typeof colorStop.opacity !== 'undefined' ? ';stop-opacity: ' + colorStop.opacity : ';'),
            '"/>\n'
          );
        }
  
        markup.push((this.type === 'linear' ? '</linearGradient>\n' : '</radialGradient>\n'));
  
        return markup.join('');
      },
      /* _TO_SVG_END_ */
  
      /**
       * Returns an instance of CanvasGradient
       * @param {CanvasRenderingContext2D} ctx Context to render on
       * @return {CanvasGradient}
       */
      toLive: function(ctx) {
        var gradient, coords = fabric.util.object.clone(this.coords), i, len;
  
        if (!this.type) {
          return;
        }
  
        if (this.type === 'linear') {
          gradient = ctx.createLinearGradient(
            coords.x1, coords.y1, coords.x2, coords.y2);
        }
        else if (this.type === 'radial') {
          gradient = ctx.createRadialGradient(
            coords.x1, coords.y1, coords.r1, coords.x2, coords.y2, coords.r2);
        }
  
        for (i = 0, len = this.colorStops.length; i < len; i++) {
          var color = this.colorStops[i].color,
              opacity = this.colorStops[i].opacity,
              offset = this.colorStops[i].offset;
  
          if (typeof opacity !== 'undefined') {
            color = new fabric.Color(color).setAlpha(opacity).toRgba();
          }
          gradient.addColorStop(offset, color);
        }
  
        return gradient;
      }
    });
  
    fabric.util.object.extend(fabric.Gradient, {
  
      /* _FROM_SVG_START_ */
      /**
       * Returns {@link fabric.Gradient} instance from an SVG element
       * @static
       * @memberOf fabric.Gradient
       * @param {SVGGradientElement} el SVG gradient element
       * @param {fabric.Object} instance
       * @param {String} opacityAttr A fill-opacity or stroke-opacity attribute to multiply to each stop's opacity.
       * @param {Object} svgOptions an object containing the size of the SVG in order to parse correctly graidents
       * that uses gradientUnits as 'userSpaceOnUse' and percentages.
       * @param {Object.number} viewBoxWidth width part of the viewBox attribute on svg
       * @param {Object.number} viewBoxHeight height part of the viewBox attribute on svg
       * @param {Object.number} width width part of the svg tag if viewBox is not specified
       * @param {Object.number} height height part of the svg tag if viewBox is not specified
       * @return {fabric.Gradient} Gradient instance
       * @see http://www.w3.org/TR/SVG/pservers.html#LinearGradientElement
       * @see http://www.w3.org/TR/SVG/pservers.html#RadialGradientElement
       */
      fromElement: function(el, instance, opacityAttr, svgOptions) {
        /**
         *  @example:
         *
         *  <linearGradient id="linearGrad1">
         *    <stop offset="0%" stop-color="white"/>
         *    <stop offset="100%" stop-color="black"/>
         *  </linearGradient>
         *
         *  OR
         *
         *  <linearGradient id="linearGrad2">
         *    <stop offset="0" style="stop-color:rgb(255,255,255)"/>
         *    <stop offset="1" style="stop-color:rgb(0,0,0)"/>
         *  </linearGradient>
         *
         *  OR
         *
         *  <radialGradient id="radialGrad1">
         *    <stop offset="0%" stop-color="white" stop-opacity="1" />
         *    <stop offset="50%" stop-color="black" stop-opacity="0.5" />
         *    <stop offset="100%" stop-color="white" stop-opacity="1" />
         *  </radialGradient>
         *
         *  OR
         *
         *  <radialGradient id="radialGrad2">
         *    <stop offset="0" stop-color="rgb(255,255,255)" />
         *    <stop offset="0.5" stop-color="rgb(0,0,0)" />
         *    <stop offset="1" stop-color="rgb(255,255,255)" />
         *  </radialGradient>
         *
         */
  
        var multiplier = parseFloat(opacityAttr) / (/%$/.test(opacityAttr) ? 100 : 1);
        multiplier = multiplier < 0 ? 0 : multiplier > 1 ? 1 : multiplier;
        if (isNaN(multiplier)) {
          multiplier = 1;
        }
  
        var colorStopEls = el.getElementsByTagName('stop'),
            type,
            gradientUnits = el.getAttribute('gradientUnits') === 'userSpaceOnUse' ?
              'pixels' : 'percentage',
            gradientTransform = el.getAttribute('gradientTransform') || '',
            colorStops = [],
            coords, i, offsetX = 0, offsetY = 0,
            transformMatrix;
        if (el.nodeName === 'linearGradient' || el.nodeName === 'LINEARGRADIENT') {
          type = 'linear';
          coords = getLinearCoords(el);
        }
        else {
          type = 'radial';
          coords = getRadialCoords(el);
        }
  
        for (i = colorStopEls.length; i--; ) {
          colorStops.push(getColorStop(colorStopEls[i], multiplier));
        }
  
        transformMatrix = fabric.parseTransformAttribute(gradientTransform);
  
        __convertPercentUnitsToValues(instance, coords, svgOptions, gradientUnits);
  
        if (gradientUnits === 'pixels') {
          offsetX = -instance.left;
          offsetY = -instance.top;
        }
  
        var gradient = new fabric.Gradient({
          id: el.getAttribute('id'),
          type: type,
          coords: coords,
          colorStops: colorStops,
          gradientUnits: gradientUnits,
          gradientTransform: transformMatrix,
          offsetX: offsetX,
          offsetY: offsetY,
        });
  
        return gradient;
      },
      /* _FROM_SVG_END_ */
  
      /**
       * Returns {@link fabric.Gradient} instance from its object representation
       * this function is uniquely used by Object.setGradient and is deprecated with it.
       * @static
       * @deprecated since 3.4.0
       * @memberOf fabric.Gradient
       * @param {Object} obj
       * @param {Object} [options] Options object
       */
      forObject: function(obj, options) {
        options || (options = { });
        __convertPercentUnitsToValues(obj, options.coords, options.gradientUnits, {
          // those values are to avoid errors. this function is uniquely used by
          viewBoxWidth: 100,
          viewBoxHeight: 100,
        });
        return new fabric.Gradient(options);
      }
    });
  
    /**
     * @private
     */
    function __convertPercentUnitsToValues(instance, options, svgOptions, gradientUnits) {
      var propValue, finalValue;
      Object.keys(options).forEach(function(prop) {
        propValue = options[prop];
        if (propValue === 'Infinity') {
          finalValue = 1;
        }
        else if (propValue === '-Infinity') {
          finalValue = 0;
        }
        else {
          finalValue = parseFloat(options[prop], 10);
          if (typeof propValue === 'string' && /^(\d+\.\d+)%|(\d+)%$/.test(propValue)) {
            finalValue *= 0.01;
            if (gradientUnits === 'pixels') {
              // then we need to fix those percentages here in svg parsing
              if (prop === 'x1' || prop === 'x2' || prop === 'r2') {
                finalValue *= svgOptions.viewBoxWidth || svgOptions.width;
              }
              if (prop === 'y1' || prop === 'y2') {
                finalValue *= svgOptions.viewBoxHeight || svgOptions.height;
              }
            }
          }
        }
        options[prop] = finalValue;
      });
    }
  })();
  
  
  (function() {
  
    'use strict';
  
    var toFixed = fabric.util.toFixed;
  
    /**
     * Pattern class
     * @class fabric.Pattern
     * @see {@link http://fabricjs.com/patterns|Pattern demo}
     * @see {@link http://fabricjs.com/dynamic-patterns|DynamicPattern demo}
     * @see {@link fabric.Pattern#initialize} for constructor definition
     */
  
  
    fabric.Pattern = fabric.util.createClass(/** @lends fabric.Pattern.prototype */ {
  
      /**
       * Repeat property of a pattern (one of repeat, repeat-x, repeat-y or no-repeat)
       * @type String
       * @default
       */
      repeat: 'repeat',
  
      /**
       * Pattern horizontal offset from object's left/top corner
       * @type Number
       * @default
       */
      offsetX: 0,
  
      /**
       * Pattern vertical offset from object's left/top corner
       * @type Number
       * @default
       */
      offsetY: 0,
  
      /**
       * crossOrigin value (one of "", "anonymous", "use-credentials")
       * @see https://developer.mozilla.org/en-US/docs/HTML/CORS_settings_attributes
       * @type String
       * @default
       */
      crossOrigin: '',
  
      /**
       * transform matrix to change the pattern, imported from svgs.
       * @type Array
       * @default
       */
      patternTransform: null,
  
      /**
       * Constructor
       * @param {Object} [options] Options object
       * @param {Function} [callback] function to invoke after callback init.
       * @return {fabric.Pattern} thisArg
       */
      initialize: function(options, callback) {
        options || (options = { });
  
        this.id = fabric.Object.__uid++;
        this.setOptions(options);
        if (!options.source || (options.source && typeof options.source !== 'string')) {
          callback && callback(this);
          return;
        }
        // function string
        if (typeof fabric.util.getFunctionBody(options.source) !== 'undefined') {
          this.source = new Function(fabric.util.getFunctionBody(options.source));
          callback && callback(this);
        }
        else {
          // img src string
          var _this = this;
          this.source = fabric.util.createImage();
          fabric.util.loadImage(options.source, function(img) {
            _this.source = img;
            callback && callback(_this);
          }, null, this.crossOrigin);
        }
      },
  
      /**
       * Returns object representation of a pattern
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object} Object representation of a pattern instance
       */
      toObject: function(propertiesToInclude) {
        var NUM_FRACTION_DIGITS = fabric.Object.NUM_FRACTION_DIGITS,
            source, object;
  
        // callback
        if (typeof this.source === 'function') {
          source = String(this.source);
        }
        // <img> element
        else if (typeof this.source.src === 'string') {
          source = this.source.src;
        }
        // <canvas> element
        else if (typeof this.source === 'object' && this.source.toDataURL) {
          source = this.source.toDataURL();
        }
  
        object = {
          type: 'pattern',
          source: source,
          repeat: this.repeat,
          crossOrigin: this.crossOrigin,
          offsetX: toFixed(this.offsetX, NUM_FRACTION_DIGITS),
          offsetY: toFixed(this.offsetY, NUM_FRACTION_DIGITS),
          patternTransform: this.patternTransform ? this.patternTransform.concat() : null
        };
        fabric.util.populateWithProperties(this, object, propertiesToInclude);
  
        return object;
      },
  
      /* _TO_SVG_START_ */
      /**
       * Returns SVG representation of a pattern
       * @param {fabric.Object} object
       * @return {String} SVG representation of a pattern
       */
      toSVG: function(object) {
        var patternSource = typeof this.source === 'function' ? this.source() : this.source,
            patternWidth = patternSource.width / object.width,
            patternHeight = patternSource.height / object.height,
            patternOffsetX = this.offsetX / object.width,
            patternOffsetY = this.offsetY / object.height,
            patternImgSrc = '';
        if (this.repeat === 'repeat-x' || this.repeat === 'no-repeat') {
          patternHeight = 1;
          if (patternOffsetY) {
            patternHeight += Math.abs(patternOffsetY);
          }
        }
        if (this.repeat === 'repeat-y' || this.repeat === 'no-repeat') {
          patternWidth = 1;
          if (patternOffsetX) {
            patternWidth += Math.abs(patternOffsetX);
          }
  
        }
        if (patternSource.src) {
          patternImgSrc = patternSource.src;
        }
        else if (patternSource.toDataURL) {
          patternImgSrc = patternSource.toDataURL();
        }
  
        return '<pattern id="SVGID_' + this.id +
                      '" x="' + patternOffsetX +
                      '" y="' + patternOffsetY +
                      '" width="' + patternWidth +
                      '" height="' + patternHeight + '">\n' +
                 '<image x="0" y="0"' +
                        ' width="' + patternSource.width +
                        '" height="' + patternSource.height +
                        '" xlink:href="' + patternImgSrc +
                 '"></image>\n' +
               '</pattern>\n';
      },
      /* _TO_SVG_END_ */
  
      setOptions: function(options) {
        for (var prop in options) {
          this[prop] = options[prop];
        }
      },
  
      /**
       * Returns an instance of CanvasPattern
       * @param {CanvasRenderingContext2D} ctx Context to create pattern
       * @return {CanvasPattern}
       */
      toLive: function(ctx) {
        var source = typeof this.source === 'function' ? this.source() : this.source;
  
        // if the image failed to load, return, and allow rest to continue loading
        if (!source) {
          return '';
        }
  
        // if an image
        if (typeof source.src !== 'undefined') {
          if (!source.complete) {
            return '';
          }
          if (source.naturalWidth === 0 || source.naturalHeight === 0) {
            return '';
          }
        }
        return ctx.createPattern(source, this.repeat);
      }
    });
  })();
  
  
  (function(global) {
  
    'use strict';
  
    var fabric = global.fabric || (global.fabric = { }),
        toFixed = fabric.util.toFixed;
  
    if (fabric.Shadow) {
      fabric.warn('fabric.Shadow is already defined.');
      return;
    }
  
    /**
     * Shadow class
     * @class fabric.Shadow
     * @see {@link http://fabricjs.com/shadows|Shadow demo}
     * @see {@link fabric.Shadow#initialize} for constructor definition
     */
    fabric.Shadow = fabric.util.createClass(/** @lends fabric.Shadow.prototype */ {
  
      /**
       * Shadow color
       * @type String
       * @default
       */
      color: 'rgb(0,0,0)',
  
      /**
       * Shadow blur
       * @type Number
       */
      blur: 0,
  
      /**
       * Shadow horizontal offset
       * @type Number
       * @default
       */
      offsetX: 0,
  
      /**
       * Shadow vertical offset
       * @type Number
       * @default
       */
      offsetY: 0,
  
      /**
       * Whether the shadow should affect stroke operations
       * @type Boolean
       * @default
       */
      affectStroke: false,
  
      /**
       * Indicates whether toObject should include default values
       * @type Boolean
       * @default
       */
      includeDefaultValues: true,
  
      /**
       * When `false`, the shadow will scale with the object.
       * When `true`, the shadow's offsetX, offsetY, and blur will not be affected by the object's scale.
       * default to false
       * @type Boolean
       * @default
       */
      nonScaling: false,
  
      /**
       * Constructor
       * @param {Object|String} [options] Options object with any of color, blur, offsetX, offsetY properties or string (e.g. "rgba(0,0,0,0.2) 2px 2px 10px")
       * @return {fabric.Shadow} thisArg
       */
      initialize: function(options) {
  
        if (typeof options === 'string') {
          options = this._parseShadow(options);
        }
  
        for (var prop in options) {
          this[prop] = options[prop];
        }
  
        this.id = fabric.Object.__uid++;
      },
  
      /**
       * @private
       * @param {String} shadow Shadow value to parse
       * @return {Object} Shadow object with color, offsetX, offsetY and blur
       */
      _parseShadow: function(shadow) {
        var shadowStr = shadow.trim(),
            offsetsAndBlur = fabric.Shadow.reOffsetsAndBlur.exec(shadowStr) || [],
            color = shadowStr.replace(fabric.Shadow.reOffsetsAndBlur, '') || 'rgb(0,0,0)';
  
        return {
          color: color.trim(),
          offsetX: parseInt(offsetsAndBlur[1], 10) || 0,
          offsetY: parseInt(offsetsAndBlur[2], 10) || 0,
          blur: parseInt(offsetsAndBlur[3], 10) || 0
        };
      },
  
      /**
       * Returns a string representation of an instance
       * @see http://www.w3.org/TR/css-text-decor-3/#text-shadow
       * @return {String} Returns CSS3 text-shadow declaration
       */
      toString: function() {
        return [this.offsetX, this.offsetY, this.blur, this.color].join('px ');
      },
  
      /* _TO_SVG_START_ */
      /**
       * Returns SVG representation of a shadow
       * @param {fabric.Object} object
       * @return {String} SVG representation of a shadow
       */
      toSVG: function(object) {
        var fBoxX = 40, fBoxY = 40, NUM_FRACTION_DIGITS = fabric.Object.NUM_FRACTION_DIGITS,
            offset = fabric.util.rotateVector(
              { x: this.offsetX, y: this.offsetY },
              fabric.util.degreesToRadians(-object.angle)),
            BLUR_BOX = 20, color = new fabric.Color(this.color);
  
        if (object.width && object.height) {
          //http://www.w3.org/TR/SVG/filters.html#FilterEffectsRegion
          // we add some extra space to filter box to contain the blur ( 20 )
          fBoxX = toFixed((Math.abs(offset.x) + this.blur) / object.width, NUM_FRACTION_DIGITS) * 100 + BLUR_BOX;
          fBoxY = toFixed((Math.abs(offset.y) + this.blur) / object.height, NUM_FRACTION_DIGITS) * 100 + BLUR_BOX;
        }
        if (object.flipX) {
          offset.x *= -1;
        }
        if (object.flipY) {
          offset.y *= -1;
        }
  
        return (
          '<filter id="SVGID_' + this.id + '" y="-' + fBoxY + '%" height="' + (100 + 2 * fBoxY) + '%" ' +
            'x="-' + fBoxX + '%" width="' + (100 + 2 * fBoxX) + '%" ' + '>\n' +
            '\t<feGaussianBlur in="SourceAlpha" stdDeviation="' +
              toFixed(this.blur ? this.blur / 2 : 0, NUM_FRACTION_DIGITS) + '"></feGaussianBlur>\n' +
            '\t<feOffset dx="' + toFixed(offset.x, NUM_FRACTION_DIGITS) +
            '" dy="' + toFixed(offset.y, NUM_FRACTION_DIGITS) + '" result="oBlur" ></feOffset>\n' +
            '\t<feFlood flood-color="' + color.toRgb() + '" flood-opacity="' + color.getAlpha() + '"/>\n' +
            '\t<feComposite in2="oBlur" operator="in" />\n' +
            '\t<feMerge>\n' +
              '\t\t<feMergeNode></feMergeNode>\n' +
              '\t\t<feMergeNode in="SourceGraphic"></feMergeNode>\n' +
            '\t</feMerge>\n' +
          '</filter>\n');
      },
      /* _TO_SVG_END_ */
  
      /**
       * Returns object representation of a shadow
       * @return {Object} Object representation of a shadow instance
       */
      toObject: function() {
        if (this.includeDefaultValues) {
          return {
            color: this.color,
            blur: this.blur,
            offsetX: this.offsetX,
            offsetY: this.offsetY,
            affectStroke: this.affectStroke,
            nonScaling: this.nonScaling
          };
        }
        var obj = { }, proto = fabric.Shadow.prototype;
  
        ['color', 'blur', 'offsetX', 'offsetY', 'affectStroke', 'nonScaling'].forEach(function(prop) {
          if (this[prop] !== proto[prop]) {
            obj[prop] = this[prop];
          }
        }, this);
  
        return obj;
      }
    });
  
    /**
     * Regex matching shadow offsetX, offsetY and blur (ex: "2px 2px 10px rgba(0,0,0,0.2)", "rgb(0,255,0) 2px 2px")
     * @static
     * @field
     * @memberOf fabric.Shadow
     */
    // eslint-disable-next-line max-len
    fabric.Shadow.reOffsetsAndBlur = /(?:\s|^)(-?\d+(?:px)?(?:\s?|$))?(-?\d+(?:px)?(?:\s?|$))?(\d+(?:px)?)?(?:\s?|$)(?:$|\s)/;
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function () {
  
    'use strict';
  
    if (fabric.StaticCanvas) {
      fabric.warn('fabric.StaticCanvas is already defined.');
      return;
    }
  
    // aliases for faster resolution
    var extend = fabric.util.object.extend,
        getElementOffset = fabric.util.getElementOffset,
        removeFromArray = fabric.util.removeFromArray,
        toFixed = fabric.util.toFixed,
        transformPoint = fabric.util.transformPoint,
        invertTransform = fabric.util.invertTransform,
        getNodeCanvas = fabric.util.getNodeCanvas,
        createCanvasElement = fabric.util.createCanvasElement,
  
        CANVAS_INIT_ERROR = new Error('Could not initialize `canvas` element');
  
    /**
     * Static canvas class
     * @class fabric.StaticCanvas
     * @mixes fabric.Collection
     * @mixes fabric.Observable
     * @see {@link http://fabricjs.com/static_canvas|StaticCanvas demo}
     * @see {@link fabric.StaticCanvas#initialize} for constructor definition
     * @fires before:render
     * @fires after:render
     * @fires canvas:cleared
     * @fires object:added
     * @fires object:removed
     */
    fabric.StaticCanvas = fabric.util.createClass(fabric.CommonMethods, /** @lends fabric.StaticCanvas.prototype */ {
  
      /**
       * Constructor
       * @param {HTMLElement | String} el &lt;canvas> element to initialize instance on
       * @param {Object} [options] Options object
       * @return {Object} thisArg
       */
      initialize: function(el, options) {
        options || (options = { });
        this.renderAndResetBound = this.renderAndReset.bind(this);
        this.requestRenderAllBound = this.requestRenderAll.bind(this);
        this._initStatic(el, options);
      },
  
      /**
       * Background color of canvas instance.
       * Should be set via {@link fabric.StaticCanvas#setBackgroundColor}.
       * @type {(String|fabric.Pattern)}
       * @default
       */
      backgroundColor: '',
  
      /**
       * Background image of canvas instance.
       * Should be set via {@link fabric.StaticCanvas#setBackgroundImage}.
       * <b>Backwards incompatibility note:</b> The "backgroundImageOpacity"
       * and "backgroundImageStretch" properties are deprecated since 1.3.9.
       * Use {@link fabric.Image#opacity}, {@link fabric.Image#width} and {@link fabric.Image#height}.
       * since 2.4.0 image caching is active, please when putting an image as background, add to the
       * canvas property a reference to the canvas it is on. Otherwise the image cannot detect the zoom
       * vale. As an alternative you can disable image objectCaching
       * @type fabric.Image
       * @default
       */
      backgroundImage: null,
  
      /**
       * Overlay color of canvas instance.
       * Should be set via {@link fabric.StaticCanvas#setOverlayColor}
       * @since 1.3.9
       * @type {(String|fabric.Pattern)}
       * @default
       */
      overlayColor: '',
  
      /**
       * Overlay image of canvas instance.
       * Should be set via {@link fabric.StaticCanvas#setOverlayImage}.
       * <b>Backwards incompatibility note:</b> The "overlayImageLeft"
       * and "overlayImageTop" properties are deprecated since 1.3.9.
       * Use {@link fabric.Image#left} and {@link fabric.Image#top}.
       * since 2.4.0 image caching is active, please when putting an image as overlay, add to the
       * canvas property a reference to the canvas it is on. Otherwise the image cannot detect the zoom
       * vale. As an alternative you can disable image objectCaching
       * @type fabric.Image
       * @default
       */
      overlayImage: null,
  
      /**
       * Indicates whether toObject/toDatalessObject should include default values
       * if set to false, takes precedence over the object value.
       * @type Boolean
       * @default
       */
      includeDefaultValues: true,
  
      /**
       * Indicates whether objects' state should be saved
       * @type Boolean
       * @default
       */
      stateful: false,
  
      /**
       * Indicates whether {@link fabric.Collection.add}, {@link fabric.Collection.insertAt} and {@link fabric.Collection.remove},
       * {@link fabric.StaticCanvas.moveTo}, {@link fabric.StaticCanvas.clear} and many more, should also re-render canvas.
       * Disabling this option will not give a performance boost when adding/removing a lot of objects to/from canvas at once
       * since the renders are quequed and executed one per frame.
       * Disabling is suggested anyway and managing the renders of the app manually is not a big effort ( canvas.requestRenderAll() )
       * Left default to true to do not break documentation and old app, fiddles.
       * @type Boolean
       * @default
       */
      renderOnAddRemove: true,
  
      /**
       * Function that determines clipping of entire canvas area
       * Being passed context as first argument.
       * If you are using code minification, ctx argument can be minified/manglied you should use
       * as a workaround `var ctx = arguments[0];` in the function;
       * See clipping canvas area in {@link https://github.com/kangax/fabric.js/wiki/FAQ}
       * @deprecated since 2.0.0
       * @type Function
       * @default
       */
      clipTo: null,
  
      /**
       * Indicates whether object controls (borders/controls) are rendered above overlay image
       * @type Boolean
       * @default
       */
      controlsAboveOverlay: false,
  
      /**
       * Indicates whether the browser can be scrolled when using a touchscreen and dragging on the canvas
       * @type Boolean
       * @default
       */
      allowTouchScrolling: false,
  
      /**
       * Indicates whether this canvas will use image smoothing, this is on by default in browsers
       * @type Boolean
       * @default
       */
      imageSmoothingEnabled: true,
  
      /**
       * The transformation (in the format of Canvas transform) which focuses the viewport
       * @type Array
       * @default
       */
      viewportTransform: fabric.iMatrix.concat(),
  
      /**
       * if set to false background image is not affected by viewport transform
       * @since 1.6.3
       * @type Boolean
       * @default
       */
      backgroundVpt: true,
  
      /**
       * if set to false overlya image is not affected by viewport transform
       * @since 1.6.3
       * @type Boolean
       * @default
       */
      overlayVpt: true,
  
      /**
       * Callback; invoked right before object is about to be scaled/rotated
       * @deprecated since 2.3.0
       * Use before:transform event
       */
      onBeforeScaleRotate: function () {
        /* NOOP */
      },
  
      /**
       * When true, canvas is scaled by devicePixelRatio for better rendering on retina screens
       * @type Boolean
       * @default
       */
      enableRetinaScaling: true,
  
      /**
       * Describe canvas element extension over design
       * properties are tl,tr,bl,br.
       * if canvas is not zoomed/panned those points are the four corner of canvas
       * if canvas is viewportTransformed you those points indicate the extension
       * of canvas element in plain untrasformed coordinates
       * The coordinates get updated with @method calcViewportBoundaries.
       * @memberOf fabric.StaticCanvas.prototype
       */
      vptCoords: { },
  
      /**
       * Based on vptCoords and object.aCoords, skip rendering of objects that
       * are not included in current viewport.
       * May greatly help in applications with crowded canvas and use of zoom/pan
       * If One of the corner of the bounding box of the object is on the canvas
       * the objects get rendered.
       * @memberOf fabric.StaticCanvas.prototype
       * @type Boolean
       * @default
       */
      skipOffscreen: true,
  
      /**
       * a fabricObject that, without stroke define a clipping area with their shape. filled in black
       * the clipPath object gets used when the canvas has rendered, and the context is placed in the
       * top left corner of the canvas.
       * clipPath will clip away controls, if you do not want this to happen use controlsAboveOverlay = true
       * @type fabric.Object
       */
      clipPath: undefined,
  
      /**
       * @private
       * @param {HTMLElement | String} el &lt;canvas> element to initialize instance on
       * @param {Object} [options] Options object
       */
      _initStatic: function(el, options) {
        var cb = this.requestRenderAllBound;
        this._objects = [];
        this._createLowerCanvas(el);
        this._initOptions(options);
        this._setImageSmoothing();
        // only initialize retina scaling once
        if (!this.interactive) {
          this._initRetinaScaling();
        }
  
        if (options.overlayImage) {
          this.setOverlayImage(options.overlayImage, cb);
        }
        if (options.backgroundImage) {
          this.setBackgroundImage(options.backgroundImage, cb);
        }
        if (options.backgroundColor) {
          this.setBackgroundColor(options.backgroundColor, cb);
        }
        if (options.overlayColor) {
          this.setOverlayColor(options.overlayColor, cb);
        }
        this.calcOffset();
      },
  
      /**
       * @private
       */
      _isRetinaScaling: function() {
        return (fabric.devicePixelRatio !== 1 && this.enableRetinaScaling);
      },
  
      /**
       * @private
       * @return {Number} retinaScaling if applied, otherwise 1;
       */
      getRetinaScaling: function() {
        return this._isRetinaScaling() ? fabric.devicePixelRatio : 1;
      },
  
      /**
       * @private
       */
      _initRetinaScaling: function() {
        if (!this._isRetinaScaling()) {
          return;
        }
        this.lowerCanvasEl.setAttribute('width', this.width * fabric.devicePixelRatio);
        this.lowerCanvasEl.setAttribute('height', this.height * fabric.devicePixelRatio);
  
        this.contextContainer.scale(fabric.devicePixelRatio, fabric.devicePixelRatio);
      },
  
      /**
       * Calculates canvas element offset relative to the document
       * This method is also attached as "resize" event handler of window
       * @return {fabric.Canvas} instance
       * @chainable
       */
      calcOffset: function () {
        this._offset = getElementOffset(this.lowerCanvasEl);
        return this;
      },
  
      /**
       * Sets {@link fabric.StaticCanvas#overlayImage|overlay image} for this canvas
       * @param {(fabric.Image|String)} image fabric.Image instance or URL of an image to set overlay to
       * @param {Function} callback callback to invoke when image is loaded and set as an overlay
       * @param {Object} [options] Optional options to set for the {@link fabric.Image|overlay image}.
       * @return {fabric.Canvas} thisArg
       * @chainable
       * @see {@link http://jsfiddle.net/fabricjs/MnzHT/|jsFiddle demo}
       * @example <caption>Normal overlayImage with left/top = 0</caption>
       * canvas.setOverlayImage('http://fabricjs.com/assets/jail_cell_bars.png', canvas.renderAll.bind(canvas), {
       *   // Needed to position overlayImage at 0/0
       *   originX: 'left',
       *   originY: 'top'
       * });
       * @example <caption>overlayImage with different properties</caption>
       * canvas.setOverlayImage('http://fabricjs.com/assets/jail_cell_bars.png', canvas.renderAll.bind(canvas), {
       *   opacity: 0.5,
       *   angle: 45,
       *   left: 400,
       *   top: 400,
       *   originX: 'left',
       *   originY: 'top'
       * });
       * @example <caption>Stretched overlayImage #1 - width/height correspond to canvas width/height</caption>
       * fabric.Image.fromURL('http://fabricjs.com/assets/jail_cell_bars.png', function(img) {
       *    img.set({width: canvas.width, height: canvas.height, originX: 'left', originY: 'top'});
       *    canvas.setOverlayImage(img, canvas.renderAll.bind(canvas));
       * });
       * @example <caption>Stretched overlayImage #2 - width/height correspond to canvas width/height</caption>
       * canvas.setOverlayImage('http://fabricjs.com/assets/jail_cell_bars.png', canvas.renderAll.bind(canvas), {
       *   width: canvas.width,
       *   height: canvas.height,
       *   // Needed to position overlayImage at 0/0
       *   originX: 'left',
       *   originY: 'top'
       * });
       * @example <caption>overlayImage loaded from cross-origin</caption>
       * canvas.setOverlayImage('http://fabricjs.com/assets/jail_cell_bars.png', canvas.renderAll.bind(canvas), {
       *   opacity: 0.5,
       *   angle: 45,
       *   left: 400,
       *   top: 400,
       *   originX: 'left',
       *   originY: 'top',
       *   crossOrigin: 'anonymous'
       * });
       */
      setOverlayImage: function (image, callback, options) {
        return this.__setBgOverlayImage('overlayImage', image, callback, options);
      },
  
      /**
       * Sets {@link fabric.StaticCanvas#backgroundImage|background image} for this canvas
       * @param {(fabric.Image|String)} image fabric.Image instance or URL of an image to set background to
       * @param {Function} callback Callback to invoke when image is loaded and set as background
       * @param {Object} [options] Optional options to set for the {@link fabric.Image|background image}.
       * @return {fabric.Canvas} thisArg
       * @chainable
       * @see {@link http://jsfiddle.net/djnr8o7a/28/|jsFiddle demo}
       * @example <caption>Normal backgroundImage with left/top = 0</caption>
       * canvas.setBackgroundImage('http://fabricjs.com/assets/honey_im_subtle.png', canvas.renderAll.bind(canvas), {
       *   // Needed to position backgroundImage at 0/0
       *   originX: 'left',
       *   originY: 'top'
       * });
       * @example <caption>backgroundImage with different properties</caption>
       * canvas.setBackgroundImage('http://fabricjs.com/assets/honey_im_subtle.png', canvas.renderAll.bind(canvas), {
       *   opacity: 0.5,
       *   angle: 45,
       *   left: 400,
       *   top: 400,
       *   originX: 'left',
       *   originY: 'top'
       * });
       * @example <caption>Stretched backgroundImage #1 - width/height correspond to canvas width/height</caption>
       * fabric.Image.fromURL('http://fabricjs.com/assets/honey_im_subtle.png', function(img) {
       *    img.set({width: canvas.width, height: canvas.height, originX: 'left', originY: 'top'});
       *    canvas.setBackgroundImage(img, canvas.renderAll.bind(canvas));
       * });
       * @example <caption>Stretched backgroundImage #2 - width/height correspond to canvas width/height</caption>
       * canvas.setBackgroundImage('http://fabricjs.com/assets/honey_im_subtle.png', canvas.renderAll.bind(canvas), {
       *   width: canvas.width,
       *   height: canvas.height,
       *   // Needed to position backgroundImage at 0/0
       *   originX: 'left',
       *   originY: 'top'
       * });
       * @example <caption>backgroundImage loaded from cross-origin</caption>
       * canvas.setBackgroundImage('http://fabricjs.com/assets/honey_im_subtle.png', canvas.renderAll.bind(canvas), {
       *   opacity: 0.5,
       *   angle: 45,
       *   left: 400,
       *   top: 400,
       *   originX: 'left',
       *   originY: 'top',
       *   crossOrigin: 'anonymous'
       * });
       */
      // TODO: fix stretched examples
      setBackgroundImage: function (image, callback, options) {
        return this.__setBgOverlayImage('backgroundImage', image, callback, options);
      },
  
      /**
       * Sets {@link fabric.StaticCanvas#overlayColor|foreground color} for this canvas
       * @param {(String|fabric.Pattern)} overlayColor Color or pattern to set foreground color to
       * @param {Function} callback Callback to invoke when foreground color is set
       * @return {fabric.Canvas} thisArg
       * @chainable
       * @see {@link http://jsfiddle.net/fabricjs/pB55h/|jsFiddle demo}
       * @example <caption>Normal overlayColor - color value</caption>
       * canvas.setOverlayColor('rgba(255, 73, 64, 0.6)', canvas.renderAll.bind(canvas));
       * @example <caption>fabric.Pattern used as overlayColor</caption>
       * canvas.setOverlayColor({
       *   source: 'http://fabricjs.com/assets/escheresque_ste.png'
       * }, canvas.renderAll.bind(canvas));
       * @example <caption>fabric.Pattern used as overlayColor with repeat and offset</caption>
       * canvas.setOverlayColor({
       *   source: 'http://fabricjs.com/assets/escheresque_ste.png',
       *   repeat: 'repeat',
       *   offsetX: 200,
       *   offsetY: 100
       * }, canvas.renderAll.bind(canvas));
       */
      setOverlayColor: function(overlayColor, callback) {
        return this.__setBgOverlayColor('overlayColor', overlayColor, callback);
      },
  
      /**
       * Sets {@link fabric.StaticCanvas#backgroundColor|background color} for this canvas
       * @param {(String|fabric.Pattern)} backgroundColor Color or pattern to set background color to
       * @param {Function} callback Callback to invoke when background color is set
       * @return {fabric.Canvas} thisArg
       * @chainable
       * @see {@link http://jsfiddle.net/fabricjs/hXzvk/|jsFiddle demo}
       * @example <caption>Normal backgroundColor - color value</caption>
       * canvas.setBackgroundColor('rgba(255, 73, 64, 0.6)', canvas.renderAll.bind(canvas));
       * @example <caption>fabric.Pattern used as backgroundColor</caption>
       * canvas.setBackgroundColor({
       *   source: 'http://fabricjs.com/assets/escheresque_ste.png'
       * }, canvas.renderAll.bind(canvas));
       * @example <caption>fabric.Pattern used as backgroundColor with repeat and offset</caption>
       * canvas.setBackgroundColor({
       *   source: 'http://fabricjs.com/assets/escheresque_ste.png',
       *   repeat: 'repeat',
       *   offsetX: 200,
       *   offsetY: 100
       * }, canvas.renderAll.bind(canvas));
       */
      setBackgroundColor: function(backgroundColor, callback) {
        return this.__setBgOverlayColor('backgroundColor', backgroundColor, callback);
      },
  
      /**
       * @private
       * @see {@link http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html#dom-context-2d-imagesmoothingenabled|WhatWG Canvas Standard}
       */
      _setImageSmoothing: function() {
        var ctx = this.getContext();
  
        ctx.imageSmoothingEnabled = ctx.imageSmoothingEnabled || ctx.webkitImageSmoothingEnabled
          || ctx.mozImageSmoothingEnabled || ctx.msImageSmoothingEnabled || ctx.oImageSmoothingEnabled;
        ctx.imageSmoothingEnabled = this.imageSmoothingEnabled;
      },
  
      /**
       * @private
       * @param {String} property Property to set ({@link fabric.StaticCanvas#backgroundImage|backgroundImage}
       * or {@link fabric.StaticCanvas#overlayImage|overlayImage})
       * @param {(fabric.Image|String|null)} image fabric.Image instance, URL of an image or null to set background or overlay to
       * @param {Function} callback Callback to invoke when image is loaded and set as background or overlay
       * @param {Object} [options] Optional options to set for the {@link fabric.Image|image}.
       */
      __setBgOverlayImage: function(property, image, callback, options) {
        if (typeof image === 'string') {
          fabric.util.loadImage(image, function(img) {
            if (img) {
              var instance = new fabric.Image(img, options);
              this[property] = instance;
              instance.canvas = this;
            }
            callback && callback(img);
          }, this, options && options.crossOrigin);
        }
        else {
          options && image.setOptions(options);
          this[property] = image;
          image && (image.canvas = this);
          callback && callback(image);
        }
  
        return this;
      },
  
      /**
       * @private
       * @param {String} property Property to set ({@link fabric.StaticCanvas#backgroundColor|backgroundColor}
       * or {@link fabric.StaticCanvas#overlayColor|overlayColor})
       * @param {(Object|String|null)} color Object with pattern information, color value or null
       * @param {Function} [callback] Callback is invoked when color is set
       */
      __setBgOverlayColor: function(property, color, callback) {
        this[property] = color;
        this._initGradient(color, property);
        this._initPattern(color, property, callback);
        return this;
      },
  
      /**
       * @private
       */
      _createCanvasElement: function() {
        var element = createCanvasElement();
        if (!element) {
          throw CANVAS_INIT_ERROR;
        }
        if (!element.style) {
          element.style = { };
        }
        if (typeof element.getContext === 'undefined') {
          throw CANVAS_INIT_ERROR;
        }
        return element;
      },
  
      /**
       * @private
       * @param {Object} [options] Options object
       */
      _initOptions: function (options) {
        var lowerCanvasEl = this.lowerCanvasEl;
        this._setOptions(options);
  
        this.width = this.width || parseInt(lowerCanvasEl.width, 10) || 0;
        this.height = this.height || parseInt(lowerCanvasEl.height, 10) || 0;
  
        if (!this.lowerCanvasEl.style) {
          return;
        }
  
        lowerCanvasEl.width = this.width;
        lowerCanvasEl.height = this.height;
  
        lowerCanvasEl.style.width = this.width + 'px';
        lowerCanvasEl.style.height = this.height + 'px';
  
        this.viewportTransform = this.viewportTransform.slice();
      },
  
      /**
       * Creates a bottom canvas
       * @private
       * @param {HTMLElement} [canvasEl]
       */
      _createLowerCanvas: function (canvasEl) {
        // canvasEl === 'HTMLCanvasElement' does not work on jsdom/node
        if (canvasEl && canvasEl.getContext) {
          this.lowerCanvasEl = canvasEl;
        }
        else {
          this.lowerCanvasEl = fabric.util.getById(canvasEl) || this._createCanvasElement();
        }
  
        fabric.util.addClass(this.lowerCanvasEl, 'lower-canvas');
  
        if (this.interactive) {
          this._applyCanvasStyle(this.lowerCanvasEl);
        }
  
        this.contextContainer = this.lowerCanvasEl.getContext('2d');
      },
  
      /**
       * Returns canvas width (in px)
       * @return {Number}
       */
      getWidth: function () {
        return this.width;
      },
  
      /**
       * Returns canvas height (in px)
       * @return {Number}
       */
      getHeight: function () {
        return this.height;
      },
  
      /**
       * Sets width of this canvas instance
       * @param {Number|String} value                         Value to set width to
       * @param {Object}        [options]                     Options object
       * @param {Boolean}       [options.backstoreOnly=false] Set the given dimensions only as canvas backstore dimensions
       * @param {Boolean}       [options.cssOnly=false]       Set the given dimensions only as css dimensions
       * @return {fabric.Canvas} instance
       * @chainable true
       */
      setWidth: function (value, options) {
        return this.setDimensions({ width: value }, options);
      },
  
      /**
       * Sets height of this canvas instance
       * @param {Number|String} value                         Value to set height to
       * @param {Object}        [options]                     Options object
       * @param {Boolean}       [options.backstoreOnly=false] Set the given dimensions only as canvas backstore dimensions
       * @param {Boolean}       [options.cssOnly=false]       Set the given dimensions only as css dimensions
       * @return {fabric.Canvas} instance
       * @chainable true
       */
      setHeight: function (value, options) {
        return this.setDimensions({ height: value }, options);
      },
  
      /**
       * Sets dimensions (width, height) of this canvas instance. when options.cssOnly flag active you should also supply the unit of measure (px/%/em)
       * @param {Object}        dimensions                    Object with width/height properties
       * @param {Number|String} [dimensions.width]            Width of canvas element
       * @param {Number|String} [dimensions.height]           Height of canvas element
       * @param {Object}        [options]                     Options object
       * @param {Boolean}       [options.backstoreOnly=false] Set the given dimensions only as canvas backstore dimensions
       * @param {Boolean}       [options.cssOnly=false]       Set the given dimensions only as css dimensions
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      setDimensions: function (dimensions, options) {
        var cssValue;
  
        options = options || {};
  
        for (var prop in dimensions) {
          cssValue = dimensions[prop];
  
          if (!options.cssOnly) {
            this._setBackstoreDimension(prop, dimensions[prop]);
            cssValue += 'px';
            this.hasLostContext = true;
          }
  
          if (!options.backstoreOnly) {
            this._setCssDimension(prop, cssValue);
          }
        }
        if (this._isCurrentlyDrawing) {
          this.freeDrawingBrush && this.freeDrawingBrush._setBrushStyles();
        }
        this._initRetinaScaling();
        this._setImageSmoothing();
        this.calcOffset();
  
        if (!options.cssOnly) {
          this.requestRenderAll();
        }
  
        return this;
      },
  
      /**
       * Helper for setting width/height
       * @private
       * @param {String} prop property (width|height)
       * @param {Number} value value to set property to
       * @return {fabric.Canvas} instance
       * @chainable true
       */
      _setBackstoreDimension: function (prop, value) {
        this.lowerCanvasEl[prop] = value;
  
        if (this.upperCanvasEl) {
          this.upperCanvasEl[prop] = value;
        }
  
        if (this.cacheCanvasEl) {
          this.cacheCanvasEl[prop] = value;
        }
  
        this[prop] = value;
  
        return this;
      },
  
      /**
       * Helper for setting css width/height
       * @private
       * @param {String} prop property (width|height)
       * @param {String} value value to set property to
       * @return {fabric.Canvas} instance
       * @chainable true
       */
      _setCssDimension: function (prop, value) {
        this.lowerCanvasEl.style[prop] = value;
  
        if (this.upperCanvasEl) {
          this.upperCanvasEl.style[prop] = value;
        }
  
        if (this.wrapperEl) {
          this.wrapperEl.style[prop] = value;
        }
  
        return this;
      },
  
      /**
       * Returns canvas zoom level
       * @return {Number}
       */
      getZoom: function () {
        return this.viewportTransform[0];
      },
  
      /**
       * Sets viewport transform of this canvas instance
       * @param {Array} vpt the transform in the form of context.transform
       * @return {fabric.Canvas} instance
       * @chainable true
       */
      setViewportTransform: function (vpt) {
        var activeObject = this._activeObject, object, ignoreVpt = false, skipAbsolute = true, i, len;
        this.viewportTransform = vpt;
        for (i = 0, len = this._objects.length; i < len; i++) {
          object = this._objects[i];
          object.group || object.setCoords(ignoreVpt, skipAbsolute);
        }
        if (activeObject && activeObject.type === 'activeSelection') {
          activeObject.setCoords(ignoreVpt, skipAbsolute);
        }
        this.calcViewportBoundaries();
        this.renderOnAddRemove && this.requestRenderAll();
        return this;
      },
  
      /**
       * Sets zoom level of this canvas instance, zoom centered around point
       * @param {fabric.Point} point to zoom with respect to
       * @param {Number} value to set zoom to, less than 1 zooms out
       * @return {fabric.Canvas} instance
       * @chainable true
       */
      zoomToPoint: function (point, value) {
        // TODO: just change the scale, preserve other transformations
        var before = point, vpt = this.viewportTransform.slice(0);
        point = transformPoint(point, invertTransform(this.viewportTransform));
        vpt[0] = value;
        vpt[3] = value;
        var after = transformPoint(point, vpt);
        vpt[4] += before.x - after.x;
        vpt[5] += before.y - after.y;
        return this.setViewportTransform(vpt);
      },
  
      /**
       * Sets zoom level of this canvas instance
       * @param {Number} value to set zoom to, less than 1 zooms out
       * @return {fabric.Canvas} instance
       * @chainable true
       */
      setZoom: function (value) {
        this.zoomToPoint(new fabric.Point(0, 0), value);
        return this;
      },
  
      /**
       * Pan viewport so as to place point at top left corner of canvas
       * @param {fabric.Point} point to move to
       * @return {fabric.Canvas} instance
       * @chainable true
       */
      absolutePan: function (point) {
        var vpt = this.viewportTransform.slice(0);
        vpt[4] = -point.x;
        vpt[5] = -point.y;
        return this.setViewportTransform(vpt);
      },
  
      /**
       * Pans viewpoint relatively
       * @param {fabric.Point} point (position vector) to move by
       * @return {fabric.Canvas} instance
       * @chainable true
       */
      relativePan: function (point) {
        return this.absolutePan(new fabric.Point(
          -point.x - this.viewportTransform[4],
          -point.y - this.viewportTransform[5]
        ));
      },
  
      /**
       * Returns &lt;canvas> element corresponding to this instance
       * @return {HTMLCanvasElement}
       */
      getElement: function () {
        return this.lowerCanvasEl;
      },
  
      /**
       * @private
       * @param {fabric.Object} obj Object that was added
       */
      _onObjectAdded: function(obj) {
        this.stateful && obj.setupState();
        obj._set('canvas', this);
        obj.setCoords();
        this.fire('object:added', { target: obj });
        obj.fire('added');
      },
  
      /**
       * @private
       * @param {fabric.Object} obj Object that was removed
       */
      _onObjectRemoved: function(obj) {
        this.fire('object:removed', { target: obj });
        obj.fire('removed');
        delete obj.canvas;
      },
  
      /**
       * Clears specified context of canvas element
       * @param {CanvasRenderingContext2D} ctx Context to clear
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      clearContext: function(ctx) {
        ctx.clearRect(0, 0, this.width, this.height);
        return this;
      },
  
      /**
       * Returns context of canvas where objects are drawn
       * @return {CanvasRenderingContext2D}
       */
      getContext: function () {
        return this.contextContainer;
      },
  
      /**
       * Clears all contexts (background, main, top) of an instance
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      clear: function () {
        this._objects.length = 0;
        this.backgroundImage = null;
        this.overlayImage = null;
        this.backgroundColor = '';
        this.overlayColor = '';
        if (this._hasITextHandlers) {
          this.off('mouse:up', this._mouseUpITextHandler);
          this._iTextInstances = null;
          this._hasITextHandlers = false;
        }
        this.clearContext(this.contextContainer);
        this.fire('canvas:cleared');
        this.renderOnAddRemove && this.requestRenderAll();
        return this;
      },
  
      /**
       * Renders the canvas
       * @return {fabric.Canvas} instance
       * @chainable
       */
      renderAll: function () {
        var canvasToDrawOn = this.contextContainer;
        this.renderCanvas(canvasToDrawOn, this._objects);
        return this;
      },
  
      /**
       * Function created to be instance bound at initialization
       * used in requestAnimationFrame rendering
       * Let the fabricJS call it. If you call it manually you could have more
       * animationFrame stacking on to of each other
       * for an imperative rendering, use canvas.renderAll
       * @private
       * @return {fabric.Canvas} instance
       * @chainable
       */
      renderAndReset: function() {
        this.isRendering = 0;
        this.renderAll();
      },
  
      /**
       * Append a renderAll request to next animation frame.
       * unless one is already in progress, in that case nothing is done
       * a boolean flag will avoid appending more.
       * @return {fabric.Canvas} instance
       * @chainable
       */
      requestRenderAll: function () {
        if (!this.isRendering) {
          this.isRendering = fabric.util.requestAnimFrame(this.renderAndResetBound);
        }
        return this;
      },
  
      /**
       * Calculate the position of the 4 corner of canvas with current viewportTransform.
       * helps to determinate when an object is in the current rendering viewport using
       * object absolute coordinates ( aCoords )
       * @return {Object} points.tl
       * @chainable
       */
      calcViewportBoundaries: function() {
        var points = { }, width = this.width, height = this.height,
            iVpt = invertTransform(this.viewportTransform);
        points.tl = transformPoint({ x: 0, y: 0 }, iVpt);
        points.br = transformPoint({ x: width, y: height }, iVpt);
        points.tr = new fabric.Point(points.br.x, points.tl.y);
        points.bl = new fabric.Point(points.tl.x, points.br.y);
        this.vptCoords = points;
        return points;
      },
  
      cancelRequestedRender: function() {
        if (this.isRendering) {
          fabric.util.cancelAnimFrame(this.isRendering);
          this.isRendering = 0;
        }
      },
  
      /**
       * Renders background, objects, overlay and controls.
       * @param {CanvasRenderingContext2D} ctx
       * @param {Array} objects to render
       * @return {fabric.Canvas} instance
       * @chainable
       */
      renderCanvas: function(ctx, objects) {
        var v = this.viewportTransform, path = this.clipPath;
        this.cancelRequestedRender();
        this.calcViewportBoundaries();
        this.clearContext(ctx);
        this.fire('before:render', { ctx: ctx, });
        if (this.clipTo) {
          fabric.util.clipContext(this, ctx);
        }
        this._renderBackground(ctx);
  
        ctx.save();
        //apply viewport transform once for all rendering process
        ctx.transform(v[0], v[1], v[2], v[3], v[4], v[5]);
        this._renderObjects(ctx, objects);
        ctx.restore();
        if (!this.controlsAboveOverlay && this.interactive) {
          this.drawControls(ctx);
        }
        if (this.clipTo) {
          ctx.restore();
        }
        if (path) {
          path.canvas = this;
          // needed to setup a couple of variables
          path.shouldCache();
          path._transformDone = true;
          path.renderCache({ forClipping: true });
          this.drawClipPathOnCanvas(ctx);
        }
        this._renderOverlay(ctx);
        if (this.controlsAboveOverlay && this.interactive) {
          this.drawControls(ctx);
        }
        this.fire('after:render', { ctx: ctx, });
      },
  
      /**
       * Paint the cached clipPath on the lowerCanvasEl
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      drawClipPathOnCanvas: function(ctx) {
        var v = this.viewportTransform, path = this.clipPath;
        ctx.save();
        ctx.transform(v[0], v[1], v[2], v[3], v[4], v[5]);
        // DEBUG: uncomment this line, comment the following
        // ctx.globalAlpha = 0.4;
        ctx.globalCompositeOperation = 'destination-in';
        path.transform(ctx);
        ctx.scale(1 / path.zoomX, 1 / path.zoomY);
        ctx.drawImage(path._cacheCanvas, -path.cacheTranslationX, -path.cacheTranslationY);
        ctx.restore();
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       * @param {Array} objects to render
       */
      _renderObjects: function(ctx, objects) {
        var i, len;
        for (i = 0, len = objects.length; i < len; ++i) {
          objects[i] && objects[i].render(ctx);
        }
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       * @param {string} property 'background' or 'overlay'
       */
      _renderBackgroundOrOverlay: function(ctx, property) {
        var fill = this[property + 'Color'], object = this[property + 'Image'],
            v = this.viewportTransform, needsVpt = this[property + 'Vpt'];
        if (!fill && !object) {
          return;
        }
        if (fill) {
          ctx.save();
          ctx.beginPath();
          ctx.moveTo(0, 0);
          ctx.lineTo(this.width, 0);
          ctx.lineTo(this.width, this.height);
          ctx.lineTo(0, this.height);
          ctx.closePath();
          ctx.fillStyle = fill.toLive
            ? fill.toLive(ctx, this)
            : fill;
          if (needsVpt) {
            ctx.transform(v[0], v[1], v[2], v[3], v[4], v[5]);
          }
          ctx.transform(1, 0, 0, 1, fill.offsetX || 0, fill.offsetY || 0);
          var m = fill.gradientTransform || fill.patternTransform;
          m && ctx.transform(m[0], m[1], m[2], m[3], m[4], m[5]);
          ctx.fill();
          ctx.restore();
        }
        if (object) {
          ctx.save();
          if (needsVpt) {
            ctx.transform(v[0], v[1], v[2], v[3], v[4], v[5]);
          }
          object.render(ctx);
          ctx.restore();
        }
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _renderBackground: function(ctx) {
        this._renderBackgroundOrOverlay(ctx, 'background');
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _renderOverlay: function(ctx) {
        this._renderBackgroundOrOverlay(ctx, 'overlay');
      },
  
      /**
       * Returns coordinates of a center of canvas.
       * Returned value is an object with top and left properties
       * @return {Object} object with "top" and "left" number values
       */
      getCenter: function () {
        return {
          top: this.height / 2,
          left: this.width / 2
        };
      },
  
      /**
       * Centers object horizontally in the canvas
       * @param {fabric.Object} object Object to center horizontally
       * @return {fabric.Canvas} thisArg
       */
      centerObjectH: function (object) {
        return this._centerObject(object, new fabric.Point(this.getCenter().left, object.getCenterPoint().y));
      },
  
      /**
       * Centers object vertically in the canvas
       * @param {fabric.Object} object Object to center vertically
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      centerObjectV: function (object) {
        return this._centerObject(object, new fabric.Point(object.getCenterPoint().x, this.getCenter().top));
      },
  
      /**
       * Centers object vertically and horizontally in the canvas
       * @param {fabric.Object} object Object to center vertically and horizontally
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      centerObject: function(object) {
        var center = this.getCenter();
  
        return this._centerObject(object, new fabric.Point(center.left, center.top));
      },
  
      /**
       * Centers object vertically and horizontally in the viewport
       * @param {fabric.Object} object Object to center vertically and horizontally
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      viewportCenterObject: function(object) {
        var vpCenter = this.getVpCenter();
  
        return this._centerObject(object, vpCenter);
      },
  
      /**
       * Centers object horizontally in the viewport, object.top is unchanged
       * @param {fabric.Object} object Object to center vertically and horizontally
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      viewportCenterObjectH: function(object) {
        var vpCenter = this.getVpCenter();
        this._centerObject(object, new fabric.Point(vpCenter.x, object.getCenterPoint().y));
        return this;
      },
  
      /**
       * Centers object Vertically in the viewport, object.top is unchanged
       * @param {fabric.Object} object Object to center vertically and horizontally
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      viewportCenterObjectV: function(object) {
        var vpCenter = this.getVpCenter();
  
        return this._centerObject(object, new fabric.Point(object.getCenterPoint().x, vpCenter.y));
      },
  
      /**
       * Calculate the point in canvas that correspond to the center of actual viewport.
       * @return {fabric.Point} vpCenter, viewport center
       * @chainable
       */
      getVpCenter: function() {
        var center = this.getCenter(),
            iVpt = invertTransform(this.viewportTransform);
        return transformPoint({ x: center.left, y: center.top }, iVpt);
      },
  
      /**
       * @private
       * @param {fabric.Object} object Object to center
       * @param {fabric.Point} center Center point
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      _centerObject: function(object, center) {
        object.setPositionByOrigin(center, 'center', 'center');
        object.setCoords();
        this.renderOnAddRemove && this.requestRenderAll();
        return this;
      },
  
      /**
       * Returs dataless JSON representation of canvas
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {String} json string
       */
      toDatalessJSON: function (propertiesToInclude) {
        return this.toDatalessObject(propertiesToInclude);
      },
  
      /**
       * Returns object representation of canvas
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object} object representation of an instance
       */
      toObject: function (propertiesToInclude) {
        return this._toObjectMethod('toObject', propertiesToInclude);
      },
  
      /**
       * Returns dataless object representation of canvas
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object} object representation of an instance
       */
      toDatalessObject: function (propertiesToInclude) {
        return this._toObjectMethod('toDatalessObject', propertiesToInclude);
      },
  
      /**
       * @private
       */
      _toObjectMethod: function (methodName, propertiesToInclude) {
  
        var clipPath = this.clipPath, data = {
          version: fabric.version,
          objects: this._toObjects(methodName, propertiesToInclude),
        };
        if (clipPath) {
          data.clipPath = this._toObject(this.clipPath, methodName, propertiesToInclude);
        }
        extend(data, this.__serializeBgOverlay(methodName, propertiesToInclude));
  
        fabric.util.populateWithProperties(this, data, propertiesToInclude);
  
        return data;
      },
  
      /**
       * @private
       */
      _toObjects: function(methodName, propertiesToInclude) {
        return this._objects.filter(function(object) {
          return !object.excludeFromExport;
        }).map(function(instance) {
          return this._toObject(instance, methodName, propertiesToInclude);
        }, this);
      },
  
      /**
       * @private
       */
      _toObject: function(instance, methodName, propertiesToInclude) {
        var originalValue;
  
        if (!this.includeDefaultValues) {
          originalValue = instance.includeDefaultValues;
          instance.includeDefaultValues = false;
        }
  
        var object = instance[methodName](propertiesToInclude);
        if (!this.includeDefaultValues) {
          instance.includeDefaultValues = originalValue;
        }
        return object;
      },
  
      /**
       * @private
       */
      __serializeBgOverlay: function(methodName, propertiesToInclude) {
        var data = { }, bgImage = this.backgroundImage, overlay = this.overlayImage;
  
        if (this.backgroundColor) {
          data.background = this.backgroundColor.toObject
            ? this.backgroundColor.toObject(propertiesToInclude)
            : this.backgroundColor;
        }
  
        if (this.overlayColor) {
          data.overlay = this.overlayColor.toObject
            ? this.overlayColor.toObject(propertiesToInclude)
            : this.overlayColor;
        }
        if (bgImage && !bgImage.excludeFromExport) {
          data.backgroundImage = this._toObject(bgImage, methodName, propertiesToInclude);
        }
        if (overlay && !overlay.excludeFromExport) {
          data.overlayImage = this._toObject(overlay, methodName, propertiesToInclude);
        }
  
        return data;
      },
  
      /* _TO_SVG_START_ */
      /**
       * When true, getSvgTransform() will apply the StaticCanvas.viewportTransform to the SVG transformation. When true,
       * a zoomed canvas will then produce zoomed SVG output.
       * @type Boolean
       * @default
       */
      svgViewportTransformation: true,
  
      /**
       * Returns SVG representation of canvas
       * @function
       * @param {Object} [options] Options object for SVG output
       * @param {Boolean} [options.suppressPreamble=false] If true xml tag is not included
       * @param {Object} [options.viewBox] SVG viewbox object
       * @param {Number} [options.viewBox.x] x-cooridnate of viewbox
       * @param {Number} [options.viewBox.y] y-coordinate of viewbox
       * @param {Number} [options.viewBox.width] Width of viewbox
       * @param {Number} [options.viewBox.height] Height of viewbox
       * @param {String} [options.encoding=UTF-8] Encoding of SVG output
       * @param {String} [options.width] desired width of svg with or without units
       * @param {String} [options.height] desired height of svg with or without units
       * @param {Function} [reviver] Method for further parsing of svg elements, called after each fabric object converted into svg representation.
       * @return {String} SVG string
       * @tutorial {@link http://fabricjs.com/fabric-intro-part-3#serialization}
       * @see {@link http://jsfiddle.net/fabricjs/jQ3ZZ/|jsFiddle demo}
       * @example <caption>Normal SVG output</caption>
       * var svg = canvas.toSVG();
       * @example <caption>SVG output without preamble (without &lt;?xml ../>)</caption>
       * var svg = canvas.toSVG({suppressPreamble: true});
       * @example <caption>SVG output with viewBox attribute</caption>
       * var svg = canvas.toSVG({
       *   viewBox: {
       *     x: 100,
       *     y: 100,
       *     width: 200,
       *     height: 300
       *   }
       * });
       * @example <caption>SVG output with different encoding (default: UTF-8)</caption>
       * var svg = canvas.toSVG({encoding: 'ISO-8859-1'});
       * @example <caption>Modify SVG output with reviver function</caption>
       * var svg = canvas.toSVG(null, function(svg) {
       *   return svg.replace('stroke-dasharray: ; stroke-linecap: butt; stroke-linejoin: miter; stroke-miterlimit: 10; ', '');
       * });
       */
      toSVG: function(options, reviver) {
        options || (options = { });
        options.reviver = reviver;
        var markup = [];
  
        this._setSVGPreamble(markup, options);
        this._setSVGHeader(markup, options);
        if (this.clipPath) {
          markup.push('<g clip-path="url(#' + this.clipPath.clipPathId + ')" >\n');
        }
        this._setSVGBgOverlayColor(markup, 'background');
        this._setSVGBgOverlayImage(markup, 'backgroundImage', reviver);
        this._setSVGObjects(markup, reviver);
        if (this.clipPath) {
          markup.push('</g>\n');
        }
        this._setSVGBgOverlayColor(markup, 'overlay');
        this._setSVGBgOverlayImage(markup, 'overlayImage', reviver);
  
        markup.push('</svg>');
  
        return markup.join('');
      },
  
      /**
       * @private
       */
      _setSVGPreamble: function(markup, options) {
        if (options.suppressPreamble) {
          return;
        }
        markup.push(
          '<?xml version="1.0" encoding="', (options.encoding || 'UTF-8'), '" standalone="no" ?>\n',
          '<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" ',
          '"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">\n'
        );
      },
  
      /**
       * @private
       */
      _setSVGHeader: function(markup, options) {
        var width = options.width || this.width,
            height = options.height || this.height,
            vpt, viewBox = 'viewBox="0 0 ' + this.width + ' ' + this.height + '" ',
            NUM_FRACTION_DIGITS = fabric.Object.NUM_FRACTION_DIGITS;
  
        if (options.viewBox) {
          viewBox = 'viewBox="' +
                  options.viewBox.x + ' ' +
                  options.viewBox.y + ' ' +
                  options.viewBox.width + ' ' +
                  options.viewBox.height + '" ';
        }
        else {
          if (this.svgViewportTransformation) {
            vpt = this.viewportTransform;
            viewBox = 'viewBox="' +
                    toFixed(-vpt[4] / vpt[0], NUM_FRACTION_DIGITS) + ' ' +
                    toFixed(-vpt[5] / vpt[3], NUM_FRACTION_DIGITS) + ' ' +
                    toFixed(this.width / vpt[0], NUM_FRACTION_DIGITS) + ' ' +
                    toFixed(this.height / vpt[3], NUM_FRACTION_DIGITS) + '" ';
          }
        }
  
        markup.push(
          '<svg ',
          'xmlns="http://www.w3.org/2000/svg" ',
          'xmlns:xlink="http://www.w3.org/1999/xlink" ',
          'version="1.1" ',
          'width="', width, '" ',
          'height="', height, '" ',
          viewBox,
          'xml:space="preserve">\n',
          '<desc>Created with Fabric.js ', fabric.version, '</desc>\n',
          '<defs>\n',
          this.createSVGFontFacesMarkup(),
          this.createSVGRefElementsMarkup(),
          this.createSVGClipPathMarkup(options),
          '</defs>\n'
        );
      },
  
      createSVGClipPathMarkup: function(options) {
        var clipPath = this.clipPath;
        if (clipPath) {
          clipPath.clipPathId = 'CLIPPATH_' + fabric.Object.__uid++;
          return  '<clipPath id="' + clipPath.clipPathId + '" >\n' +
            this.clipPath.toClipPathSVG(options.reviver) +
            '</clipPath>\n';
        }
        return '';
      },
  
      /**
       * Creates markup containing SVG referenced elements like patterns, gradients etc.
       * @return {String}
       */
      createSVGRefElementsMarkup: function() {
        var _this = this,
            markup = ['background', 'overlay'].map(function(prop) {
              var fill = _this[prop + 'Color'];
              if (fill && fill.toLive) {
                var shouldTransform = _this[prop + 'Vpt'], vpt = _this.viewportTransform,
                    object = {
                      width: _this.width / (shouldTransform ? vpt[0] : 1),
                      height: _this.height / (shouldTransform ? vpt[3] : 1)
                    };
                return fill.toSVG(
                  object,
                  { additionalTransform: shouldTransform ? fabric.util.matrixToSVG(vpt) : '' }
                );
              }
            });
        return markup.join('');
      },
  
      /**
       * Creates markup containing SVG font faces,
       * font URLs for font faces must be collected by developers
       * and are not extracted from the DOM by fabricjs
       * @param {Array} objects Array of fabric objects
       * @return {String}
       */
      createSVGFontFacesMarkup: function() {
        var markup = '', fontList = { }, obj, fontFamily,
            style, row, rowIndex, _char, charIndex, i, len,
            fontPaths = fabric.fontPaths, objects = this._objects;
  
        for (i = 0, len = objects.length; i < len; i++) {
          obj = objects[i];
          fontFamily = obj.fontFamily;
          if (obj.type.indexOf('text') === -1 || fontList[fontFamily] || !fontPaths[fontFamily]) {
            continue;
          }
          fontList[fontFamily] = true;
          if (!obj.styles) {
            continue;
          }
          style = obj.styles;
          for (rowIndex in style) {
            row = style[rowIndex];
            for (charIndex in row) {
              _char = row[charIndex];
              fontFamily = _char.fontFamily;
              if (!fontList[fontFamily] && fontPaths[fontFamily]) {
                fontList[fontFamily] = true;
              }
            }
          }
        }
  
        for (var j in fontList) {
          markup += [
            '\t\t@font-face {\n',
            '\t\t\tfont-family: \'', j, '\';\n',
            '\t\t\tsrc: url(\'', fontPaths[j], '\');\n',
            '\t\t}\n'
          ].join('');
        }
  
        if (markup) {
          markup = [
            '\t<style type="text/css">',
            '<![CDATA[\n',
            markup,
            ']]>',
            '</style>\n'
          ].join('');
        }
  
        return markup;
      },
  
      /**
       * @private
       */
      _setSVGObjects: function(markup, reviver) {
        var instance, i, len, objects = this._objects;
        for (i = 0, len = objects.length; i < len; i++) {
          instance = objects[i];
          if (instance.excludeFromExport) {
            continue;
          }
          this._setSVGObject(markup, instance, reviver);
        }
      },
  
      /**
       * @private
       */
      _setSVGObject: function(markup, instance, reviver) {
        markup.push(instance.toSVG(reviver));
      },
  
      /**
       * @private
       */
      _setSVGBgOverlayImage: function(markup, property, reviver) {
        if (this[property] && !this[property].excludeFromExport && this[property].toSVG) {
          markup.push(this[property].toSVG(reviver));
        }
      },
  
      /**
       * @private
       */
      _setSVGBgOverlayColor: function(markup, property) {
        var filler = this[property + 'Color'], vpt = this.viewportTransform, finalWidth = this.width,
            finalHeight = this.height;
        if (!filler) {
          return;
        }
        if (filler.toLive) {
          var repeat = filler.repeat, iVpt = fabric.util.invertTransform(vpt), shouldInvert = this[property + 'Vpt'],
              additionalTransform = shouldInvert ? fabric.util.matrixToSVG(iVpt) : '';
          markup.push(
            '<rect transform="' + additionalTransform + ' translate(', finalWidth / 2, ',', finalHeight / 2, ')"',
            ' x="', filler.offsetX - finalWidth / 2,
            '" y="', filler.offsetY - finalHeight / 2, '" ',
            'width="',
            (repeat === 'repeat-y' || repeat === 'no-repeat'
              ? filler.source.width
              : finalWidth ),
            '" height="',
            (repeat === 'repeat-x' || repeat === 'no-repeat'
              ? filler.source.height
              : finalHeight),
            '" fill="url(#SVGID_' + filler.id + ')"',
            '></rect>\n'
          );
        }
        else {
          markup.push(
            '<rect x="0" y="0" width="100%" height="100%" ',
            'fill="', filler, '"',
            '></rect>\n'
          );
        }
      },
      /* _TO_SVG_END_ */
  
      /**
       * Moves an object or the objects of a multiple selection
       * to the bottom of the stack of drawn objects
       * @param {fabric.Object} object Object to send to back
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      sendToBack: function (object) {
        if (!object) {
          return this;
        }
        var activeSelection = this._activeObject,
            i, obj, objs;
        if (object === activeSelection && object.type === 'activeSelection') {
          objs = activeSelection._objects;
          for (i = objs.length; i--;) {
            obj = objs[i];
            removeFromArray(this._objects, obj);
            this._objects.unshift(obj);
          }
        }
        else {
          removeFromArray(this._objects, object);
          this._objects.unshift(object);
        }
        this.renderOnAddRemove && this.requestRenderAll();
        return this;
      },
  
      /**
       * Moves an object or the objects of a multiple selection
       * to the top of the stack of drawn objects
       * @param {fabric.Object} object Object to send
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      bringToFront: function (object) {
        if (!object) {
          return this;
        }
        var activeSelection = this._activeObject,
            i, obj, objs;
        if (object === activeSelection && object.type === 'activeSelection') {
          objs = activeSelection._objects;
          for (i = 0; i < objs.length; i++) {
            obj = objs[i];
            removeFromArray(this._objects, obj);
            this._objects.push(obj);
          }
        }
        else {
          removeFromArray(this._objects, object);
          this._objects.push(object);
        }
        this.renderOnAddRemove && this.requestRenderAll();
        return this;
      },
  
      /**
       * Moves an object or a selection down in stack of drawn objects
       * An optional paramter, intersecting allowes to move the object in behind
       * the first intersecting object. Where intersection is calculated with
       * bounding box. If no intersection is found, there will not be change in the
       * stack.
       * @param {fabric.Object} object Object to send
       * @param {Boolean} [intersecting] If `true`, send object behind next lower intersecting object
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      sendBackwards: function (object, intersecting) {
        if (!object) {
          return this;
        }
        var activeSelection = this._activeObject,
            i, obj, idx, newIdx, objs, objsMoved = 0;
  
        if (object === activeSelection && object.type === 'activeSelection') {
          objs = activeSelection._objects;
          for (i = 0; i < objs.length; i++) {
            obj = objs[i];
            idx = this._objects.indexOf(obj);
            if (idx > 0 + objsMoved) {
              newIdx = idx - 1;
              removeFromArray(this._objects, obj);
              this._objects.splice(newIdx, 0, obj);
            }
            objsMoved++;
          }
        }
        else {
          idx = this._objects.indexOf(object);
          if (idx !== 0) {
            // if object is not on the bottom of stack
            newIdx = this._findNewLowerIndex(object, idx, intersecting);
            removeFromArray(this._objects, object);
            this._objects.splice(newIdx, 0, object);
          }
        }
        this.renderOnAddRemove && this.requestRenderAll();
        return this;
      },
  
      /**
       * @private
       */
      _findNewLowerIndex: function(object, idx, intersecting) {
        var newIdx, i;
  
        if (intersecting) {
          newIdx = idx;
  
          // traverse down the stack looking for the nearest intersecting object
          for (i = idx - 1; i >= 0; --i) {
  
            var isIntersecting = object.intersectsWithObject(this._objects[i]) ||
                                 object.isContainedWithinObject(this._objects[i]) ||
                                 this._objects[i].isContainedWithinObject(object);
  
            if (isIntersecting) {
              newIdx = i;
              break;
            }
          }
        }
        else {
          newIdx = idx - 1;
        }
  
        return newIdx;
      },
  
      /**
       * Moves an object or a selection up in stack of drawn objects
       * An optional paramter, intersecting allowes to move the object in front
       * of the first intersecting object. Where intersection is calculated with
       * bounding box. If no intersection is found, there will not be change in the
       * stack.
       * @param {fabric.Object} object Object to send
       * @param {Boolean} [intersecting] If `true`, send object in front of next upper intersecting object
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      bringForward: function (object, intersecting) {
        if (!object) {
          return this;
        }
        var activeSelection = this._activeObject,
            i, obj, idx, newIdx, objs, objsMoved = 0;
  
        if (object === activeSelection && object.type === 'activeSelection') {
          objs = activeSelection._objects;
          for (i = objs.length; i--;) {
            obj = objs[i];
            idx = this._objects.indexOf(obj);
            if (idx < this._objects.length - 1 - objsMoved) {
              newIdx = idx + 1;
              removeFromArray(this._objects, obj);
              this._objects.splice(newIdx, 0, obj);
            }
            objsMoved++;
          }
        }
        else {
          idx = this._objects.indexOf(object);
          if (idx !== this._objects.length - 1) {
            // if object is not on top of stack (last item in an array)
            newIdx = this._findNewUpperIndex(object, idx, intersecting);
            removeFromArray(this._objects, object);
            this._objects.splice(newIdx, 0, object);
          }
        }
        this.renderOnAddRemove && this.requestRenderAll();
        return this;
      },
  
      /**
       * @private
       */
      _findNewUpperIndex: function(object, idx, intersecting) {
        var newIdx, i, len;
  
        if (intersecting) {
          newIdx = idx;
  
          // traverse up the stack looking for the nearest intersecting object
          for (i = idx + 1, len = this._objects.length; i < len; ++i) {
  
            var isIntersecting = object.intersectsWithObject(this._objects[i]) ||
                                 object.isContainedWithinObject(this._objects[i]) ||
                                 this._objects[i].isContainedWithinObject(object);
  
            if (isIntersecting) {
              newIdx = i;
              break;
            }
          }
        }
        else {
          newIdx = idx + 1;
        }
  
        return newIdx;
      },
  
      /**
       * Moves an object to specified level in stack of drawn objects
       * @param {fabric.Object} object Object to send
       * @param {Number} index Position to move to
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      moveTo: function (object, index) {
        removeFromArray(this._objects, object);
        this._objects.splice(index, 0, object);
        return this.renderOnAddRemove && this.requestRenderAll();
      },
  
      /**
       * Clears a canvas element and dispose objects
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      dispose: function () {
        // cancel eventually ongoing renders
        if (this.isRendering) {
          fabric.util.cancelAnimFrame(this.isRendering);
          this.isRendering = 0;
        }
        this.forEachObject(function(object) {
          object.dispose && object.dispose();
        });
        this._objects = [];
        if (this.backgroundImage && this.backgroundImage.dispose) {
          this.backgroundImage.dispose();
        }
        this.backgroundImage = null;
        if (this.overlayImage && this.overlayImage.dispose) {
          this.overlayImage.dispose();
        }
        this.overlayImage = null;
        this._iTextInstances = null;
        this.contextContainer = null;
        fabric.util.cleanUpJsdomNode(this.lowerCanvasEl);
        this.lowerCanvasEl = undefined;
        return this;
      },
  
      /**
       * Returns a string representation of an instance
       * @return {String} string representation of an instance
       */
      toString: function () {
        return '#<fabric.Canvas (' + this.complexity() + '): ' +
                 '{ objects: ' + this._objects.length + ' }>';
      }
    });
  
    extend(fabric.StaticCanvas.prototype, fabric.Observable);
    extend(fabric.StaticCanvas.prototype, fabric.Collection);
    extend(fabric.StaticCanvas.prototype, fabric.DataURLExporter);
  
    extend(fabric.StaticCanvas, /** @lends fabric.StaticCanvas */ {
  
      /**
       * @static
       * @type String
       * @default
       */
      EMPTY_JSON: '{"objects": [], "background": "white"}',
  
      /**
       * Provides a way to check support of some of the canvas methods
       * (either those of HTMLCanvasElement itself, or rendering context)
       *
       * @param {String} methodName Method to check support for;
       *                            Could be one of "setLineDash"
       * @return {Boolean | null} `true` if method is supported (or at least exists),
       *                          `null` if canvas element or context can not be initialized
       */
      supports: function (methodName) {
        var el = createCanvasElement();
  
        if (!el || !el.getContext) {
          return null;
        }
  
        var ctx = el.getContext('2d');
        if (!ctx) {
          return null;
        }
  
        switch (methodName) {
  
          case 'setLineDash':
            return typeof ctx.setLineDash !== 'undefined';
  
          default:
            return null;
        }
      }
    });
  
    /**
     * Returns JSON representation of canvas
     * @function
     * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
     * @return {String} JSON string
     * @tutorial {@link http://fabricjs.com/fabric-intro-part-3#serialization}
     * @see {@link http://jsfiddle.net/fabricjs/pec86/|jsFiddle demo}
     * @example <caption>JSON without additional properties</caption>
     * var json = canvas.toJSON();
     * @example <caption>JSON with additional properties included</caption>
     * var json = canvas.toJSON(['lockMovementX', 'lockMovementY', 'lockRotation', 'lockScalingX', 'lockScalingY', 'lockUniScaling']);
     * @example <caption>JSON without default values</caption>
     * canvas.includeDefaultValues = false;
     * var json = canvas.toJSON();
     */
    fabric.StaticCanvas.prototype.toJSON = fabric.StaticCanvas.prototype.toObject;
  
    if (fabric.isLikelyNode) {
      fabric.StaticCanvas.prototype.createPNGStream = function() {
        var impl = getNodeCanvas(this.lowerCanvasEl);
        return impl && impl.createPNGStream();
      };
      fabric.StaticCanvas.prototype.createJPEGStream = function(opts) {
        var impl = getNodeCanvas(this.lowerCanvasEl);
        return impl && impl.createJPEGStream(opts);
      };
    }
  })();
  
  
  /**
   * BaseBrush class
   * @class fabric.BaseBrush
   * @see {@link http://fabricjs.com/freedrawing|Freedrawing demo}
   */
  fabric.BaseBrush = fabric.util.createClass(/** @lends fabric.BaseBrush.prototype */ {
  
    /**
     * Color of a brush
     * @type String
     * @default
     */
    color: 'rgb(0, 0, 0)',
  
    /**
     * Width of a brush, has to be a Number, no string literals
     * @type Number
     * @default
     */
    width: 1,
  
    /**
     * Shadow object representing shadow of this shape.
     * <b>Backwards incompatibility note:</b> This property replaces "shadowColor" (String), "shadowOffsetX" (Number),
     * "shadowOffsetY" (Number) and "shadowBlur" (Number) since v1.2.12
     * @type fabric.Shadow
     * @default
     */
    shadow: null,
  
    /**
     * Line endings style of a brush (one of "butt", "round", "square")
     * @type String
     * @default
     */
    strokeLineCap: 'round',
  
    /**
     * Corner style of a brush (one of "bevel", "round", "miter")
     * @type String
     * @default
     */
    strokeLineJoin: 'round',
  
    /**
     * Maximum miter length (used for strokeLineJoin = "miter") of a brush's
     * @type Number
     * @default
     */
    strokeMiterLimit:         10,
  
    /**
     * Stroke Dash Array.
     * @type Array
     * @default
     */
    strokeDashArray: null,
  
    /**
     * Sets shadow of an object
     * @param {Object|String} [options] Options object or string (e.g. "2px 2px 10px rgba(0,0,0,0.2)")
     * @return {fabric.Object} thisArg
     * @chainable
     */
    setShadow: function(options) {
      this.shadow = new fabric.Shadow(options);
      return this;
    },
  
    /**
     * Sets brush styles
     * @private
     */
    _setBrushStyles: function() {
      var ctx = this.canvas.contextTop;
      ctx.strokeStyle = this.color;
      ctx.lineWidth = this.width;
      ctx.lineCap = this.strokeLineCap;
      ctx.miterLimit = this.strokeMiterLimit;
      ctx.lineJoin = this.strokeLineJoin;
      if (fabric.StaticCanvas.supports('setLineDash')) {
        ctx.setLineDash(this.strokeDashArray || []);
      }
    },
  
    /**
     * Sets the transformation on given context
     * @param {RenderingContext2d} ctx context to render on
     * @private
     */
    _saveAndTransform: function(ctx) {
      var v = this.canvas.viewportTransform;
      ctx.save();
      ctx.transform(v[0], v[1], v[2], v[3], v[4], v[5]);
    },
  
    /**
     * Sets brush shadow styles
     * @private
     */
    _setShadow: function() {
      if (!this.shadow) {
        return;
      }
  
      var ctx = this.canvas.contextTop,
          zoom = this.canvas.getZoom();
  
      ctx.shadowColor = this.shadow.color;
      ctx.shadowBlur = this.shadow.blur * zoom;
      ctx.shadowOffsetX = this.shadow.offsetX * zoom;
      ctx.shadowOffsetY = this.shadow.offsetY * zoom;
    },
  
    needsFullRender: function() {
      var color = new fabric.Color(this.color);
      return color.getAlpha() < 1 || !!this.shadow;
    },
  
    /**
     * Removes brush shadow styles
     * @private
     */
    _resetShadow: function() {
      var ctx = this.canvas.contextTop;
  
      ctx.shadowColor = '';
      ctx.shadowBlur = ctx.shadowOffsetX = ctx.shadowOffsetY = 0;
    }
  });
  
  
  (function() {
    /**
     * PencilBrush class
     * @class fabric.PencilBrush
     * @extends fabric.BaseBrush
     */
    fabric.PencilBrush = fabric.util.createClass(fabric.BaseBrush, /** @lends fabric.PencilBrush.prototype */ {
  
      /**
       * Discard points that are less than `decimate` pixel distant from each other
       * @type Number
       * @default 0.4
       */
      decimate: 0.4,
  
      /**
       * Constructor
       * @param {fabric.Canvas} canvas
       * @return {fabric.PencilBrush} Instance of a pencil brush
       */
      initialize: function(canvas) {
        this.canvas = canvas;
        this._points = [];
      },
  
      /**
       * Invoked inside on mouse down and mouse move
       * @param {Object} pointer
       */
      _drawSegment: function (ctx, p1, p2) {
        var midPoint = p1.midPointFrom(p2);
        ctx.quadraticCurveTo(p1.x, p1.y, midPoint.x, midPoint.y);
        return midPoint;
      },
  
      /**
       * Inovoked on mouse down
       * @param {Object} pointer
       */
      onMouseDown: function(pointer, options) {
        if (!this.canvas._isMainEvent(options.e)) {
          return;
        }
        this._prepareForDrawing(pointer);
        // capture coordinates immediately
        // this allows to draw dots (when movement never occurs)
        this._captureDrawingPath(pointer);
        this._render();
      },
  
      /**
       * Inovoked on mouse move
       * @param {Object} pointer
       */
      onMouseMove: function(pointer, options) {
        if (!this.canvas._isMainEvent(options.e)) {
          return;
        }
        if (this._captureDrawingPath(pointer) && this._points.length > 1) {
          if (this.needsFullRender()) {
            // redraw curve
            // clear top canvas
            this.canvas.clearContext(this.canvas.contextTop);
            this._render();
          }
          else {
            var points = this._points, length = points.length, ctx = this.canvas.contextTop;
            // draw the curve update
            this._saveAndTransform(ctx);
            if (this.oldEnd) {
              ctx.beginPath();
              ctx.moveTo(this.oldEnd.x, this.oldEnd.y);
            }
            this.oldEnd = this._drawSegment(ctx, points[length - 2], points[length - 1], true);
            ctx.stroke();
            ctx.restore();
          }
        }
      },
  
      /**
       * Invoked on mouse up
       */
      onMouseUp: function(options) {
        if (!this.canvas._isMainEvent(options.e)) {
          return true;
        }
        this.oldEnd = undefined;
        this._finalizeAndAddPath();
        return false;
      },
  
      /**
       * @private
       * @param {Object} pointer Actual mouse position related to the canvas.
       */
      _prepareForDrawing: function(pointer) {
  
        var p = new fabric.Point(pointer.x, pointer.y);
  
        this._reset();
        this._addPoint(p);
        this.canvas.contextTop.moveTo(p.x, p.y);
      },
  
      /**
       * @private
       * @param {fabric.Point} point Point to be added to points array
       */
      _addPoint: function(point) {
        if (this._points.length > 1 && point.eq(this._points[this._points.length - 1])) {
          return false;
        }
        this._points.push(point);
        return true;
      },
  
      /**
       * Clear points array and set contextTop canvas style.
       * @private
       */
      _reset: function() {
        this._points = [];
        this._setBrushStyles();
        this._setShadow();
      },
  
      /**
       * @private
       * @param {Object} pointer Actual mouse position related to the canvas.
       */
      _captureDrawingPath: function(pointer) {
        var pointerPoint = new fabric.Point(pointer.x, pointer.y);
        return this._addPoint(pointerPoint);
      },
  
      /**
       * Draw a smooth path on the topCanvas using quadraticCurveTo
       * @private
       */
      _render: function() {
        var ctx  = this.canvas.contextTop, i, len,
            p1 = this._points[0],
            p2 = this._points[1];
  
        this._saveAndTransform(ctx);
        ctx.beginPath();
        //if we only have 2 points in the path and they are the same
        //it means that the user only clicked the canvas without moving the mouse
        //then we should be drawing a dot. A path isn't drawn between two identical dots
        //that's why we set them apart a bit
        if (this._points.length === 2 && p1.x === p2.x && p1.y === p2.y) {
          var width = this.width / 1000;
          p1 = new fabric.Point(p1.x, p1.y);
          p2 = new fabric.Point(p2.x, p2.y);
          p1.x -= width;
          p2.x += width;
        }
        ctx.moveTo(p1.x, p1.y);
  
        for (i = 1, len = this._points.length; i < len; i++) {
          // we pick the point between pi + 1 & pi + 2 as the
          // end point and p1 as our control point.
          this._drawSegment(ctx, p1, p2);
          p1 = this._points[i];
          p2 = this._points[i + 1];
        }
        // Draw last line as a straight line while
        // we wait for the next point to be able to calculate
        // the bezier control point
        ctx.lineTo(p1.x, p1.y);
        ctx.stroke();
        ctx.restore();
      },
  
      /**
       * Converts points to SVG path
       * @param {Array} points Array of points
       * @return {String} SVG path
       */
      convertPointsToSVGPath: function(points) {
        var path = [], i, width = this.width / 1000,
            p1 = new fabric.Point(points[0].x, points[0].y),
            p2 = new fabric.Point(points[1].x, points[1].y),
            len = points.length, multSignX = 1, multSignY = 0, manyPoints = len > 2;
  
        if (manyPoints) {
          multSignX = points[2].x < p2.x ? -1 : points[2].x === p2.x ? 0 : 1;
          multSignY = points[2].y < p2.y ? -1 : points[2].y === p2.y ? 0 : 1;
        }
        path.push('M ', p1.x - multSignX * width, ' ', p1.y - multSignY * width, ' ');
        for (i = 1; i < len; i++) {
          if (!p1.eq(p2)) {
            var midPoint = p1.midPointFrom(p2);
            // p1 is our bezier control point
            // midpoint is our endpoint
            // start point is p(i-1) value.
            path.push('Q ', p1.x, ' ', p1.y, ' ', midPoint.x, ' ', midPoint.y, ' ');
          }
          p1 = points[i];
          if ((i + 1) < points.length) {
            p2 = points[i + 1];
          }
        }
        if (manyPoints) {
          multSignX = p1.x > points[i - 2].x ? 1 : p1.x === points[i - 2].x ? 0 : -1;
          multSignY = p1.y > points[i - 2].y ? 1 : p1.y === points[i - 2].y ? 0 : -1;
        }
        path.push('L ', p1.x + multSignX * width, ' ', p1.y + multSignY * width);
        return path;
      },
  
      /**
       * Creates fabric.Path object to add on canvas
       * @param {String} pathData Path data
       * @return {fabric.Path} Path to add on canvas
       */
      createPath: function(pathData) {
        var path = new fabric.Path(pathData, {
          fill: null,
          stroke: this.color,
          strokeWidth: this.width,
          strokeLineCap: this.strokeLineCap,
          strokeMiterLimit: this.strokeMiterLimit,
          strokeLineJoin: this.strokeLineJoin,
          strokeDashArray: this.strokeDashArray,
        });
        if (this.shadow) {
          this.shadow.affectStroke = true;
          path.setShadow(this.shadow);
        }
  
        return path;
      },
  
      /**
       * Decimate poins array with the decimate value
       */
      decimatePoints: function(points, distance) {
        if (points.length <= 2) {
          return points;
        }
        var zoom = this.canvas.getZoom(), adjustedDistance = Math.pow(distance / zoom, 2),
            i, l = points.length - 1, lastPoint = points[0], newPoints = [lastPoint],
            cDistance;
        for (i = 1; i < l; i++) {
          cDistance = Math.pow(lastPoint.x - points[i].x, 2) + Math.pow(lastPoint.y - points[i].y, 2);
          if (cDistance >= adjustedDistance) {
            lastPoint = points[i];
            newPoints.push(lastPoint);
          }
        }
        if (newPoints.length === 1) {
          newPoints.push(new fabric.Point(newPoints[0].x, newPoints[0].y));
        }
        return newPoints;
      },
  
      /**
       * On mouseup after drawing the path on contextTop canvas
       * we use the points captured to create an new fabric path object
       * and add it to the fabric canvas.
       */
      _finalizeAndAddPath: function() {
        var ctx = this.canvas.contextTop;
        ctx.closePath();
        if (this.decimate) {
          this._points = this.decimatePoints(this._points, this.decimate);
        }
        var pathData = this.convertPointsToSVGPath(this._points).join('');
        if (pathData === 'M 0 0 Q 0 0 0 0 L 0 0') {
          // do not create 0 width/height paths, as they are
          // rendered inconsistently across browsers
          // Firefox 4, for example, renders a dot,
          // whereas Chrome 10 renders nothing
          this.canvas.requestRenderAll();
          return;
        }
  
        var path = this.createPath(pathData);
        this.canvas.clearContext(this.canvas.contextTop);
        this.canvas.add(path);
        this.canvas.requestRenderAll();
        path.setCoords();
        this._resetShadow();
  
  
        // fire event 'path' created
        this.canvas.fire('path:created', { path: path });
      }
    });
  })();
  
  
  /**
   * CircleBrush class
   * @class fabric.CircleBrush
   */
  fabric.CircleBrush = fabric.util.createClass(fabric.BaseBrush, /** @lends fabric.CircleBrush.prototype */ {
  
    /**
     * Width of a brush
     * @type Number
     * @default
     */
    width: 10,
  
    /**
     * Constructor
     * @param {fabric.Canvas} canvas
     * @return {fabric.CircleBrush} Instance of a circle brush
     */
    initialize: function(canvas) {
      this.canvas = canvas;
      this.points = [];
    },
  
    /**
     * Invoked inside on mouse down and mouse move
     * @param {Object} pointer
     */
    drawDot: function(pointer) {
      var point = this.addPoint(pointer),
          ctx = this.canvas.contextTop;
      this._saveAndTransform(ctx);
      this.dot(ctx, point);
      ctx.restore();
    },
  
    dot: function(ctx, point) {
      ctx.fillStyle = point.fill;
      ctx.beginPath();
      ctx.arc(point.x, point.y, point.radius, 0, Math.PI * 2, false);
      ctx.closePath();
      ctx.fill();
    },
  
    /**
     * Invoked on mouse down
     */
    onMouseDown: function(pointer) {
      this.points.length = 0;
      this.canvas.clearContext(this.canvas.contextTop);
      this._setShadow();
      this.drawDot(pointer);
    },
  
    /**
     * Render the full state of the brush
     * @private
     */
    _render: function() {
      var ctx  = this.canvas.contextTop, i, len,
          points = this.points;
      this._saveAndTransform(ctx);
      for (i = 0, len = points.length; i < len; i++) {
        this.dot(ctx, points[i]);
      }
      ctx.restore();
    },
  
    /**
     * Invoked on mouse move
     * @param {Object} pointer
     */
    onMouseMove: function(pointer) {
      if (this.needsFullRender()) {
        this.canvas.clearContext(this.canvas.contextTop);
        this.addPoint(pointer);
        this._render();
      }
      else {
        this.drawDot(pointer);
      }
    },
  
    /**
     * Invoked on mouse up
     */
    onMouseUp: function() {
      var originalRenderOnAddRemove = this.canvas.renderOnAddRemove, i, len;
      this.canvas.renderOnAddRemove = false;
  
      var circles = [];
  
      for (i = 0, len = this.points.length; i < len; i++) {
        var point = this.points[i],
            circle = new fabric.Circle({
              radius: point.radius,
              left: point.x,
              top: point.y,
              originX: 'center',
              originY: 'center',
              fill: point.fill
            });
  
        this.shadow && circle.setShadow(this.shadow);
  
        circles.push(circle);
      }
      var group = new fabric.Group(circles);
      group.canvas = this.canvas;
  
      this.canvas.add(group);
      this.canvas.fire('path:created', { path: group });
  
      this.canvas.clearContext(this.canvas.contextTop);
      this._resetShadow();
      this.canvas.renderOnAddRemove = originalRenderOnAddRemove;
      this.canvas.requestRenderAll();
    },
  
    /**
     * @param {Object} pointer
     * @return {fabric.Point} Just added pointer point
     */
    addPoint: function(pointer) {
      var pointerPoint = new fabric.Point(pointer.x, pointer.y),
  
          circleRadius = fabric.util.getRandomInt(
            Math.max(0, this.width - 20), this.width + 20) / 2,
  
          circleColor = new fabric.Color(this.color)
            .setAlpha(fabric.util.getRandomInt(0, 100) / 100)
            .toRgba();
  
      pointerPoint.radius = circleRadius;
      pointerPoint.fill = circleColor;
  
      this.points.push(pointerPoint);
  
      return pointerPoint;
    }
  });
  
  
  /**
   * SprayBrush class
   * @class fabric.SprayBrush
   */
  fabric.SprayBrush = fabric.util.createClass( fabric.BaseBrush, /** @lends fabric.SprayBrush.prototype */ {
  
    /**
     * Width of a spray
     * @type Number
     * @default
     */
    width:              10,
  
    /**
     * Density of a spray (number of dots per chunk)
     * @type Number
     * @default
     */
    density:            20,
  
    /**
     * Width of spray dots
     * @type Number
     * @default
     */
    dotWidth:           1,
  
    /**
     * Width variance of spray dots
     * @type Number
     * @default
     */
    dotWidthVariance:   1,
  
    /**
     * Whether opacity of a dot should be random
     * @type Boolean
     * @default
     */
    randomOpacity:        false,
  
    /**
     * Whether overlapping dots (rectangles) should be removed (for performance reasons)
     * @type Boolean
     * @default
     */
    optimizeOverlapping:  true,
  
    /**
     * Constructor
     * @param {fabric.Canvas} canvas
     * @return {fabric.SprayBrush} Instance of a spray brush
     */
    initialize: function(canvas) {
      this.canvas = canvas;
      this.sprayChunks = [];
    },
  
    /**
     * Invoked on mouse down
     * @param {Object} pointer
     */
    onMouseDown: function(pointer) {
      this.sprayChunks.length = 0;
      this.canvas.clearContext(this.canvas.contextTop);
      this._setShadow();
  
      this.addSprayChunk(pointer);
      this.render(this.sprayChunkPoints);
    },
  
    /**
     * Invoked on mouse move
     * @param {Object} pointer
     */
    onMouseMove: function(pointer) {
      this.addSprayChunk(pointer);
      this.render(this.sprayChunkPoints);
    },
  
    /**
     * Invoked on mouse up
     */
    onMouseUp: function() {
      var originalRenderOnAddRemove = this.canvas.renderOnAddRemove;
      this.canvas.renderOnAddRemove = false;
  
      var rects = [];
  
      for (var i = 0, ilen = this.sprayChunks.length; i < ilen; i++) {
        var sprayChunk = this.sprayChunks[i];
  
        for (var j = 0, jlen = sprayChunk.length; j < jlen; j++) {
  
          var rect = new fabric.Rect({
            width: sprayChunk[j].width,
            height: sprayChunk[j].width,
            left: sprayChunk[j].x + 1,
            top: sprayChunk[j].y + 1,
            originX: 'center',
            originY: 'center',
            fill: this.color
          });
          rects.push(rect);
        }
      }
  
      if (this.optimizeOverlapping) {
        rects = this._getOptimizedRects(rects);
      }
  
      var group = new fabric.Group(rects);
      this.shadow && group.setShadow(this.shadow);
      this.canvas.add(group);
      this.canvas.fire('path:created', { path: group });
  
      this.canvas.clearContext(this.canvas.contextTop);
      this._resetShadow();
      this.canvas.renderOnAddRemove = originalRenderOnAddRemove;
      this.canvas.requestRenderAll();
    },
  
    /**
     * @private
     * @param {Array} rects
     */
    _getOptimizedRects: function(rects) {
  
      // avoid creating duplicate rects at the same coordinates
      var uniqueRects = { }, key, i, len;
  
      for (i = 0, len = rects.length; i < len; i++) {
        key = rects[i].left + '' + rects[i].top;
        if (!uniqueRects[key]) {
          uniqueRects[key] = rects[i];
        }
      }
      var uniqueRectsArray = [];
      for (key in uniqueRects) {
        uniqueRectsArray.push(uniqueRects[key]);
      }
  
      return uniqueRectsArray;
    },
  
    /**
     * Render new chunk of spray brush
     */
    render: function(sprayChunk) {
      var ctx = this.canvas.contextTop, i, len;
      ctx.fillStyle = this.color;
  
      this._saveAndTransform(ctx);
  
      for (i = 0, len = sprayChunk.length; i < len; i++) {
        var point = sprayChunk[i];
        if (typeof point.opacity !== 'undefined') {
          ctx.globalAlpha = point.opacity;
        }
        ctx.fillRect(point.x, point.y, point.width, point.width);
      }
      ctx.restore();
    },
  
    /**
     * Render all spray chunks
     */
    _render: function() {
      var ctx = this.canvas.contextTop, i, ilen;
      ctx.fillStyle = this.color;
  
      this._saveAndTransform(ctx);
  
      for (i = 0, ilen = this.sprayChunks.length; i < ilen; i++) {
        this.render(this.sprayChunks[i]);
      }
      ctx.restore();
    },
  
    /**
     * @param {Object} pointer
     */
    addSprayChunk: function(pointer) {
      this.sprayChunkPoints = [];
  
      var x, y, width, radius = this.width / 2, i;
  
      for (i = 0; i < this.density; i++) {
  
        x = fabric.util.getRandomInt(pointer.x - radius, pointer.x + radius);
        y = fabric.util.getRandomInt(pointer.y - radius, pointer.y + radius);
  
        if (this.dotWidthVariance) {
          width = fabric.util.getRandomInt(
            // bottom clamp width to 1
            Math.max(1, this.dotWidth - this.dotWidthVariance),
            this.dotWidth + this.dotWidthVariance);
        }
        else {
          width = this.dotWidth;
        }
  
        var point = new fabric.Point(x, y);
        point.width = width;
  
        if (this.randomOpacity) {
          point.opacity = fabric.util.getRandomInt(0, 100) / 100;
        }
  
        this.sprayChunkPoints.push(point);
      }
  
      this.sprayChunks.push(this.sprayChunkPoints);
    }
  });
  
  
  /**
   * PatternBrush class
   * @class fabric.PatternBrush
   * @extends fabric.BaseBrush
   */
  fabric.PatternBrush = fabric.util.createClass(fabric.PencilBrush, /** @lends fabric.PatternBrush.prototype */ {
  
    getPatternSrc: function() {
  
      var dotWidth = 20,
          dotDistance = 5,
          patternCanvas = fabric.util.createCanvasElement(),
          patternCtx = patternCanvas.getContext('2d');
  
      patternCanvas.width = patternCanvas.height = dotWidth + dotDistance;
  
      patternCtx.fillStyle = this.color;
      patternCtx.beginPath();
      patternCtx.arc(dotWidth / 2, dotWidth / 2, dotWidth / 2, 0, Math.PI * 2, false);
      patternCtx.closePath();
      patternCtx.fill();
  
      return patternCanvas;
    },
  
    getPatternSrcFunction: function() {
      return String(this.getPatternSrc).replace('this.color', '"' + this.color + '"');
    },
  
    /**
     * Creates "pattern" instance property
     */
    getPattern: function() {
      return this.canvas.contextTop.createPattern(this.source || this.getPatternSrc(), 'repeat');
    },
  
    /**
     * Sets brush styles
     */
    _setBrushStyles: function() {
      this.callSuper('_setBrushStyles');
      this.canvas.contextTop.strokeStyle = this.getPattern();
    },
  
    /**
     * Creates path
     */
    createPath: function(pathData) {
      var path = this.callSuper('createPath', pathData),
          topLeft = path._getLeftTopCoords().scalarAdd(path.strokeWidth / 2);
  
      path.stroke = new fabric.Pattern({
        source: this.source || this.getPatternSrcFunction(),
        offsetX: -topLeft.x,
        offsetY: -topLeft.y
      });
      return path;
    }
  });
  
  
  (function() {
  
    var getPointer = fabric.util.getPointer,
        degreesToRadians = fabric.util.degreesToRadians,
        radiansToDegrees = fabric.util.radiansToDegrees,
        atan2 = Math.atan2,
        abs = Math.abs,
        supportLineDash = fabric.StaticCanvas.supports('setLineDash'),
  
        STROKE_OFFSET = 0.5;
  
    /**
     * Canvas class
     * @class fabric.Canvas
     * @extends fabric.StaticCanvas
     * @tutorial {@link http://fabricjs.com/fabric-intro-part-1#canvas}
     * @see {@link fabric.Canvas#initialize} for constructor definition
     *
     * @fires object:modified
     * @fires object:rotated
     * @fires object:scaled
     * @fires object:moved
     * @fires object:skewed
     * @fires object:rotating
     * @fires object:scaling
     * @fires object:moving
     * @fires object:skewing
     * @fires object:selected this event is deprecated. use selection:created
     *
     * @fires before:transform
     * @fires before:selection:cleared
     * @fires selection:cleared
     * @fires selection:updated
     * @fires selection:created
     *
     * @fires path:created
     * @fires mouse:down
     * @fires mouse:move
     * @fires mouse:up
     * @fires mouse:down:before
     * @fires mouse:move:before
     * @fires mouse:up:before
     * @fires mouse:over
     * @fires mouse:out
     * @fires mouse:dblclick
     *
     * @fires dragover
     * @fires dragenter
     * @fires dragleave
     * @fires drop
     *
     */
    fabric.Canvas = fabric.util.createClass(fabric.StaticCanvas, /** @lends fabric.Canvas.prototype */ {
  
      /**
       * Constructor
       * @param {HTMLElement | String} el &lt;canvas> element to initialize instance on
       * @param {Object} [options] Options object
       * @return {Object} thisArg
       */
      initialize: function(el, options) {
        options || (options = { });
        this.renderAndResetBound = this.renderAndReset.bind(this);
        this.requestRenderAllBound = this.requestRenderAll.bind(this);
        this._initStatic(el, options);
        this._initInteractive();
        this._createCacheCanvas();
      },
  
      /**
       * When true, objects can be transformed by one side (unproportionally)
       * @type Boolean
       * @default
       */
      uniScaleTransform:      false,
  
      /**
       * Indicates which key enable unproportional scaling
       * values: 'altKey', 'shiftKey', 'ctrlKey'.
       * If `null` or 'none' or any other string that is not a modifier key
       * feature is disabled feature disabled.
       * @since 1.6.2
       * @type String
       * @default
       */
      uniScaleKey:           'shiftKey',
  
      /**
       * When true, objects use center point as the origin of scale transformation.
       * <b>Backwards incompatibility note:</b> This property replaces "centerTransform" (Boolean).
       * @since 1.3.4
       * @type Boolean
       * @default
       */
      centeredScaling:        false,
  
      /**
       * When true, objects use center point as the origin of rotate transformation.
       * <b>Backwards incompatibility note:</b> This property replaces "centerTransform" (Boolean).
       * @since 1.3.4
       * @type Boolean
       * @default
       */
      centeredRotation:       false,
  
      /**
       * Indicates which key enable centered Transform
       * values: 'altKey', 'shiftKey', 'ctrlKey'.
       * If `null` or 'none' or any other string that is not a modifier key
       * feature is disabled feature disabled.
       * @since 1.6.2
       * @type String
       * @default
       */
      centeredKey:           'altKey',
  
      /**
       * Indicates which key enable alternate action on corner
       * values: 'altKey', 'shiftKey', 'ctrlKey'.
       * If `null` or 'none' or any other string that is not a modifier key
       * feature is disabled feature disabled.
       * @since 1.6.2
       * @type String
       * @default
       */
      altActionKey:           'shiftKey',
  
      /**
       * Indicates that canvas is interactive. This property should not be changed.
       * @type Boolean
       * @default
       */
      interactive:            true,
  
      /**
       * Indicates whether group selection should be enabled
       * @type Boolean
       * @default
       */
      selection:              true,
  
      /**
       * Indicates which key or keys enable multiple click selection
       * Pass value as a string or array of strings
       * values: 'altKey', 'shiftKey', 'ctrlKey'.
       * If `null` or empty or containing any other string that is not a modifier key
       * feature is disabled.
       * @since 1.6.2
       * @type String|Array
       * @default
       */
      selectionKey:           'shiftKey',
  
      /**
       * Indicates which key enable alternative selection
       * in case of target overlapping with active object
       * values: 'altKey', 'shiftKey', 'ctrlKey'.
       * For a series of reason that come from the general expectations on how
       * things should work, this feature works only for preserveObjectStacking true.
       * If `null` or 'none' or any other string that is not a modifier key
       * feature is disabled.
       * @since 1.6.5
       * @type null|String
       * @default
       */
      altSelectionKey:           null,
  
      /**
       * Color of selection
       * @type String
       * @default
       */
      selectionColor:         'rgba(100, 100, 255, 0.3)', // blue
  
      /**
       * Default dash array pattern
       * If not empty the selection border is dashed
       * @type Array
       */
      selectionDashArray:     [],
  
      /**
       * Color of the border of selection (usually slightly darker than color of selection itself)
       * @type String
       * @default
       */
      selectionBorderColor:   'rgba(255, 255, 255, 0.3)',
  
      /**
       * Width of a line used in object/group selection
       * @type Number
       * @default
       */
      selectionLineWidth:     1,
  
      /**
       * Select only shapes that are fully contained in the dragged selection rectangle.
       * @type Boolean
       * @default
       */
      selectionFullyContained: false,
  
      /**
       * Default cursor value used when hovering over an object on canvas
       * @type String
       * @default
       */
      hoverCursor:            'move',
  
      /**
       * Default cursor value used when moving an object on canvas
       * @type String
       * @default
       */
      moveCursor:             'move',
  
      /**
       * Default cursor value used for the entire canvas
       * @type String
       * @default
       */
      defaultCursor:          'default',
  
      /**
       * Cursor value used during free drawing
       * @type String
       * @default
       */
      freeDrawingCursor:      'crosshair',
  
      /**
       * Cursor value used for rotation point
       * @type String
       * @default
       */
      rotationCursor:         'crosshair',
  
      /**
       * Cursor value used for disabled elements ( corners with disabled action )
       * @type String
       * @since 2.0.0
       * @default
       */
      notAllowedCursor:         'not-allowed',
  
      /**
       * Default element class that's given to wrapper (div) element of canvas
       * @type String
       * @default
       */
      containerClass:         'canvas-container',
  
      /**
       * When true, object detection happens on per-pixel basis rather than on per-bounding-box
       * @type Boolean
       * @default
       */
      perPixelTargetFind:     false,
  
      /**
       * Number of pixels around target pixel to tolerate (consider active) during object detection
       * @type Number
       * @default
       */
      targetFindTolerance:    0,
  
      /**
       * When true, target detection is skipped when hovering over canvas. This can be used to improve performance.
       * @type Boolean
       * @default
       */
      skipTargetFind:         false,
  
      /**
       * When true, mouse events on canvas (mousedown/mousemove/mouseup) result in free drawing.
       * After mousedown, mousemove creates a shape,
       * and then mouseup finalizes it and adds an instance of `fabric.Path` onto canvas.
       * @tutorial {@link http://fabricjs.com/fabric-intro-part-4#free_drawing}
       * @type Boolean
       * @default
       */
      isDrawingMode:          false,
  
      /**
       * Indicates whether objects should remain in current stack position when selected.
       * When false objects are brought to top and rendered as part of the selection group
       * @type Boolean
       * @default
       */
      preserveObjectStacking: false,
  
      /**
       * Indicates the angle that an object will lock to while rotating.
       * @type Number
       * @since 1.6.7
       * @default
       */
      snapAngle: 0,
  
      /**
       * Indicates the distance from the snapAngle the rotation will lock to the snapAngle.
       * When `null`, the snapThreshold will default to the snapAngle.
       * @type null|Number
       * @since 1.6.7
       * @default
       */
      snapThreshold: null,
  
      /**
       * Indicates if the right click on canvas can output the context menu or not
       * @type Boolean
       * @since 1.6.5
       * @default
       */
      stopContextMenu: false,
  
      /**
       * Indicates if the canvas can fire right click events
       * @type Boolean
       * @since 1.6.5
       * @default
       */
      fireRightClick: false,
  
      /**
       * Indicates if the canvas can fire middle click events
       * @type Boolean
       * @since 1.7.8
       * @default
       */
      fireMiddleClick: false,
  
      /**
       * @private
       */
      _initInteractive: function() {
        this._currentTransform = null;
        this._groupSelector = null;
        this._initWrapperElement();
        this._createUpperCanvas();
        this._initEventListeners();
  
        this._initRetinaScaling();
  
        this.freeDrawingBrush = fabric.PencilBrush && new fabric.PencilBrush(this);
  
        this.calcOffset();
      },
  
      /**
       * Divides objects in two groups, one to render immediately
       * and one to render as activeGroup.
       * @return {Array} objects to render immediately and pushes the other in the activeGroup.
       */
      _chooseObjectsToRender: function() {
        var activeObjects = this.getActiveObjects(),
            object, objsToRender, activeGroupObjects;
  
        if (activeObjects.length > 0 && !this.preserveObjectStacking) {
          objsToRender = [];
          activeGroupObjects = [];
          for (var i = 0, length = this._objects.length; i < length; i++) {
            object = this._objects[i];
            if (activeObjects.indexOf(object) === -1 ) {
              objsToRender.push(object);
            }
            else {
              activeGroupObjects.push(object);
            }
          }
          if (activeObjects.length > 1) {
            this._activeObject._objects = activeGroupObjects;
          }
          objsToRender.push.apply(objsToRender, activeGroupObjects);
        }
        else {
          objsToRender = this._objects;
        }
        return objsToRender;
      },
  
      /**
       * Renders both the top canvas and the secondary container canvas.
       * @return {fabric.Canvas} instance
       * @chainable
       */
      renderAll: function () {
        if (this.contextTopDirty && !this._groupSelector && !this.isDrawingMode) {
          this.clearContext(this.contextTop);
          this.contextTopDirty = false;
        }
        if (this.hasLostContext) {
          this.renderTopLayer(this.contextTop);
        }
        var canvasToDrawOn = this.contextContainer;
        this.renderCanvas(canvasToDrawOn, this._chooseObjectsToRender());
        return this;
      },
  
      renderTopLayer: function(ctx) {
        ctx.save();
        if (this.isDrawingMode && this._isCurrentlyDrawing) {
          this.freeDrawingBrush && this.freeDrawingBrush._render();
          this.contextTopDirty = true;
        }
        // we render the top context - last object
        if (this.selection && this._groupSelector) {
          this._drawSelection(ctx);
          this.contextTopDirty = true;
        }
        ctx.restore();
      },
  
      /**
       * Method to render only the top canvas.
       * Also used to render the group selection box.
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      renderTop: function () {
        var ctx = this.contextTop;
        this.clearContext(ctx);
        this.renderTopLayer(ctx);
        this.fire('after:render');
        return this;
      },
  
      /**
       * Resets the current transform to its original values and chooses the type of resizing based on the event
       * @private
       */
      _resetCurrentTransform: function() {
        var t = this._currentTransform;
  
        t.target.set({
          scaleX: t.original.scaleX,
          scaleY: t.original.scaleY,
          skewX: t.original.skewX,
          skewY: t.original.skewY,
          left: t.original.left,
          top: t.original.top
        });
  
        if (this._shouldCenterTransform(t.target)) {
          if (t.originX !== 'center') {
            if (t.originX === 'right') {
              t.mouseXSign = -1;
            }
            else {
              t.mouseXSign = 1;
            }
          }
          if (t.originY !== 'center') {
            if (t.originY === 'bottom') {
              t.mouseYSign = -1;
            }
            else {
              t.mouseYSign = 1;
            }
          }
  
          t.originX = 'center';
          t.originY = 'center';
        }
        else {
          t.originX = t.original.originX;
          t.originY = t.original.originY;
        }
      },
  
      /**
       * Checks if point is contained within an area of given object
       * @param {Event} e Event object
       * @param {fabric.Object} target Object to test against
       * @param {Object} [point] x,y object of point coordinates we want to check.
       * @return {Boolean} true if point is contained within an area of given object
       */
      containsPoint: function (e, target, point) {
        var ignoreZoom = true,
            pointer = point || this.getPointer(e, ignoreZoom),
            xy;
  
        if (target.group && target.group === this._activeObject && target.group.type === 'activeSelection') {
          xy = this._normalizePointer(target.group, pointer);
        }
        else {
          xy = { x: pointer.x, y: pointer.y };
        }
        // http://www.geog.ubc.ca/courses/klink/gis.notes/ncgia/u32.html
        // http://idav.ucdavis.edu/~okreylos/TAship/Spring2000/PointInPolygon.html
        return (target.containsPoint(xy) || target._findTargetCorner(pointer));
      },
  
      /**
       * @private
       */
      _normalizePointer: function (object, pointer) {
        var m = object.calcTransformMatrix(),
            invertedM = fabric.util.invertTransform(m),
            vptPointer = this.restorePointerVpt(pointer);
        return fabric.util.transformPoint(vptPointer, invertedM);
      },
  
      /**
       * Returns true if object is transparent at a certain location
       * @param {fabric.Object} target Object to check
       * @param {Number} x Left coordinate
       * @param {Number} y Top coordinate
       * @return {Boolean}
       */
      isTargetTransparent: function (target, x, y) {
        // in case the target is the activeObject, we cannot execute this optimization
        // because we need to draw controls too.
        if (target.shouldCache() && target._cacheCanvas && target !== this._activeObject) {
          var normalizedPointer = this._normalizePointer(target, {x: x, y: y}),
              targetRelativeX = Math.max(target.cacheTranslationX + (normalizedPointer.x * target.zoomX), 0),
              targetRelativeY = Math.max(target.cacheTranslationY + (normalizedPointer.y * target.zoomY), 0);
  
          var isTransparent = fabric.util.isTransparent(
            target._cacheContext, Math.round(targetRelativeX), Math.round(targetRelativeY), this.targetFindTolerance);
  
          return isTransparent;
        }
  
        var ctx = this.contextCache,
            originalColor = target.selectionBackgroundColor, v = this.viewportTransform;
  
        target.selectionBackgroundColor = '';
  
        this.clearContext(ctx);
  
        ctx.save();
        ctx.transform(v[0], v[1], v[2], v[3], v[4], v[5]);
        target.render(ctx);
        ctx.restore();
  
        target === this._activeObject && target._renderControls(ctx, {
          hasBorders: false,
          transparentCorners: false
        }, {
          hasBorders: false,
        });
  
        target.selectionBackgroundColor = originalColor;
  
        var isTransparent = fabric.util.isTransparent(
          ctx, x, y, this.targetFindTolerance);
  
        return isTransparent;
      },
  
      /**
       * takes an event and determins if selection key has been pressed
       * @private
       * @param {Event} e Event object
       */
      _isSelectionKeyPressed: function(e) {
        var selectionKeyPressed = false;
  
        if (Object.prototype.toString.call(this.selectionKey) === '[object Array]') {
          selectionKeyPressed = !!this.selectionKey.find(function(key) { return e[key] === true; });
        }
        else {
          selectionKeyPressed = e[this.selectionKey];
        }
  
        return selectionKeyPressed;
      },
  
      /**
       * @private
       * @param {Event} e Event object
       * @param {fabric.Object} target
       */
      _shouldClearSelection: function (e, target) {
        var activeObjects = this.getActiveObjects(),
            activeObject = this._activeObject;
  
        return (
          !target
          ||
          (target &&
            activeObject &&
            activeObjects.length > 1 &&
            activeObjects.indexOf(target) === -1 &&
            activeObject !== target &&
            !this._isSelectionKeyPressed(e))
          ||
          (target && !target.evented)
          ||
          (target &&
            !target.selectable &&
            activeObject &&
            activeObject !== target)
        );
      },
  
      /**
       * centeredScaling from object can't override centeredScaling from canvas.
       * this should be fixed, since object setting should take precedence over canvas.
       * @private
       * @param {fabric.Object} target
       */
      _shouldCenterTransform: function (target) {
        if (!target) {
          return;
        }
  
        var t = this._currentTransform,
            centerTransform;
  
        if (t.action === 'scale' || t.action === 'scaleX' || t.action === 'scaleY') {
          centerTransform = this.centeredScaling || target.centeredScaling;
        }
        else if (t.action === 'rotate') {
          centerTransform = this.centeredRotation || target.centeredRotation;
        }
  
        return centerTransform ? !t.altKey : t.altKey;
      },
  
      /**
       * @private
       */
      _getOriginFromCorner: function(target, corner) {
        var origin = {
          x: target.originX,
          y: target.originY
        };
  
        if (corner === 'ml' || corner === 'tl' || corner === 'bl') {
          origin.x = 'right';
        }
        else if (corner === 'mr' || corner === 'tr' || corner === 'br') {
          origin.x = 'left';
        }
  
        if (corner === 'tl' || corner === 'mt' || corner === 'tr') {
          origin.y = 'bottom';
        }
        else if (corner === 'bl' || corner === 'mb' || corner === 'br') {
          origin.y = 'top';
        }
  
        return origin;
      },
  
      /**
       * @private
       * @param {Boolean} alreadySelected true if target is already selected
       * @param {String} corner a string representing the corner ml, mr, tl ...
       * @param {Event} e Event object
       * @param {fabric.Object} [target] inserted back to help overriding. Unused
       */
      _getActionFromCorner: function(alreadySelected, corner, e /* target */) {
        if (!corner || !alreadySelected) {
          return 'drag';
        }
  
        switch (corner) {
          case 'mtr':
            return 'rotate';
          case 'ml':
          case 'mr':
            return e[this.altActionKey] ? 'skewY' : 'scaleX';
          case 'mt':
          case 'mb':
            return e[this.altActionKey] ? 'skewX' : 'scaleY';
          default:
            return 'scale';
        }
      },
  
      /**
       * @private
       * @param {Event} e Event object
       * @param {fabric.Object} target
       */
      _setupCurrentTransform: function (e, target, alreadySelected) {
        if (!target) {
          return;
        }
  
        var pointer = this.getPointer(e),
            corner = target._findTargetCorner(this.getPointer(e, true)),
            action = this._getActionFromCorner(alreadySelected, corner, e, target),
            origin = this._getOriginFromCorner(target, corner);
  
        this._currentTransform = {
          target: target,
          action: action,
          corner: corner,
          scaleX: target.scaleX,
          scaleY: target.scaleY,
          skewX: target.skewX,
          skewY: target.skewY,
          // used by transation
          offsetX: pointer.x - target.left,
          offsetY: pointer.y - target.top,
          originX: origin.x,
          originY: origin.y,
          ex: pointer.x,
          ey: pointer.y,
          lastX: pointer.x,
          lastY: pointer.y,
          // unsure they are usefull anymore.
          // left: target.left,
          // top: target.top,
          theta: degreesToRadians(target.angle),
          // end of unsure
          width: target.width * target.scaleX,
          mouseXSign: 1,
          mouseYSign: 1,
          shiftKey: e.shiftKey,
          altKey: e[this.centeredKey],
          original: fabric.util.saveObjectTransform(target),
        };
  
        this._currentTransform.original.originX = origin.x;
        this._currentTransform.original.originY = origin.y;
  
        this._resetCurrentTransform();
        this._beforeTransform(e);
      },
  
      /**
       * Translates object by "setting" its left/top
       * @private
       * @param {Number} x pointer's x coordinate
       * @param {Number} y pointer's y coordinate
       * @return {Boolean} true if the translation occurred
       */
      _translateObject: function (x, y) {
        var transform = this._currentTransform,
            target = transform.target,
            newLeft = x - transform.offsetX,
            newTop = y - transform.offsetY,
            moveX = !target.get('lockMovementX') && target.left !== newLeft,
            moveY = !target.get('lockMovementY') && target.top !== newTop;
  
        moveX && target.set('left', newLeft);
        moveY && target.set('top', newTop);
        return moveX || moveY;
      },
  
      /**
       * Check if we are increasing a positive skew or lower it,
       * checking mouse direction and pressed corner.
       * @private
       */
      _changeSkewTransformOrigin: function(mouseMove, t, by) {
        var property = 'originX', origins = { 0: 'center' },
            skew = t.target.skewX, originA = 'left', originB = 'right',
            corner = t.corner === 'mt' || t.corner === 'ml' ? 1 : -1,
            flipSign = 1;
  
        mouseMove = mouseMove > 0 ? 1 : -1;
        if (by === 'y') {
          skew = t.target.skewY;
          originA = 'top';
          originB = 'bottom';
          property = 'originY';
        }
        origins[-1] = originA;
        origins[1] = originB;
  
        t.target.flipX && (flipSign *= -1);
        t.target.flipY && (flipSign *= -1);
  
        if (skew === 0) {
          t.skewSign = -corner * mouseMove * flipSign;
          t[property] = origins[-mouseMove];
        }
        else {
          skew = skew > 0 ? 1 : -1;
          t.skewSign = skew;
          t[property] = origins[skew * corner * flipSign];
        }
      },
  
      /**
       * Skew object by mouse events
       * @private
       * @param {Number} x pointer's x coordinate
       * @param {Number} y pointer's y coordinate
       * @param {String} by Either 'x' or 'y'
       * @return {Boolean} true if the skewing occurred
       */
      _skewObject: function (x, y, by) {
        var t = this._currentTransform,
            target = t.target, skewed = false,
            lockSkewingX = target.get('lockSkewingX'),
            lockSkewingY = target.get('lockSkewingY');
  
        if ((lockSkewingX && by === 'x') || (lockSkewingY && by === 'y')) {
          return false;
        }
  
        // Get the constraint point
        var center = target.getCenterPoint(),
            actualMouseByCenter = target.toLocalPoint(new fabric.Point(x, y), 'center', 'center')[by],
            lastMouseByCenter = target.toLocalPoint(new fabric.Point(t.lastX, t.lastY), 'center', 'center')[by],
            actualMouseByOrigin, constraintPosition, dim = target._getTransformedDimensions();
  
        this._changeSkewTransformOrigin(actualMouseByCenter - lastMouseByCenter, t, by);
        actualMouseByOrigin = target.toLocalPoint(new fabric.Point(x, y), t.originX, t.originY)[by];
        constraintPosition = target.translateToOriginPoint(center, t.originX, t.originY);
        // Actually skew the object
        skewed = this._setObjectSkew(actualMouseByOrigin, t, by, dim);
        t.lastX = x;
        t.lastY = y;
        // Make sure the constraints apply
        target.setPositionByOrigin(constraintPosition, t.originX, t.originY);
        return skewed;
      },
  
      /**
       * Set object skew
       * @private
       * @return {Boolean} true if the skewing occurred
       */
      _setObjectSkew: function(localMouse, transform, by, _dim) {
        var target = transform.target, newValue, skewed = false,
            skewSign = transform.skewSign, newDim, dimNoSkew,
            otherBy, _otherBy, _by, newDimMouse, skewX, skewY;
  
        if (by === 'x') {
          otherBy = 'y';
          _otherBy = 'Y';
          _by = 'X';
          skewX = 0;
          skewY = target.skewY;
        }
        else {
          otherBy = 'x';
          _otherBy = 'X';
          _by = 'Y';
          skewX = target.skewX;
          skewY = 0;
        }
  
        dimNoSkew = target._getTransformedDimensions(skewX, skewY);
        newDimMouse = 2 * Math.abs(localMouse) - dimNoSkew[by];
        if (newDimMouse <= 2) {
          newValue = 0;
        }
        else {
          newValue = skewSign * Math.atan((newDimMouse / target['scale' + _by]) /
                                          (dimNoSkew[otherBy] / target['scale' + _otherBy]));
          newValue = fabric.util.radiansToDegrees(newValue);
        }
        skewed = target['skew' + _by] !== newValue;
        target.set('skew' + _by, newValue);
        if (target['skew' + _otherBy] !== 0) {
          newDim = target._getTransformedDimensions();
          newValue = (_dim[otherBy] / newDim[otherBy]) * target['scale' + _otherBy];
          target.set('scale' + _otherBy, newValue);
        }
        return skewed;
      },
  
      /**
       * Scales object by invoking its scaleX/scaleY methods
       * @private
       * @param {Number} x pointer's x coordinate
       * @param {Number} y pointer's y coordinate
       * @param {String} by Either 'x' or 'y' - specifies dimension constraint by which to scale an object.
       *                    When not provided, an object is scaled by both dimensions equally
       * @return {Boolean} true if the scaling occurred
       */
      _scaleObject: function (x, y, by) {
        var t = this._currentTransform,
            target = t.target,
            lockScalingX = target.lockScalingX,
            lockScalingY = target.lockScalingY,
            lockScalingFlip = target.lockScalingFlip;
  
        if (lockScalingX && lockScalingY) {
          return false;
        }
  
        // Get the constraint point
        var constraintPosition = target.translateToOriginPoint(target.getCenterPoint(), t.originX, t.originY),
            localMouse = target.toLocalPoint(new fabric.Point(x, y), t.originX, t.originY),
            dim = target._getTransformedDimensions(), scaled = false;
  
        this._setLocalMouse(localMouse, t);
  
        // Actually scale the object
        scaled = this._setObjectScale(localMouse, t, lockScalingX, lockScalingY, by, lockScalingFlip, dim);
  
        // Make sure the constraints apply
        target.setPositionByOrigin(constraintPosition, t.originX, t.originY);
        return scaled;
      },
  
      /**
       * @private
       * @return {Boolean} true if the scaling occurred
       */
      _setObjectScale: function(localMouse, transform, lockScalingX, lockScalingY, by, lockScalingFlip, _dim) {
        var target = transform.target, forbidScalingX = false, forbidScalingY = false, scaled = false,
            scaleX = localMouse.x * target.scaleX / _dim.x,
            scaleY = localMouse.y * target.scaleY / _dim.y,
            changeX = target.scaleX !== scaleX,
            changeY = target.scaleY !== scaleY;
  
        transform.newScaleX = scaleX;
        transform.newScaleY = scaleY;
        if (fabric.Textbox && by === 'x' && target instanceof fabric.Textbox) {
          var w = target.width * (localMouse.x / _dim.x);
          if (w >= target.getMinWidth()) {
            scaled = w !== target.width;
            target.set('width', w);
            return scaled;
          }
          return false;
        }
  
        if (lockScalingFlip && scaleX <= 0 && scaleX < target.scaleX) {
          forbidScalingX = true;
          localMouse.x = 0;
        }
  
        if (lockScalingFlip && scaleY <= 0 && scaleY < target.scaleY) {
          forbidScalingY = true;
          localMouse.y = 0;
        }
  
        if (by === 'equally' && !lockScalingX && !lockScalingY) {
          scaled = this._scaleObjectEqually(localMouse, target, transform, _dim);
        }
        else if (!by) {
          forbidScalingX || lockScalingX || (target.set('scaleX', scaleX) && (scaled = scaled || changeX));
          forbidScalingY || lockScalingY || (target.set('scaleY', scaleY) && (scaled = scaled || changeY));
        }
        else if (by === 'x' && !target.get('lockUniScaling')) {
          forbidScalingX || lockScalingX || (target.set('scaleX', scaleX) && (scaled = changeX));
        }
        else if (by === 'y' && !target.get('lockUniScaling')) {
          forbidScalingY || lockScalingY || (target.set('scaleY', scaleY) && (scaled = changeY));
        }
        forbidScalingX || forbidScalingY || this._flipObject(transform, by);
        return scaled;
      },
  
      /**
       * @private
       * @return {Boolean} true if the scaling occurred
       */
      _scaleObjectEqually: function(localMouse, target, transform, _dim) {
  
        var dist = localMouse.y + localMouse.x,
            lastDist = _dim.y * transform.original.scaleY / target.scaleY +
                       _dim.x * transform.original.scaleX / target.scaleX,
            scaled, signX = localMouse.x < 0 ? -1 : 1,
            signY = localMouse.y < 0 ? -1 : 1, newScaleX, newScaleY;
  
        // We use transform.scaleX/Y instead of target.scaleX/Y
        // because the object may have a min scale and we'll loose the proportions
        newScaleX = signX * Math.abs(transform.original.scaleX * dist / lastDist);
        newScaleY = signY * Math.abs(transform.original.scaleY * dist / lastDist);
        scaled = newScaleX !== target.scaleX || newScaleY !== target.scaleY;
        target.set('scaleX', newScaleX);
        target.set('scaleY', newScaleY);
        return scaled;
      },
  
      /**
       * @private
       */
      _flipObject: function(transform, by) {
        if (transform.newScaleX < 0 && by !== 'y') {
          if (transform.originX === 'left') {
            transform.originX = 'right';
          }
          else if (transform.originX === 'right') {
            transform.originX = 'left';
          }
        }
  
        if (transform.newScaleY < 0 && by !== 'x') {
          if (transform.originY === 'top') {
            transform.originY = 'bottom';
          }
          else if (transform.originY === 'bottom') {
            transform.originY = 'top';
          }
        }
      },
  
      /**
       * @private
       */
      _setLocalMouse: function(localMouse, t) {
        var target = t.target, zoom = this.getZoom(),
            padding = target.padding / zoom;
  
        if (t.originX === 'right') {
          localMouse.x *= -1;
        }
        else if (t.originX === 'center') {
          localMouse.x *= t.mouseXSign * 2;
          if (localMouse.x < 0) {
            t.mouseXSign = -t.mouseXSign;
          }
        }
  
        if (t.originY === 'bottom') {
          localMouse.y *= -1;
        }
        else if (t.originY === 'center') {
          localMouse.y *= t.mouseYSign * 2;
          if (localMouse.y < 0) {
            t.mouseYSign = -t.mouseYSign;
          }
        }
  
        // adjust the mouse coordinates when dealing with padding
        if (abs(localMouse.x) > padding) {
          if (localMouse.x < 0) {
            localMouse.x += padding;
          }
          else {
            localMouse.x -= padding;
          }
        }
        else { // mouse is within the padding, set to 0
          localMouse.x = 0;
        }
  
        if (abs(localMouse.y) > padding) {
          if (localMouse.y < 0) {
            localMouse.y += padding;
          }
          else {
            localMouse.y -= padding;
          }
        }
        else {
          localMouse.y = 0;
        }
      },
  
      /**
       * Rotates object by invoking its rotate method
       * @private
       * @param {Number} x pointer's x coordinate
       * @param {Number} y pointer's y coordinate
       * @return {Boolean} true if the rotation occurred
       */
      _rotateObject: function (x, y) {
  
        var t = this._currentTransform,
            target = t.target, constraintPosition,
            constraintPosition = target.translateToOriginPoint(target.getCenterPoint(), t.originX, t.originY);
  
        if (target.lockRotation) {
          return false;
        }
  
        var lastAngle = atan2(t.ey - constraintPosition.y, t.ex - constraintPosition.x),
            curAngle = atan2(y - constraintPosition.y, x - constraintPosition.x),
            angle = radiansToDegrees(curAngle - lastAngle + t.theta),
            hasRotated = true;
  
        if (target.snapAngle > 0) {
          var snapAngle  = target.snapAngle,
              snapThreshold  = target.snapThreshold || snapAngle,
              rightAngleLocked = Math.ceil(angle / snapAngle) * snapAngle,
              leftAngleLocked = Math.floor(angle / snapAngle) * snapAngle;
  
          if (Math.abs(angle - leftAngleLocked) < snapThreshold) {
            angle = leftAngleLocked;
          }
          else if (Math.abs(angle - rightAngleLocked) < snapThreshold) {
            angle = rightAngleLocked;
          }
        }
  
        // normalize angle to positive value
        if (angle < 0) {
          angle = 360 + angle;
        }
        angle %= 360;
  
        if (target.angle === angle) {
          hasRotated = false;
        }
        else {
          // rotation only happen here
          target.angle = angle;
          // Make sure the constraints apply
          target.setPositionByOrigin(constraintPosition, t.originX, t.originY);
        }
  
        return hasRotated;
      },
  
      /**
       * Set the cursor type of the canvas element
       * @param {String} value Cursor type of the canvas element.
       * @see http://www.w3.org/TR/css3-ui/#cursor
       */
      setCursor: function (value) {
        this.upperCanvasEl.style.cursor = value;
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx to draw the selection on
       */
      _drawSelection: function (ctx) {
        var groupSelector = this._groupSelector,
            left = groupSelector.left,
            top = groupSelector.top,
            aleft = abs(left),
            atop = abs(top);
  
        if (this.selectionColor) {
          ctx.fillStyle = this.selectionColor;
  
          ctx.fillRect(
            groupSelector.ex - ((left > 0) ? 0 : -left),
            groupSelector.ey - ((top > 0) ? 0 : -top),
            aleft,
            atop
          );
        }
  
        if (!this.selectionLineWidth || !this.selectionBorderColor) {
          return;
        }
        ctx.lineWidth = this.selectionLineWidth;
        ctx.strokeStyle = this.selectionBorderColor;
  
        // selection border
        if (this.selectionDashArray.length > 1 && !supportLineDash) {
  
          var px = groupSelector.ex + STROKE_OFFSET - ((left > 0) ? 0 : aleft),
              py = groupSelector.ey + STROKE_OFFSET - ((top > 0) ? 0 : atop);
  
          ctx.beginPath();
  
          fabric.util.drawDashedLine(ctx, px, py, px + aleft, py, this.selectionDashArray);
          fabric.util.drawDashedLine(ctx, px, py + atop - 1, px + aleft, py + atop - 1, this.selectionDashArray);
          fabric.util.drawDashedLine(ctx, px, py, px, py + atop, this.selectionDashArray);
          fabric.util.drawDashedLine(ctx, px + aleft - 1, py, px + aleft - 1, py + atop, this.selectionDashArray);
  
          ctx.closePath();
          ctx.stroke();
        }
        else {
          fabric.Object.prototype._setLineDash.call(this, ctx, this.selectionDashArray);
          ctx.strokeRect(
            groupSelector.ex + STROKE_OFFSET - ((left > 0) ? 0 : aleft),
            groupSelector.ey + STROKE_OFFSET - ((top > 0) ? 0 : atop),
            aleft,
            atop
          );
        }
      },
  
      /**
       * Method that determines what object we are clicking on
       * the skipGroup parameter is for internal use, is needed for shift+click action
       * 11/09/2018 TODO: would be cool if findTarget could discern between being a full target
       * or the outside part of the corner.
       * @param {Event} e mouse event
       * @param {Boolean} skipGroup when true, activeGroup is skipped and only objects are traversed through
       * @return {fabric.Object} the target found
       */
      findTarget: function (e, skipGroup) {
        if (this.skipTargetFind) {
          return;
        }
  
        var ignoreZoom = true,
            pointer = this.getPointer(e, ignoreZoom),
            activeObject = this._activeObject,
            aObjects = this.getActiveObjects(),
            activeTarget, activeTargetSubs;
  
        // first check current group (if one exists)
        // active group does not check sub targets like normal groups.
        // if active group just exits.
        this.targets = [];
  
        if (aObjects.length > 1 && !skipGroup && activeObject === this._searchPossibleTargets([activeObject], pointer)) {
          return activeObject;
        }
        // if we hit the corner of an activeObject, let's return that.
        if (aObjects.length === 1 && activeObject._findTargetCorner(pointer)) {
          return activeObject;
        }
        if (aObjects.length === 1 &&
          activeObject === this._searchPossibleTargets([activeObject], pointer)) {
          if (!this.preserveObjectStacking) {
            return activeObject;
          }
          else {
            activeTarget = activeObject;
            activeTargetSubs = this.targets;
            this.targets = [];
          }
        }
        var target = this._searchPossibleTargets(this._objects, pointer);
        if (e[this.altSelectionKey] && target && activeTarget && target !== activeTarget) {
          target = activeTarget;
          this.targets = activeTargetSubs;
        }
        return target;
      },
  
      /**
       * Checks point is inside the object.
       * @param {Object} [pointer] x,y object of point coordinates we want to check.
       * @param {fabric.Object} obj Object to test against
       * @param {Object} [globalPointer] x,y object of point coordinates relative to canvas used to search per pixel target.
       * @return {Boolean} true if point is contained within an area of given object
       * @private
       */
      _checkTarget: function(pointer, obj, globalPointer) {
        if (obj &&
            obj.visible &&
            obj.evented &&
            this.containsPoint(null, obj, pointer)){
          if ((this.perPixelTargetFind || obj.perPixelTargetFind) && !obj.isEditing) {
            var isTransparent = this.isTargetTransparent(obj, globalPointer.x, globalPointer.y);
            if (!isTransparent) {
              return true;
            }
          }
          else {
            return true;
          }
        }
      },
  
      /**
       * Function used to search inside objects an object that contains pointer in bounding box or that contains pointerOnCanvas when painted
       * @param {Array} [objects] objects array to look into
       * @param {Object} [pointer] x,y object of point coordinates we want to check.
       * @return {fabric.Object} object that contains pointer
       * @private
       */
      _searchPossibleTargets: function(objects, pointer) {
        // Cache all targets where their bounding box contains point.
        var target, i = objects.length, subTarget;
        // Do not check for currently grouped objects, since we check the parent group itself.
        // until we call this function specifically to search inside the activeGroup
        while (i--) {
          var objToCheck = objects[i];
          var pointerToUse = objToCheck.group && objToCheck.group.type !== 'activeSelection' ?
            this._normalizePointer(objToCheck.group, pointer) : pointer;
          if (this._checkTarget(pointerToUse, objToCheck, pointer)) {
            target = objects[i];
            if (target.subTargetCheck && target instanceof fabric.Group) {
              subTarget = this._searchPossibleTargets(target._objects, pointer);
              subTarget && this.targets.push(subTarget);
            }
            break;
          }
        }
        return target;
      },
  
      /**
       * Returns pointer coordinates without the effect of the viewport
       * @param {Object} pointer with "x" and "y" number values
       * @return {Object} object with "x" and "y" number values
       */
      restorePointerVpt: function(pointer) {
        return fabric.util.transformPoint(
          pointer,
          fabric.util.invertTransform(this.viewportTransform)
        );
      },
  
      /**
       * Returns pointer coordinates relative to canvas.
       * Can return coordinates with or without viewportTransform.
       * ignoreZoom false gives back coordinates that represent
       * the point clicked on canvas element.
       * ignoreZoom true gives back coordinates after being processed
       * by the viewportTransform ( sort of coordinates of what is displayed
       * on the canvas where you are clicking.
       * ignoreZoom true = HTMLElement coordinates relative to top,left
       * ignoreZoom false, default = fabric space coordinates, the same used for shape position
       * To interact with your shapes top and left you want to use ignoreZoom true
       * most of the time, while ignoreZoom false will give you coordinates
       * compatible with the object.oCoords system.
       * of the time.
       * @param {Event} e
       * @param {Boolean} ignoreZoom
       * @return {Object} object with "x" and "y" number values
       */
      getPointer: function (e, ignoreZoom) {
        // return cached values if we are in the event processing chain
        if (this._absolutePointer && !ignoreZoom) {
          return this._absolutePointer;
        }
        if (this._pointer && ignoreZoom) {
          return this._pointer;
        }
  
        var pointer = getPointer(e),
            upperCanvasEl = this.upperCanvasEl,
            bounds = upperCanvasEl.getBoundingClientRect(),
            boundsWidth = bounds.width || 0,
            boundsHeight = bounds.height || 0,
            cssScale;
  
        if (!boundsWidth || !boundsHeight ) {
          if ('top' in bounds && 'bottom' in bounds) {
            boundsHeight = Math.abs( bounds.top - bounds.bottom );
          }
          if ('right' in bounds && 'left' in bounds) {
            boundsWidth = Math.abs( bounds.right - bounds.left );
          }
        }
  
        this.calcOffset();
        pointer.x = pointer.x - this._offset.left;
        pointer.y = pointer.y - this._offset.top;
        if (!ignoreZoom) {
          pointer = this.restorePointerVpt(pointer);
        }
  
        if (boundsWidth === 0 || boundsHeight === 0) {
          // If bounds are not available (i.e. not visible), do not apply scale.
          cssScale = { width: 1, height: 1 };
        }
        else {
          cssScale = {
            width: upperCanvasEl.width / boundsWidth,
            height: upperCanvasEl.height / boundsHeight
          };
        }
  
        return {
          x: pointer.x * cssScale.width,
          y: pointer.y * cssScale.height
        };
      },
  
      /**
       * @private
       * @throws {CANVAS_INIT_ERROR} If canvas can not be initialized
       */
      _createUpperCanvas: function () {
        var lowerCanvasClass = this.lowerCanvasEl.className.replace(/\s*lower-canvas\s*/, '');
  
        // there is no need to create a new upperCanvas element if we have already one.
        if (this.upperCanvasEl) {
          this.upperCanvasEl.className = '';
        }
        else {
          this.upperCanvasEl = this._createCanvasElement();
        }
        fabric.util.addClass(this.upperCanvasEl, 'upper-canvas ' + lowerCanvasClass);
  
        this.wrapperEl.appendChild(this.upperCanvasEl);
  
        this._copyCanvasStyle(this.lowerCanvasEl, this.upperCanvasEl);
        this._applyCanvasStyle(this.upperCanvasEl);
        this.contextTop = this.upperCanvasEl.getContext('2d');
      },
  
      /**
       * @private
       */
      _createCacheCanvas: function () {
        this.cacheCanvasEl = this._createCanvasElement();
        this.cacheCanvasEl.setAttribute('width', this.width);
        this.cacheCanvasEl.setAttribute('height', this.height);
        this.contextCache = this.cacheCanvasEl.getContext('2d');
      },
  
      /**
       * @private
       */
      _initWrapperElement: function () {
        this.wrapperEl = fabric.util.wrapElement(this.lowerCanvasEl, 'div', {
          'class': this.containerClass
        });
        fabric.util.setStyle(this.wrapperEl, {
          width: this.width + 'px',
          height: this.height + 'px',
          position: 'relative'
        });
        fabric.util.makeElementUnselectable(this.wrapperEl);
      },
  
      /**
       * @private
       * @param {HTMLElement} element canvas element to apply styles on
       */
      _applyCanvasStyle: function (element) {
        var width = this.width || element.width,
            height = this.height || element.height;
  
        fabric.util.setStyle(element, {
          position: 'absolute',
          width: width + 'px',
          height: height + 'px',
          left: 0,
          top: 0,
          'touch-action': this.allowTouchScrolling ? 'manipulation' : 'none',
          '-ms-touch-action': this.allowTouchScrolling ? 'manipulation' : 'none'
        });
        element.width = width;
        element.height = height;
        fabric.util.makeElementUnselectable(element);
      },
  
      /**
       * Copy the entire inline style from one element (fromEl) to another (toEl)
       * @private
       * @param {Element} fromEl Element style is copied from
       * @param {Element} toEl Element copied style is applied to
       */
      _copyCanvasStyle: function (fromEl, toEl) {
        toEl.style.cssText = fromEl.style.cssText;
      },
  
      /**
       * Returns context of canvas where object selection is drawn
       * @return {CanvasRenderingContext2D}
       */
      getSelectionContext: function() {
        return this.contextTop;
      },
  
      /**
       * Returns &lt;canvas> element on which object selection is drawn
       * @return {HTMLCanvasElement}
       */
      getSelectionElement: function () {
        return this.upperCanvasEl;
      },
  
      /**
       * Returns currently active object
       * @return {fabric.Object} active object
       */
      getActiveObject: function () {
        return this._activeObject;
      },
  
      /**
       * Returns an array with the current selected objects
       * @return {fabric.Object} active object
       */
      getActiveObjects: function () {
        var active = this._activeObject;
        if (active) {
          if (active.type === 'activeSelection' && active._objects) {
            return active._objects.slice(0);
          }
          else {
            return [active];
          }
        }
        return [];
      },
  
      /**
       * @private
       * @param {fabric.Object} obj Object that was removed
       */
      _onObjectRemoved: function(obj) {
        // removing active object should fire "selection:cleared" events
        if (obj === this._activeObject) {
          this.fire('before:selection:cleared', { target: obj });
          this._discardActiveObject();
          this.fire('selection:cleared', { target: obj });
          obj.fire('deselected');
        }
        if (this._hoveredTarget === obj) {
          this._hoveredTarget = null;
        }
        this.callSuper('_onObjectRemoved', obj);
      },
  
      /**
       * @private
       * Compares the old activeObject with the current one and fires correct events
       * @param {fabric.Object} obj old activeObject
       */
      _fireSelectionEvents: function(oldObjects, e) {
        var somethingChanged = false, objects = this.getActiveObjects(),
            added = [], removed = [], opt = { e: e };
        oldObjects.forEach(function(oldObject) {
          if (objects.indexOf(oldObject) === -1) {
            somethingChanged = true;
            oldObject.fire('deselected', opt);
            removed.push(oldObject);
          }
        });
        objects.forEach(function(object) {
          if (oldObjects.indexOf(object) === -1) {
            somethingChanged = true;
            object.fire('selected', opt);
            added.push(object);
          }
        });
        if (oldObjects.length > 0 && objects.length > 0) {
          opt.selected = added;
          opt.deselected = removed;
          // added for backward compatibility
          opt.updated = added[0] || removed[0];
          opt.target = this._activeObject;
          somethingChanged && this.fire('selection:updated', opt);
        }
        else if (objects.length > 0) {
          // deprecated event
          if (objects.length === 1) {
            opt.target = added[0];
            this.fire('object:selected', opt);
          }
          opt.selected = added;
          // added for backward compatibility
          opt.target = this._activeObject;
          this.fire('selection:created', opt);
        }
        else if (oldObjects.length > 0) {
          opt.deselected = removed;
          this.fire('selection:cleared', opt);
        }
      },
  
      /**
       * Sets given object as the only active object on canvas
       * @param {fabric.Object} object Object to set as an active one
       * @param {Event} [e] Event (passed along when firing "object:selected")
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      setActiveObject: function (object, e) {
        var currentActives = this.getActiveObjects();
        this._setActiveObject(object, e);
        this._fireSelectionEvents(currentActives, e);
        return this;
      },
  
      /**
       * @private
       * @param {Object} object to set as active
       * @param {Event} [e] Event (passed along when firing "object:selected")
       * @return {Boolean} true if the selection happened
       */
      _setActiveObject: function(object, e) {
        if (this._activeObject === object) {
          return false;
        }
        if (!this._discardActiveObject(e, object)) {
          return false;
        }
        if (object.onSelect({ e: e })) {
          return false;
        }
        this._activeObject = object;
        return true;
      },
  
      /**
       * @private
       */
      _discardActiveObject: function(e, object) {
        var obj = this._activeObject;
        if (obj) {
          // onDeselect return TRUE to cancel selection;
          if (obj.onDeselect({ e: e, object: object })) {
            return false;
          }
          this._activeObject = null;
        }
        return true;
      },
  
      /**
       * Discards currently active object and fire events. If the function is called by fabric
       * as a consequence of a mouse event, the event is passed as a parameter and
       * sent to the fire function for the custom events. When used as a method the
       * e param does not have any application.
       * @param {event} e
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      discardActiveObject: function (e) {
        var currentActives = this.getActiveObjects(), activeObject = this.getActiveObject();
        if (currentActives.length) {
          this.fire('before:selection:cleared', { target: activeObject, e: e });
        }
        this._discardActiveObject(e);
        this._fireSelectionEvents(currentActives, e);
        return this;
      },
  
      /**
       * Clears a canvas element and removes all event listeners
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      dispose: function () {
        var wrapper = this.wrapperEl;
        this.removeListeners();
        wrapper.removeChild(this.upperCanvasEl);
        wrapper.removeChild(this.lowerCanvasEl);
        this.contextCache = null;
        this.contextTop = null;
        ['upperCanvasEl', 'cacheCanvasEl'].forEach((function(element) {
          fabric.util.cleanUpJsdomNode(this[element]);
          this[element] = undefined;
        }).bind(this));
        if (wrapper.parentNode) {
          wrapper.parentNode.replaceChild(this.lowerCanvasEl, this.wrapperEl);
        }
        delete this.wrapperEl;
        fabric.StaticCanvas.prototype.dispose.call(this);
        return this;
      },
  
      /**
       * Clears all contexts (background, main, top) of an instance
       * @return {fabric.Canvas} thisArg
       * @chainable
       */
      clear: function () {
        // this.discardActiveGroup();
        this.discardActiveObject();
        this.clearContext(this.contextTop);
        return this.callSuper('clear');
      },
  
      /**
       * Draws objects' controls (borders/controls)
       * @param {CanvasRenderingContext2D} ctx Context to render controls on
       */
      drawControls: function(ctx) {
        var activeObject = this._activeObject;
  
        if (activeObject) {
          activeObject._renderControls(ctx);
        }
      },
  
      /**
       * @private
       */
      _toObject: function(instance, methodName, propertiesToInclude) {
        //If the object is part of the current selection group, it should
        //be transformed appropriately
        //i.e. it should be serialised as it would appear if the selection group
        //were to be destroyed.
        var originalProperties = this._realizeGroupTransformOnObject(instance),
            object = this.callSuper('_toObject', instance, methodName, propertiesToInclude);
        //Undo the damage we did by changing all of its properties
        this._unwindGroupTransformOnObject(instance, originalProperties);
        return object;
      },
  
      /**
       * Realises an object's group transformation on it
       * @private
       * @param {fabric.Object} [instance] the object to transform (gets mutated)
       * @returns the original values of instance which were changed
       */
      _realizeGroupTransformOnObject: function(instance) {
        if (instance.group && instance.group.type === 'activeSelection' && this._activeObject === instance.group) {
          var layoutProps = ['angle', 'flipX', 'flipY', 'left', 'scaleX', 'scaleY', 'skewX', 'skewY', 'top'];
          //Copy all the positionally relevant properties across now
          var originalValues = {};
          layoutProps.forEach(function(prop) {
            originalValues[prop] = instance[prop];
          });
          this._activeObject.realizeTransform(instance);
          return originalValues;
        }
        else {
          return null;
        }
      },
  
      /**
       * Restores the changed properties of instance
       * @private
       * @param {fabric.Object} [instance] the object to un-transform (gets mutated)
       * @param {Object} [originalValues] the original values of instance, as returned by _realizeGroupTransformOnObject
       */
      _unwindGroupTransformOnObject: function(instance, originalValues) {
        if (originalValues) {
          instance.set(originalValues);
        }
      },
  
      /**
       * @private
       */
      _setSVGObject: function(markup, instance, reviver) {
        //If the object is in a selection group, simulate what would happen to that
        //object when the group is deselected
        var originalProperties = this._realizeGroupTransformOnObject(instance);
        this.callSuper('_setSVGObject', markup, instance, reviver);
        this._unwindGroupTransformOnObject(instance, originalProperties);
      },
  
      setViewportTransform: function (vpt) {
        if (this.renderOnAddRemove && this._activeObject && this._activeObject.isEditing) {
          this._activeObject.clearContextTop();
        }
        fabric.StaticCanvas.prototype.setViewportTransform.call(this, vpt);
      }
    });
  
    // copying static properties manually to work around Opera's bug,
    // where "prototype" property is enumerable and overrides existing prototype
    for (var prop in fabric.StaticCanvas) {
      if (prop !== 'prototype') {
        fabric.Canvas[prop] = fabric.StaticCanvas[prop];
      }
    }
  })();
  
  
  (function() {
  
    var cursorOffset = {
          mt: 0, // n
          tr: 1, // ne
          mr: 2, // e
          br: 3, // se
          mb: 4, // s
          bl: 5, // sw
          ml: 6, // w
          tl: 7 // nw
        },
        addListener = fabric.util.addListener,
        removeListener = fabric.util.removeListener,
        RIGHT_CLICK = 3, MIDDLE_CLICK = 2, LEFT_CLICK = 1,
        addEventOptions = { passive: false };
  
    function checkClick(e, value) {
      return e.button && (e.button === value - 1);
    }
  
    fabric.util.object.extend(fabric.Canvas.prototype, /** @lends fabric.Canvas.prototype */ {
  
      /**
       * Map of cursor style values for each of the object controls
       * @private
       */
      cursorMap: [
        'n-resize',
        'ne-resize',
        'e-resize',
        'se-resize',
        's-resize',
        'sw-resize',
        'w-resize',
        'nw-resize'
      ],
  
      /**
       * Contains the id of the touch event that owns the fabric transform
       * @type Number
       * @private
       */
      mainTouchId: null,
  
      /**
       * Adds mouse listeners to canvas
       * @private
       */
      _initEventListeners: function () {
        // in case we initialized the class twice. This should not happen normally
        // but in some kind of applications where the canvas element may be changed
        // this is a workaround to having double listeners.
        this.removeListeners();
        this._bindEvents();
        this.addOrRemove(addListener, 'add');
      },
  
      /**
       * return an event prefix pointer or mouse.
       * @private
       */
      _getEventPrefix: function () {
        return this.enablePointerEvents ? 'pointer' : 'mouse';
      },
  
      addOrRemove: function(functor, eventjsFunctor) {
        var canvasElement = this.upperCanvasEl,
            eventTypePrefix = this._getEventPrefix();
        functor(fabric.window, 'resize', this._onResize);
        functor(canvasElement, eventTypePrefix + 'down', this._onMouseDown);
        functor(canvasElement, eventTypePrefix + 'move', this._onMouseMove, addEventOptions);
        functor(canvasElement, eventTypePrefix + 'out', this._onMouseOut);
        functor(canvasElement, eventTypePrefix + 'enter', this._onMouseEnter);
        functor(canvasElement, 'wheel', this._onMouseWheel);
        functor(canvasElement, 'contextmenu', this._onContextMenu);
        functor(canvasElement, 'dblclick', this._onDoubleClick);
        functor(canvasElement, 'dragover', this._onDragOver);
        functor(canvasElement, 'dragenter', this._onDragEnter);
        functor(canvasElement, 'dragleave', this._onDragLeave);
        functor(canvasElement, 'drop', this._onDrop);
        if (!this.enablePointerEvents) {
          functor(canvasElement, 'touchstart', this._onTouchStart, addEventOptions);
        }
        if (typeof eventjs !== 'undefined' && eventjsFunctor in eventjs) {
          eventjs[eventjsFunctor](canvasElement, 'gesture', this._onGesture);
          eventjs[eventjsFunctor](canvasElement, 'drag', this._onDrag);
          eventjs[eventjsFunctor](canvasElement, 'orientation', this._onOrientationChange);
          eventjs[eventjsFunctor](canvasElement, 'shake', this._onShake);
          eventjs[eventjsFunctor](canvasElement, 'longpress', this._onLongPress);
        }
      },
  
      /**
       * Removes all event listeners
       */
      removeListeners: function() {
        this.addOrRemove(removeListener, 'remove');
        // if you dispose on a mouseDown, before mouse up, you need to clean document to...
        var eventTypePrefix = this._getEventPrefix();
        removeListener(fabric.document, eventTypePrefix + 'up', this._onMouseUp);
        removeListener(fabric.document, 'touchend', this._onTouchEnd, addEventOptions);
        removeListener(fabric.document, eventTypePrefix + 'move', this._onMouseMove, addEventOptions);
        removeListener(fabric.document, 'touchmove', this._onMouseMove, addEventOptions);
      },
  
      /**
       * @private
       */
      _bindEvents: function() {
        if (this.eventsBound) {
          // for any reason we pass here twice we do not want to bind events twice.
          return;
        }
        this._onMouseDown = this._onMouseDown.bind(this);
        this._onTouchStart = this._onTouchStart.bind(this);
        this._onMouseMove = this._onMouseMove.bind(this);
        this._onMouseUp = this._onMouseUp.bind(this);
        this._onTouchEnd = this._onTouchEnd.bind(this);
        this._onResize = this._onResize.bind(this);
        this._onGesture = this._onGesture.bind(this);
        this._onDrag = this._onDrag.bind(this);
        this._onShake = this._onShake.bind(this);
        this._onLongPress = this._onLongPress.bind(this);
        this._onOrientationChange = this._onOrientationChange.bind(this);
        this._onMouseWheel = this._onMouseWheel.bind(this);
        this._onMouseOut = this._onMouseOut.bind(this);
        this._onMouseEnter = this._onMouseEnter.bind(this);
        this._onContextMenu = this._onContextMenu.bind(this);
        this._onDoubleClick = this._onDoubleClick.bind(this);
        this._onDragOver = this._onDragOver.bind(this);
        this._onDragEnter = this._simpleEventHandler.bind(this, 'dragenter');
        this._onDragLeave = this._simpleEventHandler.bind(this, 'dragleave');
        this._onDrop = this._simpleEventHandler.bind(this, 'drop');
        this.eventsBound = true;
      },
  
      /**
       * @private
       * @param {Event} [e] Event object fired on Event.js gesture
       * @param {Event} [self] Inner Event object
       */
      _onGesture: function(e, self) {
        this.__onTransformGesture && this.__onTransformGesture(e, self);
      },
  
      /**
       * @private
       * @param {Event} [e] Event object fired on Event.js drag
       * @param {Event} [self] Inner Event object
       */
      _onDrag: function(e, self) {
        this.__onDrag && this.__onDrag(e, self);
      },
  
      /**
       * @private
       * @param {Event} [e] Event object fired on wheel event
       */
      _onMouseWheel: function(e) {
        this.__onMouseWheel(e);
      },
  
      /**
       * @private
       * @param {Event} e Event object fired on mousedown
       */
      _onMouseOut: function(e) {
        var target = this._hoveredTarget;
        this.fire('mouse:out', { target: target, e: e });
        this._hoveredTarget = null;
        target && target.fire('mouseout', { e: e });
        if (this._iTextInstances) {
          this._iTextInstances.forEach(function(obj) {
            if (obj.isEditing) {
              obj.hiddenTextarea.focus();
            }
          });
        }
      },
  
      /**
       * @private
       * @param {Event} e Event object fired on mouseenter
       */
      _onMouseEnter: function(e) {
        // This find target and consequent 'mouse:over' is used to
        // clear old instances on hovered target.
        // calling findTarget has the side effect of killing target.__corner.
        // as a short term fix we are not firing this if we are currently transforming.
        // as a long term fix we need to separate the action of finding a target with the
        // side effects we added to it.
        if (!this.currentTransform && !this.findTarget(e)) {
          this.fire('mouse:over', { target: null, e: e });
          this._hoveredTarget = null;
        }
      },
  
      /**
       * @private
       * @param {Event} [e] Event object fired on Event.js orientation change
       * @param {Event} [self] Inner Event object
       */
      _onOrientationChange: function(e, self) {
        this.__onOrientationChange && this.__onOrientationChange(e, self);
      },
  
      /**
       * @private
       * @param {Event} [e] Event object fired on Event.js shake
       * @param {Event} [self] Inner Event object
       */
      _onShake: function(e, self) {
        this.__onShake && this.__onShake(e, self);
      },
  
      /**
       * @private
       * @param {Event} [e] Event object fired on Event.js shake
       * @param {Event} [self] Inner Event object
       */
      _onLongPress: function(e, self) {
        this.__onLongPress && this.__onLongPress(e, self);
      },
  
      /**
       * prevent default to allow drop event to be fired
       * @private
       * @param {Event} [e] Event object fired on Event.js shake
       */
      _onDragOver: function(e) {
        e.preventDefault();
        var target = this._simpleEventHandler('dragover', e);
        this._fireEnterLeaveEvents(target, e);
      },
  
      /**
       * @private
       * @param {Event} e Event object fired on mousedown
       */
      _onContextMenu: function (e) {
        if (this.stopContextMenu) {
          e.stopPropagation();
          e.preventDefault();
        }
        return false;
      },
  
      /**
       * @private
       * @param {Event} e Event object fired on mousedown
       */
      _onDoubleClick: function (e) {
        this._cacheTransformEventData(e);
        this._handleEvent(e, 'dblclick');
        this._resetTransformEventData(e);
      },
  
      /**
       * Return a the id of an event.
       * returns either the pointerId or the identifier or 0 for the mouse event
       * @private
       * @param {Event} evt Event object
       */
      getPointerId: function(evt) {
        var changedTouches = evt.changedTouches;
  
        if (changedTouches) {
          return changedTouches[0] && changedTouches[0].identifier;
        }
  
        if (this.enablePointerEvents) {
          return evt.pointerId;
        }
  
        return -1;
      },
  
      /**
       * Determines if an event has the id of the event that is considered main
       * @private
       * @param {evt} event Event object
       */
      _isMainEvent: function(evt) {
        if (evt.isPrimary === true) {
          return true;
        }
        if (evt.isPrimary === false) {
          return false;
        }
        if (evt.type === 'touchend' && evt.touches.length === 0) {
          return true;
        }
        if (evt.changedTouches) {
          return evt.changedTouches[0].identifier === this.mainTouchId;
        }
        return true;
      },
  
      /**
       * @private
       * @param {Event} e Event object fired on mousedown
       */
      _onTouchStart: function(e) {
        e.preventDefault();
        if (this.mainTouchId === null) {
          this.mainTouchId = this.getPointerId(e);
        }
        this.__onMouseDown(e);
        this._resetTransformEventData();
        var canvasElement = this.upperCanvasEl,
            eventTypePrefix = this._getEventPrefix();
        addListener(fabric.document, 'touchend', this._onTouchEnd, addEventOptions);
        addListener(fabric.document, 'touchmove', this._onMouseMove, addEventOptions);
        // Unbind mousedown to prevent double triggers from touch devices
        removeListener(canvasElement, eventTypePrefix + 'down', this._onMouseDown);
      },
  
      /**
       * @private
       * @param {Event} e Event object fired on mousedown
       */
      _onMouseDown: function (e) {
        this.__onMouseDown(e);
        this._resetTransformEventData();
        var canvasElement = this.upperCanvasEl,
            eventTypePrefix = this._getEventPrefix();
        removeListener(canvasElement, eventTypePrefix + 'move', this._onMouseMove, addEventOptions);
        addListener(fabric.document, eventTypePrefix + 'up', this._onMouseUp);
        addListener(fabric.document, eventTypePrefix + 'move', this._onMouseMove, addEventOptions);
      },
  
      /**
       * @private
       * @param {Event} e Event object fired on mousedown
       */
      _onTouchEnd: function(e) {
        if (e.touches.length > 0) {
          // if there are still touches stop here
          return;
        }
        this.__onMouseUp(e);
        this._resetTransformEventData();
        this.mainTouchId = null;
        var eventTypePrefix = this._getEventPrefix();
        removeListener(fabric.document, 'touchend', this._onTouchEnd, addEventOptions);
        removeListener(fabric.document, 'touchmove', this._onMouseMove, addEventOptions);
        var _this = this;
        if (this._willAddMouseDown) {
          clearTimeout(this._willAddMouseDown);
        }
        this._willAddMouseDown = setTimeout(function() {
          // Wait 400ms before rebinding mousedown to prevent double triggers
          // from touch devices
          addListener(_this.upperCanvasEl, eventTypePrefix + 'down', _this._onMouseDown);
          _this._willAddMouseDown = 0;
        }, 400);
      },
  
      /**
       * @private
       * @param {Event} e Event object fired on mouseup
       */
      _onMouseUp: function (e) {
        this.__onMouseUp(e);
        this._resetTransformEventData();
        var canvasElement = this.upperCanvasEl,
            eventTypePrefix = this._getEventPrefix();
        if (this._isMainEvent(e)) {
          removeListener(fabric.document, eventTypePrefix + 'up', this._onMouseUp);
          removeListener(fabric.document, eventTypePrefix + 'move', this._onMouseMove, addEventOptions);
          addListener(canvasElement, eventTypePrefix + 'move', this._onMouseMove, addEventOptions);
        }
      },
  
      /**
       * @private
       * @param {Event} e Event object fired on mousemove
       */
      _onMouseMove: function (e) {
        !this.allowTouchScrolling && e.preventDefault && e.preventDefault();
        this.__onMouseMove(e);
      },
  
      /**
       * @private
       */
      _onResize: function () {
        this.calcOffset();
      },
  
      /**
       * Decides whether the canvas should be redrawn in mouseup and mousedown events.
       * @private
       * @param {Object} target
       */
      _shouldRender: function(target) {
        var activeObject = this._activeObject;
  
        if (
          !!activeObject !== !!target ||
          (activeObject && target && (activeObject !== target))
        ) {
          // this covers: switch of target, from target to no target, selection of target
          // multiSelection with key and mouse
          return true;
        }
        else if (activeObject && activeObject.isEditing) {
          // if we mouse up/down over a editing textbox a cursor change,
          // there is no need to re render
          return false;
        }
        return false;
      },
  
      /**
       * Method that defines the actions when mouse is released on canvas.
       * The method resets the currentTransform parameters, store the image corner
       * position in the image object and render the canvas on top.
       * @private
       * @param {Event} e Event object fired on mouseup
       */
      __onMouseUp: function (e) {
        var target, transform = this._currentTransform,
            groupSelector = this._groupSelector, shouldRender = false,
            isClick = (!groupSelector || (groupSelector.left === 0 && groupSelector.top === 0));
        this._cacheTransformEventData(e);
        target = this._target;
        this._handleEvent(e, 'up:before');
        // if right/middle click just fire events and return
        // target undefined will make the _handleEvent search the target
        if (checkClick(e, RIGHT_CLICK)) {
          if (this.fireRightClick) {
            this._handleEvent(e, 'up', RIGHT_CLICK, isClick);
          }
          return;
        }
  
        if (checkClick(e, MIDDLE_CLICK)) {
          if (this.fireMiddleClick) {
            this._handleEvent(e, 'up', MIDDLE_CLICK, isClick);
          }
          this._resetTransformEventData();
          return;
        }
  
        if (this.isDrawingMode && this._isCurrentlyDrawing) {
          this._onMouseUpInDrawingMode(e);
          return;
        }
  
        if (!this._isMainEvent(e)) {
          return;
        }
        if (transform) {
          this._finalizeCurrentTransform(e);
          shouldRender = transform.actionPerformed;
        }
  
        if (!isClick) {
          this._maybeGroupObjects(e);
          shouldRender || (shouldRender = this._shouldRender(target));
        }
        if (target) {
          target.isMoving = false;
        }
        this._setCursorFromEvent(e, target);
        this._handleEvent(e, 'up', LEFT_CLICK, isClick);
        this._groupSelector = null;
        this._currentTransform = null;
        // reset the target information about which corner is selected
        target && (target.__corner = 0);
        if (shouldRender) {
          this.requestRenderAll();
        }
        else if (!isClick) {
          this.renderTop();
        }
      },
  
      /**
       * @private
       * Handle event firing for target and subtargets
       * @param {Event} e event from mouse
       * @param {String} eventType event to fire (up, down or move)
       * @return {Fabric.Object} target return the the target found, for internal reasons.
       */
      _simpleEventHandler: function(eventType, e) {
        var target = this.findTarget(e),
            targets = this.targets,
            options = {
              e: e,
              target: target,
              subTargets: targets,
            };
        this.fire(eventType, options);
        target && target.fire(eventType, options);
        if (!targets) {
          return target;
        }
        for (var i = 0; i < targets.length; i++) {
          targets[i].fire(eventType, options);
        }
        return target;
      },
  
      /**
       * @private
       * Handle event firing for target and subtargets
       * @param {Event} e event from mouse
       * @param {String} eventType event to fire (up, down or move)
       * @param {fabric.Object} targetObj receiving event
       * @param {Number} [button] button used in the event 1 = left, 2 = middle, 3 = right
       * @param {Boolean} isClick for left button only, indicates that the mouse up happened without move.
       */
      _handleEvent: function(e, eventType, button, isClick) {
        var target = this._target,
            targets = this.targets || [],
            options = {
              e: e,
              target: target,
              subTargets: targets,
              button: button || LEFT_CLICK,
              isClick: isClick || false,
              pointer: this._pointer,
              absolutePointer: this._absolutePointer,
              transform: this._currentTransform
            };
        this.fire('mouse:' + eventType, options);
        target && target.fire('mouse' + eventType, options);
        for (var i = 0; i < targets.length; i++) {
          targets[i].fire('mouse' + eventType, options);
        }
      },
  
      /**
       * @private
       * @param {Event} e send the mouse event that generate the finalize down, so it can be used in the event
       */
      _finalizeCurrentTransform: function(e) {
  
        var transform = this._currentTransform,
            target = transform.target,
            eventName,
            options = {
              e: e,
              target: target,
              transform: transform,
            };
  
        if (target._scaling) {
          target._scaling = false;
        }
  
        target.setCoords();
  
        if (transform.actionPerformed || (this.stateful && target.hasStateChanged())) {
          if (transform.actionPerformed) {
            eventName = this._addEventOptions(options, transform);
            this._fire(eventName, options);
          }
          this._fire('modified', options);
        }
      },
  
      /**
       * Mutate option object in order to add by property and give back the event name.
       * @private
       * @param {Object} options to mutate
       * @param {Object} transform to inspect action from
       */
      _addEventOptions: function(options, transform) {
        // we can probably add more details at low cost
        // scale change, rotation changes, translation changes
        var eventName, by;
        switch (transform.action) {
          case 'scaleX':
            eventName = 'scaled';
            by = 'x';
            break;
          case 'scaleY':
            eventName = 'scaled';
            by = 'y';
            break;
          case 'skewX':
            eventName = 'skewed';
            by = 'x';
            break;
          case 'skewY':
            eventName = 'skewed';
            by = 'y';
            break;
          case 'scale':
            eventName = 'scaled';
            by = 'equally';
            break;
          case 'rotate':
            eventName = 'rotated';
            break;
          case 'drag':
            eventName = 'moved';
            break;
        }
        options.by = by;
        return eventName;
      },
  
      /**
       * @private
       * @param {Event} e Event object fired on mousedown
       */
      _onMouseDownInDrawingMode: function(e) {
        this._isCurrentlyDrawing = true;
        if (this.getActiveObject()) {
          this.discardActiveObject(e).requestRenderAll();
        }
        if (this.clipTo) {
          fabric.util.clipContext(this, this.contextTop);
        }
        var pointer = this.getPointer(e);
        this.freeDrawingBrush.onMouseDown(pointer, { e: e, pointer: pointer });
        this._handleEvent(e, 'down');
      },
  
      /**
       * @private
       * @param {Event} e Event object fired on mousemove
       */
      _onMouseMoveInDrawingMode: function(e) {
        if (this._isCurrentlyDrawing) {
          var pointer = this.getPointer(e);
          this.freeDrawingBrush.onMouseMove(pointer, { e: e, pointer: pointer });
        }
        this.setCursor(this.freeDrawingCursor);
        this._handleEvent(e, 'move');
      },
  
      /**
       * @private
       * @param {Event} e Event object fired on mouseup
       */
      _onMouseUpInDrawingMode: function(e) {
        if (this.clipTo) {
          this.contextTop.restore();
        }
        var pointer = this.getPointer(e);
        this._isCurrentlyDrawing = this.freeDrawingBrush.onMouseUp({ e: e, pointer: pointer });
        this._handleEvent(e, 'up');
      },
  
      /**
       * Method that defines the actions when mouse is clicked on canvas.
       * The method inits the currentTransform parameters and renders all the
       * canvas so the current image can be placed on the top canvas and the rest
       * in on the container one.
       * @private
       * @param {Event} e Event object fired on mousedown
       */
      __onMouseDown: function (e) {
        this._cacheTransformEventData(e);
        this._handleEvent(e, 'down:before');
        var target = this._target;
        // if right click just fire events
        if (checkClick(e, RIGHT_CLICK)) {
          if (this.fireRightClick) {
            this._handleEvent(e, 'down', RIGHT_CLICK);
          }
          return;
        }
  
        if (checkClick(e, MIDDLE_CLICK)) {
          if (this.fireMiddleClick) {
            this._handleEvent(e, 'down', MIDDLE_CLICK);
          }
          return;
        }
  
        if (this.isDrawingMode) {
          this._onMouseDownInDrawingMode(e);
          return;
        }
  
        if (!this._isMainEvent(e)) {
          return;
        }
  
        // ignore if some object is being transformed at this moment
        if (this._currentTransform) {
          return;
        }
  
        var pointer = this._pointer;
        // save pointer for check in __onMouseUp event
        this._previousPointer = pointer;
        var shouldRender = this._shouldRender(target),
            shouldGroup = this._shouldGroup(e, target);
        if (this._shouldClearSelection(e, target)) {
          this.discardActiveObject(e);
        }
        else if (shouldGroup) {
          this._handleGrouping(e, target);
          target = this._activeObject;
        }
  
        if (this.selection && (!target ||
          (!target.selectable && !target.isEditing && target !== this._activeObject))) {
          this._groupSelector = {
            ex: pointer.x,
            ey: pointer.y,
            top: 0,
            left: 0
          };
        }
  
        if (target) {
          var alreadySelected = target === this._activeObject;
          if (target.selectable) {
            this.setActiveObject(target, e);
          }
          if (target === this._activeObject && (target.__corner || !shouldGroup)) {
            this._setupCurrentTransform(e, target, alreadySelected);
          }
        }
        this._handleEvent(e, 'down');
        // we must renderAll so that we update the visuals
        (shouldRender || shouldGroup) && this.requestRenderAll();
      },
  
      /**
       * reset cache form common information needed during event processing
       * @private
       */
      _resetTransformEventData: function() {
        this._target = null;
        this._pointer = null;
        this._absolutePointer = null;
      },
  
      /**
       * Cache common information needed during event processing
       * @private
       * @param {Event} e Event object fired on event
       */
      _cacheTransformEventData: function(e) {
        // reset in order to avoid stale caching
        this._resetTransformEventData();
        this._pointer = this.getPointer(e, true);
        this._absolutePointer = this.restorePointerVpt(this._pointer);
        this._target = this._currentTransform ? this._currentTransform.target : this.findTarget(e) || null;
      },
  
      /**
       * @private
       */
      _beforeTransform: function(e) {
        var t = this._currentTransform;
        this.stateful && t.target.saveState();
        this.fire('before:transform', {
          e: e,
          transform: t,
        });
        // determine if it's a drag or rotate case
        if (t.corner) {
          this.onBeforeScaleRotate(t.target);
        }
      },
  
      /**
       * Method that defines the actions when mouse is hovering the canvas.
       * The currentTransform parameter will define whether the user is rotating/scaling/translating
       * an image or neither of them (only hovering). A group selection is also possible and would cancel
       * all any other type of action.
       * In case of an image transformation only the top canvas will be rendered.
       * @private
       * @param {Event} e Event object fired on mousemove
       */
      __onMouseMove: function (e) {
        this._handleEvent(e, 'move:before');
        this._cacheTransformEventData(e);
        var target, pointer;
  
        if (this.isDrawingMode) {
          this._onMouseMoveInDrawingMode(e);
          return;
        }
  
        if (!this._isMainEvent(e)) {
          return;
        }
  
        var groupSelector = this._groupSelector;
  
        // We initially clicked in an empty area, so we draw a box for multiple selection
        if (groupSelector) {
          pointer = this._pointer;
  
          groupSelector.left = pointer.x - groupSelector.ex;
          groupSelector.top = pointer.y - groupSelector.ey;
  
          this.renderTop();
        }
        else if (!this._currentTransform) {
          target = this.findTarget(e) || null;
          this._setCursorFromEvent(e, target);
          this._fireOverOutEvents(target, e);
        }
        else {
          this._transformObject(e);
        }
        this._handleEvent(e, 'move');
        this._resetTransformEventData();
      },
  
      /**
       * Manage the mouseout, mouseover events for the fabric object on the canvas
       * @param {Fabric.Object} target the target where the target from the mousemove event
       * @param {Event} e Event object fired on mousemove
       * @private
       */
      _fireOverOutEvents: function(target, e) {
        this.fireSyntheticInOutEvents(target, e, {
          targetName: '_hoveredTarget',
          canvasEvtOut: 'mouse:out',
          evtOut: 'mouseout',
          canvasEvtIn: 'mouse:over',
          evtIn: 'mouseover',
        });
      },
  
      /**
       * Manage the dragEnter, dragLeave events for the fabric objects on the canvas
       * @param {Fabric.Object} target the target where the target from the onDrag event
       * @param {Event} e Event object fired on ondrag
       * @private
       */
      _fireEnterLeaveEvents: function(target, e) {
        this.fireSyntheticInOutEvents(target, e, {
          targetName: '_draggedoverTarget',
          evtOut: 'dragleave',
          evtIn: 'dragenter',
        });
      },
  
      /**
       * Manage the synthetic in/out events for the fabric objects on the canvas
       * @param {Fabric.Object} target the target where the target from the supported events
       * @param {Event} e Event object fired
       * @param {Object} config configuration for the function to work
       * @param {String} config.targetName property on the canvas where the old target is stored
       * @param {String} [config.canvasEvtOut] name of the event to fire at canvas level for out
       * @param {String} config.evtOut name of the event to fire for out
       * @param {String} [config.canvasEvtIn] name of the event to fire at canvas level for in
       * @param {String} config.evtIn name of the event to fire for in
       * @private
       */
      fireSyntheticInOutEvents: function(target, e, config) {
        var inOpt, outOpt, oldTarget = this[config.targetName], outFires, inFires,
            targetChanged = oldTarget !== target, canvasEvtIn = config.canvasEvtIn, canvasEvtOut = config.canvasEvtOut;
        if (targetChanged) {
          inOpt = { e: e, target: target, previousTarget: oldTarget };
          outOpt = { e: e, target: oldTarget, nextTarget: target };
          this[config.targetName] = target;
        }
        inFires = target && targetChanged;
        outFires = oldTarget && targetChanged;
        if (outFires) {
          canvasEvtOut && this.fire(canvasEvtOut, outOpt);
          oldTarget.fire(config.evtOut, outOpt);
        }
        if (inFires) {
          canvasEvtIn && this.fire(canvasEvtIn, inOpt);
          target.fire(config.evtIn, inOpt);
        }
      },
  
      /**
       * Method that defines actions when an Event Mouse Wheel
       * @param {Event} e Event object fired on mouseup
       */
      __onMouseWheel: function(e) {
        this._cacheTransformEventData(e);
        this._handleEvent(e, 'wheel');
        this._resetTransformEventData();
      },
  
      /**
       * @private
       * @param {Event} e Event fired on mousemove
       */
      _transformObject: function(e) {
        var pointer = this.getPointer(e),
            transform = this._currentTransform;
  
        transform.reset = false;
        transform.target.isMoving = true;
        transform.shiftKey = e.shiftKey;
        transform.altKey = e[this.centeredKey];
  
        this._beforeScaleTransform(e, transform);
        this._performTransformAction(e, transform, pointer);
  
        transform.actionPerformed && this.requestRenderAll();
      },
  
      /**
       * @private
       */
      _performTransformAction: function(e, transform, pointer) {
        var x = pointer.x,
            y = pointer.y,
            action = transform.action,
            actionPerformed = false,
            options = {
              target: transform.target,
              e: e,
              transform: transform,
              pointer: pointer
            };
  
        if (action === 'rotate') {
          (actionPerformed = this._rotateObject(x, y)) && this._fire('rotating', options);
        }
        else if (action === 'scale') {
          (actionPerformed = this._onScale(e, transform, x, y)) && this._fire('scaling', options);
        }
        else if (action === 'scaleX') {
          (actionPerformed = this._scaleObject(x, y, 'x')) && this._fire('scaling', options);
        }
        else if (action === 'scaleY') {
          (actionPerformed = this._scaleObject(x, y, 'y')) && this._fire('scaling', options);
        }
        else if (action === 'skewX') {
          (actionPerformed = this._skewObject(x, y, 'x')) && this._fire('skewing', options);
        }
        else if (action === 'skewY') {
          (actionPerformed = this._skewObject(x, y, 'y')) && this._fire('skewing', options);
        }
        else {
          actionPerformed = this._translateObject(x, y);
          if (actionPerformed) {
            this._fire('moving', options);
            this.setCursor(options.target.moveCursor || this.moveCursor);
          }
        }
        transform.actionPerformed = transform.actionPerformed || actionPerformed;
      },
  
      /**
       * @private
       */
      _fire: function(eventName, options) {
        this.fire('object:' + eventName, options);
        options.target.fire(eventName, options);
      },
  
      /**
       * @private
       */
      _beforeScaleTransform: function(e, transform) {
        if (transform.action === 'scale' || transform.action === 'scaleX' || transform.action === 'scaleY') {
          var centerTransform = this._shouldCenterTransform(transform.target);
  
          // Switch from a normal resize to center-based
          if ((centerTransform && (transform.originX !== 'center' || transform.originY !== 'center')) ||
             // Switch from center-based resize to normal one
             (!centerTransform && transform.originX === 'center' && transform.originY === 'center')
          ) {
            this._resetCurrentTransform();
            transform.reset = true;
          }
        }
      },
  
      /**
       * @private
       * @param {Event} e Event object
       * @param {Object} transform current transform
       * @param {Number} x mouse position x from origin
       * @param {Number} y mouse position y from origin
       * @return {Boolean} true if the scaling occurred
       */
      _onScale: function(e, transform, x, y) {
        if (this._isUniscalePossible(e, transform.target)) {
          transform.currentAction = 'scale';
          return this._scaleObject(x, y);
        }
        else {
          // Switch from a normal resize to proportional
          if (!transform.reset && transform.currentAction === 'scale') {
            this._resetCurrentTransform();
          }
  
          transform.currentAction = 'scaleEqually';
          return this._scaleObject(x, y, 'equally');
        }
      },
  
      /**
       * @private
       * @param {Event} e Event object
       * @param {fabric.Object} target current target
       * @return {Boolean} true if unproportional scaling is possible
       */
      _isUniscalePossible: function(e, target) {
        return (e[this.uniScaleKey] || this.uniScaleTransform) && !target.get('lockUniScaling');
      },
  
      /**
       * Sets the cursor depending on where the canvas is being hovered.
       * Note: very buggy in Opera
       * @param {Event} e Event object
       * @param {Object} target Object that the mouse is hovering, if so.
       */
      _setCursorFromEvent: function (e, target) {
        if (!target) {
          this.setCursor(this.defaultCursor);
          return false;
        }
        var hoverCursor = target.hoverCursor || this.hoverCursor,
            activeSelection = this._activeObject && this._activeObject.type === 'activeSelection' ?
              this._activeObject : null,
            // only show proper corner when group selection is not active
            corner = (!activeSelection || !activeSelection.contains(target))
                      && target._findTargetCorner(this.getPointer(e, true));
  
        if (!corner) {
          this.setCursor(hoverCursor);
        }
        else {
          this.setCursor(this.getCornerCursor(corner, target, e));
        }
      },
  
      /**
       * @private
       */
      getCornerCursor: function(corner, target, e) {
        if (this.actionIsDisabled(corner, target, e)) {
          return this.notAllowedCursor;
        }
        else if (corner in cursorOffset) {
          return this._getRotatedCornerCursor(corner, target, e);
        }
        else if (corner === 'mtr' && target.hasRotatingPoint) {
          return this.rotationCursor;
        }
        else {
          return this.defaultCursor;
        }
      },
  
      actionIsDisabled: function(corner, target, e) {
        if (corner === 'mt' || corner === 'mb') {
          return e[this.altActionKey] ? target.lockSkewingX : target.lockScalingY;
        }
        else if (corner === 'ml' || corner === 'mr') {
          return e[this.altActionKey] ? target.lockSkewingY : target.lockScalingX;
        }
        else if (corner === 'mtr') {
          return target.lockRotation;
        }
        else {
          return this._isUniscalePossible(e, target) ?
            target.lockScalingX && target.lockScalingY : target.lockScalingX || target.lockScalingY;
        }
      },
  
      /**
       * @private
       */
      _getRotatedCornerCursor: function(corner, target, e) {
        var n = Math.round((target.angle % 360) / 45);
  
        if (n < 0) {
          n += 8; // full circle ahead
        }
        n += cursorOffset[corner];
        if (e[this.altActionKey] && cursorOffset[corner] % 2 === 0) {
          //if we are holding shift and we are on a mx corner...
          n += 2;
        }
        // normalize n to be from 0 to 7
        n %= 8;
  
        return this.cursorMap[n];
      }
    });
  })();
  
  
  (function() {
  
    var min = Math.min,
        max = Math.max;
  
    fabric.util.object.extend(fabric.Canvas.prototype, /** @lends fabric.Canvas.prototype */ {
  
      /**
       * @private
       * @param {Event} e Event object
       * @param {fabric.Object} target
       * @return {Boolean}
       */
      _shouldGroup: function(e, target) {
        var activeObject = this._activeObject;
        return activeObject && this._isSelectionKeyPressed(e) && target && target.selectable && this.selection &&
              (activeObject !== target || activeObject.type === 'activeSelection') && !target.onSelect({ e: e });
      },
  
      /**
       * @private
       * @param {Event} e Event object
       * @param {fabric.Object} target
       */
      _handleGrouping: function (e, target) {
        var activeObject = this._activeObject;
        // avoid multi select when shift click on a corner
        if (activeObject.__corner) {
          return;
        }
        if (target === activeObject) {
          // if it's a group, find target again, using activeGroup objects
          target = this.findTarget(e, true);
          // if even object is not found or we are on activeObjectCorner, bail out
          if (!target || !target.selectable) {
            return;
          }
        }
        if (activeObject && activeObject.type === 'activeSelection') {
          this._updateActiveSelection(target, e);
        }
        else {
          this._createActiveSelection(target, e);
        }
      },
  
      /**
       * @private
       */
      _updateActiveSelection: function(target, e) {
        var activeSelection = this._activeObject,
            currentActiveObjects = activeSelection._objects.slice(0);
        if (activeSelection.contains(target)) {
          activeSelection.removeWithUpdate(target);
          this._hoveredTarget = target;
          if (activeSelection.size() === 1) {
            // activate last remaining object
            this._setActiveObject(activeSelection.item(0), e);
          }
        }
        else {
          activeSelection.addWithUpdate(target);
          this._hoveredTarget = activeSelection;
        }
        this._fireSelectionEvents(currentActiveObjects, e);
      },
  
      /**
       * @private
       */
      _createActiveSelection: function(target, e) {
        var currentActives = this.getActiveObjects(), group = this._createGroup(target);
        this._hoveredTarget = group;
        this._setActiveObject(group, e);
        this._fireSelectionEvents(currentActives, e);
      },
  
      /**
       * @private
       * @param {Object} target
       */
      _createGroup: function(target) {
        var objects = this._objects,
            isActiveLower = objects.indexOf(this._activeObject) < objects.indexOf(target),
            groupObjects = isActiveLower
              ? [this._activeObject, target]
              : [target, this._activeObject];
        this._activeObject.isEditing && this._activeObject.exitEditing();
        return new fabric.ActiveSelection(groupObjects, {
          canvas: this
        });
      },
  
      /**
       * @private
       * @param {Event} e mouse event
       */
      _groupSelectedObjects: function (e) {
  
        var group = this._collectObjects(e),
            aGroup;
  
        // do not create group for 1 element only
        if (group.length === 1) {
          this.setActiveObject(group[0], e);
        }
        else if (group.length > 1) {
          aGroup = new fabric.ActiveSelection(group.reverse(), {
            canvas: this
          });
          this.setActiveObject(aGroup, e);
        }
      },
  
      /**
       * @private
       */
      _collectObjects: function(e) {
        var group = [],
            currentObject,
            x1 = this._groupSelector.ex,
            y1 = this._groupSelector.ey,
            x2 = x1 + this._groupSelector.left,
            y2 = y1 + this._groupSelector.top,
            selectionX1Y1 = new fabric.Point(min(x1, x2), min(y1, y2)),
            selectionX2Y2 = new fabric.Point(max(x1, x2), max(y1, y2)),
            allowIntersect = !this.selectionFullyContained,
            isClick = x1 === x2 && y1 === y2;
        // we iterate reverse order to collect top first in case of click.
        for (var i = this._objects.length; i--; ) {
          currentObject = this._objects[i];
  
          if (!currentObject || !currentObject.selectable || !currentObject.visible) {
            continue;
          }
  
          if ((allowIntersect && currentObject.intersectsWithRect(selectionX1Y1, selectionX2Y2)) ||
              currentObject.isContainedWithinRect(selectionX1Y1, selectionX2Y2) ||
              (allowIntersect && currentObject.containsPoint(selectionX1Y1)) ||
              (allowIntersect && currentObject.containsPoint(selectionX2Y2))
          ) {
            group.push(currentObject);
            // only add one object if it's a click
            if (isClick) {
              break;
            }
          }
        }
  
        if (group.length > 1) {
          group = group.filter(function(object) {
            return !object.onSelect({ e: e });
          });
        }
  
        return group;
      },
  
      /**
       * @private
       */
      _maybeGroupObjects: function(e) {
        if (this.selection && this._groupSelector) {
          this._groupSelectedObjects(e);
        }
        this.setCursor(this.defaultCursor);
        // clear selection and current transformation
        this._groupSelector = null;
      }
    });
  
  })();
  
  
  (function () {
    fabric.util.object.extend(fabric.StaticCanvas.prototype, /** @lends fabric.StaticCanvas.prototype */ {
  
      /**
       * Exports canvas element to a dataurl image. Note that when multiplier is used, cropping is scaled appropriately
       * @param {Object} [options] Options object
       * @param {String} [options.format=png] The format of the output image. Either "jpeg" or "png"
       * @param {Number} [options.quality=1] Quality level (0..1). Only used for jpeg.
       * @param {Number} [options.multiplier=1] Multiplier to scale by, to have consistent
       * @param {Number} [options.left] Cropping left offset. Introduced in v1.2.14
       * @param {Number} [options.top] Cropping top offset. Introduced in v1.2.14
       * @param {Number} [options.width] Cropping width. Introduced in v1.2.14
       * @param {Number} [options.height] Cropping height. Introduced in v1.2.14
       * @param {Boolean} [options.enableRetinaScaling] Enable retina scaling for clone image. Introduce in 2.0.0
       * @return {String} Returns a data: URL containing a representation of the object in the format specified by options.format
       * @see {@link http://jsfiddle.net/fabricjs/NfZVb/|jsFiddle demo}
       * @example <caption>Generate jpeg dataURL with lower quality</caption>
       * var dataURL = canvas.toDataURL({
       *   format: 'jpeg',
       *   quality: 0.8
       * });
       * @example <caption>Generate cropped png dataURL (clipping of canvas)</caption>
       * var dataURL = canvas.toDataURL({
       *   format: 'png',
       *   left: 100,
       *   top: 100,
       *   width: 200,
       *   height: 200
       * });
       * @example <caption>Generate double scaled png dataURL</caption>
       * var dataURL = canvas.toDataURL({
       *   format: 'png',
       *   multiplier: 2
       * });
       */
      toDataURL: function (options) {
        options || (options = { });
  
        var format = options.format || 'png',
            quality = options.quality || 1,
            multiplier = (options.multiplier || 1) * (options.enableRetinaScaling ? this.getRetinaScaling() : 1),
            canvasEl = this.toCanvasElement(multiplier, options);
        return fabric.util.toDataURL(canvasEl, format, quality);
      },
  
      /**
       * Create a new HTMLCanvas element painted with the current canvas content.
       * No need to resize the actual one or repaint it.
       * Will transfer object ownership to a new canvas, paint it, and set everything back.
       * This is an intermediary step used to get to a dataUrl but also it is useful to
       * create quick image copies of a canvas without passing for the dataUrl string
       * @param {Number} [multiplier] a zoom factor.
       * @param {Object} [cropping] Cropping informations
       * @param {Number} [cropping.left] Cropping left offset.
       * @param {Number} [cropping.top] Cropping top offset.
       * @param {Number} [cropping.width] Cropping width.
       * @param {Number} [cropping.height] Cropping height.
       */
      toCanvasElement: function(multiplier, cropping) {
        multiplier = multiplier || 1;
        cropping = cropping || { };
        var scaledWidth = (cropping.width || this.width) * multiplier,
            scaledHeight = (cropping.height || this.height) * multiplier,
            zoom = this.getZoom(),
            originalWidth = this.width,
            originalHeight = this.height,
            newZoom = zoom * multiplier,
            vp = this.viewportTransform,
            translateX = (vp[4] - (cropping.left || 0)) * multiplier,
            translateY = (vp[5] - (cropping.top || 0)) * multiplier,
            originalInteractive = this.interactive,
            newVp = [newZoom, 0, 0, newZoom, translateX, translateY],
            originalRetina = this.enableRetinaScaling,
            canvasEl = fabric.util.createCanvasElement(),
            originalContextTop = this.contextTop;
        canvasEl.width = scaledWidth;
        canvasEl.height = scaledHeight;
        this.contextTop = null;
        this.enableRetinaScaling = false;
        this.interactive = false;
        this.viewportTransform = newVp;
        this.width = scaledWidth;
        this.height = scaledHeight;
        this.calcViewportBoundaries();
        this.renderCanvas(canvasEl.getContext('2d'), this._objects);
        this.viewportTransform = vp;
        this.width = originalWidth;
        this.height = originalHeight;
        this.calcViewportBoundaries();
        this.interactive = originalInteractive;
        this.enableRetinaScaling = originalRetina;
        this.contextTop = originalContextTop;
        return canvasEl;
      },
    });
  
  })();
  
  
  fabric.util.object.extend(fabric.StaticCanvas.prototype, /** @lends fabric.StaticCanvas.prototype */ {
  
    /**
     * Populates canvas with data from the specified dataless JSON.
     * JSON format must conform to the one of {@link fabric.Canvas#toDatalessJSON}
     * @deprecated since 1.2.2
     * @param {String|Object} json JSON string or object
     * @param {Function} callback Callback, invoked when json is parsed
     *                            and corresponding objects (e.g: {@link fabric.Image})
     *                            are initialized
     * @param {Function} [reviver] Method for further parsing of JSON elements, called after each fabric object created.
     * @return {fabric.Canvas} instance
     * @chainable
     * @tutorial {@link http://fabricjs.com/fabric-intro-part-3#deserialization}
     */
    loadFromDatalessJSON: function (json, callback, reviver) {
      return this.loadFromJSON(json, callback, reviver);
    },
  
    /**
     * Populates canvas with data from the specified JSON.
     * JSON format must conform to the one of {@link fabric.Canvas#toJSON}
     * @param {String|Object} json JSON string or object
     * @param {Function} callback Callback, invoked when json is parsed
     *                            and corresponding objects (e.g: {@link fabric.Image})
     *                            are initialized
     * @param {Function} [reviver] Method for further parsing of JSON elements, called after each fabric object created.
     * @return {fabric.Canvas} instance
     * @chainable
     * @tutorial {@link http://fabricjs.com/fabric-intro-part-3#deserialization}
     * @see {@link http://jsfiddle.net/fabricjs/fmgXt/|jsFiddle demo}
     * @example <caption>loadFromJSON</caption>
     * canvas.loadFromJSON(json, canvas.renderAll.bind(canvas));
     * @example <caption>loadFromJSON with reviver</caption>
     * canvas.loadFromJSON(json, canvas.renderAll.bind(canvas), function(o, object) {
     *   // `o` = json object
     *   // `object` = fabric.Object instance
     *   // ... do some stuff ...
     * });
     */
    loadFromJSON: function (json, callback, reviver) {
      if (!json) {
        return;
      }
  
      // serialize if it wasn't already
      var serialized = (typeof json === 'string')
        ? JSON.parse(json)
        : fabric.util.object.clone(json);
  
      var _this = this,
          clipPath = serialized.clipPath,
          renderOnAddRemove = this.renderOnAddRemove;
  
      this.renderOnAddRemove = false;
  
      delete serialized.clipPath;
  
      this._enlivenObjects(serialized.objects, function (enlivenedObjects) {
        _this.clear();
        _this._setBgOverlay(serialized, function () {
          if (clipPath) {
            _this._enlivenObjects([clipPath], function (enlivenedCanvasClip) {
              _this.clipPath = enlivenedCanvasClip[0];
              _this.__setupCanvas.call(_this, serialized, enlivenedObjects, renderOnAddRemove, callback);
            });
          }
          else {
            _this.__setupCanvas.call(_this, serialized, enlivenedObjects, renderOnAddRemove, callback);
          }
        });
      }, reviver);
      return this;
    },
  
    /**
     * @private
     * @param {Object} serialized Object with background and overlay information
     * @param {Array} restored canvas objects
     * @param {Function} cached renderOnAddRemove callback
     * @param {Function} callback Invoked after all background and overlay images/patterns loaded
     */
    __setupCanvas: function(serialized, enlivenedObjects, renderOnAddRemove, callback) {
      var _this = this;
      enlivenedObjects.forEach(function(obj, index) {
        // we splice the array just in case some custom classes restored from JSON
        // will add more object to canvas at canvas init.
        _this.insertAt(obj, index);
      });
      this.renderOnAddRemove = renderOnAddRemove;
      // remove parts i cannot set as options
      delete serialized.objects;
      delete serialized.backgroundImage;
      delete serialized.overlayImage;
      delete serialized.background;
      delete serialized.overlay;
      // this._initOptions does too many things to just
      // call it. Normally loading an Object from JSON
      // create the Object instance. Here the Canvas is
      // already an instance and we are just loading things over it
      this._setOptions(serialized);
      this.renderAll();
      callback && callback();
    },
  
    /**
     * @private
     * @param {Object} serialized Object with background and overlay information
     * @param {Function} callback Invoked after all background and overlay images/patterns loaded
     */
    _setBgOverlay: function(serialized, callback) {
      var loaded = {
        backgroundColor: false,
        overlayColor: false,
        backgroundImage: false,
        overlayImage: false
      };
  
      if (!serialized.backgroundImage && !serialized.overlayImage && !serialized.background && !serialized.overlay) {
        callback && callback();
        return;
      }
  
      var cbIfLoaded = function () {
        if (loaded.backgroundImage && loaded.overlayImage && loaded.backgroundColor && loaded.overlayColor) {
          callback && callback();
        }
      };
  
      this.__setBgOverlay('backgroundImage', serialized.backgroundImage, loaded, cbIfLoaded);
      this.__setBgOverlay('overlayImage', serialized.overlayImage, loaded, cbIfLoaded);
      this.__setBgOverlay('backgroundColor', serialized.background, loaded, cbIfLoaded);
      this.__setBgOverlay('overlayColor', serialized.overlay, loaded, cbIfLoaded);
    },
  
    /**
     * @private
     * @param {String} property Property to set (backgroundImage, overlayImage, backgroundColor, overlayColor)
     * @param {(Object|String)} value Value to set
     * @param {Object} loaded Set loaded property to true if property is set
     * @param {Object} callback Callback function to invoke after property is set
     */
    __setBgOverlay: function(property, value, loaded, callback) {
      var _this = this;
  
      if (!value) {
        loaded[property] = true;
        callback && callback();
        return;
      }
  
      if (property === 'backgroundImage' || property === 'overlayImage') {
        fabric.util.enlivenObjects([value], function(enlivedObject){
          _this[property] = enlivedObject[0];
          loaded[property] = true;
          callback && callback();
        });
      }
      else {
        this['set' + fabric.util.string.capitalize(property, true)](value, function() {
          loaded[property] = true;
          callback && callback();
        });
      }
    },
  
    /**
     * @private
     * @param {Array} objects
     * @param {Function} callback
     * @param {Function} [reviver]
     */
    _enlivenObjects: function (objects, callback, reviver) {
      if (!objects || objects.length === 0) {
        callback && callback([]);
        return;
      }
  
      fabric.util.enlivenObjects(objects, function(enlivenedObjects) {
        callback && callback(enlivenedObjects);
      }, null, reviver);
    },
  
    /**
     * @private
     * @param {String} format
     * @param {Function} callback
     */
    _toDataURL: function (format, callback) {
      this.clone(function (clone) {
        callback(clone.toDataURL(format));
      });
    },
  
    /**
     * @private
     * @param {String} format
     * @param {Number} multiplier
     * @param {Function} callback
     */
    _toDataURLWithMultiplier: function (format, multiplier, callback) {
      this.clone(function (clone) {
        callback(clone.toDataURLWithMultiplier(format, multiplier));
      });
    },
  
    /**
     * Clones canvas instance
     * @param {Object} [callback] Receives cloned instance as a first argument
     * @param {Array} [properties] Array of properties to include in the cloned canvas and children
     */
    clone: function (callback, properties) {
      var data = JSON.stringify(this.toJSON(properties));
      this.cloneWithoutData(function(clone) {
        clone.loadFromJSON(data, function() {
          callback && callback(clone);
        });
      });
    },
  
    /**
     * Clones canvas instance without cloning existing data.
     * This essentially copies canvas dimensions, clipping properties, etc.
     * but leaves data empty (so that you can populate it with your own)
     * @param {Object} [callback] Receives cloned instance as a first argument
     */
    cloneWithoutData: function(callback) {
      var el = fabric.util.createCanvasElement();
  
      el.width = this.width;
      el.height = this.height;
  
      var clone = new fabric.Canvas(el);
      clone.clipTo = this.clipTo;
      if (this.backgroundImage) {
        clone.setBackgroundImage(this.backgroundImage.src, function() {
          clone.renderAll();
          callback && callback(clone);
        });
        clone.backgroundImageOpacity = this.backgroundImageOpacity;
        clone.backgroundImageStretch = this.backgroundImageStretch;
      }
      else {
        callback && callback(clone);
      }
    }
  });
  
  
  (function(global) {
  
    'use strict';
  
    var fabric = global.fabric || (global.fabric = { }),
        extend = fabric.util.object.extend,
        clone = fabric.util.object.clone,
        toFixed = fabric.util.toFixed,
        capitalize = fabric.util.string.capitalize,
        degreesToRadians = fabric.util.degreesToRadians,
        supportsLineDash = fabric.StaticCanvas.supports('setLineDash'),
        objectCaching = !fabric.isLikelyNode,
        ALIASING_LIMIT = 2;
  
    if (fabric.Object) {
      return;
    }
  
    /**
     * Root object class from which all 2d shape classes inherit from
     * @class fabric.Object
     * @tutorial {@link http://fabricjs.com/fabric-intro-part-1#objects}
     * @see {@link fabric.Object#initialize} for constructor definition
     *
     * @fires added
     * @fires removed
     *
     * @fires selected
     * @fires deselected
     * @fires modified
     * @fires modified
     * @fires moved
     * @fires scaled
     * @fires rotated
     * @fires skewed
     *
     * @fires rotating
     * @fires scaling
     * @fires moving
     * @fires skewing
     *
     * @fires mousedown
     * @fires mouseup
     * @fires mouseover
     * @fires mouseout
     * @fires mousewheel
     * @fires mousedblclick
     *
     * @fires dragover
     * @fires dragenter
     * @fires dragleave
     * @fires drop
     */
    fabric.Object = fabric.util.createClass(fabric.CommonMethods, /** @lends fabric.Object.prototype */ {
  
      /**
       * Type of an object (rect, circle, path, etc.).
       * Note that this property is meant to be read-only and not meant to be modified.
       * If you modify, certain parts of Fabric (such as JSON loading) won't work correctly.
       * @type String
       * @default
       */
      type:                     'object',
  
      /**
       * Horizontal origin of transformation of an object (one of "left", "right", "center")
       * See http://jsfiddle.net/1ow02gea/244/ on how originX/originY affect objects in groups
       * @type String
       * @default
       */
      originX:                  'left',
  
      /**
       * Vertical origin of transformation of an object (one of "top", "bottom", "center")
       * See http://jsfiddle.net/1ow02gea/244/ on how originX/originY affect objects in groups
       * @type String
       * @default
       */
      originY:                  'top',
  
      /**
       * Top position of an object. Note that by default it's relative to object top. You can change this by setting originY={top/center/bottom}
       * @type Number
       * @default
       */
      top:                      0,
  
      /**
       * Left position of an object. Note that by default it's relative to object left. You can change this by setting originX={left/center/right}
       * @type Number
       * @default
       */
      left:                     0,
  
      /**
       * Object width
       * @type Number
       * @default
       */
      width:                    0,
  
      /**
       * Object height
       * @type Number
       * @default
       */
      height:                   0,
  
      /**
       * Object scale factor (horizontal)
       * @type Number
       * @default
       */
      scaleX:                   1,
  
      /**
       * Object scale factor (vertical)
       * @type Number
       * @default
       */
      scaleY:                   1,
  
      /**
       * When true, an object is rendered as flipped horizontally
       * @type Boolean
       * @default
       */
      flipX:                    false,
  
      /**
       * When true, an object is rendered as flipped vertically
       * @type Boolean
       * @default
       */
      flipY:                    false,
  
      /**
       * Opacity of an object
       * @type Number
       * @default
       */
      opacity:                  1,
  
      /**
       * Angle of rotation of an object (in degrees)
       * @type Number
       * @default
       */
      angle:                    0,
  
      /**
       * Angle of skew on x axes of an object (in degrees)
       * @type Number
       * @default
       */
      skewX:                    0,
  
      /**
       * Angle of skew on y axes of an object (in degrees)
       * @type Number
       * @default
       */
      skewY:                    0,
  
      /**
       * Size of object's controlling corners (in pixels)
       * @type Number
       * @default
       */
      cornerSize:               13,
  
      /**
       * When true, object's controlling corners are rendered as transparent inside (i.e. stroke instead of fill)
       * @type Boolean
       * @default
       */
      transparentCorners:       true,
  
      /**
       * Default cursor value used when hovering over this object on canvas
       * @type String
       * @default
       */
      hoverCursor:              null,
  
      /**
       * Default cursor value used when moving this object on canvas
       * @type String
       * @default
       */
      moveCursor:               null,
  
      /**
       * Padding between object and its controlling borders (in pixels)
       * @type Number
       * @default
       */
      padding:                  0,
  
      /**
       * Color of controlling borders of an object (when it's active)
       * @type String
       * @default
       */
      borderColor:              'rgba(102,153,255,0.75)',
  
      /**
       * Array specifying dash pattern of an object's borders (hasBorder must be true)
       * @since 1.6.2
       * @type Array
       */
      borderDashArray:          null,
  
      /**
       * Color of controlling corners of an object (when it's active)
       * @type String
       * @default
       */
      cornerColor:              'rgba(102,153,255,0.5)',
  
      /**
       * Color of controlling corners of an object (when it's active and transparentCorners false)
       * @since 1.6.2
       * @type String
       * @default
       */
      cornerStrokeColor:        null,
  
      /**
       * Specify style of control, 'rect' or 'circle'
       * @since 1.6.2
       * @type String
       */
      cornerStyle:          'rect',
  
      /**
       * Array specifying dash pattern of an object's control (hasBorder must be true)
       * @since 1.6.2
       * @type Array
       */
      cornerDashArray:          null,
  
      /**
       * When true, this object will use center point as the origin of transformation
       * when being scaled via the controls.
       * <b>Backwards incompatibility note:</b> This property replaces "centerTransform" (Boolean).
       * @since 1.3.4
       * @type Boolean
       * @default
       */
      centeredScaling:          false,
  
      /**
       * When true, this object will use center point as the origin of transformation
       * when being rotated via the controls.
       * <b>Backwards incompatibility note:</b> This property replaces "centerTransform" (Boolean).
       * @since 1.3.4
       * @type Boolean
       * @default
       */
      centeredRotation:         true,
  
      /**
       * Color of object's fill
       * takes css colors https://www.w3.org/TR/css-color-3/
       * @type String
       * @default
       */
      fill:                     'rgb(0,0,0)',
  
      /**
       * Fill rule used to fill an object
       * accepted values are nonzero, evenodd
       * <b>Backwards incompatibility note:</b> This property was used for setting globalCompositeOperation until v1.4.12 (use `fabric.Object#globalCompositeOperation` instead)
       * @type String
       * @default
       */
      fillRule:                 'nonzero',
  
      /**
       * Composite rule used for canvas globalCompositeOperation
       * @type String
       * @default
       */
      globalCompositeOperation: 'source-over',
  
      /**
       * Background color of an object.
       * takes css colors https://www.w3.org/TR/css-color-3/
       * @type String
       * @default
       */
      backgroundColor:          '',
  
      /**
       * Selection Background color of an object. colored layer behind the object when it is active.
       * does not mix good with globalCompositeOperation methods.
       * @type String
       * @default
       */
      selectionBackgroundColor:          '',
  
      /**
       * When defined, an object is rendered via stroke and this property specifies its color
       * takes css colors https://www.w3.org/TR/css-color-3/
       * @type String
       * @default
       */
      stroke:                   null,
  
      /**
       * Width of a stroke used to render this object
       * @type Number
       * @default
       */
      strokeWidth:              1,
  
      /**
       * Array specifying dash pattern of an object's stroke (stroke must be defined)
       * @type Array
       */
      strokeDashArray:          null,
  
      /**
       * Line offset of an object's stroke
       * @type Number
       * @default
       */
      strokeDashOffset: 0,
  
      /**
       * Line endings style of an object's stroke (one of "butt", "round", "square")
       * @type String
       * @default
       */
      strokeLineCap:            'butt',
  
      /**
       * Corner style of an object's stroke (one of "bevil", "round", "miter")
       * @type String
       * @default
       */
      strokeLineJoin:           'miter',
  
      /**
       * Maximum miter length (used for strokeLineJoin = "miter") of an object's stroke
       * @type Number
       * @default
       */
      strokeMiterLimit:         4,
  
      /**
       * Shadow object representing shadow of this shape
       * @type fabric.Shadow
       * @default
       */
      shadow:                   null,
  
      /**
       * Opacity of object's controlling borders when object is active and moving
       * @type Number
       * @default
       */
      borderOpacityWhenMoving:  0.4,
  
      /**
       * Scale factor of object's controlling borders
       * @type Number
       * @default
       */
      borderScaleFactor:        1,
  
      /**
       * Transform matrix (similar to SVG's transform matrix)
       * This property has been depreacted. Since caching and and qrDecompose this
       * property can be handled with the standard top,left,scaleX,scaleY,angle and skewX.
       * A documentation example on how to parse and merge a transformMatrix will be provided before
       * completely removing it in fabric 4.0
       * If you are starting a project now, DO NOT use it.
       * @deprecated since 3.2.0
       * @type Array
       */
      transformMatrix:          null,
  
      /**
       * Minimum allowed scale value of an object
       * @type Number
       * @default
       */
      minScaleLimit:            0,
  
      /**
       * When set to `false`, an object can not be selected for modification (using either point-click-based or group-based selection).
       * But events still fire on it.
       * @type Boolean
       * @default
       */
      selectable:               true,
  
      /**
       * When set to `false`, an object can not be a target of events. All events propagate through it. Introduced in v1.3.4
       * @type Boolean
       * @default
       */
      evented:                  true,
  
      /**
       * When set to `false`, an object is not rendered on canvas
       * @type Boolean
       * @default
       */
      visible:                  true,
  
      /**
       * When set to `false`, object's controls are not displayed and can not be used to manipulate object
       * @type Boolean
       * @default
       */
      hasControls:              true,
  
      /**
       * When set to `false`, object's controlling borders are not rendered
       * @type Boolean
       * @default
       */
      hasBorders:               true,
  
      /**
       * When set to `false`, object's controlling rotating point will not be visible or selectable
       * @type Boolean
       * @default
       */
      hasRotatingPoint:         true,
  
      /**
       * Offset for object's controlling rotating point (when enabled via `hasRotatingPoint`)
       * @type Number
       * @default
       */
      rotatingPointOffset:      40,
  
      /**
       * When set to `true`, objects are "found" on canvas on per-pixel basis rather than according to bounding box
       * @type Boolean
       * @default
       */
      perPixelTargetFind:       false,
  
      /**
       * When `false`, default object's values are not included in its serialization
       * @type Boolean
       * @default
       */
      includeDefaultValues:     true,
  
      /**
       * Function that determines clipping of an object (context is passed as a first argument).
       * If you are using code minification, ctx argument can be minified/manglied you should use
       * as a workaround `var ctx = arguments[0];` in the function;
       * Note that context origin is at the object's center point (not left/top corner)
       * @deprecated since 2.0.0
       * @type Function
       */
      clipTo:                   null,
  
      /**
       * When `true`, object horizontal movement is locked
       * @type Boolean
       * @default
       */
      lockMovementX:            false,
  
      /**
       * When `true`, object vertical movement is locked
       * @type Boolean
       * @default
       */
      lockMovementY:            false,
  
      /**
       * When `true`, object rotation is locked
       * @type Boolean
       * @default
       */
      lockRotation:             false,
  
      /**
       * When `true`, object horizontal scaling is locked
       * @type Boolean
       * @default
       */
      lockScalingX:             false,
  
      /**
       * When `true`, object vertical scaling is locked
       * @type Boolean
       * @default
       */
      lockScalingY:             false,
  
      /**
       * When `true`, object non-uniform scaling is locked
       * @type Boolean
       * @default
       */
      lockUniScaling:           false,
  
      /**
       * When `true`, object horizontal skewing is locked
       * @type Boolean
       * @default
       */
      lockSkewingX:             false,
  
      /**
       * When `true`, object vertical skewing is locked
       * @type Boolean
       * @default
       */
      lockSkewingY:             false,
  
      /**
       * When `true`, object cannot be flipped by scaling into negative values
       * @type Boolean
       * @default
       */
      lockScalingFlip:          false,
  
      /**
       * When `true`, object is not exported in OBJECT/JSON
       * @since 1.6.3
       * @type Boolean
       * @default
       */
      excludeFromExport:        false,
  
      /**
       * When `true`, object is cached on an additional canvas.
       * When `false`, object is not cached unless necessary ( clipPath )
       * default to true
       * @since 1.7.0
       * @type Boolean
       * @default true
       */
      objectCaching:            objectCaching,
  
      /**
       * When `true`, object properties are checked for cache invalidation. In some particular
       * situation you may want this to be disabled ( spray brush, very big, groups)
       * or if your application does not allow you to modify properties for groups child you want
       * to disable it for groups.
       * default to false
       * since 1.7.0
       * @type Boolean
       * @default false
       */
      statefullCache:            false,
  
      /**
       * When `true`, cache does not get updated during scaling. The picture will get blocky if scaled
       * too much and will be redrawn with correct details at the end of scaling.
       * this setting is performance and application dependant.
       * default to true
       * since 1.7.0
       * @type Boolean
       * @default true
       */
      noScaleCache:              true,
  
      /**
       * When `false`, the stoke width will scale with the object.
       * When `true`, the stroke will always match the exact pixel size entered for stroke width.
       * default to false
       * @since 2.6.0
       * @type Boolean
       * @default false
       * @type Boolean
       * @default false
       */
      strokeUniform:              false,
  
      /**
       * When set to `true`, object's cache will be rerendered next render call.
       * since 1.7.0
       * @type Boolean
       * @default true
       */
      dirty:                true,
  
      /**
       * keeps the value of the last hovered corner during mouse move.
       * 0 is no corner, or 'mt', 'ml', 'mtr' etc..
       * It should be private, but there is no harm in using it as
       * a read-only property.
       * @type number|string|any
       * @default 0
       */
      __corner: 0,
  
      /**
       * Determines if the fill or the stroke is drawn first (one of "fill" or "stroke")
       * @type String
       * @default
       */
      paintFirst:           'fill',
  
      /**
       * List of properties to consider when checking if state
       * of an object is changed (fabric.Object#hasStateChanged)
       * as well as for history (undo/redo) purposes
       * @type Array
       */
      stateProperties: (
        'top left width height scaleX scaleY flipX flipY originX originY transformMatrix ' +
        'stroke strokeWidth strokeDashArray strokeLineCap strokeDashOffset strokeLineJoin strokeMiterLimit ' +
        'angle opacity fill globalCompositeOperation shadow clipTo visible backgroundColor ' +
        'skewX skewY fillRule paintFirst clipPath strokeUniform'
      ).split(' '),
  
      /**
       * List of properties to consider when checking if cache needs refresh
       * Those properties are checked by statefullCache ON ( or lazy mode if we want ) or from single
       * calls to Object.set(key, value). If the key is in this list, the object is marked as dirty
       * and refreshed at the next render
       * @type Array
       */
      cacheProperties: (
        'fill stroke strokeWidth strokeDashArray width height paintFirst strokeUniform' +
        ' strokeLineCap strokeDashOffset strokeLineJoin strokeMiterLimit backgroundColor clipPath'
      ).split(' '),
  
      /**
       * a fabricObject that, without stroke define a clipping area with their shape. filled in black
       * the clipPath object gets used when the object has rendered, and the context is placed in the center
       * of the object cacheCanvas.
       * If you want 0,0 of a clipPath to align with an object center, use clipPath.originX/Y to 'center'
       * @type fabric.Object
       */
      clipPath: undefined,
  
      /**
       * Meaningful ONLY when the object is used as clipPath.
       * if true, the clipPath will make the object clip to the outside of the clipPath
       * since 2.4.0
       * @type boolean
       * @default false
       */
      inverted: false,
  
      /**
       * Meaningful ONLY when the object is used as clipPath.
       * if true, the clipPath will have its top and left relative to canvas, and will
       * not be influenced by the object transform. This will make the clipPath relative
       * to the canvas, but clipping just a particular object.
       * WARNING this is beta, this feature may change or be renamed.
       * since 2.4.0
       * @type boolean
       * @default false
       */
      absolutePositioned: false,
  
      /**
       * Constructor
       * @param {Object} [options] Options object
       */
      initialize: function(options) {
        if (options) {
          this.setOptions(options);
        }
      },
  
      /**
       * Create a the canvas used to keep the cached copy of the object
       * @private
       */
      _createCacheCanvas: function() {
        this._cacheProperties = {};
        this._cacheCanvas = fabric.util.createCanvasElement();
        this._cacheContext = this._cacheCanvas.getContext('2d');
        this._updateCacheCanvas();
        // if canvas gets created, is empty, so dirty.
        this.dirty = true;
      },
  
      /**
       * Limit the cache dimensions so that X * Y do not cross fabric.perfLimitSizeTotal
       * and each side do not cross fabric.cacheSideLimit
       * those numbers are configurable so that you can get as much detail as you want
       * making bargain with performances.
       * @param {Object} dims
       * @param {Object} dims.width width of canvas
       * @param {Object} dims.height height of canvas
       * @param {Object} dims.zoomX zoomX zoom value to unscale the canvas before drawing cache
       * @param {Object} dims.zoomY zoomY zoom value to unscale the canvas before drawing cache
       * @return {Object}.width width of canvas
       * @return {Object}.height height of canvas
       * @return {Object}.zoomX zoomX zoom value to unscale the canvas before drawing cache
       * @return {Object}.zoomY zoomY zoom value to unscale the canvas before drawing cache
       */
      _limitCacheSize: function(dims) {
        var perfLimitSizeTotal = fabric.perfLimitSizeTotal,
            width = dims.width, height = dims.height,
            max = fabric.maxCacheSideLimit, min = fabric.minCacheSideLimit;
        if (width <= max && height <= max && width * height <= perfLimitSizeTotal) {
          if (width < min) {
            dims.width = min;
          }
          if (height < min) {
            dims.height = min;
          }
          return dims;
        }
        var ar = width / height, limitedDims = fabric.util.limitDimsByArea(ar, perfLimitSizeTotal),
            capValue = fabric.util.capValue,
            x = capValue(min, limitedDims.x, max),
            y = capValue(min, limitedDims.y, max);
        if (width > x) {
          dims.zoomX /= width / x;
          dims.width = x;
          dims.capped = true;
        }
        if (height > y) {
          dims.zoomY /= height / y;
          dims.height = y;
          dims.capped = true;
        }
        return dims;
      },
  
      /**
       * Return the dimension and the zoom level needed to create a cache canvas
       * big enough to host the object to be cached.
       * @private
       * @return {Object}.x width of object to be cached
       * @return {Object}.y height of object to be cached
       * @return {Object}.width width of canvas
       * @return {Object}.height height of canvas
       * @return {Object}.zoomX zoomX zoom value to unscale the canvas before drawing cache
       * @return {Object}.zoomY zoomY zoom value to unscale the canvas before drawing cache
       */
      _getCacheCanvasDimensions: function() {
        var objectScale = this.getTotalObjectScaling(),
            // caculate dimensions without skewing
            dim = this._getTransformedDimensions(0, 0),
            neededX = dim.x * objectScale.scaleX / this.scaleX,
            neededY = dim.y * objectScale.scaleY / this.scaleY;
        return {
          // for sure this ALIASING_LIMIT is slightly creating problem
          // in situation in which the cache canvas gets an upper limit
          // also objectScale contains already scaleX and scaleY
          width: neededX + ALIASING_LIMIT,
          height: neededY + ALIASING_LIMIT,
          zoomX: objectScale.scaleX,
          zoomY: objectScale.scaleY,
          x: neededX,
          y: neededY
        };
      },
  
      /**
       * Update width and height of the canvas for cache
       * returns true or false if canvas needed resize.
       * @private
       * @return {Boolean} true if the canvas has been resized
       */
      _updateCacheCanvas: function() {
        var targetCanvas = this.canvas;
        if (this.noScaleCache && targetCanvas && targetCanvas._currentTransform) {
          var target = targetCanvas._currentTransform.target,
              action = targetCanvas._currentTransform.action;
          if (this === target && action.slice && action.slice(0, 5) === 'scale') {
            return false;
          }
        }
        var canvas = this._cacheCanvas,
            dims = this._limitCacheSize(this._getCacheCanvasDimensions()),
            minCacheSize = fabric.minCacheSideLimit,
            width = dims.width, height = dims.height, drawingWidth, drawingHeight,
            zoomX = dims.zoomX, zoomY = dims.zoomY,
            dimensionsChanged = width !== this.cacheWidth || height !== this.cacheHeight,
            zoomChanged = this.zoomX !== zoomX || this.zoomY !== zoomY,
            shouldRedraw = dimensionsChanged || zoomChanged,
            additionalWidth = 0, additionalHeight = 0, shouldResizeCanvas = false;
        if (dimensionsChanged) {
          var canvasWidth = this._cacheCanvas.width,
              canvasHeight = this._cacheCanvas.height,
              sizeGrowing = width > canvasWidth || height > canvasHeight,
              sizeShrinking = (width < canvasWidth * 0.9 || height < canvasHeight * 0.9) &&
                canvasWidth > minCacheSize && canvasHeight > minCacheSize;
          shouldResizeCanvas = sizeGrowing || sizeShrinking;
          if (sizeGrowing && !dims.capped && (width > minCacheSize || height > minCacheSize)) {
            additionalWidth = width * 0.1;
            additionalHeight = height * 0.1;
          }
        }
        if (shouldRedraw) {
          if (shouldResizeCanvas) {
            canvas.width = Math.ceil(width + additionalWidth);
            canvas.height = Math.ceil(height + additionalHeight);
          }
          else {
            this._cacheContext.setTransform(1, 0, 0, 1, 0, 0);
            this._cacheContext.clearRect(0, 0, canvas.width, canvas.height);
          }
          drawingWidth = dims.x / 2;
          drawingHeight = dims.y / 2;
          this.cacheTranslationX = Math.round(canvas.width / 2 - drawingWidth) + drawingWidth;
          this.cacheTranslationY = Math.round(canvas.height / 2 - drawingHeight) + drawingHeight;
          this.cacheWidth = width;
          this.cacheHeight = height;
          this._cacheContext.translate(this.cacheTranslationX, this.cacheTranslationY);
          this._cacheContext.scale(zoomX, zoomY);
          this.zoomX = zoomX;
          this.zoomY = zoomY;
          return true;
        }
        return false;
      },
  
      /**
       * Sets object's properties from options
       * @param {Object} [options] Options object
       */
      setOptions: function(options) {
        this._setOptions(options);
        this._initGradient(options.fill, 'fill');
        this._initGradient(options.stroke, 'stroke');
        this._initClipping(options);
        this._initPattern(options.fill, 'fill');
        this._initPattern(options.stroke, 'stroke');
      },
  
      /**
       * Transforms context when rendering an object
       * @param {CanvasRenderingContext2D} ctx Context
       */
      transform: function(ctx) {
        var m;
        if (this.group && !this.group._transformDone) {
          m = this.calcTransformMatrix();
        }
        else {
          m = this.calcOwnMatrix();
        }
        ctx.transform(m[0], m[1], m[2], m[3], m[4], m[5]);
      },
  
      /**
       * Returns an object representation of an instance
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object} Object representation of an instance
       */
      toObject: function(propertiesToInclude) {
        var NUM_FRACTION_DIGITS = fabric.Object.NUM_FRACTION_DIGITS,
  
            object = {
              type:                     this.type,
              version:                  fabric.version,
              originX:                  this.originX,
              originY:                  this.originY,
              left:                     toFixed(this.left, NUM_FRACTION_DIGITS),
              top:                      toFixed(this.top, NUM_FRACTION_DIGITS),
              width:                    toFixed(this.width, NUM_FRACTION_DIGITS),
              height:                   toFixed(this.height, NUM_FRACTION_DIGITS),
              fill:                     (this.fill && this.fill.toObject) ? this.fill.toObject() : this.fill,
              stroke:                   (this.stroke && this.stroke.toObject) ? this.stroke.toObject() : this.stroke,
              strokeWidth:              toFixed(this.strokeWidth, NUM_FRACTION_DIGITS),
              strokeDashArray:          this.strokeDashArray ? this.strokeDashArray.concat() : this.strokeDashArray,
              strokeLineCap:            this.strokeLineCap,
              strokeDashOffset:         this.strokeDashOffset,
              strokeLineJoin:           this.strokeLineJoin,
              strokeMiterLimit:         toFixed(this.strokeMiterLimit, NUM_FRACTION_DIGITS),
              scaleX:                   toFixed(this.scaleX, NUM_FRACTION_DIGITS),
              scaleY:                   toFixed(this.scaleY, NUM_FRACTION_DIGITS),
              angle:                    toFixed(this.angle, NUM_FRACTION_DIGITS),
              flipX:                    this.flipX,
              flipY:                    this.flipY,
              opacity:                  toFixed(this.opacity, NUM_FRACTION_DIGITS),
              shadow:                   (this.shadow && this.shadow.toObject) ? this.shadow.toObject() : this.shadow,
              visible:                  this.visible,
              clipTo:                   this.clipTo && String(this.clipTo),
              backgroundColor:          this.backgroundColor,
              fillRule:                 this.fillRule,
              paintFirst:               this.paintFirst,
              globalCompositeOperation: this.globalCompositeOperation,
              transformMatrix:          this.transformMatrix ? this.transformMatrix.concat() : null,
              skewX:                    toFixed(this.skewX, NUM_FRACTION_DIGITS),
              skewY:                    toFixed(this.skewY, NUM_FRACTION_DIGITS),
            };
  
        if (this.clipPath) {
          object.clipPath = this.clipPath.toObject(propertiesToInclude);
          object.clipPath.inverted = this.clipPath.inverted;
          object.clipPath.absolutePositioned = this.clipPath.absolutePositioned;
        }
  
        fabric.util.populateWithProperties(this, object, propertiesToInclude);
        if (!this.includeDefaultValues) {
          object = this._removeDefaultValues(object);
        }
  
        return object;
      },
  
      /**
       * Returns (dataless) object representation of an instance
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object} Object representation of an instance
       */
      toDatalessObject: function(propertiesToInclude) {
        // will be overwritten by subclasses
        return this.toObject(propertiesToInclude);
      },
  
      /**
       * @private
       * @param {Object} object
       */
      _removeDefaultValues: function(object) {
        var prototype = fabric.util.getKlass(object.type).prototype,
            stateProperties = prototype.stateProperties;
        stateProperties.forEach(function(prop) {
          if (prop === 'left' || prop === 'top') {
            return;
          }
          if (object[prop] === prototype[prop]) {
            delete object[prop];
          }
          var isArray = Object.prototype.toString.call(object[prop]) === '[object Array]' &&
                        Object.prototype.toString.call(prototype[prop]) === '[object Array]';
  
          // basically a check for [] === []
          if (isArray && object[prop].length === 0 && prototype[prop].length === 0) {
            delete object[prop];
          }
        });
  
        return object;
      },
  
      /**
       * Returns a string representation of an instance
       * @return {String}
       */
      toString: function() {
        return '#<fabric.' + capitalize(this.type) + '>';
      },
  
      /**
       * Return the object scale factor counting also the group scaling
       * @return {Object} object with scaleX and scaleY properties
       */
      getObjectScaling: function() {
        var scaleX = this.scaleX, scaleY = this.scaleY;
        if (this.group) {
          var scaling = this.group.getObjectScaling();
          scaleX *= scaling.scaleX;
          scaleY *= scaling.scaleY;
        }
        return { scaleX: scaleX, scaleY: scaleY };
      },
  
      /**
       * Return the object scale factor counting also the group scaling, zoom and retina
       * @return {Object} object with scaleX and scaleY properties
       */
      getTotalObjectScaling: function() {
        var scale = this.getObjectScaling(), scaleX = scale.scaleX, scaleY = scale.scaleY;
        if (this.canvas) {
          var zoom = this.canvas.getZoom();
          var retina = this.canvas.getRetinaScaling();
          scaleX *= zoom * retina;
          scaleY *= zoom * retina;
        }
        return { scaleX: scaleX, scaleY: scaleY };
      },
  
      /**
       * Return the object opacity counting also the group property
       * @return {Number}
       */
      getObjectOpacity: function() {
        var opacity = this.opacity;
        if (this.group) {
          opacity *= this.group.getObjectOpacity();
        }
        return opacity;
      },
  
      /**
       * @private
       * @param {String} key
       * @param {*} value
       * @return {fabric.Object} thisArg
       */
      _set: function(key, value) {
        var shouldConstrainValue = (key === 'scaleX' || key === 'scaleY'),
            isChanged = this[key] !== value, groupNeedsUpdate = false;
  
        if (shouldConstrainValue) {
          value = this._constrainScale(value);
        }
        if (key === 'scaleX' && value < 0) {
          this.flipX = !this.flipX;
          value *= -1;
        }
        else if (key === 'scaleY' && value < 0) {
          this.flipY = !this.flipY;
          value *= -1;
        }
        else if (key === 'shadow' && value && !(value instanceof fabric.Shadow)) {
          value = new fabric.Shadow(value);
        }
        else if (key === 'dirty' && this.group) {
          this.group.set('dirty', value);
        }
  
        this[key] = value;
  
        if (isChanged) {
          groupNeedsUpdate = this.group && this.group.isOnACache();
          if (this.cacheProperties.indexOf(key) > -1) {
            this.dirty = true;
            groupNeedsUpdate && this.group.set('dirty', true);
          }
          else if (groupNeedsUpdate && this.stateProperties.indexOf(key) > -1) {
            this.group.set('dirty', true);
          }
        }
  
        return this;
      },
  
      /**
       * This callback function is called by the parent group of an object every
       * time a non-delegated property changes on the group. It is passed the key
       * and value as parameters. Not adding in this function's signature to avoid
       * Travis build error about unused variables.
       */
      setOnGroup: function() {
        // implemented by sub-classes, as needed.
      },
  
      /**
       * Retrieves viewportTransform from Object's canvas if possible
       * @method getViewportTransform
       * @memberOf fabric.Object.prototype
       * @return {Array}
       */
      getViewportTransform: function() {
        if (this.canvas && this.canvas.viewportTransform) {
          return this.canvas.viewportTransform;
        }
        return fabric.iMatrix.concat();
      },
  
      /*
       * @private
       * return if the object would be visible in rendering
       * @memberOf fabric.Object.prototype
       * @return {Boolean}
       */
      isNotVisible: function() {
        return this.opacity === 0 ||
          (this.width === 0 && this.height === 0 && this.strokeWidth === 0) ||
          !this.visible;
      },
  
      /**
       * Renders an object on a specified context
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      render: function(ctx) {
        // do not render if width/height are zeros or object is not visible
        if (this.isNotVisible()) {
          return;
        }
        if (this.canvas && this.canvas.skipOffscreen && !this.group && !this.isOnScreen()) {
          return;
        }
        ctx.save();
        this._setupCompositeOperation(ctx);
        this.drawSelectionBackground(ctx);
        this.transform(ctx);
        this._setOpacity(ctx);
        this._setShadow(ctx, this);
        if (this.transformMatrix) {
          ctx.transform.apply(ctx, this.transformMatrix);
        }
        this.clipTo && fabric.util.clipContext(this, ctx);
        if (this.shouldCache()) {
          this.renderCache();
          this.drawCacheOnCanvas(ctx);
        }
        else {
          this._removeCacheCanvas();
          this.dirty = false;
          this.drawObject(ctx);
          if (this.objectCaching && this.statefullCache) {
            this.saveState({ propertySet: 'cacheProperties' });
          }
        }
        this.clipTo && ctx.restore();
        ctx.restore();
      },
  
      renderCache: function(options) {
        options = options || {};
        if (!this._cacheCanvas) {
          this._createCacheCanvas();
        }
        if (this.isCacheDirty()) {
          this.statefullCache && this.saveState({ propertySet: 'cacheProperties' });
          this.drawObject(this._cacheContext, options.forClipping);
          this.dirty = false;
        }
      },
  
      /**
       * Remove cacheCanvas and its dimensions from the objects
       */
      _removeCacheCanvas: function() {
        this._cacheCanvas = null;
        this.cacheWidth = 0;
        this.cacheHeight = 0;
      },
  
      /**
       * return true if the object will draw a stroke
       * Does not consider text styles. This is just a shortcut used at rendering time
       * We want it to be an aproximation and be fast.
       * wrote to avoid extra caching, it has to return true when stroke happens,
       * can guess when it will not happen at 100% chance, does not matter if it misses
       * some use case where the stroke is invisible.
       * @since 3.0.0
       * @returns Boolean
       */
      hasStroke: function() {
        return this.stroke && this.stroke !== 'transparent' && this.strokeWidth !== 0;
      },
  
      /**
       * return true if the object will draw a fill
       * Does not consider text styles. This is just a shortcut used at rendering time
       * We want it to be an aproximation and be fast.
       * wrote to avoid extra caching, it has to return true when fill happens,
       * can guess when it will not happen at 100% chance, does not matter if it misses
       * some use case where the fill is invisible.
       * @since 3.0.0
       * @returns Boolean
       */
      hasFill: function() {
        return this.fill && this.fill !== 'transparent';
      },
  
      /**
       * When set to `true`, force the object to have its own cache, even if it is inside a group
       * it may be needed when your object behave in a particular way on the cache and always needs
       * its own isolated canvas to render correctly.
       * Created to be overridden
       * since 1.7.12
       * @returns Boolean
       */
      needsItsOwnCache: function() {
        if (this.paintFirst === 'stroke' &&
          this.hasFill() && this.hasStroke() && typeof this.shadow === 'object') {
          return true;
        }
        if (this.clipPath) {
          return true;
        }
        return false;
      },
  
      /**
       * Decide if the object should cache or not. Create its own cache level
       * objectCaching is a global flag, wins over everything
       * needsItsOwnCache should be used when the object drawing method requires
       * a cache step. None of the fabric classes requires it.
       * Generally you do not cache objects in groups because the group outside is cached.
       * Read as: cache if is needed, or if the feature is enabled but we are not already caching.
       * @return {Boolean}
       */
      shouldCache: function() {
        this.ownCaching = this.needsItsOwnCache() || (
          this.objectCaching &&
          (!this.group || !this.group.isOnACache())
        );
        return this.ownCaching;
      },
  
      /**
       * Check if this object or a child object will cast a shadow
       * used by Group.shouldCache to know if child has a shadow recursively
       * @return {Boolean}
       */
      willDrawShadow: function() {
        return !!this.shadow && (this.shadow.offsetX !== 0 || this.shadow.offsetY !== 0);
      },
  
      /**
       * Execute the drawing operation for an object clipPath
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      drawClipPathOnCache: function(ctx) {
        var path = this.clipPath;
        ctx.save();
        // DEBUG: uncomment this line, comment the following
        // ctx.globalAlpha = 0.4
        if (path.inverted) {
          ctx.globalCompositeOperation = 'destination-out';
        }
        else {
          ctx.globalCompositeOperation = 'destination-in';
        }
        //ctx.scale(1 / 2, 1 / 2);
        if (path.absolutePositioned) {
          var m = fabric.util.invertTransform(this.calcTransformMatrix());
          ctx.transform(m[0], m[1], m[2], m[3], m[4], m[5]);
        }
        path.transform(ctx);
        ctx.scale(1 / path.zoomX, 1 / path.zoomY);
        ctx.drawImage(path._cacheCanvas, -path.cacheTranslationX, -path.cacheTranslationY);
        ctx.restore();
      },
  
      /**
       * Execute the drawing operation for an object on a specified context
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      drawObject: function(ctx, forClipping) {
        var originalFill = this.fill, originalStroke = this.stroke;
        if (forClipping) {
          this.fill = 'black';
          this.stroke = '';
          this._setClippingProperties(ctx);
        }
        else {
          this._renderBackground(ctx);
          this._setStrokeStyles(ctx, this);
          this._setFillStyles(ctx, this);
        }
        this._render(ctx);
        this._drawClipPath(ctx);
        this.fill = originalFill;
        this.stroke = originalStroke;
      },
  
      _drawClipPath: function(ctx) {
        var path = this.clipPath;
        if (!path) { return; }
        // needed to setup a couple of variables
        // path canvas gets overridden with this one.
        // TODO find a better solution?
        path.canvas = this.canvas;
        path.shouldCache();
        path._transformDone = true;
        path.renderCache({ forClipping: true });
        this.drawClipPathOnCache(ctx);
      },
  
      /**
       * Paint the cached copy of the object on the target context.
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      drawCacheOnCanvas: function(ctx) {
        ctx.scale(1 / this.zoomX, 1 / this.zoomY);
        ctx.drawImage(this._cacheCanvas, -this.cacheTranslationX, -this.cacheTranslationY);
      },
  
      /**
       * Check if cache is dirty
       * @param {Boolean} skipCanvas skip canvas checks because this object is painted
       * on parent canvas.
       */
      isCacheDirty: function(skipCanvas) {
        if (this.isNotVisible()) {
          return false;
        }
        if (this._cacheCanvas && !skipCanvas && this._updateCacheCanvas()) {
          // in this case the context is already cleared.
          return true;
        }
        else {
          if (this.dirty ||
            (this.clipPath && this.clipPath.absolutePositioned) ||
            (this.statefullCache && this.hasStateChanged('cacheProperties'))
          ) {
            if (this._cacheCanvas && !skipCanvas) {
              var width = this.cacheWidth / this.zoomX;
              var height = this.cacheHeight / this.zoomY;
              this._cacheContext.clearRect(-width / 2, -height / 2, width, height);
            }
            return true;
          }
        }
        return false;
      },
  
      /**
       * Draws a background for the object big as its untransformed dimensions
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _renderBackground: function(ctx) {
        if (!this.backgroundColor) {
          return;
        }
        var dim = this._getNonTransformedDimensions();
        ctx.fillStyle = this.backgroundColor;
  
        ctx.fillRect(
          -dim.x / 2,
          -dim.y / 2,
          dim.x,
          dim.y
        );
        // if there is background color no other shadows
        // should be casted
        this._removeShadow(ctx);
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _setOpacity: function(ctx) {
        if (this.group && !this.group._transformDone) {
          ctx.globalAlpha = this.getObjectOpacity();
        }
        else {
          ctx.globalAlpha *= this.opacity;
        }
      },
  
      _setStrokeStyles: function(ctx, decl) {
        if (decl.stroke) {
          ctx.lineWidth = decl.strokeWidth;
          ctx.lineCap = decl.strokeLineCap;
          ctx.lineDashOffset = decl.strokeDashOffset;
          ctx.lineJoin = decl.strokeLineJoin;
          ctx.miterLimit = decl.strokeMiterLimit;
          ctx.strokeStyle = decl.stroke.toLive
            ? decl.stroke.toLive(ctx, this)
            : decl.stroke;
        }
      },
  
      _setFillStyles: function(ctx, decl) {
        if (decl.fill) {
          ctx.fillStyle = decl.fill.toLive
            ? decl.fill.toLive(ctx, this)
            : decl.fill;
        }
      },
  
      _setClippingProperties: function(ctx) {
        ctx.globalAlpha = 1;
        ctx.strokeStyle = 'transparent';
        ctx.fillStyle = '#000000';
      },
  
      /**
       * @private
       * Sets line dash
       * @param {CanvasRenderingContext2D} ctx Context to set the dash line on
       * @param {Array} dashArray array representing dashes
       * @param {Function} alternative function to call if browser does not support lineDash
       */
      _setLineDash: function(ctx, dashArray, alternative) {
        if (!dashArray) {
          return;
        }
        // Spec requires the concatenation of two copies the dash list when the number of elements is odd
        if (1 & dashArray.length) {
          dashArray.push.apply(dashArray, dashArray);
        }
        if (supportsLineDash) {
          ctx.setLineDash(dashArray);
        }
        else {
          alternative && alternative(ctx);
        }
      },
  
      /**
       * Renders controls and borders for the object
       * @param {CanvasRenderingContext2D} ctx Context to render on
       * @param {Object} [styleOverride] properties to override the object style
       */
      _renderControls: function(ctx, styleOverride) {
        var vpt = this.getViewportTransform(),
            matrix = this.calcTransformMatrix(),
            options, drawBorders, drawControls;
        styleOverride = styleOverride || { };
        drawBorders = typeof styleOverride.hasBorders !== 'undefined' ? styleOverride.hasBorders : this.hasBorders;
        drawControls = typeof styleOverride.hasControls !== 'undefined' ? styleOverride.hasControls : this.hasControls;
        matrix = fabric.util.multiplyTransformMatrices(vpt, matrix);
        options = fabric.util.qrDecompose(matrix);
        ctx.save();
        ctx.translate(options.translateX, options.translateY);
        ctx.lineWidth = 1 * this.borderScaleFactor;
        if (!this.group) {
          ctx.globalAlpha = this.isMoving ? this.borderOpacityWhenMoving : 1;
        }
        if (styleOverride.forActiveSelection) {
          ctx.rotate(degreesToRadians(options.angle));
          drawBorders && this.drawBordersInGroup(ctx, options, styleOverride);
        }
        else {
          ctx.rotate(degreesToRadians(this.angle));
          drawBorders && this.drawBorders(ctx, styleOverride);
        }
        drawControls && this.drawControls(ctx, styleOverride);
        ctx.restore();
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _setShadow: function(ctx) {
        if (!this.shadow) {
          return;
        }
  
        var shadow = this.shadow, canvas = this.canvas, scaling,
            multX = (canvas && canvas.viewportTransform[0]) || 1,
            multY = (canvas && canvas.viewportTransform[3]) || 1;
        if (shadow.nonScaling) {
          scaling = { scaleX: 1, scaleY: 1 };
        }
        else {
          scaling = this.getObjectScaling();
        }
        if (canvas && canvas._isRetinaScaling()) {
          multX *= fabric.devicePixelRatio;
          multY *= fabric.devicePixelRatio;
        }
        ctx.shadowColor = shadow.color;
        ctx.shadowBlur = shadow.blur * fabric.browserShadowBlurConstant *
          (multX + multY) * (scaling.scaleX + scaling.scaleY) / 4;
        ctx.shadowOffsetX = shadow.offsetX * multX * scaling.scaleX;
        ctx.shadowOffsetY = shadow.offsetY * multY * scaling.scaleY;
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _removeShadow: function(ctx) {
        if (!this.shadow) {
          return;
        }
  
        ctx.shadowColor = '';
        ctx.shadowBlur = ctx.shadowOffsetX = ctx.shadowOffsetY = 0;
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       * @param {Object} filler fabric.Pattern or fabric.Gradient
       * @return {Object} offset.offsetX offset for text rendering
       * @return {Object} offset.offsetY offset for text rendering
       */
      _applyPatternGradientTransform: function(ctx, filler) {
        if (!filler || !filler.toLive) {
          return { offsetX: 0, offsetY: 0 };
        }
        var t = filler.gradientTransform || filler.patternTransform;
        var offsetX = -this.width / 2 + filler.offsetX || 0,
            offsetY = -this.height / 2 + filler.offsetY || 0;
  
        if (filler.gradientUnits === 'percentage') {
          ctx.transform(this.width, 0, 0, this.height, offsetX, offsetY);
        }
        else {
          ctx.transform(1, 0, 0, 1, offsetX, offsetY);
        }
        if (t) {
          ctx.transform(t[0], t[1], t[2], t[3], t[4], t[5]);
        }
        return { offsetX: offsetX, offsetY: offsetY };
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _renderPaintInOrder: function(ctx) {
        if (this.paintFirst === 'stroke') {
          this._renderStroke(ctx);
          this._renderFill(ctx);
        }
        else {
          this._renderFill(ctx);
          this._renderStroke(ctx);
        }
      },
  
      /**
       * @private
       * function that actually render something on the context.
       * empty here to allow Obects to work on tests to benchmark fabric functionalites
       * not related to rendering
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _render: function(/* ctx */) {
  
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _renderFill: function(ctx) {
        if (!this.fill) {
          return;
        }
  
        ctx.save();
        this._applyPatternGradientTransform(ctx, this.fill);
        if (this.fillRule === 'evenodd') {
          ctx.fill('evenodd');
        }
        else {
          ctx.fill();
        }
        ctx.restore();
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _renderStroke: function(ctx) {
        if (!this.stroke || this.strokeWidth === 0) {
          return;
        }
  
        if (this.shadow && !this.shadow.affectStroke) {
          this._removeShadow(ctx);
        }
  
        ctx.save();
        if (this.strokeUniform) {
          ctx.scale(1 / this.scaleX, 1 / this.scaleY);
        }
        this._setLineDash(ctx, this.strokeDashArray, this._renderDashedStroke);
        if (this.stroke.toLive && this.stroke.gradientUnits === 'percentage') {
          // need to transform gradient in a pattern.
          // this is a slow process. If you are hitting this codepath, and the object
          // is not using caching, you should consider switching it on.
          // we need a canvas as big as the current object caching canvas.
          this._applyPatternForTransformedGradient(ctx, this.stroke);
        }
        else {
          this._applyPatternGradientTransform(ctx, this.stroke);
        }
        ctx.stroke();
        ctx.restore();
      },
  
      /**
       * This function try to patch the missing gradientTransform on canvas gradients.
       * transforming a context to transform the gradient, is going to transform the stroke too.
       * we want to transform the gradient but not the stroke operation, so we create
       * a transformed gradient on a pattern and then we use the pattern instead of the gradient.
       * this method has drwabacks: is slow, is in low resolution, needs a patch for when the size
       * is limited.
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       * @param {fabric.Gradient} filler a fabric gradient instance
       */
      _applyPatternForTransformedGradient: function(ctx, filler) {
        var dims = this._limitCacheSize(this._getCacheCanvasDimensions()),
            pCanvas = fabric.util.createCanvasElement(), pCtx, retinaScaling = this.canvas.getRetinaScaling(),
            width = dims.x / this.scaleX / retinaScaling, height = dims.y / this.scaleY / retinaScaling;
        pCanvas.width = width;
        pCanvas.height = height;
        pCtx = pCanvas.getContext('2d');
        pCtx.beginPath(); pCtx.moveTo(0, 0); pCtx.lineTo(width, 0); pCtx.lineTo(width, height);
        pCtx.lineTo(0, height); pCtx.closePath();
        pCtx.translate(width / 2, height / 2);
        pCtx.scale(
          dims.zoomX / this.scaleX / retinaScaling,
          dims.zoomY / this.scaleY / retinaScaling
        );
        this._applyPatternGradientTransform(pCtx, filler);
        pCtx.fillStyle = filler.toLive(ctx);
        pCtx.fill();
        ctx.translate(-this.width / 2 - this.strokeWidth / 2, -this.height / 2 - this.strokeWidth / 2);
        ctx.scale(
          retinaScaling * this.scaleX / dims.zoomX,
          retinaScaling * this.scaleY / dims.zoomY
        );
        ctx.strokeStyle = pCtx.createPattern(pCanvas, 'no-repeat');
      },
  
      /**
       * This function is an helper for svg import. it returns the center of the object in the svg
       * untransformed coordinates
       * @private
       * @return {Object} center point from element coordinates
       */
      _findCenterFromElement: function() {
        return { x: this.left + this.width / 2, y: this.top + this.height / 2 };
      },
  
      /**
       * This function is an helper for svg import. it decompose the transformMatrix
       * and assign properties to object.
       * untransformed coordinates
       * @private
       * @chainable
       */
      _assignTransformMatrixProps: function() {
        if (this.transformMatrix) {
          var options = fabric.util.qrDecompose(this.transformMatrix);
          this.flipX = false;
          this.flipY = false;
          this.set('scaleX', options.scaleX);
          this.set('scaleY', options.scaleY);
          this.angle = options.angle;
          this.skewX = options.skewX;
          this.skewY = 0;
        }
      },
  
      /**
       * This function is an helper for svg import. it removes the transform matrix
       * and set to object properties that fabricjs can handle
       * @private
       * @param {Object} preserveAspectRatioOptions
       * @return {thisArg}
       */
      _removeTransformMatrix: function(preserveAspectRatioOptions) {
        var center = this._findCenterFromElement();
        if (this.transformMatrix) {
          this._assignTransformMatrixProps();
          center = fabric.util.transformPoint(center, this.transformMatrix);
        }
        this.transformMatrix = null;
        if (preserveAspectRatioOptions) {
          this.scaleX *= preserveAspectRatioOptions.scaleX;
          this.scaleY *= preserveAspectRatioOptions.scaleY;
          this.cropX = preserveAspectRatioOptions.cropX;
          this.cropY = preserveAspectRatioOptions.cropY;
          center.x += preserveAspectRatioOptions.offsetLeft;
          center.y += preserveAspectRatioOptions.offsetTop;
          this.width = preserveAspectRatioOptions.width;
          this.height = preserveAspectRatioOptions.height;
        }
        this.setPositionByOrigin(center, 'center', 'center');
      },
  
      /**
       * Clones an instance, using a callback method will work for every object.
       * @param {Function} callback Callback is invoked with a clone as a first argument
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       */
      clone: function(callback, propertiesToInclude) {
        var objectForm = this.toObject(propertiesToInclude);
        if (this.constructor.fromObject) {
          this.constructor.fromObject(objectForm, callback);
        }
        else {
          fabric.Object._fromObject('Object', objectForm, callback);
        }
      },
  
      /**
       * Creates an instance of fabric.Image out of an object
       * could make use of both toDataUrl or toCanvasElement.
       * @param {Function} callback callback, invoked with an instance as a first argument
       * @param {Object} [options] for clone as image, passed to toDataURL
       * @param {String} [options.format=png] The format of the output image. Either "jpeg" or "png"
       * @param {Number} [options.quality=1] Quality level (0..1). Only used for jpeg.
       * @param {Number} [options.multiplier=1] Multiplier to scale by
       * @param {Number} [options.left] Cropping left offset. Introduced in v1.2.14
       * @param {Number} [options.top] Cropping top offset. Introduced in v1.2.14
       * @param {Number} [options.width] Cropping width. Introduced in v1.2.14
       * @param {Number} [options.height] Cropping height. Introduced in v1.2.14
       * @param {Boolean} [options.enableRetinaScaling] Enable retina scaling for clone image. Introduce in 1.6.4
       * @param {Boolean} [options.withoutTransform] Remove current object transform ( no scale , no angle, no flip, no skew ). Introduced in 2.3.4
       * @param {Boolean} [options.withoutShadow] Remove current object shadow. Introduced in 2.4.2
       * @return {fabric.Object} thisArg
       */
      cloneAsImage: function(callback, options) {
        var canvasEl = this.toCanvasElement(options);
        if (callback) {
          callback(new fabric.Image(canvasEl));
        }
        return this;
      },
  
      /**
       * Converts an object into a HTMLCanvas element
       * @param {Object} options Options object
       * @param {Number} [options.multiplier=1] Multiplier to scale by
       * @param {Number} [options.left] Cropping left offset. Introduced in v1.2.14
       * @param {Number} [options.top] Cropping top offset. Introduced in v1.2.14
       * @param {Number} [options.width] Cropping width. Introduced in v1.2.14
       * @param {Number} [options.height] Cropping height. Introduced in v1.2.14
       * @param {Boolean} [options.enableRetinaScaling] Enable retina scaling for clone image. Introduce in 1.6.4
       * @param {Boolean} [options.withoutTransform] Remove current object transform ( no scale , no angle, no flip, no skew ). Introduced in 2.3.4
       * @param {Boolean} [options.withoutShadow] Remove current object shadow. Introduced in 2.4.2
       * @return {String} Returns a data: URL containing a representation of the object in the format specified by options.format
       */
      toCanvasElement: function(options) {
        options || (options = { });
  
        var utils = fabric.util, origParams = utils.saveObjectTransform(this),
            originalGroup = this.group,
            originalShadow = this.shadow, abs = Math.abs,
            multiplier = (options.multiplier || 1) * (options.enableRetinaScaling ? fabric.devicePixelRatio : 1);
        delete this.group;
        if (options.withoutTransform) {
          utils.resetObjectTransform(this);
        }
        if (options.withoutShadow) {
          this.shadow = null;
        }
  
        var el = fabric.util.createCanvasElement(),
            // skip canvas zoom and calculate with setCoords now.
            boundingRect = this.getBoundingRect(true, true),
            shadow = this.shadow, scaling,
            shadowOffset = { x: 0, y: 0 }, shadowBlur;
  
        if (shadow) {
          shadowBlur = shadow.blur;
          if (shadow.nonScaling) {
            scaling = { scaleX: 1, scaleY: 1 };
          }
          else {
            scaling = this.getObjectScaling();
          }
          // consider non scaling shadow.
          shadowOffset.x = 2 * Math.round(abs(shadow.offsetX) + shadowBlur) * (abs(scaling.scaleX));
          shadowOffset.y = 2 * Math.round(abs(shadow.offsetY) + shadowBlur) * (abs(scaling.scaleY));
        }
        el.width = boundingRect.width + shadowOffset.x;
        el.height = boundingRect.height + shadowOffset.y;
        el.width += el.width % 2 ? 2 - el.width % 2 : 0;
        el.height += el.height % 2 ? 2 - el.height % 2 : 0;
        var canvas = new fabric.StaticCanvas(el, {
          enableRetinaScaling: false,
          renderOnAddRemove: false,
          skipOffscreen: false,
        });
        if (options.format === 'jpeg') {
          canvas.backgroundColor = '#fff';
        }
        this.setPositionByOrigin(new fabric.Point(canvas.width / 2, canvas.height / 2), 'center', 'center');
  
        var originalCanvas = this.canvas;
        canvas.add(this);
        var canvasEl = canvas.toCanvasElement(multiplier || 1, options);
        this.shadow = originalShadow;
        this.canvas = originalCanvas;
        if (originalGroup) {
          this.group = originalGroup;
        }
        this.set(origParams).setCoords();
        // canvas.dispose will call image.dispose that will nullify the elements
        // since this canvas is a simple element for the process, we remove references
        // to objects in this way in order to avoid object trashing.
        canvas._objects = [];
        canvas.dispose();
        canvas = null;
  
        return canvasEl;
      },
  
      /**
       * Converts an object into a data-url-like string
       * @param {Object} options Options object
       * @param {String} [options.format=png] The format of the output image. Either "jpeg" or "png"
       * @param {Number} [options.quality=1] Quality level (0..1). Only used for jpeg.
       * @param {Number} [options.multiplier=1] Multiplier to scale by
       * @param {Number} [options.left] Cropping left offset. Introduced in v1.2.14
       * @param {Number} [options.top] Cropping top offset. Introduced in v1.2.14
       * @param {Number} [options.width] Cropping width. Introduced in v1.2.14
       * @param {Number} [options.height] Cropping height. Introduced in v1.2.14
       * @param {Boolean} [options.enableRetinaScaling] Enable retina scaling for clone image. Introduce in 1.6.4
       * @param {Boolean} [options.withoutTransform] Remove current object transform ( no scale , no angle, no flip, no skew ). Introduced in 2.3.4
       * @param {Boolean} [options.withoutShadow] Remove current object shadow. Introduced in 2.4.2
       * @return {String} Returns a data: URL containing a representation of the object in the format specified by options.format
       */
      toDataURL: function(options) {
        options || (options = { });
        return fabric.util.toDataURL(this.toCanvasElement(options), options.format || 'png', options.quality || 1);
      },
  
      /**
       * Returns true if specified type is identical to the type of an instance
       * @param {String} type Type to check against
       * @return {Boolean}
       */
      isType: function(type) {
        return this.type === type;
      },
  
      /**
       * Returns complexity of an instance
       * @return {Number} complexity of this instance (is 1 unless subclassed)
       */
      complexity: function() {
        return 1;
      },
  
      /**
       * Returns a JSON representation of an instance
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object} JSON
       */
      toJSON: function(propertiesToInclude) {
        // delegate, not alias
        return this.toObject(propertiesToInclude);
      },
  
      /**
       * Sets gradient (fill or stroke) of an object
       * percentages for x1,x2,y1,y2,r1,r2 together with gradientUnits 'pixels', are not supported.
       * <b>Backwards incompatibility note:</b> This method was named "setGradientFill" until v1.1.0
       * @param {String} property Property name 'stroke' or 'fill'
       * @param {Object} [options] Options object
       * @param {String} [options.type] Type of gradient 'radial' or 'linear'
       * @param {Number} [options.x1=0] x-coordinate of start point
       * @param {Number} [options.y1=0] y-coordinate of start point
       * @param {Number} [options.x2=0] x-coordinate of end point
       * @param {Number} [options.y2=0] y-coordinate of end point
       * @param {Number} [options.r1=0] Radius of start point (only for radial gradients)
       * @param {Number} [options.r2=0] Radius of end point (only for radial gradients)
       * @param {Object} [options.colorStops] Color stops object eg. {0: 'ff0000', 1: '000000'}
       * @param {Object} [options.gradientTransform] transformMatrix for gradient
       * @return {fabric.Object} thisArg
       * @chainable
       * @deprecated since 3.4.0
       * @see {@link http://jsfiddle.net/fabricjs/58y8b/|jsFiddle demo}
       * @example <caption>Set linear gradient</caption>
       * object.setGradient('fill', {
       *   type: 'linear',
       *   x1: -object.width / 2,
       *   y1: 0,
       *   x2: object.width / 2,
       *   y2: 0,
       *   colorStops: {
       *     0: 'red',
       *     0.5: '#005555',
       *     1: 'rgba(0,0,255,0.5)'
       *   }
       * });
       * canvas.renderAll();
       * @example <caption>Set radial gradient</caption>
       * object.setGradient('fill', {
       *   type: 'radial',
       *   x1: 0,
       *   y1: 0,
       *   x2: 0,
       *   y2: 0,
       *   r1: object.width / 2,
       *   r2: 10,
       *   colorStops: {
       *     0: 'red',
       *     0.5: '#005555',
       *     1: 'rgba(0,0,255,0.5)'
       *   }
       * });
       * canvas.renderAll();
       */
      setGradient: function(property, options) {
        options || (options = { });
  
        var gradient = { colorStops: [] };
  
        gradient.type = options.type || (options.r1 || options.r2 ? 'radial' : 'linear');
        gradient.coords = {
          x1: options.x1,
          y1: options.y1,
          x2: options.x2,
          y2: options.y2
        };
        gradient.gradientUnits = options.gradientUnits || 'pixels';
        if (options.r1 || options.r2) {
          gradient.coords.r1 = options.r1;
          gradient.coords.r2 = options.r2;
        }
  
        gradient.gradientTransform = options.gradientTransform;
        fabric.Gradient.prototype.addColorStop.call(gradient, options.colorStops);
  
        return this.set(property, fabric.Gradient.forObject(this, gradient));
      },
  
      /**
       * Sets pattern fill of an object
       * @param {Object} options Options object
       * @param {(String|HTMLImageElement)} options.source Pattern source
       * @param {String} [options.repeat=repeat] Repeat property of a pattern (one of repeat, repeat-x, repeat-y or no-repeat)
       * @param {Number} [options.offsetX=0] Pattern horizontal offset from object's left/top corner
       * @param {Number} [options.offsetY=0] Pattern vertical offset from object's left/top corner
       * @param {Function} [callback] Callback to invoke when image set as a pattern
       * @return {fabric.Object} thisArg
       * @chainable
       * @deprecated since 3.5.0
       * @see {@link http://jsfiddle.net/fabricjs/QT3pa/|jsFiddle demo}
       * @example <caption>Set pattern</caption>
       * object.setPatternFill({
       *   source: 'http://fabricjs.com/assets/escheresque_ste.png',
       *   repeat: 'repeat'
       * },canvas.renderAll.bind(canvas));
       */
      setPatternFill: function(options, callback) {
        return this.set('fill', new fabric.Pattern(options, callback));
      },
  
      /**
       * Sets {@link fabric.Object#shadow|shadow} of an object
       * @param {Object|String} [options] Options object or string (e.g. "2px 2px 10px rgba(0,0,0,0.2)")
       * @param {String} [options.color=rgb(0,0,0)] Shadow color
       * @param {Number} [options.blur=0] Shadow blur
       * @param {Number} [options.offsetX=0] Shadow horizontal offset
       * @param {Number} [options.offsetY=0] Shadow vertical offset
       * @return {fabric.Object} thisArg
       * @chainable
       * @deprecated since 3.5.0
       * @see {@link http://jsfiddle.net/fabricjs/7gvJG/|jsFiddle demo}
       * @example <caption>Set shadow with string notation</caption>
       * object.setShadow('2px 2px 10px rgba(0,0,0,0.2)');
       * canvas.renderAll();
       * @example <caption>Set shadow with object notation</caption>
       * object.setShadow({
       *   color: 'red',
       *   blur: 10,
       *   offsetX: 20,
       *   offsetY: 20
       * });
       * canvas.renderAll();
       */
      setShadow: function(options) {
        return this.set('shadow', options ? new fabric.Shadow(options) : null);
      },
  
      /**
       * Sets "color" of an instance (alias of `set('fill', &hellip;)`)
       * @param {String} color Color value
       * @return {fabric.Object} thisArg
       * @deprecated since 3.5.0
       * @chainable
       */
      setColor: function(color) {
        this.set('fill', color);
        return this;
      },
  
      /**
       * Sets "angle" of an instance with centered rotation
       * @param {Number} angle Angle value (in degrees)
       * @return {fabric.Object} thisArg
       * @chainable
       */
      rotate: function(angle) {
        var shouldCenterOrigin = (this.originX !== 'center' || this.originY !== 'center') && this.centeredRotation;
  
        if (shouldCenterOrigin) {
          this._setOriginToCenter();
        }
  
        this.set('angle', angle);
  
        if (shouldCenterOrigin) {
          this._resetOrigin();
        }
  
        return this;
      },
  
      /**
       * Centers object horizontally on canvas to which it was added last.
       * You might need to call `setCoords` on an object after centering, to update controls area.
       * @return {fabric.Object} thisArg
       * @chainable
       */
      centerH: function () {
        this.canvas && this.canvas.centerObjectH(this);
        return this;
      },
  
      /**
       * Centers object horizontally on current viewport of canvas to which it was added last.
       * You might need to call `setCoords` on an object after centering, to update controls area.
       * @return {fabric.Object} thisArg
       * @chainable
       */
      viewportCenterH: function () {
        this.canvas && this.canvas.viewportCenterObjectH(this);
        return this;
      },
  
      /**
       * Centers object vertically on canvas to which it was added last.
       * You might need to call `setCoords` on an object after centering, to update controls area.
       * @return {fabric.Object} thisArg
       * @chainable
       */
      centerV: function () {
        this.canvas && this.canvas.centerObjectV(this);
        return this;
      },
  
      /**
       * Centers object vertically on current viewport of canvas to which it was added last.
       * You might need to call `setCoords` on an object after centering, to update controls area.
       * @return {fabric.Object} thisArg
       * @chainable
       */
      viewportCenterV: function () {
        this.canvas && this.canvas.viewportCenterObjectV(this);
        return this;
      },
  
      /**
       * Centers object vertically and horizontally on canvas to which is was added last
       * You might need to call `setCoords` on an object after centering, to update controls area.
       * @return {fabric.Object} thisArg
       * @chainable
       */
      center: function () {
        this.canvas && this.canvas.centerObject(this);
        return this;
      },
  
      /**
       * Centers object on current viewport of canvas to which it was added last.
       * You might need to call `setCoords` on an object after centering, to update controls area.
       * @return {fabric.Object} thisArg
       * @chainable
       */
      viewportCenter: function () {
        this.canvas && this.canvas.viewportCenterObject(this);
        return this;
      },
  
      /**
       * Returns coordinates of a pointer relative to an object
       * @param {Event} e Event to operate upon
       * @param {Object} [pointer] Pointer to operate upon (instead of event)
       * @return {Object} Coordinates of a pointer (x, y)
       */
      getLocalPointer: function(e, pointer) {
        pointer = pointer || this.canvas.getPointer(e);
        var pClicked = new fabric.Point(pointer.x, pointer.y),
            objectLeftTop = this._getLeftTopCoords();
        if (this.angle) {
          pClicked = fabric.util.rotatePoint(
            pClicked, objectLeftTop, degreesToRadians(-this.angle));
        }
        return {
          x: pClicked.x - objectLeftTop.x,
          y: pClicked.y - objectLeftTop.y
        };
      },
  
      /**
       * Sets canvas globalCompositeOperation for specific object
       * custom composition operation for the particular object can be specified using globalCompositeOperation property
       * @param {CanvasRenderingContext2D} ctx Rendering canvas context
       */
      _setupCompositeOperation: function (ctx) {
        if (this.globalCompositeOperation) {
          ctx.globalCompositeOperation = this.globalCompositeOperation;
        }
      }
    });
  
    fabric.util.createAccessors && fabric.util.createAccessors(fabric.Object);
  
    extend(fabric.Object.prototype, fabric.Observable);
  
    /**
     * Defines the number of fraction digits to use when serializing object values.
     * You can use it to increase/decrease precision of such values like left, top, scaleX, scaleY, etc.
     * @static
     * @memberOf fabric.Object
     * @constant
     * @type Number
     */
    fabric.Object.NUM_FRACTION_DIGITS = 2;
  
    fabric.Object._fromObject = function(className, object, callback, extraParam) {
      var klass = fabric[className];
      object = clone(object, true);
      fabric.util.enlivenPatterns([object.fill, object.stroke], function(patterns) {
        if (typeof patterns[0] !== 'undefined') {
          object.fill = patterns[0];
        }
        if (typeof patterns[1] !== 'undefined') {
          object.stroke = patterns[1];
        }
        fabric.util.enlivenObjects([object.clipPath], function(enlivedProps) {
          object.clipPath = enlivedProps[0];
          var instance = extraParam ? new klass(object[extraParam], object) : new klass(object);
          callback && callback(instance);
        });
      });
    };
  
    /**
     * Unique id used internally when creating SVG elements
     * @static
     * @memberOf fabric.Object
     * @type Number
     */
    fabric.Object.__uid = 0;
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function() {
  
    var degreesToRadians = fabric.util.degreesToRadians,
        originXOffset = {
          left: -0.5,
          center: 0,
          right: 0.5
        },
        originYOffset = {
          top: -0.5,
          center: 0,
          bottom: 0.5
        };
  
    fabric.util.object.extend(fabric.Object.prototype, /** @lends fabric.Object.prototype */ {
  
      /**
       * Translates the coordinates from a set of origin to another (based on the object's dimensions)
       * @param {fabric.Point} point The point which corresponds to the originX and originY params
       * @param {String} fromOriginX Horizontal origin: 'left', 'center' or 'right'
       * @param {String} fromOriginY Vertical origin: 'top', 'center' or 'bottom'
       * @param {String} toOriginX Horizontal origin: 'left', 'center' or 'right'
       * @param {String} toOriginY Vertical origin: 'top', 'center' or 'bottom'
       * @return {fabric.Point}
       */
      translateToGivenOrigin: function(point, fromOriginX, fromOriginY, toOriginX, toOriginY) {
        var x = point.x,
            y = point.y,
            offsetX, offsetY, dim;
  
        if (typeof fromOriginX === 'string') {
          fromOriginX = originXOffset[fromOriginX];
        }
        else {
          fromOriginX -= 0.5;
        }
  
        if (typeof toOriginX === 'string') {
          toOriginX = originXOffset[toOriginX];
        }
        else {
          toOriginX -= 0.5;
        }
  
        offsetX = toOriginX - fromOriginX;
  
        if (typeof fromOriginY === 'string') {
          fromOriginY = originYOffset[fromOriginY];
        }
        else {
          fromOriginY -= 0.5;
        }
  
        if (typeof toOriginY === 'string') {
          toOriginY = originYOffset[toOriginY];
        }
        else {
          toOriginY -= 0.5;
        }
  
        offsetY = toOriginY - fromOriginY;
  
        if (offsetX || offsetY) {
          dim = this._getTransformedDimensions();
          x = point.x + offsetX * dim.x;
          y = point.y + offsetY * dim.y;
        }
  
        return new fabric.Point(x, y);
      },
  
      /**
       * Translates the coordinates from origin to center coordinates (based on the object's dimensions)
       * @param {fabric.Point} point The point which corresponds to the originX and originY params
       * @param {String} originX Horizontal origin: 'left', 'center' or 'right'
       * @param {String} originY Vertical origin: 'top', 'center' or 'bottom'
       * @return {fabric.Point}
       */
      translateToCenterPoint: function(point, originX, originY) {
        var p = this.translateToGivenOrigin(point, originX, originY, 'center', 'center');
        if (this.angle) {
          return fabric.util.rotatePoint(p, point, degreesToRadians(this.angle));
        }
        return p;
      },
  
      /**
       * Translates the coordinates from center to origin coordinates (based on the object's dimensions)
       * @param {fabric.Point} center The point which corresponds to center of the object
       * @param {String} originX Horizontal origin: 'left', 'center' or 'right'
       * @param {String} originY Vertical origin: 'top', 'center' or 'bottom'
       * @return {fabric.Point}
       */
      translateToOriginPoint: function(center, originX, originY) {
        var p = this.translateToGivenOrigin(center, 'center', 'center', originX, originY);
        if (this.angle) {
          return fabric.util.rotatePoint(p, center, degreesToRadians(this.angle));
        }
        return p;
      },
  
      /**
       * Returns the real center coordinates of the object
       * @return {fabric.Point}
       */
      getCenterPoint: function() {
        var leftTop = new fabric.Point(this.left, this.top);
        return this.translateToCenterPoint(leftTop, this.originX, this.originY);
      },
  
      /**
       * Returns the coordinates of the object based on center coordinates
       * @param {fabric.Point} point The point which corresponds to the originX and originY params
       * @return {fabric.Point}
       */
      // getOriginPoint: function(center) {
      //   return this.translateToOriginPoint(center, this.originX, this.originY);
      // },
  
      /**
       * Returns the coordinates of the object as if it has a different origin
       * @param {String} originX Horizontal origin: 'left', 'center' or 'right'
       * @param {String} originY Vertical origin: 'top', 'center' or 'bottom'
       * @return {fabric.Point}
       */
      getPointByOrigin: function(originX, originY) {
        var center = this.getCenterPoint();
        return this.translateToOriginPoint(center, originX, originY);
      },
  
      /**
       * Returns the point in local coordinates
       * @param {fabric.Point} point The point relative to the global coordinate system
       * @param {String} originX Horizontal origin: 'left', 'center' or 'right'
       * @param {String} originY Vertical origin: 'top', 'center' or 'bottom'
       * @return {fabric.Point}
       */
      toLocalPoint: function(point, originX, originY) {
        var center = this.getCenterPoint(),
            p, p2;
  
        if (typeof originX !== 'undefined' && typeof originY !== 'undefined' ) {
          p = this.translateToGivenOrigin(center, 'center', 'center', originX, originY);
        }
        else {
          p = new fabric.Point(this.left, this.top);
        }
  
        p2 = new fabric.Point(point.x, point.y);
        if (this.angle) {
          p2 = fabric.util.rotatePoint(p2, center, -degreesToRadians(this.angle));
        }
        return p2.subtractEquals(p);
      },
  
      /**
       * Returns the point in global coordinates
       * @param {fabric.Point} The point relative to the local coordinate system
       * @return {fabric.Point}
       */
      // toGlobalPoint: function(point) {
      //   return fabric.util.rotatePoint(point, this.getCenterPoint(), degreesToRadians(this.angle)).addEquals(new fabric.Point(this.left, this.top));
      // },
  
      /**
       * Sets the position of the object taking into consideration the object's origin
       * @param {fabric.Point} pos The new position of the object
       * @param {String} originX Horizontal origin: 'left', 'center' or 'right'
       * @param {String} originY Vertical origin: 'top', 'center' or 'bottom'
       * @return {void}
       */
      setPositionByOrigin: function(pos, originX, originY) {
        var center = this.translateToCenterPoint(pos, originX, originY),
            position = this.translateToOriginPoint(center, this.originX, this.originY);
        this.set('left', position.x);
        this.set('top', position.y);
      },
  
      /**
       * @param {String} to One of 'left', 'center', 'right'
       */
      adjustPosition: function(to) {
        var angle = degreesToRadians(this.angle),
            hypotFull = this.getScaledWidth(),
            xFull = fabric.util.cos(angle) * hypotFull,
            yFull = fabric.util.sin(angle) * hypotFull,
            offsetFrom, offsetTo;
  
        //TODO: this function does not consider mixed situation like top, center.
        if (typeof this.originX === 'string') {
          offsetFrom = originXOffset[this.originX];
        }
        else {
          offsetFrom = this.originX - 0.5;
        }
        if (typeof to === 'string') {
          offsetTo = originXOffset[to];
        }
        else {
          offsetTo = to - 0.5;
        }
        this.left += xFull * (offsetTo - offsetFrom);
        this.top += yFull * (offsetTo - offsetFrom);
        this.setCoords();
        this.originX = to;
      },
  
      /**
       * Sets the origin/position of the object to it's center point
       * @private
       * @return {void}
       */
      _setOriginToCenter: function() {
        this._originalOriginX = this.originX;
        this._originalOriginY = this.originY;
  
        var center = this.getCenterPoint();
  
        this.originX = 'center';
        this.originY = 'center';
  
        this.left = center.x;
        this.top = center.y;
      },
  
      /**
       * Resets the origin/position of the object to it's original origin
       * @private
       * @return {void}
       */
      _resetOrigin: function() {
        var originPoint = this.translateToOriginPoint(
          this.getCenterPoint(),
          this._originalOriginX,
          this._originalOriginY);
  
        this.originX = this._originalOriginX;
        this.originY = this._originalOriginY;
  
        this.left = originPoint.x;
        this.top = originPoint.y;
  
        this._originalOriginX = null;
        this._originalOriginY = null;
      },
  
      /**
       * @private
       */
      _getLeftTopCoords: function() {
        return this.translateToOriginPoint(this.getCenterPoint(), 'left', 'top');
      },
    });
  
  })();
  
  
  (function() {
  
    function getCoords(coords) {
      return [
        new fabric.Point(coords.tl.x, coords.tl.y),
        new fabric.Point(coords.tr.x, coords.tr.y),
        new fabric.Point(coords.br.x, coords.br.y),
        new fabric.Point(coords.bl.x, coords.bl.y)
      ];
    }
  
    var degreesToRadians = fabric.util.degreesToRadians,
        multiplyMatrices = fabric.util.multiplyTransformMatrices,
        transformPoint = fabric.util.transformPoint;
  
    fabric.util.object.extend(fabric.Object.prototype, /** @lends fabric.Object.prototype */ {
  
      /**
       * Describe object's corner position in canvas element coordinates.
       * properties are tl,mt,tr,ml,mr,bl,mb,br,mtr for the main controls.
       * each property is an object with x, y and corner.
       * The `corner` property contains in a similar manner the 4 points of the
       * interactive area of the corner.
       * The coordinates depends from this properties: width, height, scaleX, scaleY
       * skewX, skewY, angle, strokeWidth, viewportTransform, top, left, padding.
       * The coordinates get updated with @method setCoords.
       * You can calculate them without updating with @method calcCoords;
       * @memberOf fabric.Object.prototype
       */
      oCoords: null,
  
      /**
       * Describe object's corner position in canvas object absolute coordinates
       * properties are tl,tr,bl,br and describe the four main corner.
       * each property is an object with x, y, instance of Fabric.Point.
       * The coordinates depends from this properties: width, height, scaleX, scaleY
       * skewX, skewY, angle, strokeWidth, top, left.
       * Those coordinates are useful to understand where an object is. They get updated
       * with oCoords but they do not need to be updated when zoom or panning change.
       * The coordinates get updated with @method setCoords.
       * You can calculate them without updating with @method calcCoords(true);
       * @memberOf fabric.Object.prototype
       */
      aCoords: null,
  
      /**
       * storage for object transform matrix
       */
      ownMatrixCache: null,
  
      /**
       * storage for object full transform matrix
       */
      matrixCache: null,
  
      /**
       * return correct set of coordinates for intersection
       */
      getCoords: function(absolute, calculate) {
        if (!this.oCoords) {
          this.setCoords();
        }
        var coords = absolute ? this.aCoords : this.oCoords;
        return getCoords(calculate ? this.calcCoords(absolute) : coords);
      },
  
      /**
       * Checks if object intersects with an area formed by 2 points
       * @param {Object} pointTL top-left point of area
       * @param {Object} pointBR bottom-right point of area
       * @param {Boolean} [absolute] use coordinates without viewportTransform
       * @param {Boolean} [calculate] use coordinates of current position instead of .oCoords
       * @return {Boolean} true if object intersects with an area formed by 2 points
       */
      intersectsWithRect: function(pointTL, pointBR, absolute, calculate) {
        var coords = this.getCoords(absolute, calculate),
            intersection = fabric.Intersection.intersectPolygonRectangle(
              coords,
              pointTL,
              pointBR
            );
        return intersection.status === 'Intersection';
      },
  
      /**
       * Checks if object intersects with another object
       * @param {Object} other Object to test
       * @param {Boolean} [absolute] use coordinates without viewportTransform
       * @param {Boolean} [calculate] use coordinates of current position instead of .oCoords
       * @return {Boolean} true if object intersects with another object
       */
      intersectsWithObject: function(other, absolute, calculate) {
        var intersection = fabric.Intersection.intersectPolygonPolygon(
          this.getCoords(absolute, calculate),
          other.getCoords(absolute, calculate)
        );
  
        return intersection.status === 'Intersection'
          || other.isContainedWithinObject(this, absolute, calculate)
          || this.isContainedWithinObject(other, absolute, calculate);
      },
  
      /**
       * Checks if object is fully contained within area of another object
       * @param {Object} other Object to test
       * @param {Boolean} [absolute] use coordinates without viewportTransform
       * @param {Boolean} [calculate] use coordinates of current position instead of .oCoords
       * @return {Boolean} true if object is fully contained within area of another object
       */
      isContainedWithinObject: function(other, absolute, calculate) {
        var points = this.getCoords(absolute, calculate),
            i = 0, lines = other._getImageLines(
              calculate ? other.calcCoords(absolute) : absolute ? other.aCoords : other.oCoords
            );
        for (; i < 4; i++) {
          if (!other.containsPoint(points[i], lines)) {
            return false;
          }
        }
        return true;
      },
  
      /**
       * Checks if object is fully contained within area formed by 2 points
       * @param {Object} pointTL top-left point of area
       * @param {Object} pointBR bottom-right point of area
       * @param {Boolean} [absolute] use coordinates without viewportTransform
       * @param {Boolean} [calculate] use coordinates of current position instead of .oCoords
       * @return {Boolean} true if object is fully contained within area formed by 2 points
       */
      isContainedWithinRect: function(pointTL, pointBR, absolute, calculate) {
        var boundingRect = this.getBoundingRect(absolute, calculate);
  
        return (
          boundingRect.left >= pointTL.x &&
          boundingRect.left + boundingRect.width <= pointBR.x &&
          boundingRect.top >= pointTL.y &&
          boundingRect.top + boundingRect.height <= pointBR.y
        );
      },
  
      /**
       * Checks if point is inside the object
       * @param {fabric.Point} point Point to check against
       * @param {Object} [lines] object returned from @method _getImageLines
       * @param {Boolean} [absolute] use coordinates without viewportTransform
       * @param {Boolean} [calculate] use coordinates of current position instead of .oCoords
       * @return {Boolean} true if point is inside the object
       */
      containsPoint: function(point, lines, absolute, calculate) {
        var lines = lines || this._getImageLines(
              calculate ? this.calcCoords(absolute) : absolute ? this.aCoords : this.oCoords
            ),
            xPoints = this._findCrossPoints(point, lines);
  
        // if xPoints is odd then point is inside the object
        return (xPoints !== 0 && xPoints % 2 === 1);
      },
  
      /**
       * Checks if object is contained within the canvas with current viewportTransform
       * the check is done stopping at first point that appears on screen
       * @param {Boolean} [calculate] use coordinates of current position instead of .aCoords
       * @return {Boolean} true if object is fully or partially contained within canvas
       */
      isOnScreen: function(calculate) {
        if (!this.canvas) {
          return false;
        }
        var pointTL = this.canvas.vptCoords.tl, pointBR = this.canvas.vptCoords.br;
        var points = this.getCoords(true, calculate), point;
        for (var i = 0; i < 4; i++) {
          point = points[i];
          if (point.x <= pointBR.x && point.x >= pointTL.x && point.y <= pointBR.y && point.y >= pointTL.y) {
            return true;
          }
        }
        // no points on screen, check intersection with absolute coordinates
        if (this.intersectsWithRect(pointTL, pointBR, true, calculate)) {
          return true;
        }
        return this._containsCenterOfCanvas(pointTL, pointBR, calculate);
      },
  
      /**
       * Checks if the object contains the midpoint between canvas extremities
       * Does not make sense outside the context of isOnScreen and isPartiallyOnScreen
       * @private
       * @param {Fabric.Point} pointTL Top Left point
       * @param {Fabric.Point} pointBR Top Right point
       * @param {Boolean} calculate use coordinates of current position instead of .oCoords
       * @return {Boolean} true if the object contains the point
       */
      _containsCenterOfCanvas: function(pointTL, pointBR, calculate) {
        // worst case scenario the object is so big that contains the screen
        var centerPoint = { x: (pointTL.x + pointBR.x) / 2, y: (pointTL.y + pointBR.y) / 2 };
        if (this.containsPoint(centerPoint, null, true, calculate)) {
          return true;
        }
        return false;
      },
  
      /**
       * Checks if object is partially contained within the canvas with current viewportTransform
       * @param {Boolean} [calculate] use coordinates of current position instead of .oCoords
       * @return {Boolean} true if object is partially contained within canvas
       */
      isPartiallyOnScreen: function(calculate) {
        if (!this.canvas) {
          return false;
        }
        var pointTL = this.canvas.vptCoords.tl, pointBR = this.canvas.vptCoords.br;
        if (this.intersectsWithRect(pointTL, pointBR, true, calculate)) {
          return true;
        }
        return this._containsCenterOfCanvas(pointTL, pointBR, calculate);
      },
  
      /**
       * Method that returns an object with the object edges in it, given the coordinates of the corners
       * @private
       * @param {Object} oCoords Coordinates of the object corners
       */
      _getImageLines: function(oCoords) {
        return {
          topline: {
            o: oCoords.tl,
            d: oCoords.tr
          },
          rightline: {
            o: oCoords.tr,
            d: oCoords.br
          },
          bottomline: {
            o: oCoords.br,
            d: oCoords.bl
          },
          leftline: {
            o: oCoords.bl,
            d: oCoords.tl
          }
        };
      },
  
      /**
       * Helper method to determine how many cross points are between the 4 object edges
       * and the horizontal line determined by a point on canvas
       * @private
       * @param {fabric.Point} point Point to check
       * @param {Object} lines Coordinates of the object being evaluated
       */
      // remove yi, not used but left code here just in case.
      _findCrossPoints: function(point, lines) {
        var b1, b2, a1, a2, xi, // yi,
            xcount = 0,
            iLine;
  
        for (var lineKey in lines) {
          iLine = lines[lineKey];
          // optimisation 1: line below point. no cross
          if ((iLine.o.y < point.y) && (iLine.d.y < point.y)) {
            continue;
          }
          // optimisation 2: line above point. no cross
          if ((iLine.o.y >= point.y) && (iLine.d.y >= point.y)) {
            continue;
          }
          // optimisation 3: vertical line case
          if ((iLine.o.x === iLine.d.x) && (iLine.o.x >= point.x)) {
            xi = iLine.o.x;
            // yi = point.y;
          }
          // calculate the intersection point
          else {
            b1 = 0;
            b2 = (iLine.d.y - iLine.o.y) / (iLine.d.x - iLine.o.x);
            a1 = point.y - b1 * point.x;
            a2 = iLine.o.y - b2 * iLine.o.x;
  
            xi = -(a1 - a2) / (b1 - b2);
            // yi = a1 + b1 * xi;
          }
          // dont count xi < point.x cases
          if (xi >= point.x) {
            xcount += 1;
          }
          // optimisation 4: specific for square images
          if (xcount === 2) {
            break;
          }
        }
        return xcount;
      },
  
      /**
       * Returns coordinates of object's bounding rectangle (left, top, width, height)
       * the box is intended as aligned to axis of canvas.
       * @param {Boolean} [absolute] use coordinates without viewportTransform
       * @param {Boolean} [calculate] use coordinates of current position instead of .oCoords / .aCoords
       * @return {Object} Object with left, top, width, height properties
       */
      getBoundingRect: function(absolute, calculate) {
        var coords = this.getCoords(absolute, calculate);
        return fabric.util.makeBoundingBoxFromPoints(coords);
      },
  
      /**
       * Returns width of an object's bounding box counting transformations
       * before 2.0 it was named getWidth();
       * @return {Number} width value
       */
      getScaledWidth: function() {
        return this._getTransformedDimensions().x;
      },
  
      /**
       * Returns height of an object bounding box counting transformations
       * before 2.0 it was named getHeight();
       * @return {Number} height value
       */
      getScaledHeight: function() {
        return this._getTransformedDimensions().y;
      },
  
      /**
       * Makes sure the scale is valid and modifies it if necessary
       * @private
       * @param {Number} value
       * @return {Number}
       */
      _constrainScale: function(value) {
        if (Math.abs(value) < this.minScaleLimit) {
          if (value < 0) {
            return -this.minScaleLimit;
          }
          else {
            return this.minScaleLimit;
          }
        }
        else if (value === 0) {
          return 0.0001;
        }
        return value;
      },
  
      /**
       * Scales an object (equally by x and y)
       * @param {Number} value Scale factor
       * @return {fabric.Object} thisArg
       * @chainable
       */
      scale: function(value) {
        this._set('scaleX', value);
        this._set('scaleY', value);
        return this.setCoords();
      },
  
      /**
       * Scales an object to a given width, with respect to bounding box (scaling by x/y equally)
       * @param {Number} value New width value
       * @param {Boolean} absolute ignore viewport
       * @return {fabric.Object} thisArg
       * @chainable
       */
      scaleToWidth: function(value, absolute) {
        // adjust to bounding rect factor so that rotated shapes would fit as well
        var boundingRectFactor = this.getBoundingRect(absolute).width / this.getScaledWidth();
        return this.scale(value / this.width / boundingRectFactor);
      },
  
      /**
       * Scales an object to a given height, with respect to bounding box (scaling by x/y equally)
       * @param {Number} value New height value
       * @param {Boolean} absolute ignore viewport
       * @return {fabric.Object} thisArg
       * @chainable
       */
      scaleToHeight: function(value, absolute) {
        // adjust to bounding rect factor so that rotated shapes would fit as well
        var boundingRectFactor = this.getBoundingRect(absolute).height / this.getScaledHeight();
        return this.scale(value / this.height / boundingRectFactor);
      },
  
      /**
       * Calculates and returns the .coords of an object.
       * @return {Object} Object with tl, tr, br, bl ....
       * @chainable
       */
      calcCoords: function(absolute) {
        var rotateMatrix = this._calcRotateMatrix(),
            translateMatrix = this._calcTranslateMatrix(),
            startMatrix = multiplyMatrices(translateMatrix, rotateMatrix),
            vpt = this.getViewportTransform(),
            finalMatrix = absolute ? startMatrix : multiplyMatrices(vpt, startMatrix),
            dim = this._getTransformedDimensions(),
            w = dim.x / 2, h = dim.y / 2,
            tl = transformPoint({ x: -w, y: -h }, finalMatrix),
            tr = transformPoint({ x: w, y: -h }, finalMatrix),
            bl = transformPoint({ x: -w, y: h }, finalMatrix),
            br = transformPoint({ x: w, y: h }, finalMatrix);
        if (!absolute) {
          var padding = this.padding, angle = degreesToRadians(this.angle),
              cos = fabric.util.cos(angle), sin = fabric.util.sin(angle),
              cosP = cos * padding, sinP = sin * padding, cosPSinP = cosP + sinP,
              cosPMinusSinP = cosP - sinP;
          if (padding) {
            tl.x -= cosPMinusSinP;
            tl.y -= cosPSinP;
            tr.x += cosPSinP;
            tr.y -= cosPMinusSinP;
            bl.x -= cosPSinP;
            bl.y += cosPMinusSinP;
            br.x += cosPMinusSinP;
            br.y += cosPSinP;
          }
          var ml  = new fabric.Point((tl.x + bl.x) / 2, (tl.y + bl.y) / 2),
              mt  = new fabric.Point((tr.x + tl.x) / 2, (tr.y + tl.y) / 2),
              mr  = new fabric.Point((br.x + tr.x) / 2, (br.y + tr.y) / 2),
              mb  = new fabric.Point((br.x + bl.x) / 2, (br.y + bl.y) / 2),
              mtr = new fabric.Point(mt.x + sin * this.rotatingPointOffset, mt.y - cos * this.rotatingPointOffset);
        }
  
        // if (!absolute) {
        //   var canvas = this.canvas;
        //   setTimeout(function() {
        //     canvas.contextTop.clearRect(0, 0, 700, 700);
        //     canvas.contextTop.fillStyle = 'green';
        //     canvas.contextTop.fillRect(mb.x, mb.y, 3, 3);
        //     canvas.contextTop.fillRect(bl.x, bl.y, 3, 3);
        //     canvas.contextTop.fillRect(br.x, br.y, 3, 3);
        //     canvas.contextTop.fillRect(tl.x, tl.y, 3, 3);
        //     canvas.contextTop.fillRect(tr.x, tr.y, 3, 3);
        //     canvas.contextTop.fillRect(ml.x, ml.y, 3, 3);
        //     canvas.contextTop.fillRect(mr.x, mr.y, 3, 3);
        //     canvas.contextTop.fillRect(mt.x, mt.y, 3, 3);
        //     canvas.contextTop.fillRect(mtr.x, mtr.y, 3, 3);
        //   }, 50);
        // }
  
        var coords = {
          // corners
          tl: tl, tr: tr, br: br, bl: bl,
        };
        if (!absolute) {
          // middle
          coords.ml = ml;
          coords.mt = mt;
          coords.mr = mr;
          coords.mb = mb;
          // rotating point
          coords.mtr = mtr;
        }
        return coords;
      },
  
      /**
       * Sets corner position coordinates based on current angle, width and height.
       * See {@link https://github.com/kangax/fabric.js/wiki/When-to-call-setCoords|When-to-call-setCoords}
       * @param {Boolean} [ignoreZoom] set oCoords with or without the viewport transform.
       * @param {Boolean} [skipAbsolute] skip calculation of aCoords, useful in setViewportTransform
       * @return {fabric.Object} thisArg
       * @chainable
       */
      setCoords: function(ignoreZoom, skipAbsolute) {
        this.oCoords = this.calcCoords(ignoreZoom);
        if (!skipAbsolute) {
          this.aCoords = this.calcCoords(true);
        }
  
        // set coordinates of the draggable boxes in the corners used to scale/rotate the image
        ignoreZoom || (this._setCornerCoords && this._setCornerCoords());
  
        return this;
      },
  
      /**
       * calculate rotation matrix of an object
       * @return {Array} rotation matrix for the object
       */
      _calcRotateMatrix: function() {
        return fabric.util.calcRotateMatrix(this);
      },
  
      /**
       * calculate the translation matrix for an object transform
       * @return {Array} rotation matrix for the object
       */
      _calcTranslateMatrix: function() {
        var center = this.getCenterPoint();
        return [1, 0, 0, 1, center.x, center.y];
      },
  
      transformMatrixKey: function(skipGroup) {
        var sep = '_', prefix = '';
        if (!skipGroup && this.group) {
          prefix = this.group.transformMatrixKey(skipGroup) + sep;
        };
        return prefix + this.top + sep + this.left + sep + this.scaleX + sep + this.scaleY +
          sep + this.skewX + sep + this.skewY + sep + this.angle + sep + this.originX + sep + this.originY +
          sep + this.width + sep + this.height + sep + this.strokeWidth + this.flipX + this.flipY;
      },
  
      /**
       * calculate transform matrix that represents the current transformations from the
       * object's properties.
       * @param {Boolean} [skipGroup] return transform matrix for object not counting parent transformations
       * @return {Array} transform matrix for the object
       */
      calcTransformMatrix: function(skipGroup) {
        if (skipGroup) {
          return this.calcOwnMatrix();
        }
        var key = this.transformMatrixKey(), cache = this.matrixCache || (this.matrixCache = {});
        if (cache.key === key) {
          return cache.value;
        }
        var matrix = this.calcOwnMatrix();
        if (this.group) {
          matrix = multiplyMatrices(this.group.calcTransformMatrix(), matrix);
        }
        cache.key = key;
        cache.value = matrix;
        return matrix;
      },
  
      /**
       * calculate transform matrix that represents the current transformations from the
       * object's properties, this matrix does not include the group transformation
       * @return {Array} transform matrix for the object
       */
      calcOwnMatrix: function() {
        var key = this.transformMatrixKey(true), cache = this.ownMatrixCache || (this.ownMatrixCache = {});
        if (cache.key === key) {
          return cache.value;
        }
        var tMatrix = this._calcTranslateMatrix();
        this.translateX = tMatrix[4];
        this.translateY = tMatrix[5];
        cache.key = key;
        cache.value = fabric.util.composeMatrix(this);
        return cache.value;
      },
  
      /*
       * Calculate object dimensions from its properties
       * @private
       * @deprecated since 3.4.0, please use fabric.util._calcDimensionsTransformMatrix
       * not including or including flipX, flipY to emulate the flipping boolean
       * @return {Object} .x width dimension
       * @return {Object} .y height dimension
       */
      _calcDimensionsTransformMatrix: function(skewX, skewY, flipping) {
        return fabric.util.calcDimensionsMatrix({
          skewX: skewX,
          skewY: skewY,
          scaleX: this.scaleX * (flipping && this.flipX ? -1 : 1),
          scaleY: this.scaleY * (flipping && this.flipY ? -1 : 1)
        });
      },
  
      /*
       * Calculate object dimensions from its properties
       * @private
       * @return {Object} .x width dimension
       * @return {Object} .y height dimension
       */
      _getNonTransformedDimensions: function() {
        var strokeWidth = this.strokeWidth,
            w = this.width + strokeWidth,
            h = this.height + strokeWidth;
        return { x: w, y: h };
      },
  
      /*
       * Calculate object bounding box dimensions from its properties scale, skew.
       * @param {Number} skewX, a value to override current skewX
       * @param {Number} skewY, a value to override current skewY
       * @private
       * @return {Object} .x width dimension
       * @return {Object} .y height dimension
       */
      _getTransformedDimensions: function(skewX, skewY) {
        if (typeof skewX === 'undefined') {
          skewX = this.skewX;
        }
        if (typeof skewY === 'undefined') {
          skewY = this.skewY;
        }
        var dimensions = this._getNonTransformedDimensions(), dimX, dimY,
            noSkew = skewX === 0 && skewY === 0;
  
        if (this.strokeUniform) {
          dimX = this.width;
          dimY = this.height;
        }
        else {
          dimX = dimensions.x;
          dimY = dimensions.y;
        }
        if (noSkew) {
          return this._finalizeDimensions(dimX * this.scaleX, dimY * this.scaleY);
        }
        else {
          dimX /= 2;
          dimY /= 2;
        }
        var points = [
              {
                x: -dimX,
                y: -dimY
              },
              {
                x: dimX,
                y: -dimY
              },
              {
                x: -dimX,
                y: dimY
              },
              {
                x: dimX,
                y: dimY
              }],
            transformMatrix = fabric.util.calcDimensionsMatrix({
              scaleX: this.scaleX,
              scaleY: this.scaleY,
              skewX: this.skewX,
              skewY: this.skewY,
            }),
            bbox = fabric.util.makeBoundingBoxFromPoints(points, transformMatrix);
        return this._finalizeDimensions(bbox.width, bbox.height);
      },
  
      /*
       * Calculate object bounding box dimensions from its properties scale, skew.
       * @param Number width width of the bbox
       * @param Number height height of the bbox
       * @private
       * @return {Object} .x finalized width dimension
       * @return {Object} .y finalized height dimension
       */
      _finalizeDimensions: function(width, height) {
        return this.strokeUniform ?
          { x: width + this.strokeWidth, y: height + this.strokeWidth }
          :
          { x: width, y: height };
      },
      /*
       * Calculate object dimensions for controls, including padding and canvas zoom.
       * private
       */
      _calculateCurrentDimensions: function()  {
        var vpt = this.getViewportTransform(),
            dim = this._getTransformedDimensions(),
            p = fabric.util.transformPoint(dim, vpt, true);
  
        return p.scalarAdd(2 * this.padding);
      },
    });
  })();
  
  
  fabric.util.object.extend(fabric.Object.prototype, /** @lends fabric.Object.prototype */ {
  
    /**
     * Moves an object to the bottom of the stack of drawn objects
     * @return {fabric.Object} thisArg
     * @chainable
     */
    sendToBack: function() {
      if (this.group) {
        fabric.StaticCanvas.prototype.sendToBack.call(this.group, this);
      }
      else {
        this.canvas.sendToBack(this);
      }
      return this;
    },
  
    /**
     * Moves an object to the top of the stack of drawn objects
     * @return {fabric.Object} thisArg
     * @chainable
     */
    bringToFront: function() {
      if (this.group) {
        fabric.StaticCanvas.prototype.bringToFront.call(this.group, this);
      }
      else {
        this.canvas.bringToFront(this);
      }
      return this;
    },
  
    /**
     * Moves an object down in stack of drawn objects
     * @param {Boolean} [intersecting] If `true`, send object behind next lower intersecting object
     * @return {fabric.Object} thisArg
     * @chainable
     */
    sendBackwards: function(intersecting) {
      if (this.group) {
        fabric.StaticCanvas.prototype.sendBackwards.call(this.group, this, intersecting);
      }
      else {
        this.canvas.sendBackwards(this, intersecting);
      }
      return this;
    },
  
    /**
     * Moves an object up in stack of drawn objects
     * @param {Boolean} [intersecting] If `true`, send object in front of next upper intersecting object
     * @return {fabric.Object} thisArg
     * @chainable
     */
    bringForward: function(intersecting) {
      if (this.group) {
        fabric.StaticCanvas.prototype.bringForward.call(this.group, this, intersecting);
      }
      else {
        this.canvas.bringForward(this, intersecting);
      }
      return this;
    },
  
    /**
     * Moves an object to specified level in stack of drawn objects
     * @param {Number} index New position of object
     * @return {fabric.Object} thisArg
     * @chainable
     */
    moveTo: function(index) {
      if (this.group && this.group.type !== 'activeSelection') {
        fabric.StaticCanvas.prototype.moveTo.call(this.group, this, index);
      }
      else {
        this.canvas.moveTo(this, index);
      }
      return this;
    }
  });
  
  
  /* _TO_SVG_START_ */
  (function() {
    function getSvgColorString(prop, value) {
      if (!value) {
        return prop + ': none; ';
      }
      else if (value.toLive) {
        return prop + ': url(#SVGID_' + value.id + '); ';
      }
      else {
        var color = new fabric.Color(value),
            str = prop + ': ' + color.toRgb() + '; ',
            opacity = color.getAlpha();
        if (opacity !== 1) {
          //change the color in rgb + opacity
          str += prop + '-opacity: ' + opacity.toString() + '; ';
        }
        return str;
      }
    }
  
    var toFixed = fabric.util.toFixed;
  
    fabric.util.object.extend(fabric.Object.prototype, /** @lends fabric.Object.prototype */ {
      /**
       * Returns styles-string for svg-export
       * @param {Boolean} skipShadow a boolean to skip shadow filter output
       * @return {String}
       */
      getSvgStyles: function(skipShadow) {
  
        var fillRule = this.fillRule ? this.fillRule : 'nonzero',
            strokeWidth = this.strokeWidth ? this.strokeWidth : '0',
            strokeDashArray = this.strokeDashArray ? this.strokeDashArray.join(' ') : 'none',
            strokeDashOffset = this.strokeDashOffset ? this.strokeDashOffset : '0',
            strokeLineCap = this.strokeLineCap ? this.strokeLineCap : 'butt',
            strokeLineJoin = this.strokeLineJoin ? this.strokeLineJoin : 'miter',
            strokeMiterLimit = this.strokeMiterLimit ? this.strokeMiterLimit : '4',
            opacity = typeof this.opacity !== 'undefined' ? this.opacity : '1',
            visibility = this.visible ? '' : ' visibility: hidden;',
            filter = skipShadow ? '' : this.getSvgFilter(),
            fill = getSvgColorString('fill', this.fill),
            stroke = getSvgColorString('stroke', this.stroke);
  
        return [
          stroke,
          'stroke-width: ', strokeWidth, '; ',
          'stroke-dasharray: ', strokeDashArray, '; ',
          'stroke-linecap: ', strokeLineCap, '; ',
          'stroke-dashoffset: ', strokeDashOffset, '; ',
          'stroke-linejoin: ', strokeLineJoin, '; ',
          'stroke-miterlimit: ', strokeMiterLimit, '; ',
          fill,
          'fill-rule: ', fillRule, '; ',
          'opacity: ', opacity, ';',
          filter,
          visibility
        ].join('');
      },
  
      /**
       * Returns styles-string for svg-export
       * @param {Object} style the object from which to retrieve style properties
       * @param {Boolean} useWhiteSpace a boolean to include an additional attribute in the style.
       * @return {String}
       */
      getSvgSpanStyles: function(style, useWhiteSpace) {
        var term = '; ';
        var fontFamily = style.fontFamily ?
          'font-family: ' + (((style.fontFamily.indexOf('\'') === -1 && style.fontFamily.indexOf('"') === -1) ?
            '\'' + style.fontFamily  + '\'' : style.fontFamily)) + term : '';
        var strokeWidth = style.strokeWidth ? 'stroke-width: ' + style.strokeWidth + term : '',
            fontFamily = fontFamily,
            fontSize = style.fontSize ? 'font-size: ' + style.fontSize + 'px' + term : '',
            fontStyle = style.fontStyle ? 'font-style: ' + style.fontStyle + term : '',
            fontWeight = style.fontWeight ? 'font-weight: ' + style.fontWeight + term : '',
            fill = style.fill ? getSvgColorString('fill', style.fill) : '',
            stroke = style.stroke ? getSvgColorString('stroke', style.stroke) : '',
            textDecoration = this.getSvgTextDecoration(style),
            deltaY = style.deltaY ? 'baseline-shift: ' + (-style.deltaY) + '; ' : '';
        if (textDecoration) {
          textDecoration = 'text-decoration: ' + textDecoration + term;
        }
  
        return [
          stroke,
          strokeWidth,
          fontFamily,
          fontSize,
          fontStyle,
          fontWeight,
          textDecoration,
          fill,
          deltaY,
          useWhiteSpace ? 'white-space: pre; ' : ''
        ].join('');
      },
  
      /**
       * Returns text-decoration property for svg-export
       * @param {Object} style the object from which to retrieve style properties
       * @return {String}
       */
      getSvgTextDecoration: function(style) {
        if ('overline' in style || 'underline' in style || 'linethrough' in style) {
          return (style.overline ? 'overline ' : '') +
            (style.underline ? 'underline ' : '') + (style.linethrough ? 'line-through ' : '');
        }
        return '';
      },
  
      /**
       * Returns filter for svg shadow
       * @return {String}
       */
      getSvgFilter: function() {
        return this.shadow ? 'filter: url(#SVGID_' + this.shadow.id + ');' : '';
      },
  
      /**
       * Returns id attribute for svg output
       * @return {String}
       */
      getSvgCommons: function() {
        return [
          this.id ? 'id="' + this.id + '" ' : '',
          this.clipPath ? 'clip-path="url(#' + this.clipPath.clipPathId + ')" ' : '',
        ].join('');
      },
  
      /**
       * Returns transform-string for svg-export
       * @param {Boolean} use the full transform or the single object one.
       * @return {String}
       */
      getSvgTransform: function(full, additionalTransform) {
        var transform = full ? this.calcTransformMatrix() : this.calcOwnMatrix(),
            svgTransform = 'transform="' + fabric.util.matrixToSVG(transform);
        return svgTransform +
          (additionalTransform || '') + this.getSvgTransformMatrix() + '" ';
      },
  
      /**
       * Returns transform-string for svg-export from the transform matrix of single elements
       * @return {String}
       */
      getSvgTransformMatrix: function() {
        return this.transformMatrix ? ' ' + fabric.util.matrixToSVG(this.transformMatrix) : '';
      },
  
      _setSVGBg: function(textBgRects) {
        if (this.backgroundColor) {
          var NUM_FRACTION_DIGITS = fabric.Object.NUM_FRACTION_DIGITS;
          textBgRects.push(
            '\t\t<rect ',
            this._getFillAttributes(this.backgroundColor),
            ' x="',
            toFixed(-this.width / 2, NUM_FRACTION_DIGITS),
            '" y="',
            toFixed(-this.height / 2, NUM_FRACTION_DIGITS),
            '" width="',
            toFixed(this.width, NUM_FRACTION_DIGITS),
            '" height="',
            toFixed(this.height, NUM_FRACTION_DIGITS),
            '"></rect>\n');
        }
      },
  
      /**
       * Returns svg representation of an instance
       * @param {Function} [reviver] Method for further parsing of svg representation.
       * @return {String} svg representation of an instance
       */
      toSVG: function(reviver) {
        return this._createBaseSVGMarkup(this._toSVG(reviver), { reviver: reviver });
      },
  
      /**
       * Returns svg clipPath representation of an instance
       * @param {Function} [reviver] Method for further parsing of svg representation.
       * @return {String} svg representation of an instance
       */
      toClipPathSVG: function(reviver) {
        return '\t' + this._createBaseClipPathSVGMarkup(this._toSVG(reviver), { reviver: reviver });
      },
  
      /**
       * @private
       */
      _createBaseClipPathSVGMarkup: function(objectMarkup, options) {
        options = options || {};
        var reviver = options.reviver,
            additionalTransform = options.additionalTransform || '',
            commonPieces = [
              this.getSvgTransform(true, additionalTransform),
              this.getSvgCommons(),
            ].join(''),
            // insert commons in the markup, style and svgCommons
            index = objectMarkup.indexOf('COMMON_PARTS');
        objectMarkup[index] = commonPieces;
        return reviver ? reviver(objectMarkup.join('')) : objectMarkup.join('');
      },
  
      /**
       * @private
       */
      _createBaseSVGMarkup: function(objectMarkup, options) {
        options = options || {};
        var noStyle = options.noStyle,
            reviver = options.reviver,
            styleInfo = noStyle ? '' : 'style="' + this.getSvgStyles() + '" ',
            shadowInfo = options.withShadow ? 'style="' + this.getSvgFilter() + '" ' : '',
            clipPath = this.clipPath,
            vectorEffect = this.strokeUniform ? 'vector-effect="non-scaling-stroke" ' : '',
            absoluteClipPath = clipPath && clipPath.absolutePositioned,
            stroke = this.stroke, fill = this.fill, shadow = this.shadow,
            commonPieces, markup = [], clipPathMarkup,
            // insert commons in the markup, style and svgCommons
            index = objectMarkup.indexOf('COMMON_PARTS'),
            additionalTransform = options.additionalTransform;
        if (clipPath) {
          clipPath.clipPathId = 'CLIPPATH_' + fabric.Object.__uid++;
          clipPathMarkup = '<clipPath id="' + clipPath.clipPathId + '" >\n' +
            clipPath.toClipPathSVG(reviver) +
            '</clipPath>\n';
        }
        if (absoluteClipPath) {
          markup.push(
            '<g ', shadowInfo, this.getSvgCommons(), ' >\n'
          );
        }
        markup.push(
          '<g ',
          this.getSvgTransform(false),
          !absoluteClipPath ? shadowInfo + this.getSvgCommons() : '',
          ' >\n'
        );
        commonPieces = [
          styleInfo,
          vectorEffect,
          noStyle ? '' : this.addPaintOrder(), ' ',
          additionalTransform ? 'transform="' + additionalTransform + '" ' : '',
        ].join('');
        objectMarkup[index] = commonPieces;
        if (fill && fill.toLive) {
          markup.push(fill.toSVG(this));
        }
        if (stroke && stroke.toLive) {
          markup.push(stroke.toSVG(this));
        }
        if (shadow) {
          markup.push(shadow.toSVG(this));
        }
        if (clipPath) {
          markup.push(clipPathMarkup);
        }
        markup.push(objectMarkup.join(''));
        markup.push('</g>\n');
        absoluteClipPath && markup.push('</g>\n');
        return reviver ? reviver(markup.join('')) : markup.join('');
      },
  
      addPaintOrder: function() {
        return this.paintFirst !== 'fill' ? ' paint-order="' + this.paintFirst + '" ' : '';
      }
    });
  })();
  /* _TO_SVG_END_ */
  
  
  (function() {
  
    var extend = fabric.util.object.extend,
        originalSet = 'stateProperties';
  
    /*
      Depends on `stateProperties`
    */
    function saveProps(origin, destination, props) {
      var tmpObj = { }, deep = true;
      props.forEach(function(prop) {
        tmpObj[prop] = origin[prop];
      });
      extend(origin[destination], tmpObj, deep);
    }
  
    function _isEqual(origValue, currentValue, firstPass) {
      if (origValue === currentValue) {
        // if the objects are identical, return
        return true;
      }
      else if (Array.isArray(origValue)) {
        if (!Array.isArray(currentValue) || origValue.length !== currentValue.length) {
          return false;
        }
        for (var i = 0, len = origValue.length; i < len; i++) {
          if (!_isEqual(origValue[i], currentValue[i])) {
            return false;
          }
        }
        return true;
      }
      else if (origValue && typeof origValue === 'object') {
        var keys = Object.keys(origValue), key;
        if (!currentValue ||
            typeof currentValue !== 'object' ||
            (!firstPass && keys.length !== Object.keys(currentValue).length)
        ) {
          return false;
        }
        for (var i = 0, len = keys.length; i < len; i++) {
          key = keys[i];
          // since clipPath is in the statefull cache list and the clipPath objects
          // would be iterated as an object, this would lead to possible infinite recursion
          if (key === 'canvas') {
            continue;
          }
          if (!_isEqual(origValue[key], currentValue[key])) {
            return false;
          }
        }
        return true;
      }
    }
  
  
    fabric.util.object.extend(fabric.Object.prototype, /** @lends fabric.Object.prototype */ {
  
      /**
       * Returns true if object state (one of its state properties) was changed
       * @param {String} [propertySet] optional name for the set of property we want to save
       * @return {Boolean} true if instance' state has changed since `{@link fabric.Object#saveState}` was called
       */
      hasStateChanged: function(propertySet) {
        propertySet = propertySet || originalSet;
        var dashedPropertySet = '_' + propertySet;
        if (Object.keys(this[dashedPropertySet]).length < this[propertySet].length) {
          return true;
        }
        return !_isEqual(this[dashedPropertySet], this, true);
      },
  
      /**
       * Saves state of an object
       * @param {Object} [options] Object with additional `stateProperties` array to include when saving state
       * @return {fabric.Object} thisArg
       */
      saveState: function(options) {
        var propertySet = options && options.propertySet || originalSet,
            destination = '_' + propertySet;
        if (!this[destination]) {
          return this.setupState(options);
        }
        saveProps(this, destination, this[propertySet]);
        if (options && options.stateProperties) {
          saveProps(this, destination, options.stateProperties);
        }
        return this;
      },
  
      /**
       * Setups state of an object
       * @param {Object} [options] Object with additional `stateProperties` array to include when saving state
       * @return {fabric.Object} thisArg
       */
      setupState: function(options) {
        options = options || { };
        var propertySet = options.propertySet || originalSet;
        options.propertySet = propertySet;
        this['_' + propertySet] = { };
        this.saveState(options);
        return this;
      }
    });
  })();
  
  
  (function() {
  
    var degreesToRadians = fabric.util.degreesToRadians;
  
    fabric.util.object.extend(fabric.Object.prototype, /** @lends fabric.Object.prototype */ {
  
      /**
       * The object interactivity controls.
       * @private
       */
      _controlsVisibility: null,
  
      /**
       * Determines which corner has been clicked
       * @private
       * @param {Object} pointer The pointer indicating the mouse position
       * @return {String|Boolean} corner code (tl, tr, bl, br, etc.), or false if nothing is found
       */
      _findTargetCorner: function(pointer) {
        // objects in group, anykind, are not self modificable,
        // must not return an hovered corner.
        if (!this.hasControls || this.group || (!this.canvas || this.canvas._activeObject !== this)) {
          return false;
        }
  
        var ex = pointer.x,
            ey = pointer.y,
            xPoints,
            lines;
        this.__corner = 0;
        for (var i in this.oCoords) {
  
          if (!this.isControlVisible(i)) {
            continue;
          }
  
          if (i === 'mtr' && !this.hasRotatingPoint) {
            continue;
          }
  
          if (this.get('lockUniScaling') &&
             (i === 'mt' || i === 'mr' || i === 'mb' || i === 'ml')) {
            continue;
          }
  
          lines = this._getImageLines(this.oCoords[i].corner);
  
          // debugging
  
          // canvas.contextTop.fillRect(lines.bottomline.d.x, lines.bottomline.d.y, 2, 2);
          // canvas.contextTop.fillRect(lines.bottomline.o.x, lines.bottomline.o.y, 2, 2);
  
          // canvas.contextTop.fillRect(lines.leftline.d.x, lines.leftline.d.y, 2, 2);
          // canvas.contextTop.fillRect(lines.leftline.o.x, lines.leftline.o.y, 2, 2);
  
          // canvas.contextTop.fillRect(lines.topline.d.x, lines.topline.d.y, 2, 2);
          // canvas.contextTop.fillRect(lines.topline.o.x, lines.topline.o.y, 2, 2);
  
          // canvas.contextTop.fillRect(lines.rightline.d.x, lines.rightline.d.y, 2, 2);
          // canvas.contextTop.fillRect(lines.rightline.o.x, lines.rightline.o.y, 2, 2);
  
          xPoints = this._findCrossPoints({ x: ex, y: ey }, lines);
          if (xPoints !== 0 && xPoints % 2 === 1) {
            this.__corner = i;
            return i;
          }
        }
        return false;
      },
  
      /**
       * Sets the coordinates of the draggable boxes in the corners of
       * the image used to scale/rotate it.
       * @private
       */
      _setCornerCoords: function() {
        var coords = this.oCoords,
            newTheta = degreesToRadians(45 - this.angle),
            /* Math.sqrt(2 * Math.pow(this.cornerSize, 2)) / 2, */
            /* 0.707106 stands for sqrt(2)/2 */
            cornerHypotenuse = this.cornerSize * 0.707106,
            cosHalfOffset = cornerHypotenuse * fabric.util.cos(newTheta),
            sinHalfOffset = cornerHypotenuse * fabric.util.sin(newTheta),
            x, y;
  
        for (var point in coords) {
          x = coords[point].x;
          y = coords[point].y;
          coords[point].corner = {
            tl: {
              x: x - sinHalfOffset,
              y: y - cosHalfOffset
            },
            tr: {
              x: x + cosHalfOffset,
              y: y - sinHalfOffset
            },
            bl: {
              x: x - cosHalfOffset,
              y: y + sinHalfOffset
            },
            br: {
              x: x + sinHalfOffset,
              y: y + cosHalfOffset
            }
          };
        }
      },
  
      /**
       * Draws a colored layer behind the object, inside its selection borders.
       * Requires public options: padding, selectionBackgroundColor
       * this function is called when the context is transformed
       * has checks to be skipped when the object is on a staticCanvas
       * @param {CanvasRenderingContext2D} ctx Context to draw on
       * @return {fabric.Object} thisArg
       * @chainable
       */
      drawSelectionBackground: function(ctx) {
        if (!this.selectionBackgroundColor ||
          (this.canvas && !this.canvas.interactive) ||
          (this.canvas && this.canvas._activeObject !== this)
        ) {
          return this;
        }
        ctx.save();
        var center = this.getCenterPoint(), wh = this._calculateCurrentDimensions(),
            vpt = this.canvas.viewportTransform;
        ctx.translate(center.x, center.y);
        ctx.scale(1 / vpt[0], 1 / vpt[3]);
        ctx.rotate(degreesToRadians(this.angle));
        ctx.fillStyle = this.selectionBackgroundColor;
        ctx.fillRect(-wh.x / 2, -wh.y / 2, wh.x, wh.y);
        ctx.restore();
        return this;
      },
  
      /**
       * Draws borders of an object's bounding box.
       * Requires public properties: width, height
       * Requires public options: padding, borderColor
       * @param {CanvasRenderingContext2D} ctx Context to draw on
       * @param {Object} styleOverride object to override the object style
       * @return {fabric.Object} thisArg
       * @chainable
       */
      drawBorders: function(ctx, styleOverride) {
        styleOverride = styleOverride || {};
        var wh = this._calculateCurrentDimensions(),
            strokeWidth = 1 / this.borderScaleFactor,
            width = wh.x + strokeWidth,
            height = wh.y + strokeWidth,
            drawRotatingPoint = typeof styleOverride.hasRotatingPoint !== 'undefined' ?
              styleOverride.hasRotatingPoint : this.hasRotatingPoint,
            hasControls = typeof styleOverride.hasControls !== 'undefined' ?
              styleOverride.hasControls : this.hasControls,
            rotatingPointOffset = typeof styleOverride.rotatingPointOffset !== 'undefined' ?
              styleOverride.rotatingPointOffset : this.rotatingPointOffset;
  
        ctx.save();
        ctx.strokeStyle = styleOverride.borderColor || this.borderColor;
        this._setLineDash(ctx, styleOverride.borderDashArray || this.borderDashArray, null);
  
        ctx.strokeRect(
          -width / 2,
          -height / 2,
          width,
          height
        );
  
        if (drawRotatingPoint && this.isControlVisible('mtr') && hasControls) {
  
          var rotateHeight = -height / 2;
  
          ctx.beginPath();
          ctx.moveTo(0, rotateHeight);
          ctx.lineTo(0, rotateHeight - rotatingPointOffset);
          ctx.stroke();
        }
  
        ctx.restore();
        return this;
      },
  
      /**
       * Draws borders of an object's bounding box when it is inside a group.
       * Requires public properties: width, height
       * Requires public options: padding, borderColor
       * @param {CanvasRenderingContext2D} ctx Context to draw on
       * @param {object} options object representing current object parameters
       * @param {Object} styleOverride object to override the object style
       * @return {fabric.Object} thisArg
       * @chainable
       */
      drawBordersInGroup: function(ctx, options, styleOverride) {
        styleOverride = styleOverride || {};
        var p = this._getNonTransformedDimensions(),
            matrix = fabric.util.composeMatrix({
              scaleX: options.scaleX,
              scaleY: options.scaleY,
              skewX: options.skewX
            }),
            wh = fabric.util.transformPoint(p, matrix),
            strokeWidth = 1 / this.borderScaleFactor,
            width = wh.x + strokeWidth,
            height = wh.y + strokeWidth;
  
        ctx.save();
        this._setLineDash(ctx, styleOverride.borderDashArray || this.borderDashArray, null);
        ctx.strokeStyle = styleOverride.borderColor || this.borderColor;
  
        ctx.strokeRect(
          -width / 2,
          -height / 2,
          width,
          height
        );
  
        ctx.restore();
        return this;
      },
  
      /**
       * Draws corners of an object's bounding box.
       * Requires public properties: width, height
       * Requires public options: cornerSize, padding
       * @param {CanvasRenderingContext2D} ctx Context to draw on
       * @param {Object} styleOverride object to override the object style
       * @return {fabric.Object} thisArg
       * @chainable
       */
      drawControls: function(ctx, styleOverride) {
        styleOverride = styleOverride || {};
        var wh = this._calculateCurrentDimensions(),
            width = wh.x,
            height = wh.y,
            scaleOffset = styleOverride.cornerSize || this.cornerSize,
            left = -(width + scaleOffset) / 2,
            top = -(height + scaleOffset) / 2,
            transparentCorners = typeof styleOverride.transparentCorners !== 'undefined' ?
              styleOverride.transparentCorners : this.transparentCorners,
            hasRotatingPoint = typeof styleOverride.hasRotatingPoint !== 'undefined' ?
              styleOverride.hasRotatingPoint : this.hasRotatingPoint,
            methodName = transparentCorners ? 'stroke' : 'fill';
  
        ctx.save();
        ctx.strokeStyle = ctx.fillStyle = styleOverride.cornerColor || this.cornerColor;
        if (!this.transparentCorners) {
          ctx.strokeStyle = styleOverride.cornerStrokeColor || this.cornerStrokeColor;
        }
        this._setLineDash(ctx, styleOverride.cornerDashArray || this.cornerDashArray, null);
  
        // top-left
        this._drawControl('tl', ctx, methodName,
          left,
          top, styleOverride);
  
        // top-right
        this._drawControl('tr', ctx, methodName,
          left + width,
          top, styleOverride);
  
        // bottom-left
        this._drawControl('bl', ctx, methodName,
          left,
          top + height, styleOverride);
  
        // bottom-right
        this._drawControl('br', ctx, methodName,
          left + width,
          top + height, styleOverride);
  
        if (!this.get('lockUniScaling')) {
  
          // middle-top
          this._drawControl('mt', ctx, methodName,
            left + width / 2,
            top, styleOverride);
  
          // middle-bottom
          this._drawControl('mb', ctx, methodName,
            left + width / 2,
            top + height, styleOverride);
  
          // middle-right
          this._drawControl('mr', ctx, methodName,
            left + width,
            top + height / 2, styleOverride);
  
          // middle-left
          this._drawControl('ml', ctx, methodName,
            left,
            top + height / 2, styleOverride);
        }
  
        // middle-top-rotate
        if (hasRotatingPoint) {
          this._drawControl('mtr', ctx, methodName,
            left + width / 2,
            top - this.rotatingPointOffset, styleOverride);
        }
  
        ctx.restore();
  
        return this;
      },
  
      /**
       * @private
       */
      _drawControl: function(control, ctx, methodName, left, top, styleOverride) {
        styleOverride = styleOverride || {};
        if (!this.isControlVisible(control)) {
          return;
        }
        var size = this.cornerSize, stroke = !this.transparentCorners && this.cornerStrokeColor;
        switch (styleOverride.cornerStyle || this.cornerStyle) {
          case 'circle':
            ctx.beginPath();
            ctx.arc(left + size / 2, top + size / 2, size / 2, 0, 2 * Math.PI, false);
            ctx[methodName]();
            if (stroke) {
              ctx.stroke();
            }
            break;
          default:
            this.transparentCorners || ctx.clearRect(left, top, size, size);
            ctx[methodName + 'Rect'](left, top, size, size);
            if (stroke) {
              ctx.strokeRect(left, top, size, size);
            }
        }
      },
  
      /**
       * Returns true if the specified control is visible, false otherwise.
       * @param {String} controlName The name of the control. Possible values are 'tl', 'tr', 'br', 'bl', 'ml', 'mt', 'mr', 'mb', 'mtr'.
       * @returns {Boolean} true if the specified control is visible, false otherwise
       */
      isControlVisible: function(controlName) {
        return this._getControlsVisibility()[controlName];
      },
  
      /**
       * Sets the visibility of the specified control.
       * @param {String} controlName The name of the control. Possible values are 'tl', 'tr', 'br', 'bl', 'ml', 'mt', 'mr', 'mb', 'mtr'.
       * @param {Boolean} visible true to set the specified control visible, false otherwise
       * @return {fabric.Object} thisArg
       * @chainable
       */
      setControlVisible: function(controlName, visible) {
        this._getControlsVisibility()[controlName] = visible;
        return this;
      },
  
      /**
       * Sets the visibility state of object controls.
       * @param {Object} [options] Options object
       * @param {Boolean} [options.bl] true to enable the bottom-left control, false to disable it
       * @param {Boolean} [options.br] true to enable the bottom-right control, false to disable it
       * @param {Boolean} [options.mb] true to enable the middle-bottom control, false to disable it
       * @param {Boolean} [options.ml] true to enable the middle-left control, false to disable it
       * @param {Boolean} [options.mr] true to enable the middle-right control, false to disable it
       * @param {Boolean} [options.mt] true to enable the middle-top control, false to disable it
       * @param {Boolean} [options.tl] true to enable the top-left control, false to disable it
       * @param {Boolean} [options.tr] true to enable the top-right control, false to disable it
       * @param {Boolean} [options.mtr] true to enable the middle-top-rotate control, false to disable it
       * @return {fabric.Object} thisArg
       * @chainable
       */
      setControlsVisibility: function(options) {
        options || (options = { });
  
        for (var p in options) {
          this.setControlVisible(p, options[p]);
        }
        return this;
      },
  
      /**
       * Returns the instance of the control visibility set for this object.
       * @private
       * @returns {Object}
       */
      _getControlsVisibility: function() {
        if (!this._controlsVisibility) {
          this._controlsVisibility = {
            tl: true,
            tr: true,
            br: true,
            bl: true,
            ml: true,
            mt: true,
            mr: true,
            mb: true,
            mtr: true
          };
        }
        return this._controlsVisibility;
      },
  
      /**
       * This callback function is called every time _discardActiveObject or _setActiveObject
       * try to to deselect this object. If the function returns true, the process is cancelled
       * @param {Object} [options] options sent from the upper functions
       * @param {Event} [options.e] event if the process is generated by an event
       */
      onDeselect: function() {
        // implemented by sub-classes, as needed.
      },
  
  
      /**
       * This callback function is called every time _discardActiveObject or _setActiveObject
       * try to to select this object. If the function returns true, the process is cancelled
       * @param {Object} [options] options sent from the upper functions
       * @param {Event} [options.e] event if the process is generated by an event
       */
      onSelect: function() {
        // implemented by sub-classes, as needed.
      }
    });
  })();
  
  
  fabric.util.object.extend(fabric.StaticCanvas.prototype, /** @lends fabric.StaticCanvas.prototype */ {
  
    /**
     * Animation duration (in ms) for fx* methods
     * @type Number
     * @default
     */
    FX_DURATION: 500,
  
    /**
     * Centers object horizontally with animation.
     * @param {fabric.Object} object Object to center
     * @param {Object} [callbacks] Callbacks object with optional "onComplete" and/or "onChange" properties
     * @param {Function} [callbacks.onComplete] Invoked on completion
     * @param {Function} [callbacks.onChange] Invoked on every step of animation
     * @return {fabric.Canvas} thisArg
     * @chainable
     */
    fxCenterObjectH: function (object, callbacks) {
      callbacks = callbacks || { };
  
      var empty = function() { },
          onComplete = callbacks.onComplete || empty,
          onChange = callbacks.onChange || empty,
          _this = this;
  
      fabric.util.animate({
        startValue: object.left,
        endValue: this.getCenter().left,
        duration: this.FX_DURATION,
        onChange: function(value) {
          object.set('left', value);
          _this.requestRenderAll();
          onChange();
        },
        onComplete: function() {
          object.setCoords();
          onComplete();
        }
      });
  
      return this;
    },
  
    /**
     * Centers object vertically with animation.
     * @param {fabric.Object} object Object to center
     * @param {Object} [callbacks] Callbacks object with optional "onComplete" and/or "onChange" properties
     * @param {Function} [callbacks.onComplete] Invoked on completion
     * @param {Function} [callbacks.onChange] Invoked on every step of animation
     * @return {fabric.Canvas} thisArg
     * @chainable
     */
    fxCenterObjectV: function (object, callbacks) {
      callbacks = callbacks || { };
  
      var empty = function() { },
          onComplete = callbacks.onComplete || empty,
          onChange = callbacks.onChange || empty,
          _this = this;
  
      fabric.util.animate({
        startValue: object.top,
        endValue: this.getCenter().top,
        duration: this.FX_DURATION,
        onChange: function(value) {
          object.set('top', value);
          _this.requestRenderAll();
          onChange();
        },
        onComplete: function() {
          object.setCoords();
          onComplete();
        }
      });
  
      return this;
    },
  
    /**
     * Same as `fabric.Canvas#remove` but animated
     * @param {fabric.Object} object Object to remove
     * @param {Object} [callbacks] Callbacks object with optional "onComplete" and/or "onChange" properties
     * @param {Function} [callbacks.onComplete] Invoked on completion
     * @param {Function} [callbacks.onChange] Invoked on every step of animation
     * @return {fabric.Canvas} thisArg
     * @chainable
     */
    fxRemove: function (object, callbacks) {
      callbacks = callbacks || { };
  
      var empty = function() { },
          onComplete = callbacks.onComplete || empty,
          onChange = callbacks.onChange || empty,
          _this = this;
  
      fabric.util.animate({
        startValue: object.opacity,
        endValue: 0,
        duration: this.FX_DURATION,
        onChange: function(value) {
          object.set('opacity', value);
          _this.requestRenderAll();
          onChange();
        },
        onComplete: function () {
          _this.remove(object);
          onComplete();
        }
      });
  
      return this;
    }
  });
  
  fabric.util.object.extend(fabric.Object.prototype, /** @lends fabric.Object.prototype */ {
    /**
     * Animates object's properties
     * @param {String|Object} property Property to animate (if string) or properties to animate (if object)
     * @param {Number|Object} value Value to animate property to (if string was given first) or options object
     * @return {fabric.Object} thisArg
     * @tutorial {@link http://fabricjs.com/fabric-intro-part-2#animation}
     * @chainable
     *
     * As object — multiple properties
     *
     * object.animate({ left: ..., top: ... });
     * object.animate({ left: ..., top: ... }, { duration: ... });
     *
     * As string — one property
     *
     * object.animate('left', ...);
     * object.animate('left', { duration: ... });
     *
     */
    animate: function() {
      if (arguments[0] && typeof arguments[0] === 'object') {
        var propsToAnimate = [], prop, skipCallbacks;
        for (prop in arguments[0]) {
          propsToAnimate.push(prop);
        }
        for (var i = 0, len = propsToAnimate.length; i < len; i++) {
          prop = propsToAnimate[i];
          skipCallbacks = i !== len - 1;
          this._animate(prop, arguments[0][prop], arguments[1], skipCallbacks);
        }
      }
      else {
        this._animate.apply(this, arguments);
      }
      return this;
    },
  
    /**
     * @private
     * @param {String} property Property to animate
     * @param {String} to Value to animate to
     * @param {Object} [options] Options object
     * @param {Boolean} [skipCallbacks] When true, callbacks like onchange and oncomplete are not invoked
     */
    _animate: function(property, to, options, skipCallbacks) {
      var _this = this, propPair;
  
      to = to.toString();
  
      if (!options) {
        options = { };
      }
      else {
        options = fabric.util.object.clone(options);
      }
  
      if (~property.indexOf('.')) {
        propPair = property.split('.');
      }
  
      var currentValue = propPair
        ? this.get(propPair[0])[propPair[1]]
        : this.get(property);
  
      if (!('from' in options)) {
        options.from = currentValue;
      }
  
      if (~to.indexOf('=')) {
        to = currentValue + parseFloat(to.replace('=', ''));
      }
      else {
        to = parseFloat(to);
      }
  
      fabric.util.animate({
        startValue: options.from,
        endValue: to,
        byValue: options.by,
        easing: options.easing,
        duration: options.duration,
        abort: options.abort && function() {
          return options.abort.call(_this);
        },
        onChange: function(value, valueProgress, timeProgress) {
          if (propPair) {
            _this[propPair[0]][propPair[1]] = value;
          }
          else {
            _this.set(property, value);
          }
          if (skipCallbacks) {
            return;
          }
          options.onChange && options.onChange(value, valueProgress, timeProgress);
        },
        onComplete: function(value, valueProgress, timeProgress) {
          if (skipCallbacks) {
            return;
          }
  
          _this.setCoords();
          options.onComplete && options.onComplete(value, valueProgress, timeProgress);
        }
      });
    }
  });
  
  
  (function(global) {
  
    'use strict';
  
    var fabric = global.fabric || (global.fabric = { }),
        extend = fabric.util.object.extend,
        clone = fabric.util.object.clone,
        coordProps = { x1: 1, x2: 1, y1: 1, y2: 1 },
        supportsLineDash = fabric.StaticCanvas.supports('setLineDash');
  
    if (fabric.Line) {
      fabric.warn('fabric.Line is already defined');
      return;
    }
  
    /**
     * Line class
     * @class fabric.Line
     * @extends fabric.Object
     * @see {@link fabric.Line#initialize} for constructor definition
     */
    fabric.Line = fabric.util.createClass(fabric.Object, /** @lends fabric.Line.prototype */ {
  
      /**
       * Type of an object
       * @type String
       * @default
       */
      type: 'line',
  
      /**
       * x value or first line edge
       * @type Number
       * @default
       */
      x1: 0,
  
      /**
       * y value or first line edge
       * @type Number
       * @default
       */
      y1: 0,
  
      /**
       * x value or second line edge
       * @type Number
       * @default
       */
      x2: 0,
  
      /**
       * y value or second line edge
       * @type Number
       * @default
       */
      y2: 0,
  
      cacheProperties: fabric.Object.prototype.cacheProperties.concat('x1', 'x2', 'y1', 'y2'),
  
      /**
       * Constructor
       * @param {Array} [points] Array of points
       * @param {Object} [options] Options object
       * @return {fabric.Line} thisArg
       */
      initialize: function(points, options) {
        if (!points) {
          points = [0, 0, 0, 0];
        }
  
        this.callSuper('initialize', options);
  
        this.set('x1', points[0]);
        this.set('y1', points[1]);
        this.set('x2', points[2]);
        this.set('y2', points[3]);
  
        this._setWidthHeight(options);
      },
  
      /**
       * @private
       * @param {Object} [options] Options
       */
      _setWidthHeight: function(options) {
        options || (options = { });
  
        this.width = Math.abs(this.x2 - this.x1);
        this.height = Math.abs(this.y2 - this.y1);
  
        this.left = 'left' in options
          ? options.left
          : this._getLeftToOriginX();
  
        this.top = 'top' in options
          ? options.top
          : this._getTopToOriginY();
      },
  
      /**
       * @private
       * @param {String} key
       * @param {*} value
       */
      _set: function(key, value) {
        this.callSuper('_set', key, value);
        if (typeof coordProps[key] !== 'undefined') {
          this._setWidthHeight();
        }
        return this;
      },
  
      /**
       * @private
       * @return {Number} leftToOriginX Distance from left edge of canvas to originX of Line.
       */
      _getLeftToOriginX: makeEdgeToOriginGetter(
        { // property names
          origin: 'originX',
          axis1: 'x1',
          axis2: 'x2',
          dimension: 'width'
        },
        { // possible values of origin
          nearest: 'left',
          center: 'center',
          farthest: 'right'
        }
      ),
  
      /**
       * @private
       * @return {Number} topToOriginY Distance from top edge of canvas to originY of Line.
       */
      _getTopToOriginY: makeEdgeToOriginGetter(
        { // property names
          origin: 'originY',
          axis1: 'y1',
          axis2: 'y2',
          dimension: 'height'
        },
        { // possible values of origin
          nearest: 'top',
          center: 'center',
          farthest: 'bottom'
        }
      ),
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _render: function(ctx) {
        ctx.beginPath();
  
        if (!this.strokeDashArray || this.strokeDashArray && supportsLineDash) {
          // move from center (of virtual box) to its left/top corner
          // we can't assume x1, y1 is top left and x2, y2 is bottom right
          var p = this.calcLinePoints();
          ctx.moveTo(p.x1, p.y1);
          ctx.lineTo(p.x2, p.y2);
        }
  
        ctx.lineWidth = this.strokeWidth;
  
        // TODO: test this
        // make sure setting "fill" changes color of a line
        // (by copying fillStyle to strokeStyle, since line is stroked, not filled)
        var origStrokeStyle = ctx.strokeStyle;
        ctx.strokeStyle = this.stroke || ctx.fillStyle;
        this.stroke && this._renderStroke(ctx);
        ctx.strokeStyle = origStrokeStyle;
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _renderDashedStroke: function(ctx) {
        var p = this.calcLinePoints();
  
        ctx.beginPath();
        fabric.util.drawDashedLine(ctx, p.x1, p.y1, p.x2, p.y2, this.strokeDashArray);
        ctx.closePath();
      },
  
      /**
       * This function is an helper for svg import. it returns the center of the object in the svg
       * untransformed coordinates
       * @private
       * @return {Object} center point from element coordinates
       */
      _findCenterFromElement: function() {
        return {
          x: (this.x1 + this.x2) / 2,
          y: (this.y1 + this.y2) / 2,
        };
      },
  
      /**
       * Returns object representation of an instance
       * @methd toObject
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object} object representation of an instance
       */
      toObject: function(propertiesToInclude) {
        return extend(this.callSuper('toObject', propertiesToInclude), this.calcLinePoints());
      },
  
      /*
       * Calculate object dimensions from its properties
       * @private
       */
      _getNonTransformedDimensions: function() {
        var dim = this.callSuper('_getNonTransformedDimensions');
        if (this.strokeLineCap === 'butt') {
          if (this.width === 0) {
            dim.y -= this.strokeWidth;
          }
          if (this.height === 0) {
            dim.x -= this.strokeWidth;
          }
        }
        return dim;
      },
  
      /**
       * Recalculates line points given width and height
       * @private
       */
      calcLinePoints: function() {
        var xMult = this.x1 <= this.x2 ? -1 : 1,
            yMult = this.y1 <= this.y2 ? -1 : 1,
            x1 = (xMult * this.width * 0.5),
            y1 = (yMult * this.height * 0.5),
            x2 = (xMult * this.width * -0.5),
            y2 = (yMult * this.height * -0.5);
  
        return {
          x1: x1,
          x2: x2,
          y1: y1,
          y2: y2
        };
      },
  
      /* _TO_SVG_START_ */
      /**
       * Returns svg representation of an instance
       * @return {Array} an array of strings with the specific svg representation
       * of the instance
       */
      _toSVG: function() {
        var p = this.calcLinePoints();
        return [
          '<line ', 'COMMON_PARTS',
          'x1="', p.x1,
          '" y1="', p.y1,
          '" x2="', p.x2,
          '" y2="', p.y2,
          '" />\n'
        ];
      },
      /* _TO_SVG_END_ */
    });
  
    /* _FROM_SVG_START_ */
    /**
     * List of attribute names to account for when parsing SVG element (used by {@link fabric.Line.fromElement})
     * @static
     * @memberOf fabric.Line
     * @see http://www.w3.org/TR/SVG/shapes.html#LineElement
     */
    fabric.Line.ATTRIBUTE_NAMES = fabric.SHARED_ATTRIBUTES.concat('x1 y1 x2 y2'.split(' '));
  
    /**
     * Returns fabric.Line instance from an SVG element
     * @static
     * @memberOf fabric.Line
     * @param {SVGElement} element Element to parse
     * @param {Object} [options] Options object
     * @param {Function} [callback] callback function invoked after parsing
     */
    fabric.Line.fromElement = function(element, callback, options) {
      options = options || { };
      var parsedAttributes = fabric.parseAttributes(element, fabric.Line.ATTRIBUTE_NAMES),
          points = [
            parsedAttributes.x1 || 0,
            parsedAttributes.y1 || 0,
            parsedAttributes.x2 || 0,
            parsedAttributes.y2 || 0
          ];
      callback(new fabric.Line(points, extend(parsedAttributes, options)));
    };
    /* _FROM_SVG_END_ */
  
    /**
     * Returns fabric.Line instance from an object representation
     * @static
     * @memberOf fabric.Line
     * @param {Object} object Object to create an instance from
     * @param {function} [callback] invoked with new instance as first argument
     */
    fabric.Line.fromObject = function(object, callback) {
      function _callback(instance) {
        delete instance.points;
        callback && callback(instance);
      };
      var options = clone(object, true);
      options.points = [object.x1, object.y1, object.x2, object.y2];
      fabric.Object._fromObject('Line', options, _callback, 'points');
    };
  
    /**
     * Produces a function that calculates distance from canvas edge to Line origin.
     */
    function makeEdgeToOriginGetter(propertyNames, originValues) {
      var origin = propertyNames.origin,
          axis1 = propertyNames.axis1,
          axis2 = propertyNames.axis2,
          dimension = propertyNames.dimension,
          nearest = originValues.nearest,
          center = originValues.center,
          farthest = originValues.farthest;
  
      return function() {
        switch (this.get(origin)) {
          case nearest:
            return Math.min(this.get(axis1), this.get(axis2));
          case center:
            return Math.min(this.get(axis1), this.get(axis2)) + (0.5 * this.get(dimension));
          case farthest:
            return Math.max(this.get(axis1), this.get(axis2));
        }
      };
  
    }
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric = global.fabric || (global.fabric = { }),
        pi = Math.PI;
  
    if (fabric.Circle) {
      fabric.warn('fabric.Circle is already defined.');
      return;
    }
  
    /**
     * Circle class
     * @class fabric.Circle
     * @extends fabric.Object
     * @see {@link fabric.Circle#initialize} for constructor definition
     */
    fabric.Circle = fabric.util.createClass(fabric.Object, /** @lends fabric.Circle.prototype */ {
  
      /**
       * Type of an object
       * @type String
       * @default
       */
      type: 'circle',
  
      /**
       * Radius of this circle
       * @type Number
       * @default
       */
      radius: 0,
  
      /**
       * Start angle of the circle, moving clockwise
       * deprectated type, this should be in degree, this was an oversight.
       * probably will change to degrees in next major version
       * @type Number
       * @default 0
       */
      startAngle: 0,
  
      /**
       * End angle of the circle
       * deprectated type, this should be in degree, this was an oversight.
       * probably will change to degrees in next major version
       * @type Number
       * @default 2Pi
       */
      endAngle: pi * 2,
  
      cacheProperties: fabric.Object.prototype.cacheProperties.concat('radius', 'startAngle', 'endAngle'),
  
      /**
       * @private
       * @param {String} key
       * @param {*} value
       * @return {fabric.Circle} thisArg
       */
      _set: function(key, value) {
        this.callSuper('_set', key, value);
  
        if (key === 'radius') {
          this.setRadius(value);
        }
  
        return this;
      },
  
      /**
       * Returns object representation of an instance
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object} object representation of an instance
       */
      toObject: function(propertiesToInclude) {
        return this.callSuper('toObject', ['radius', 'startAngle', 'endAngle'].concat(propertiesToInclude));
      },
  
      /* _TO_SVG_START_ */
  
      /**
       * Returns svg representation of an instance
       * @return {Array} an array of strings with the specific svg representation
       * of the instance
       */
      _toSVG: function() {
        var svgString, x = 0, y = 0,
            angle = (this.endAngle - this.startAngle) % ( 2 * pi);
  
        if (angle === 0) {
          svgString = [
            '<circle ', 'COMMON_PARTS',
            'cx="' + x + '" cy="' + y + '" ',
            'r="', this.radius,
            '" />\n'
          ];
        }
        else {
          var startX = fabric.util.cos(this.startAngle) * this.radius,
              startY = fabric.util.sin(this.startAngle) * this.radius,
              endX = fabric.util.cos(this.endAngle) * this.radius,
              endY = fabric.util.sin(this.endAngle) * this.radius,
              largeFlag = angle > pi ? '1' : '0';
          svgString = [
            '<path d="M ' + startX + ' ' + startY,
            ' A ' + this.radius + ' ' + this.radius,
            ' 0 ', +largeFlag + ' 1', ' ' + endX + ' ' + endY,
            '" ', 'COMMON_PARTS', ' />\n'
          ];
        }
        return svgString;
      },
      /* _TO_SVG_END_ */
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx context to render on
       */
      _render: function(ctx) {
        ctx.beginPath();
        ctx.arc(
          0,
          0,
          this.radius,
          this.startAngle,
          this.endAngle, false);
        this._renderPaintInOrder(ctx);
      },
  
      /**
       * Returns horizontal radius of an object (according to how an object is scaled)
       * @return {Number}
       */
      getRadiusX: function() {
        return this.get('radius') * this.get('scaleX');
      },
  
      /**
       * Returns vertical radius of an object (according to how an object is scaled)
       * @return {Number}
       */
      getRadiusY: function() {
        return this.get('radius') * this.get('scaleY');
      },
  
      /**
       * Sets radius of an object (and updates width accordingly)
       * @return {fabric.Circle} thisArg
       */
      setRadius: function(value) {
        this.radius = value;
        return this.set('width', value * 2).set('height', value * 2);
      },
    });
  
    /* _FROM_SVG_START_ */
    /**
     * List of attribute names to account for when parsing SVG element (used by {@link fabric.Circle.fromElement})
     * @static
     * @memberOf fabric.Circle
     * @see: http://www.w3.org/TR/SVG/shapes.html#CircleElement
     */
    fabric.Circle.ATTRIBUTE_NAMES = fabric.SHARED_ATTRIBUTES.concat('cx cy r'.split(' '));
  
    /**
     * Returns {@link fabric.Circle} instance from an SVG element
     * @static
     * @memberOf fabric.Circle
     * @param {SVGElement} element Element to parse
     * @param {Function} [callback] Options callback invoked after parsing is finished
     * @param {Object} [options] Options object
     * @throws {Error} If value of `r` attribute is missing or invalid
     */
    fabric.Circle.fromElement = function(element, callback) {
      var parsedAttributes = fabric.parseAttributes(element, fabric.Circle.ATTRIBUTE_NAMES);
  
      if (!isValidRadius(parsedAttributes)) {
        throw new Error('value of `r` attribute is required and can not be negative');
      }
  
      parsedAttributes.left = (parsedAttributes.left || 0) - parsedAttributes.radius;
      parsedAttributes.top = (parsedAttributes.top || 0) - parsedAttributes.radius;
      callback(new fabric.Circle(parsedAttributes));
    };
  
    /**
     * @private
     */
    function isValidRadius(attributes) {
      return (('radius' in attributes) && (attributes.radius >= 0));
    }
    /* _FROM_SVG_END_ */
  
    /**
     * Returns {@link fabric.Circle} instance from an object representation
     * @static
     * @memberOf fabric.Circle
     * @param {Object} object Object to create an instance from
     * @param {function} [callback] invoked with new instance as first argument
     * @return {Object} Instance of fabric.Circle
     */
    fabric.Circle.fromObject = function(object, callback) {
      return fabric.Object._fromObject('Circle', object, callback);
    };
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric = global.fabric || (global.fabric = { });
  
    if (fabric.Triangle) {
      fabric.warn('fabric.Triangle is already defined');
      return;
    }
  
    /**
     * Triangle class
     * @class fabric.Triangle
     * @extends fabric.Object
     * @return {fabric.Triangle} thisArg
     * @see {@link fabric.Triangle#initialize} for constructor definition
     */
    fabric.Triangle = fabric.util.createClass(fabric.Object, /** @lends fabric.Triangle.prototype */ {
  
      /**
       * Type of an object
       * @type String
       * @default
       */
      type: 'triangle',
  
      /**
       * Width is set to 100 to compensate the old initialize code that was setting it to 100
       * @type Number
       * @default
       */
      width: 100,
  
      /**
       * Height is set to 100 to compensate the old initialize code that was setting it to 100
       * @type Number
       * @default
       */
      height: 100,
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _render: function(ctx) {
        var widthBy2 = this.width / 2,
            heightBy2 = this.height / 2;
  
        ctx.beginPath();
        ctx.moveTo(-widthBy2, heightBy2);
        ctx.lineTo(0, -heightBy2);
        ctx.lineTo(widthBy2, heightBy2);
        ctx.closePath();
  
        this._renderPaintInOrder(ctx);
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _renderDashedStroke: function(ctx) {
        var widthBy2 = this.width / 2,
            heightBy2 = this.height / 2;
  
        ctx.beginPath();
        fabric.util.drawDashedLine(ctx, -widthBy2, heightBy2, 0, -heightBy2, this.strokeDashArray);
        fabric.util.drawDashedLine(ctx, 0, -heightBy2, widthBy2, heightBy2, this.strokeDashArray);
        fabric.util.drawDashedLine(ctx, widthBy2, heightBy2, -widthBy2, heightBy2, this.strokeDashArray);
        ctx.closePath();
      },
  
      /* _TO_SVG_START_ */
      /**
       * Returns svg representation of an instance
       * @return {Array} an array of strings with the specific svg representation
       * of the instance
       */
      _toSVG: function() {
        var widthBy2 = this.width / 2,
            heightBy2 = this.height / 2,
            points = [
              -widthBy2 + ' ' + heightBy2,
              '0 ' + -heightBy2,
              widthBy2 + ' ' + heightBy2
            ].join(',');
        return [
          '<polygon ', 'COMMON_PARTS',
          'points="', points,
          '" />'
        ];
      },
      /* _TO_SVG_END_ */
    });
  
    /**
     * Returns {@link fabric.Triangle} instance from an object representation
     * @static
     * @memberOf fabric.Triangle
     * @param {Object} object Object to create an instance from
     * @param {function} [callback] invoked with new instance as first argument
     */
    fabric.Triangle.fromObject = function(object, callback) {
      return fabric.Object._fromObject('Triangle', object, callback);
    };
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric = global.fabric || (global.fabric = { }),
        piBy2   = Math.PI * 2;
  
    if (fabric.Ellipse) {
      fabric.warn('fabric.Ellipse is already defined.');
      return;
    }
  
    /**
     * Ellipse class
     * @class fabric.Ellipse
     * @extends fabric.Object
     * @return {fabric.Ellipse} thisArg
     * @see {@link fabric.Ellipse#initialize} for constructor definition
     */
    fabric.Ellipse = fabric.util.createClass(fabric.Object, /** @lends fabric.Ellipse.prototype */ {
  
      /**
       * Type of an object
       * @type String
       * @default
       */
      type: 'ellipse',
  
      /**
       * Horizontal radius
       * @type Number
       * @default
       */
      rx:   0,
  
      /**
       * Vertical radius
       * @type Number
       * @default
       */
      ry:   0,
  
      cacheProperties: fabric.Object.prototype.cacheProperties.concat('rx', 'ry'),
  
      /**
       * Constructor
       * @param {Object} [options] Options object
       * @return {fabric.Ellipse} thisArg
       */
      initialize: function(options) {
        this.callSuper('initialize', options);
        this.set('rx', options && options.rx || 0);
        this.set('ry', options && options.ry || 0);
      },
  
      /**
       * @private
       * @param {String} key
       * @param {*} value
       * @return {fabric.Ellipse} thisArg
       */
      _set: function(key, value) {
        this.callSuper('_set', key, value);
        switch (key) {
  
          case 'rx':
            this.rx = value;
            this.set('width', value * 2);
            break;
  
          case 'ry':
            this.ry = value;
            this.set('height', value * 2);
            break;
  
        }
        return this;
      },
  
      /**
       * Returns horizontal radius of an object (according to how an object is scaled)
       * @return {Number}
       */
      getRx: function() {
        return this.get('rx') * this.get('scaleX');
      },
  
      /**
       * Returns Vertical radius of an object (according to how an object is scaled)
       * @return {Number}
       */
      getRy: function() {
        return this.get('ry') * this.get('scaleY');
      },
  
      /**
       * Returns object representation of an instance
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object} object representation of an instance
       */
      toObject: function(propertiesToInclude) {
        return this.callSuper('toObject', ['rx', 'ry'].concat(propertiesToInclude));
      },
  
      /* _TO_SVG_START_ */
      /**
       * Returns svg representation of an instance
       * @return {Array} an array of strings with the specific svg representation
       * of the instance
       */
      _toSVG: function() {
        return [
          '<ellipse ', 'COMMON_PARTS',
          'cx="0" cy="0" ',
          'rx="', this.rx,
          '" ry="', this.ry,
          '" />\n'
        ];
      },
      /* _TO_SVG_END_ */
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx context to render on
       */
      _render: function(ctx) {
        ctx.beginPath();
        ctx.save();
        ctx.transform(1, 0, 0, this.ry / this.rx, 0, 0);
        ctx.arc(
          0,
          0,
          this.rx,
          0,
          piBy2,
          false);
        ctx.restore();
        this._renderPaintInOrder(ctx);
      },
    });
  
    /* _FROM_SVG_START_ */
    /**
     * List of attribute names to account for when parsing SVG element (used by {@link fabric.Ellipse.fromElement})
     * @static
     * @memberOf fabric.Ellipse
     * @see http://www.w3.org/TR/SVG/shapes.html#EllipseElement
     */
    fabric.Ellipse.ATTRIBUTE_NAMES = fabric.SHARED_ATTRIBUTES.concat('cx cy rx ry'.split(' '));
  
    /**
     * Returns {@link fabric.Ellipse} instance from an SVG element
     * @static
     * @memberOf fabric.Ellipse
     * @param {SVGElement} element Element to parse
     * @param {Function} [callback] Options callback invoked after parsing is finished
     * @return {fabric.Ellipse}
     */
    fabric.Ellipse.fromElement = function(element, callback) {
  
      var parsedAttributes = fabric.parseAttributes(element, fabric.Ellipse.ATTRIBUTE_NAMES);
  
      parsedAttributes.left = (parsedAttributes.left || 0) - parsedAttributes.rx;
      parsedAttributes.top = (parsedAttributes.top || 0) - parsedAttributes.ry;
      callback(new fabric.Ellipse(parsedAttributes));
    };
    /* _FROM_SVG_END_ */
  
    /**
     * Returns {@link fabric.Ellipse} instance from an object representation
     * @static
     * @memberOf fabric.Ellipse
     * @param {Object} object Object to create an instance from
     * @param {function} [callback] invoked with new instance as first argument
     * @return {fabric.Ellipse}
     */
    fabric.Ellipse.fromObject = function(object, callback) {
      return fabric.Object._fromObject('Ellipse', object, callback);
    };
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric = global.fabric || (global.fabric = { }),
        extend = fabric.util.object.extend;
  
    if (fabric.Rect) {
      fabric.warn('fabric.Rect is already defined');
      return;
    }
  
    /**
     * Rectangle class
     * @class fabric.Rect
     * @extends fabric.Object
     * @return {fabric.Rect} thisArg
     * @see {@link fabric.Rect#initialize} for constructor definition
     */
    fabric.Rect = fabric.util.createClass(fabric.Object, /** @lends fabric.Rect.prototype */ {
  
      /**
       * List of properties to consider when checking if state of an object is changed ({@link fabric.Object#hasStateChanged})
       * as well as for history (undo/redo) purposes
       * @type Array
       */
      stateProperties: fabric.Object.prototype.stateProperties.concat('rx', 'ry'),
  
      /**
       * Type of an object
       * @type String
       * @default
       */
      type: 'rect',
  
      /**
       * Horizontal border radius
       * @type Number
       * @default
       */
      rx:   0,
  
      /**
       * Vertical border radius
       * @type Number
       * @default
       */
      ry:   0,
  
      cacheProperties: fabric.Object.prototype.cacheProperties.concat('rx', 'ry'),
  
      /**
       * Constructor
       * @param {Object} [options] Options object
       * @return {Object} thisArg
       */
      initialize: function(options) {
        this.callSuper('initialize', options);
        this._initRxRy();
      },
  
      /**
       * Initializes rx/ry attributes
       * @private
       */
      _initRxRy: function() {
        if (this.rx && !this.ry) {
          this.ry = this.rx;
        }
        else if (this.ry && !this.rx) {
          this.rx = this.ry;
        }
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _render: function(ctx) {
  
        // 1x1 case (used in spray brush) optimization was removed because
        // with caching and higher zoom level this makes more damage than help
  
        var rx = this.rx ? Math.min(this.rx, this.width / 2) : 0,
            ry = this.ry ? Math.min(this.ry, this.height / 2) : 0,
            w = this.width,
            h = this.height,
            x = -this.width / 2,
            y = -this.height / 2,
            isRounded = rx !== 0 || ry !== 0,
            /* "magic number" for bezier approximations of arcs (http://itc.ktu.lt/itc354/Riskus354.pdf) */
            k = 1 - 0.5522847498;
        ctx.beginPath();
  
        ctx.moveTo(x + rx, y);
  
        ctx.lineTo(x + w - rx, y);
        isRounded && ctx.bezierCurveTo(x + w - k * rx, y, x + w, y + k * ry, x + w, y + ry);
  
        ctx.lineTo(x + w, y + h - ry);
        isRounded && ctx.bezierCurveTo(x + w, y + h - k * ry, x + w - k * rx, y + h, x + w - rx, y + h);
  
        ctx.lineTo(x + rx, y + h);
        isRounded && ctx.bezierCurveTo(x + k * rx, y + h, x, y + h - k * ry, x, y + h - ry);
  
        ctx.lineTo(x, y + ry);
        isRounded && ctx.bezierCurveTo(x, y + k * ry, x + k * rx, y, x + rx, y);
  
        ctx.closePath();
  
        this._renderPaintInOrder(ctx);
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _renderDashedStroke: function(ctx) {
        var x = -this.width / 2,
            y = -this.height / 2,
            w = this.width,
            h = this.height;
  
        ctx.beginPath();
        fabric.util.drawDashedLine(ctx, x, y, x + w, y, this.strokeDashArray);
        fabric.util.drawDashedLine(ctx, x + w, y, x + w, y + h, this.strokeDashArray);
        fabric.util.drawDashedLine(ctx, x + w, y + h, x, y + h, this.strokeDashArray);
        fabric.util.drawDashedLine(ctx, x, y + h, x, y, this.strokeDashArray);
        ctx.closePath();
      },
  
      /**
       * Returns object representation of an instance
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object} object representation of an instance
       */
      toObject: function(propertiesToInclude) {
        return this.callSuper('toObject', ['rx', 'ry'].concat(propertiesToInclude));
      },
  
      /* _TO_SVG_START_ */
      /**
       * Returns svg representation of an instance
       * @return {Array} an array of strings with the specific svg representation
       * of the instance
       */
      _toSVG: function() {
        var x = -this.width / 2, y = -this.height / 2;
        return [
          '<rect ', 'COMMON_PARTS',
          'x="', x, '" y="', y,
          '" rx="', this.rx, '" ry="', this.ry,
          '" width="', this.width, '" height="', this.height,
          '" />\n'
        ];
      },
      /* _TO_SVG_END_ */
    });
  
    /* _FROM_SVG_START_ */
    /**
     * List of attribute names to account for when parsing SVG element (used by `fabric.Rect.fromElement`)
     * @static
     * @memberOf fabric.Rect
     * @see: http://www.w3.org/TR/SVG/shapes.html#RectElement
     */
    fabric.Rect.ATTRIBUTE_NAMES = fabric.SHARED_ATTRIBUTES.concat('x y rx ry width height'.split(' '));
  
    /**
     * Returns {@link fabric.Rect} instance from an SVG element
     * @static
     * @memberOf fabric.Rect
     * @param {SVGElement} element Element to parse
     * @param {Function} callback callback function invoked after parsing
     * @param {Object} [options] Options object
     */
    fabric.Rect.fromElement = function(element, callback, options) {
      if (!element) {
        return callback(null);
      }
      options = options || { };
  
      var parsedAttributes = fabric.parseAttributes(element, fabric.Rect.ATTRIBUTE_NAMES);
  
      parsedAttributes.left = parsedAttributes.left || 0;
      parsedAttributes.top  = parsedAttributes.top  || 0;
      parsedAttributes.height  = parsedAttributes.height || 0;
      parsedAttributes.width  = parsedAttributes.width || 0;
      var rect = new fabric.Rect(extend((options ? fabric.util.object.clone(options) : { }), parsedAttributes));
      rect.visible = rect.visible && rect.width > 0 && rect.height > 0;
      callback(rect);
    };
    /* _FROM_SVG_END_ */
  
    /**
     * Returns {@link fabric.Rect} instance from an object representation
     * @static
     * @memberOf fabric.Rect
     * @param {Object} object Object to create an instance from
     * @param {Function} [callback] Callback to invoke when an fabric.Rect instance is created
     */
    fabric.Rect.fromObject = function(object, callback) {
      return fabric.Object._fromObject('Rect', object, callback);
    };
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric = global.fabric || (global.fabric = { }),
        extend = fabric.util.object.extend,
        min = fabric.util.array.min,
        max = fabric.util.array.max,
        toFixed = fabric.util.toFixed;
  
    if (fabric.Polyline) {
      fabric.warn('fabric.Polyline is already defined');
      return;
    }
  
    /**
     * Polyline class
     * @class fabric.Polyline
     * @extends fabric.Object
     * @see {@link fabric.Polyline#initialize} for constructor definition
     */
    fabric.Polyline = fabric.util.createClass(fabric.Object, /** @lends fabric.Polyline.prototype */ {
  
      /**
       * Type of an object
       * @type String
       * @default
       */
      type: 'polyline',
  
      /**
       * Points array
       * @type Array
       * @default
       */
      points: null,
  
      cacheProperties: fabric.Object.prototype.cacheProperties.concat('points'),
  
      /**
       * Constructor
       * @param {Array} points Array of points (where each point is an object with x and y)
       * @param {Object} [options] Options object
       * @return {fabric.Polyline} thisArg
       * @example
       * var poly = new fabric.Polyline([
       *     { x: 10, y: 10 },
       *     { x: 50, y: 30 },
       *     { x: 40, y: 70 },
       *     { x: 60, y: 50 },
       *     { x: 100, y: 150 },
       *     { x: 40, y: 100 }
       *   ], {
       *   stroke: 'red',
       *   left: 100,
       *   top: 100
       * });
       */
      initialize: function(points, options) {
        options = options || {};
        this.points = points || [];
        this.callSuper('initialize', options);
        this._setPositionDimensions(options);
      },
  
      _setPositionDimensions: function(options) {
        var calcDim = this._calcDimensions(options), correctLeftTop;
        this.width = calcDim.width;
        this.height = calcDim.height;
        if (!options.fromSVG) {
          correctLeftTop = this.translateToGivenOrigin(
            { x: calcDim.left - this.strokeWidth / 2, y: calcDim.top - this.strokeWidth / 2 },
            'left',
            'top',
            this.originX,
            this.originY
          );
        }
        if (typeof options.left === 'undefined') {
          this.left = options.fromSVG ? calcDim.left : correctLeftTop.x;
        }
        if (typeof options.top === 'undefined') {
          this.top = options.fromSVG ? calcDim.top : correctLeftTop.y;
        }
        this.pathOffset = {
          x: calcDim.left + this.width / 2,
          y: calcDim.top + this.height / 2
        };
      },
  
      /**
       * Calculate the polygon min and max point from points array,
       * returning an object with left, top, widht, height to measure the
       * polygon size
       * @return {Object} object.left X coordinate of the polygon leftmost point
       * @return {Object} object.top Y coordinate of the polygon topmost point
       * @return {Object} object.width distance between X coordinates of the polygon leftmost and rightmost point
       * @return {Object} object.height distance between Y coordinates of the polygon topmost and bottommost point
       * @private
       */
      _calcDimensions: function() {
  
        var points = this.points,
            minX = min(points, 'x') || 0,
            minY = min(points, 'y') || 0,
            maxX = max(points, 'x') || 0,
            maxY = max(points, 'y') || 0,
            width = (maxX - minX),
            height = (maxY - minY);
  
        return {
          left: minX,
          top: minY,
          width: width,
          height: height
        };
      },
  
      /**
       * Returns object representation of an instance
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object} Object representation of an instance
       */
      toObject: function(propertiesToInclude) {
        return extend(this.callSuper('toObject', propertiesToInclude), {
          points: this.points.concat()
        });
      },
  
      /* _TO_SVG_START_ */
      /**
       * Returns svg representation of an instance
       * @return {Array} an array of strings with the specific svg representation
       * of the instance
       */
      _toSVG: function() {
        var points = [], diffX = this.pathOffset.x, diffY = this.pathOffset.y,
            NUM_FRACTION_DIGITS = fabric.Object.NUM_FRACTION_DIGITS;
  
        for (var i = 0, len = this.points.length; i < len; i++) {
          points.push(
            toFixed(this.points[i].x - diffX, NUM_FRACTION_DIGITS), ',',
            toFixed(this.points[i].y - diffY, NUM_FRACTION_DIGITS), ' '
          );
        }
        return [
          '<' + this.type + ' ', 'COMMON_PARTS',
          'points="', points.join(''),
          '" />\n'
        ];
      },
      /* _TO_SVG_END_ */
  
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      commonRender: function(ctx) {
        var point, len = this.points.length,
            x = this.pathOffset.x,
            y = this.pathOffset.y;
  
        if (!len || isNaN(this.points[len - 1].y)) {
          // do not draw if no points or odd points
          // NaN comes from parseFloat of a empty string in parser
          return false;
        }
        ctx.beginPath();
        ctx.moveTo(this.points[0].x - x, this.points[0].y - y);
        for (var i = 0; i < len; i++) {
          point = this.points[i];
          ctx.lineTo(point.x - x, point.y - y);
        }
        return true;
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _render: function(ctx) {
        if (!this.commonRender(ctx)) {
          return;
        }
        this._renderPaintInOrder(ctx);
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _renderDashedStroke: function(ctx) {
        var p1, p2;
  
        ctx.beginPath();
        for (var i = 0, len = this.points.length; i < len; i++) {
          p1 = this.points[i];
          p2 = this.points[i + 1] || p1;
          fabric.util.drawDashedLine(ctx, p1.x, p1.y, p2.x, p2.y, this.strokeDashArray);
        }
      },
  
      /**
       * Returns complexity of an instance
       * @return {Number} complexity of this instance
       */
      complexity: function() {
        return this.get('points').length;
      }
    });
  
    /* _FROM_SVG_START_ */
    /**
     * List of attribute names to account for when parsing SVG element (used by {@link fabric.Polyline.fromElement})
     * @static
     * @memberOf fabric.Polyline
     * @see: http://www.w3.org/TR/SVG/shapes.html#PolylineElement
     */
    fabric.Polyline.ATTRIBUTE_NAMES = fabric.SHARED_ATTRIBUTES.concat();
  
    /**
     * Returns fabric.Polyline instance from an SVG element
     * @static
     * @memberOf fabric.Polyline
     * @param {SVGElement} element Element to parser
     * @param {Function} callback callback function invoked after parsing
     * @param {Object} [options] Options object
     */
    fabric.Polyline.fromElementGenerator = function(_class) {
      return function(element, callback, options) {
        if (!element) {
          return callback(null);
        }
        options || (options = { });
  
        var points = fabric.parsePointsAttribute(element.getAttribute('points')),
            parsedAttributes = fabric.parseAttributes(element, fabric[_class].ATTRIBUTE_NAMES);
        parsedAttributes.fromSVG = true;
        callback(new fabric[_class](points, extend(parsedAttributes, options)));
      };
    };
  
    fabric.Polyline.fromElement = fabric.Polyline.fromElementGenerator('Polyline');
  
    /* _FROM_SVG_END_ */
  
    /**
     * Returns fabric.Polyline instance from an object representation
     * @static
     * @memberOf fabric.Polyline
     * @param {Object} object Object to create an instance from
     * @param {Function} [callback] Callback to invoke when an fabric.Path instance is created
     */
    fabric.Polyline.fromObject = function(object, callback) {
      return fabric.Object._fromObject('Polyline', object, callback, 'points');
    };
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric = global.fabric || (global.fabric = { });
  
    if (fabric.Polygon) {
      fabric.warn('fabric.Polygon is already defined');
      return;
    }
  
    /**
     * Polygon class
     * @class fabric.Polygon
     * @extends fabric.Polyline
     * @see {@link fabric.Polygon#initialize} for constructor definition
     */
    fabric.Polygon = fabric.util.createClass(fabric.Polyline, /** @lends fabric.Polygon.prototype */ {
  
      /**
       * Type of an object
       * @type String
       * @default
       */
      type: 'polygon',
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _render: function(ctx) {
        if (!this.commonRender(ctx)) {
          return;
        }
        ctx.closePath();
        this._renderPaintInOrder(ctx);
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _renderDashedStroke: function(ctx) {
        this.callSuper('_renderDashedStroke', ctx);
        ctx.closePath();
      },
    });
  
    /* _FROM_SVG_START_ */
    /**
     * List of attribute names to account for when parsing SVG element (used by `fabric.Polygon.fromElement`)
     * @static
     * @memberOf fabric.Polygon
     * @see: http://www.w3.org/TR/SVG/shapes.html#PolygonElement
     */
    fabric.Polygon.ATTRIBUTE_NAMES = fabric.SHARED_ATTRIBUTES.concat();
  
    /**
     * Returns {@link fabric.Polygon} instance from an SVG element
     * @static
     * @memberOf fabric.Polygon
     * @param {SVGElement} element Element to parse
     * @param {Function} callback callback function invoked after parsing
     * @param {Object} [options] Options object
     */
    fabric.Polygon.fromElement = fabric.Polyline.fromElementGenerator('Polygon');
    /* _FROM_SVG_END_ */
  
    /**
     * Returns fabric.Polygon instance from an object representation
     * @static
     * @memberOf fabric.Polygon
     * @param {Object} object Object to create an instance from
     * @param {Function} [callback] Callback to invoke when an fabric.Path instance is created
     */
    fabric.Polygon.fromObject = function(object, callback) {
      return fabric.Object._fromObject('Polygon', object, callback, 'points');
    };
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric = global.fabric || (global.fabric = { }),
        min = fabric.util.array.min,
        max = fabric.util.array.max,
        extend = fabric.util.object.extend,
        _toString = Object.prototype.toString,
        drawArc = fabric.util.drawArc,
        toFixed = fabric.util.toFixed,
        commandLengths = {
          m: 2,
          l: 2,
          h: 1,
          v: 1,
          c: 6,
          s: 4,
          q: 4,
          t: 2,
          a: 7
        },
        repeatedCommands = {
          m: 'l',
          M: 'L'
        };
  
    if (fabric.Path) {
      fabric.warn('fabric.Path is already defined');
      return;
    }
  
    /**
     * Path class
     * @class fabric.Path
     * @extends fabric.Object
     * @tutorial {@link http://fabricjs.com/fabric-intro-part-1#path_and_pathgroup}
     * @see {@link fabric.Path#initialize} for constructor definition
     */
    fabric.Path = fabric.util.createClass(fabric.Object, /** @lends fabric.Path.prototype */ {
  
      /**
       * Type of an object
       * @type String
       * @default
       */
      type: 'path',
  
      /**
       * Array of path points
       * @type Array
       * @default
       */
      path: null,
  
      cacheProperties: fabric.Object.prototype.cacheProperties.concat('path', 'fillRule'),
  
      stateProperties: fabric.Object.prototype.stateProperties.concat('path'),
  
      /**
       * Constructor
       * @param {Array|String} path Path data (sequence of coordinates and corresponding "command" tokens)
       * @param {Object} [options] Options object
       * @return {fabric.Path} thisArg
       */
      initialize: function(path, options) {
        options = options || { };
        this.callSuper('initialize', options);
  
        if (!path) {
          path = [];
        }
  
        var fromArray = _toString.call(path) === '[object Array]';
  
        this.path = fromArray
          ? path
          // one of commands (m,M,l,L,q,Q,c,C,etc.) followed by non-command characters (i.e. command values)
          : path.match && path.match(/[mzlhvcsqta][^mzlhvcsqta]*/gi);
  
        if (!this.path) {
          return;
        }
  
        if (!fromArray) {
          this.path = this._parsePath();
        }
  
        fabric.Polyline.prototype._setPositionDimensions.call(this, options);
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx context to render path on
       */
      _renderPathCommands: function(ctx) {
        var current, // current instruction
            previous = null,
            subpathStartX = 0,
            subpathStartY = 0,
            x = 0, // current x
            y = 0, // current y
            controlX = 0, // current control point x
            controlY = 0, // current control point y
            tempX,
            tempY,
            l = -this.pathOffset.x,
            t = -this.pathOffset.y;
  
        ctx.beginPath();
  
        for (var i = 0, len = this.path.length; i < len; ++i) {
  
          current = this.path[i];
  
          switch (current[0]) { // first letter
  
            case 'l': // lineto, relative
              x += current[1];
              y += current[2];
              ctx.lineTo(x + l, y + t);
              break;
  
            case 'L': // lineto, absolute
              x = current[1];
              y = current[2];
              ctx.lineTo(x + l, y + t);
              break;
  
            case 'h': // horizontal lineto, relative
              x += current[1];
              ctx.lineTo(x + l, y + t);
              break;
  
            case 'H': // horizontal lineto, absolute
              x = current[1];
              ctx.lineTo(x + l, y + t);
              break;
  
            case 'v': // vertical lineto, relative
              y += current[1];
              ctx.lineTo(x + l, y + t);
              break;
  
            case 'V': // verical lineto, absolute
              y = current[1];
              ctx.lineTo(x + l, y + t);
              break;
  
            case 'm': // moveTo, relative
              x += current[1];
              y += current[2];
              subpathStartX = x;
              subpathStartY = y;
              ctx.moveTo(x + l, y + t);
              break;
  
            case 'M': // moveTo, absolute
              x = current[1];
              y = current[2];
              subpathStartX = x;
              subpathStartY = y;
              ctx.moveTo(x + l, y + t);
              break;
  
            case 'c': // bezierCurveTo, relative
              tempX = x + current[5];
              tempY = y + current[6];
              controlX = x + current[3];
              controlY = y + current[4];
              ctx.bezierCurveTo(
                x + current[1] + l, // x1
                y + current[2] + t, // y1
                controlX + l, // x2
                controlY + t, // y2
                tempX + l,
                tempY + t
              );
              x = tempX;
              y = tempY;
              break;
  
            case 'C': // bezierCurveTo, absolute
              x = current[5];
              y = current[6];
              controlX = current[3];
              controlY = current[4];
              ctx.bezierCurveTo(
                current[1] + l,
                current[2] + t,
                controlX + l,
                controlY + t,
                x + l,
                y + t
              );
              break;
  
            case 's': // shorthand cubic bezierCurveTo, relative
  
              // transform to absolute x,y
              tempX = x + current[3];
              tempY = y + current[4];
  
              if (previous[0].match(/[CcSs]/) === null) {
                // If there is no previous command or if the previous command was not a C, c, S, or s,
                // the control point is coincident with the current point
                controlX = x;
                controlY = y;
              }
              else {
                // calculate reflection of previous control points
                controlX = 2 * x - controlX;
                controlY = 2 * y - controlY;
              }
  
              ctx.bezierCurveTo(
                controlX + l,
                controlY + t,
                x + current[1] + l,
                y + current[2] + t,
                tempX + l,
                tempY + t
              );
              // set control point to 2nd one of this command
              // "... the first control point is assumed to be
              // the reflection of the second control point on
              // the previous command relative to the current point."
              controlX = x + current[1];
              controlY = y + current[2];
  
              x = tempX;
              y = tempY;
              break;
  
            case 'S': // shorthand cubic bezierCurveTo, absolute
              tempX = current[3];
              tempY = current[4];
              if (previous[0].match(/[CcSs]/) === null) {
                // If there is no previous command or if the previous command was not a C, c, S, or s,
                // the control point is coincident with the current point
                controlX = x;
                controlY = y;
              }
              else {
                // calculate reflection of previous control points
                controlX = 2 * x - controlX;
                controlY = 2 * y - controlY;
              }
              ctx.bezierCurveTo(
                controlX + l,
                controlY + t,
                current[1] + l,
                current[2] + t,
                tempX + l,
                tempY + t
              );
              x = tempX;
              y = tempY;
  
              // set control point to 2nd one of this command
              // "... the first control point is assumed to be
              // the reflection of the second control point on
              // the previous command relative to the current point."
              controlX = current[1];
              controlY = current[2];
  
              break;
  
            case 'q': // quadraticCurveTo, relative
              // transform to absolute x,y
              tempX = x + current[3];
              tempY = y + current[4];
  
              controlX = x + current[1];
              controlY = y + current[2];
  
              ctx.quadraticCurveTo(
                controlX + l,
                controlY + t,
                tempX + l,
                tempY + t
              );
              x = tempX;
              y = tempY;
              break;
  
            case 'Q': // quadraticCurveTo, absolute
              tempX = current[3];
              tempY = current[4];
  
              ctx.quadraticCurveTo(
                current[1] + l,
                current[2] + t,
                tempX + l,
                tempY + t
              );
              x = tempX;
              y = tempY;
              controlX = current[1];
              controlY = current[2];
              break;
  
            case 't': // shorthand quadraticCurveTo, relative
  
              // transform to absolute x,y
              tempX = x + current[1];
              tempY = y + current[2];
  
              if (previous[0].match(/[QqTt]/) === null) {
                // If there is no previous command or if the previous command was not a Q, q, T or t,
                // assume the control point is coincident with the current point
                controlX = x;
                controlY = y;
              }
              else {
                // calculate reflection of previous control point
                controlX = 2 * x - controlX;
                controlY = 2 * y - controlY;
              }
  
              ctx.quadraticCurveTo(
                controlX + l,
                controlY + t,
                tempX + l,
                tempY + t
              );
              x = tempX;
              y = tempY;
  
              break;
  
            case 'T':
              tempX = current[1];
              tempY = current[2];
  
              if (previous[0].match(/[QqTt]/) === null) {
                // If there is no previous command or if the previous command was not a Q, q, T or t,
                // assume the control point is coincident with the current point
                controlX = x;
                controlY = y;
              }
              else {
                // calculate reflection of previous control point
                controlX = 2 * x - controlX;
                controlY = 2 * y - controlY;
              }
              ctx.quadraticCurveTo(
                controlX + l,
                controlY + t,
                tempX + l,
                tempY + t
              );
              x = tempX;
              y = tempY;
              break;
  
            case 'a':
              // TODO: optimize this
              drawArc(ctx, x + l, y + t, [
                current[1],
                current[2],
                current[3],
                current[4],
                current[5],
                current[6] + x + l,
                current[7] + y + t
              ]);
              x += current[6];
              y += current[7];
              break;
  
            case 'A':
              // TODO: optimize this
              drawArc(ctx, x + l, y + t, [
                current[1],
                current[2],
                current[3],
                current[4],
                current[5],
                current[6] + l,
                current[7] + t
              ]);
              x = current[6];
              y = current[7];
              break;
  
            case 'z':
            case 'Z':
              x = subpathStartX;
              y = subpathStartY;
              ctx.closePath();
              break;
          }
          previous = current;
        }
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx context to render path on
       */
      _render: function(ctx) {
        this._renderPathCommands(ctx);
        this._renderPaintInOrder(ctx);
      },
  
      /**
       * Returns string representation of an instance
       * @return {String} string representation of an instance
       */
      toString: function() {
        return '#<fabric.Path (' + this.complexity() +
          '): { "top": ' + this.top + ', "left": ' + this.left + ' }>';
      },
  
      /**
       * Returns object representation of an instance
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object} object representation of an instance
       */
      toObject: function(propertiesToInclude) {
        return extend(this.callSuper('toObject', propertiesToInclude), {
          path: this.path.map(function(item) { return item.slice(); }),
        });
      },
  
      /**
       * Returns dataless object representation of an instance
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object} object representation of an instance
       */
      toDatalessObject: function(propertiesToInclude) {
        var o = this.toObject(['sourcePath'].concat(propertiesToInclude));
        if (o.sourcePath) {
          delete o.path;
        }
        return o;
      },
  
      /* _TO_SVG_START_ */
      /**
       * Returns svg representation of an instance
       * @return {Array} an array of strings with the specific svg representation
       * of the instance
       */
      _toSVG: function() {
        var path = this.path.map(function(path) {
          return path.join(' ');
        }).join(' ');
        return [
          '<path ', 'COMMON_PARTS',
          'd="', path,
          '" stroke-linecap="round" ',
          '/>\n'
        ];
      },
  
      _getOffsetTransform: function() {
        var digits = fabric.Object.NUM_FRACTION_DIGITS;
        return ' translate(' + toFixed(-this.pathOffset.x, digits) + ', ' +
            toFixed(-this.pathOffset.y, digits) + ')';
      },
  
      /**
       * Returns svg clipPath representation of an instance
       * @param {Function} [reviver] Method for further parsing of svg representation.
       * @return {String} svg representation of an instance
       */
      toClipPathSVG: function(reviver) {
        var additionalTransform = this._getOffsetTransform();
        return '\t' + this._createBaseClipPathSVGMarkup(
          this._toSVG(), { reviver: reviver, additionalTransform: additionalTransform }
        );
      },
  
      /**
       * Returns svg representation of an instance
       * @param {Function} [reviver] Method for further parsing of svg representation.
       * @return {String} svg representation of an instance
       */
      toSVG: function(reviver) {
        var additionalTransform = this._getOffsetTransform();
        return this._createBaseSVGMarkup(this._toSVG(), { reviver: reviver, additionalTransform: additionalTransform  });
      },
      /* _TO_SVG_END_ */
  
      /**
       * Returns number representation of an instance complexity
       * @return {Number} complexity of this instance
       */
      complexity: function() {
        return this.path.length;
      },
  
      /**
       * @private
       */
      _parsePath: function() {
        var result = [],
            coords = [],
            currentPath,
            parsed,
            re = /([-+]?((\d+\.\d+)|((\d+)|(\.\d+)))(?:e[-+]?\d+)?)/ig,
            match,
            coordsStr;
  
        for (var i = 0, coordsParsed, len = this.path.length; i < len; i++) {
          currentPath = this.path[i];
  
          coordsStr = currentPath.slice(1).trim();
          coords.length = 0;
  
          while ((match = re.exec(coordsStr))) {
            coords.push(match[0]);
          }
  
          coordsParsed = [currentPath.charAt(0)];
  
          for (var j = 0, jlen = coords.length; j < jlen; j++) {
            parsed = parseFloat(coords[j]);
            if (!isNaN(parsed)) {
              coordsParsed.push(parsed);
            }
          }
  
          var command = coordsParsed[0],
              commandLength = commandLengths[command.toLowerCase()],
              repeatedCommand = repeatedCommands[command] || command;
  
          if (coordsParsed.length - 1 > commandLength) {
            for (var k = 1, klen = coordsParsed.length; k < klen; k += commandLength) {
              result.push([command].concat(coordsParsed.slice(k, k + commandLength)));
              command = repeatedCommand;
            }
          }
          else {
            result.push(coordsParsed);
          }
        }
  
        return result;
      },
  
      /**
       * @private
       */
      _calcDimensions: function() {
  
        var aX = [],
            aY = [],
            current, // current instruction
            previous = null,
            subpathStartX = 0,
            subpathStartY = 0,
            x = 0, // current x
            y = 0, // current y
            controlX = 0, // current control point x
            controlY = 0, // current control point y
            tempX,
            tempY,
            bounds;
  
        for (var i = 0, len = this.path.length; i < len; ++i) {
  
          current = this.path[i];
  
          switch (current[0]) { // first letter
  
            case 'l': // lineto, relative
              x += current[1];
              y += current[2];
              bounds = [];
              break;
  
            case 'L': // lineto, absolute
              x = current[1];
              y = current[2];
              bounds = [];
              break;
  
            case 'h': // horizontal lineto, relative
              x += current[1];
              bounds = [];
              break;
  
            case 'H': // horizontal lineto, absolute
              x = current[1];
              bounds = [];
              break;
  
            case 'v': // vertical lineto, relative
              y += current[1];
              bounds = [];
              break;
  
            case 'V': // verical lineto, absolute
              y = current[1];
              bounds = [];
              break;
  
            case 'm': // moveTo, relative
              x += current[1];
              y += current[2];
              subpathStartX = x;
              subpathStartY = y;
              bounds = [];
              break;
  
            case 'M': // moveTo, absolute
              x = current[1];
              y = current[2];
              subpathStartX = x;
              subpathStartY = y;
              bounds = [];
              break;
  
            case 'c': // bezierCurveTo, relative
              tempX = x + current[5];
              tempY = y + current[6];
              controlX = x + current[3];
              controlY = y + current[4];
              bounds = fabric.util.getBoundsOfCurve(x, y,
                x + current[1], // x1
                y + current[2], // y1
                controlX, // x2
                controlY, // y2
                tempX,
                tempY
              );
              x = tempX;
              y = tempY;
              break;
  
            case 'C': // bezierCurveTo, absolute
              controlX = current[3];
              controlY = current[4];
              bounds = fabric.util.getBoundsOfCurve(x, y,
                current[1],
                current[2],
                controlX,
                controlY,
                current[5],
                current[6]
              );
              x = current[5];
              y = current[6];
              break;
  
            case 's': // shorthand cubic bezierCurveTo, relative
  
              // transform to absolute x,y
              tempX = x + current[3];
              tempY = y + current[4];
  
              if (previous[0].match(/[CcSs]/) === null) {
                // If there is no previous command or if the previous command was not a C, c, S, or s,
                // the control point is coincident with the current point
                controlX = x;
                controlY = y;
              }
              else {
                // calculate reflection of previous control points
                controlX = 2 * x - controlX;
                controlY = 2 * y - controlY;
              }
  
              bounds = fabric.util.getBoundsOfCurve(x, y,
                controlX,
                controlY,
                x + current[1],
                y + current[2],
                tempX,
                tempY
              );
              // set control point to 2nd one of this command
              // "... the first control point is assumed to be
              // the reflection of the second control point on
              // the previous command relative to the current point."
              controlX = x + current[1];
              controlY = y + current[2];
              x = tempX;
              y = tempY;
              break;
  
            case 'S': // shorthand cubic bezierCurveTo, absolute
              tempX = current[3];
              tempY = current[4];
              if (previous[0].match(/[CcSs]/) === null) {
                // If there is no previous command or if the previous command was not a C, c, S, or s,
                // the control point is coincident with the current point
                controlX = x;
                controlY = y;
              }
              else {
                // calculate reflection of previous control points
                controlX = 2 * x - controlX;
                controlY = 2 * y - controlY;
              }
              bounds = fabric.util.getBoundsOfCurve(x, y,
                controlX,
                controlY,
                current[1],
                current[2],
                tempX,
                tempY
              );
              x = tempX;
              y = tempY;
              // set control point to 2nd one of this command
              // "... the first control point is assumed to be
              // the reflection of the second control point on
              // the previous command relative to the current point."
              controlX = current[1];
              controlY = current[2];
              break;
  
            case 'q': // quadraticCurveTo, relative
              // transform to absolute x,y
              tempX = x + current[3];
              tempY = y + current[4];
              controlX = x + current[1];
              controlY = y + current[2];
              bounds = fabric.util.getBoundsOfCurve(x, y,
                controlX,
                controlY,
                controlX,
                controlY,
                tempX,
                tempY
              );
              x = tempX;
              y = tempY;
              break;
  
            case 'Q': // quadraticCurveTo, absolute
              controlX = current[1];
              controlY = current[2];
              bounds = fabric.util.getBoundsOfCurve(x, y,
                controlX,
                controlY,
                controlX,
                controlY,
                current[3],
                current[4]
              );
              x = current[3];
              y = current[4];
              break;
  
            case 't': // shorthand quadraticCurveTo, relative
              // transform to absolute x,y
              tempX = x + current[1];
              tempY = y + current[2];
              if (previous[0].match(/[QqTt]/) === null) {
                // If there is no previous command or if the previous command was not a Q, q, T or t,
                // assume the control point is coincident with the current point
                controlX = x;
                controlY = y;
              }
              else {
                // calculate reflection of previous control point
                controlX = 2 * x - controlX;
                controlY = 2 * y - controlY;
              }
  
              bounds = fabric.util.getBoundsOfCurve(x, y,
                controlX,
                controlY,
                controlX,
                controlY,
                tempX,
                tempY
              );
              x = tempX;
              y = tempY;
  
              break;
  
            case 'T':
              tempX = current[1];
              tempY = current[2];
  
              if (previous[0].match(/[QqTt]/) === null) {
                // If there is no previous command or if the previous command was not a Q, q, T or t,
                // assume the control point is coincident with the current point
                controlX = x;
                controlY = y;
              }
              else {
                // calculate reflection of previous control point
                controlX = 2 * x - controlX;
                controlY = 2 * y - controlY;
              }
              bounds = fabric.util.getBoundsOfCurve(x, y,
                controlX,
                controlY,
                controlX,
                controlY,
                tempX,
                tempY
              );
              x = tempX;
              y = tempY;
              break;
  
            case 'a':
              // TODO: optimize this
              bounds = fabric.util.getBoundsOfArc(x, y,
                current[1],
                current[2],
                current[3],
                current[4],
                current[5],
                current[6] + x,
                current[7] + y
              );
              x += current[6];
              y += current[7];
              break;
  
            case 'A':
              // TODO: optimize this
              bounds = fabric.util.getBoundsOfArc(x, y,
                current[1],
                current[2],
                current[3],
                current[4],
                current[5],
                current[6],
                current[7]
              );
              x = current[6];
              y = current[7];
              break;
  
            case 'z':
            case 'Z':
              x = subpathStartX;
              y = subpathStartY;
              break;
          }
          previous = current;
          bounds.forEach(function (point) {
            aX.push(point.x);
            aY.push(point.y);
          });
          aX.push(x);
          aY.push(y);
        }
  
        var minX = min(aX) || 0,
            minY = min(aY) || 0,
            maxX = max(aX) || 0,
            maxY = max(aY) || 0,
            deltaX = maxX - minX,
            deltaY = maxY - minY;
  
        return {
          left: minX,
          top: minY,
          width: deltaX,
          height: deltaY
        };
      }
    });
  
    /**
     * Creates an instance of fabric.Path from an object
     * @static
     * @memberOf fabric.Path
     * @param {Object} object
     * @param {Function} [callback] Callback to invoke when an fabric.Path instance is created
     */
    fabric.Path.fromObject = function(object, callback) {
      if (typeof object.sourcePath === 'string') {
        var pathUrl = object.sourcePath;
        fabric.loadSVGFromURL(pathUrl, function (elements) {
          var path = elements[0];
          path.setOptions(object);
          callback && callback(path);
        });
      }
      else {
        fabric.Object._fromObject('Path', object, callback, 'path');
      }
    };
  
    /* _FROM_SVG_START_ */
    /**
     * List of attribute names to account for when parsing SVG element (used by `fabric.Path.fromElement`)
     * @static
     * @memberOf fabric.Path
     * @see http://www.w3.org/TR/SVG/paths.html#PathElement
     */
    fabric.Path.ATTRIBUTE_NAMES = fabric.SHARED_ATTRIBUTES.concat(['d']);
  
    /**
     * Creates an instance of fabric.Path from an SVG <path> element
     * @static
     * @memberOf fabric.Path
     * @param {SVGElement} element to parse
     * @param {Function} callback Callback to invoke when an fabric.Path instance is created
     * @param {Object} [options] Options object
     * @param {Function} [callback] Options callback invoked after parsing is finished
     */
    fabric.Path.fromElement = function(element, callback, options) {
      var parsedAttributes = fabric.parseAttributes(element, fabric.Path.ATTRIBUTE_NAMES);
      parsedAttributes.fromSVG = true;
      callback(new fabric.Path(parsedAttributes.d, extend(parsedAttributes, options)));
    };
    /* _FROM_SVG_END_ */
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric = global.fabric || (global.fabric = { }),
        min = fabric.util.array.min,
        max = fabric.util.array.max;
  
    if (fabric.Group) {
      return;
    }
  
    /**
     * Group class
     * @class fabric.Group
     * @extends fabric.Object
     * @mixes fabric.Collection
     * @tutorial {@link http://fabricjs.com/fabric-intro-part-3#groups}
     * @see {@link fabric.Group#initialize} for constructor definition
     */
    fabric.Group = fabric.util.createClass(fabric.Object, fabric.Collection, /** @lends fabric.Group.prototype */ {
  
      /**
       * Type of an object
       * @type String
       * @default
       */
      type: 'group',
  
      /**
       * Width of stroke
       * @type Number
       * @default
       */
      strokeWidth: 0,
  
      /**
       * Indicates if click events should also check for subtargets
       * @type Boolean
       * @default
       */
      subTargetCheck: false,
  
      /**
       * Groups are container, do not render anything on theyr own, ence no cache properties
       * @type Array
       * @default
       */
      cacheProperties: [],
  
      /**
       * setOnGroup is a method used for TextBox that is no more used since 2.0.0 The behavior is still
       * available setting this boolean to true.
       * @type Boolean
       * @since 2.0.0
       * @default
       */
      useSetOnGroup: false,
  
      /**
       * Constructor
       * @param {Object} objects Group objects
       * @param {Object} [options] Options object
       * @param {Boolean} [isAlreadyGrouped] if true, objects have been grouped already.
       * @return {Object} thisArg
       */
      initialize: function(objects, options, isAlreadyGrouped) {
        options = options || {};
        this._objects = [];
        // if objects enclosed in a group have been grouped already,
        // we cannot change properties of objects.
        // Thus we need to set options to group without objects,
        isAlreadyGrouped && this.callSuper('initialize', options);
        this._objects = objects || [];
        for (var i = this._objects.length; i--; ) {
          this._objects[i].group = this;
        }
  
        if (!isAlreadyGrouped) {
          var center = options && options.centerPoint;
          // we want to set origins before calculating the bounding box.
          // so that the topleft can be set with that in mind.
          // if specific top and left are passed, are overwritten later
          // with the callSuper('initialize', options)
          if (options.originX !== undefined) {
            this.originX = options.originX;
          }
          if (options.originY !== undefined) {
            this.originY = options.originY;
          }
          // if coming from svg i do not want to calc bounds.
          // i assume width and height are passed along options
          center || this._calcBounds();
          this._updateObjectsCoords(center);
          delete options.centerPoint;
          this.callSuper('initialize', options);
        }
        else {
          this._updateObjectsACoords();
        }
  
        this.setCoords();
      },
  
      /**
       * @private
       * @param {Boolean} [skipCoordsChange] if true, coordinates of objects enclosed in a group do not change
       */
      _updateObjectsACoords: function() {
        var ignoreZoom = true, skipAbsolute = true;
        for (var i = this._objects.length; i--; ){
          this._objects[i].setCoords(ignoreZoom, skipAbsolute);
        }
      },
  
      /**
       * @private
       * @param {Boolean} [skipCoordsChange] if true, coordinates of objects enclosed in a group do not change
       */
      _updateObjectsCoords: function(center) {
        var center = center || this.getCenterPoint();
        for (var i = this._objects.length; i--; ){
          this._updateObjectCoords(this._objects[i], center);
        }
      },
  
      /**
       * @private
       * @param {Object} object
       * @param {fabric.Point} center, current center of group.
       */
      _updateObjectCoords: function(object, center) {
        var objectLeft = object.left,
            objectTop = object.top,
            ignoreZoom = true, skipAbsolute = true;
  
        object.set({
          left: objectLeft - center.x,
          top: objectTop - center.y
        });
        object.group = this;
        object.setCoords(ignoreZoom, skipAbsolute);
      },
  
      /**
       * Returns string represenation of a group
       * @return {String}
       */
      toString: function() {
        return '#<fabric.Group: (' + this.complexity() + ')>';
      },
  
      /**
       * Adds an object to a group; Then recalculates group's dimension, position.
       * @param {Object} object
       * @return {fabric.Group} thisArg
       * @chainable
       */
      addWithUpdate: function(object) {
        this._restoreObjectsState();
        fabric.util.resetObjectTransform(this);
        if (object) {
          this._objects.push(object);
          object.group = this;
          object._set('canvas', this.canvas);
        }
        this._calcBounds();
        this._updateObjectsCoords();
        this.setCoords();
        this.dirty = true;
        return this;
      },
  
      /**
       * Removes an object from a group; Then recalculates group's dimension, position.
       * @param {Object} object
       * @return {fabric.Group} thisArg
       * @chainable
       */
      removeWithUpdate: function(object) {
        this._restoreObjectsState();
        fabric.util.resetObjectTransform(this);
  
        this.remove(object);
        this._calcBounds();
        this._updateObjectsCoords();
        this.setCoords();
        this.dirty = true;
        return this;
      },
  
      /**
       * @private
       */
      _onObjectAdded: function(object) {
        this.dirty = true;
        object.group = this;
        object._set('canvas', this.canvas);
      },
  
      /**
       * @private
       */
      _onObjectRemoved: function(object) {
        this.dirty = true;
        delete object.group;
      },
  
      /**
       * @private
       */
      _set: function(key, value) {
        var i = this._objects.length;
        if (this.useSetOnGroup) {
          while (i--) {
            this._objects[i].setOnGroup(key, value);
          }
        }
        if (key === 'canvas') {
          while (i--) {
            this._objects[i]._set(key, value);
          }
        }
        fabric.Object.prototype._set.call(this, key, value);
      },
  
      /**
       * Returns object representation of an instance
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object} object representation of an instance
       */
      toObject: function(propertiesToInclude) {
        var _includeDefaultValues = this.includeDefaultValues;
        var objsToObject = this._objects.map(function(obj) {
          var originalDefaults = obj.includeDefaultValues;
          obj.includeDefaultValues = _includeDefaultValues;
          var _obj = obj.toObject(propertiesToInclude);
          obj.includeDefaultValues = originalDefaults;
          return _obj;
        });
        var obj = fabric.Object.prototype.toObject.call(this, propertiesToInclude);
        obj.objects = objsToObject;
        return obj;
      },
  
      /**
       * Returns object representation of an instance, in dataless mode.
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object} object representation of an instance
       */
      toDatalessObject: function(propertiesToInclude) {
        var objsToObject, sourcePath = this.sourcePath;
        if (sourcePath) {
          objsToObject = sourcePath;
        }
        else {
          var _includeDefaultValues = this.includeDefaultValues;
          objsToObject = this._objects.map(function(obj) {
            var originalDefaults = obj.includeDefaultValues;
            obj.includeDefaultValues = _includeDefaultValues;
            var _obj = obj.toDatalessObject(propertiesToInclude);
            obj.includeDefaultValues = originalDefaults;
            return _obj;
          });
        }
        var obj = fabric.Object.prototype.toDatalessObject.call(this, propertiesToInclude);
        obj.objects = objsToObject;
        return obj;
      },
  
      /**
       * Renders instance on a given context
       * @param {CanvasRenderingContext2D} ctx context to render instance on
       */
      render: function(ctx) {
        this._transformDone = true;
        this.callSuper('render', ctx);
        this._transformDone = false;
      },
  
      /**
       * Decide if the object should cache or not. Create its own cache level
       * needsItsOwnCache should be used when the object drawing method requires
       * a cache step. None of the fabric classes requires it.
       * Generally you do not cache objects in groups because the group is already cached.
       * @return {Boolean}
       */
      shouldCache: function() {
        var ownCache = fabric.Object.prototype.shouldCache.call(this);
        if (ownCache) {
          for (var i = 0, len = this._objects.length; i < len; i++) {
            if (this._objects[i].willDrawShadow()) {
              this.ownCaching = false;
              return false;
            }
          }
        }
        return ownCache;
      },
  
      /**
       * Check if this object or a child object will cast a shadow
       * @return {Boolean}
       */
      willDrawShadow: function() {
        if (this.shadow) {
          return fabric.Object.prototype.willDrawShadow.call(this);
        }
        for (var i = 0, len = this._objects.length; i < len; i++) {
          if (this._objects[i].willDrawShadow()) {
            return true;
          }
        }
        return false;
      },
  
      /**
       * Check if this group or its parent group are caching, recursively up
       * @return {Boolean}
       */
      isOnACache: function() {
        return this.ownCaching || (this.group && this.group.isOnACache());
      },
  
      /**
       * Execute the drawing operation for an object on a specified context
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      drawObject: function(ctx) {
        for (var i = 0, len = this._objects.length; i < len; i++) {
          this._objects[i].render(ctx);
        }
        this._drawClipPath(ctx);
      },
  
      /**
       * Check if cache is dirty
       */
      isCacheDirty: function(skipCanvas) {
        if (this.callSuper('isCacheDirty', skipCanvas)) {
          return true;
        }
        if (!this.statefullCache) {
          return false;
        }
        for (var i = 0, len = this._objects.length; i < len; i++) {
          if (this._objects[i].isCacheDirty(true)) {
            if (this._cacheCanvas) {
              // if this group has not a cache canvas there is nothing to clean
              var x = this.cacheWidth / this.zoomX, y = this.cacheHeight / this.zoomY;
              this._cacheContext.clearRect(-x / 2, -y / 2, x, y);
            }
            return true;
          }
        }
        return false;
      },
  
      /**
       * Retores original state of each of group objects (original state is that which was before group was created).
       * @private
       * @return {fabric.Group} thisArg
       * @chainable
       */
      _restoreObjectsState: function() {
        this._objects.forEach(this._restoreObjectState, this);
        return this;
      },
  
      /**
       * Realises the transform from this group onto the supplied object
       * i.e. it tells you what would happen if the supplied object was in
       * the group, and then the group was destroyed. It mutates the supplied
       * object.
       * @param {fabric.Object} object
       * @return {fabric.Object} transformedObject
       */
      realizeTransform: function(object) {
        var matrix = object.calcTransformMatrix(),
            options = fabric.util.qrDecompose(matrix),
            center = new fabric.Point(options.translateX, options.translateY);
        object.flipX = false;
        object.flipY = false;
        object.set('scaleX', options.scaleX);
        object.set('scaleY', options.scaleY);
        object.skewX = options.skewX;
        object.skewY = options.skewY;
        object.angle = options.angle;
        object.setPositionByOrigin(center, 'center', 'center');
        return object;
      },
  
      /**
       * Restores original state of a specified object in group
       * @private
       * @param {fabric.Object} object
       * @return {fabric.Group} thisArg
       */
      _restoreObjectState: function(object) {
        this.realizeTransform(object);
        object.setCoords();
        delete object.group;
        return this;
      },
  
      /**
       * Destroys a group (restoring state of its objects)
       * @return {fabric.Group} thisArg
       * @chainable
       */
      destroy: function() {
        // when group is destroyed objects needs to get a repaint to be eventually
        // displayed on canvas.
        this._objects.forEach(function(object) {
          object.set('dirty', true);
        });
        return this._restoreObjectsState();
      },
  
      /**
       * make a group an active selection, remove the group from canvas
       * the group has to be on canvas for this to work.
       * @return {fabric.ActiveSelection} thisArg
       * @chainable
       */
      toActiveSelection: function() {
        if (!this.canvas) {
          return;
        }
        var objects = this._objects, canvas = this.canvas;
        this._objects = [];
        var options = this.toObject();
        delete options.objects;
        var activeSelection = new fabric.ActiveSelection([]);
        activeSelection.set(options);
        activeSelection.type = 'activeSelection';
        canvas.remove(this);
        objects.forEach(function(object) {
          object.group = activeSelection;
          object.dirty = true;
          canvas.add(object);
        });
        activeSelection.canvas = canvas;
        activeSelection._objects = objects;
        canvas._activeObject = activeSelection;
        activeSelection.setCoords();
        return activeSelection;
      },
  
      /**
       * Destroys a group (restoring state of its objects)
       * @return {fabric.Group} thisArg
       * @chainable
       */
      ungroupOnCanvas: function() {
        return this._restoreObjectsState();
      },
  
      /**
       * Sets coordinates of all objects inside group
       * @return {fabric.Group} thisArg
       * @chainable
       */
      setObjectsCoords: function() {
        var ignoreZoom = true, skipAbsolute = true;
        this.forEachObject(function(object) {
          object.setCoords(ignoreZoom, skipAbsolute);
        });
        return this;
      },
  
      /**
       * @private
       */
      _calcBounds: function(onlyWidthHeight) {
        var aX = [],
            aY = [],
            o, prop,
            props = ['tr', 'br', 'bl', 'tl'],
            i = 0, iLen = this._objects.length,
            j, jLen = props.length,
            ignoreZoom = true;
  
        for ( ; i < iLen; ++i) {
          o = this._objects[i];
          o.setCoords(ignoreZoom);
          for (j = 0; j < jLen; j++) {
            prop = props[j];
            aX.push(o.oCoords[prop].x);
            aY.push(o.oCoords[prop].y);
          }
        }
  
        this._getBounds(aX, aY, onlyWidthHeight);
      },
  
      /**
       * @private
       */
      _getBounds: function(aX, aY, onlyWidthHeight) {
        var minXY = new fabric.Point(min(aX), min(aY)),
            maxXY = new fabric.Point(max(aX), max(aY)),
            top = minXY.y || 0, left = minXY.x || 0,
            width = (maxXY.x - minXY.x) || 0,
            height = (maxXY.y - minXY.y) || 0;
        this.width = width;
        this.height = height;
        if (!onlyWidthHeight) {
          // the bounding box always finds the topleft most corner.
          // whatever is the group origin, we set up here the left/top position.
          this.setPositionByOrigin({ x: left, y: top }, 'left', 'top');
        }
      },
  
      /* _TO_SVG_START_ */
      /**
       * Returns svg representation of an instance
       * @param {Function} [reviver] Method for further parsing of svg representation.
       * @return {String} svg representation of an instance
       */
      _toSVG: function(reviver) {
        var svgString = ['<g ', 'COMMON_PARTS', ' >\n'];
  
        for (var i = 0, len = this._objects.length; i < len; i++) {
          svgString.push('\t\t', this._objects[i].toSVG(reviver));
        }
        svgString.push('</g>\n');
        return svgString;
      },
  
      /**
       * Returns styles-string for svg-export, specific version for group
       * @return {String}
       */
      getSvgStyles: function() {
        var opacity = typeof this.opacity !== 'undefined' && this.opacity !== 1 ?
              'opacity: ' + this.opacity + ';' : '',
            visibility = this.visible ? '' : ' visibility: hidden;';
        return [
          opacity,
          this.getSvgFilter(),
          visibility
        ].join('');
      },
  
      /**
       * Returns svg clipPath representation of an instance
       * @param {Function} [reviver] Method for further parsing of svg representation.
       * @return {String} svg representation of an instance
       */
      toClipPathSVG: function(reviver) {
        var svgString = [];
  
        for (var i = 0, len = this._objects.length; i < len; i++) {
          svgString.push('\t', this._objects[i].toClipPathSVG(reviver));
        }
  
        return this._createBaseClipPathSVGMarkup(svgString, { reviver: reviver });
      },
      /* _TO_SVG_END_ */
    });
  
    /**
     * Returns {@link fabric.Group} instance from an object representation
     * @static
     * @memberOf fabric.Group
     * @param {Object} object Object to create a group from
     * @param {Function} [callback] Callback to invoke when an group instance is created
     */
    fabric.Group.fromObject = function(object, callback) {
      var objects = object.objects,
          options = fabric.util.object.clone(object, true);
      delete options.objects;
      if (typeof objects === 'string') {
        // it has to be an url or something went wrong.
        fabric.loadSVGFromURL(objects, function (elements) {
          var group = fabric.util.groupSVGElements(elements, object, objects);
          group.set(options);
          callback && callback(group);
        });
        return;
      }
      fabric.util.enlivenObjects(objects, function(enlivenedObjects) {
        fabric.util.enlivenObjects([object.clipPath], function(enlivedClipPath) {
          var options = fabric.util.object.clone(object, true);
          options.clipPath = enlivedClipPath[0];
          delete options.objects;
          callback && callback(new fabric.Group(enlivenedObjects, options, true));
        });
      });
    };
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric = global.fabric || (global.fabric = { });
  
    if (fabric.ActiveSelection) {
      return;
    }
  
    /**
     * Group class
     * @class fabric.ActiveSelection
     * @extends fabric.Group
     * @tutorial {@link http://fabricjs.com/fabric-intro-part-3#groups}
     * @see {@link fabric.ActiveSelection#initialize} for constructor definition
     */
    fabric.ActiveSelection = fabric.util.createClass(fabric.Group, /** @lends fabric.ActiveSelection.prototype */ {
  
      /**
       * Type of an object
       * @type String
       * @default
       */
      type: 'activeSelection',
  
      /**
       * Constructor
       * @param {Object} objects ActiveSelection objects
       * @param {Object} [options] Options object
       * @return {Object} thisArg
       */
      initialize: function(objects, options) {
        options = options || {};
        this._objects = objects || [];
        for (var i = this._objects.length; i--; ) {
          this._objects[i].group = this;
        }
  
        if (options.originX) {
          this.originX = options.originX;
        }
        if (options.originY) {
          this.originY = options.originY;
        }
        this._calcBounds();
        this._updateObjectsCoords();
        fabric.Object.prototype.initialize.call(this, options);
        this.setCoords();
      },
  
      /**
       * Change te activeSelection to a normal group,
       * High level function that automatically adds it to canvas as
       * active object. no events fired.
       * @since 2.0.0
       * @return {fabric.Group}
       */
      toGroup: function() {
        var objects = this._objects.concat();
        this._objects = [];
        var options = fabric.Object.prototype.toObject.call(this);
        var newGroup = new fabric.Group([]);
        delete options.type;
        newGroup.set(options);
        objects.forEach(function(object) {
          object.canvas.remove(object);
          object.group = newGroup;
        });
        newGroup._objects = objects;
        if (!this.canvas) {
          return newGroup;
        }
        var canvas = this.canvas;
        canvas.add(newGroup);
        canvas._activeObject = newGroup;
        newGroup.setCoords();
        return newGroup;
      },
  
      /**
       * If returns true, deselection is cancelled.
       * @since 2.0.0
       * @return {Boolean} [cancel]
       */
      onDeselect: function() {
        this.destroy();
        return false;
      },
  
      /**
       * Returns string representation of a group
       * @return {String}
       */
      toString: function() {
        return '#<fabric.ActiveSelection: (' + this.complexity() + ')>';
      },
  
      /**
       * Decide if the object should cache or not. Create its own cache level
       * objectCaching is a global flag, wins over everything
       * needsItsOwnCache should be used when the object drawing method requires
       * a cache step. None of the fabric classes requires it.
       * Generally you do not cache objects in groups because the group outside is cached.
       * @return {Boolean}
       */
      shouldCache: function() {
        return false;
      },
  
      /**
       * Check if this group or its parent group are caching, recursively up
       * @return {Boolean}
       */
      isOnACache: function() {
        return false;
      },
  
      /**
       * Renders controls and borders for the object
       * @param {CanvasRenderingContext2D} ctx Context to render on
       * @param {Object} [styleOverride] properties to override the object style
       * @param {Object} [childrenOverride] properties to override the children overrides
       */
      _renderControls: function(ctx, styleOverride, childrenOverride) {
        ctx.save();
        ctx.globalAlpha = this.isMoving ? this.borderOpacityWhenMoving : 1;
        this.callSuper('_renderControls', ctx, styleOverride);
        childrenOverride = childrenOverride || { };
        if (typeof childrenOverride.hasControls === 'undefined') {
          childrenOverride.hasControls = false;
        }
        if (typeof childrenOverride.hasRotatingPoint === 'undefined') {
          childrenOverride.hasRotatingPoint = false;
        }
        childrenOverride.forActiveSelection = true;
        for (var i = 0, len = this._objects.length; i < len; i++) {
          this._objects[i]._renderControls(ctx, childrenOverride);
        }
        ctx.restore();
      },
    });
  
    /**
     * Returns {@link fabric.ActiveSelection} instance from an object representation
     * @static
     * @memberOf fabric.ActiveSelection
     * @param {Object} object Object to create a group from
     * @param {Function} [callback] Callback to invoke when an ActiveSelection instance is created
     */
    fabric.ActiveSelection.fromObject = function(object, callback) {
      fabric.util.enlivenObjects(object.objects, function(enlivenedObjects) {
        delete object.objects;
        callback && callback(new fabric.ActiveSelection(enlivenedObjects, object, true));
      });
    };
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var extend = fabric.util.object.extend;
  
    if (!global.fabric) {
      global.fabric = { };
    }
  
    if (global.fabric.Image) {
      fabric.warn('fabric.Image is already defined.');
      return;
    }
  
    /**
     * Image class
     * @class fabric.Image
     * @extends fabric.Object
     * @tutorial {@link http://fabricjs.com/fabric-intro-part-1#images}
     * @see {@link fabric.Image#initialize} for constructor definition
     */
    fabric.Image = fabric.util.createClass(fabric.Object, /** @lends fabric.Image.prototype */ {
  
      /**
       * Type of an object
       * @type String
       * @default
       */
      type: 'image',
  
      /**
       * crossOrigin value (one of "", "anonymous", "use-credentials")
       * @see https://developer.mozilla.org/en-US/docs/HTML/CORS_settings_attributes
       * @type String
       * @default
       */
      crossOrigin: '',
  
      /**
       * Width of a stroke.
       * For image quality a stroke multiple of 2 gives better results.
       * @type Number
       * @default
       */
      strokeWidth: 0,
  
      /**
       * When calling {@link fabric.Image.getSrc}, return value from element src with `element.getAttribute('src')`.
       * This allows for relative urls as image src.
       * @since 2.7.0
       * @type Boolean
       * @default
       */
      srcFromAttribute: false,
  
      /**
       * private
       * contains last value of scaleX to detect
       * if the Image got resized after the last Render
       * @type Number
       */
      _lastScaleX: 1,
  
      /**
       * private
       * contains last value of scaleY to detect
       * if the Image got resized after the last Render
       * @type Number
       */
      _lastScaleY: 1,
  
      /**
       * private
       * contains last value of scaling applied by the apply filter chain
       * @type Number
       */
      _filterScalingX: 1,
  
      /**
       * private
       * contains last value of scaling applied by the apply filter chain
       * @type Number
       */
      _filterScalingY: 1,
  
      /**
       * minimum scale factor under which any resizeFilter is triggered to resize the image
       * 0 will disable the automatic resize. 1 will trigger automatically always.
       * number bigger than 1 are not implemented yet.
       * @type Number
       */
      minimumScaleTrigger: 0.5,
  
      /**
       * List of properties to consider when checking if
       * state of an object is changed ({@link fabric.Object#hasStateChanged})
       * as well as for history (undo/redo) purposes
       * @type Array
       */
      stateProperties: fabric.Object.prototype.stateProperties.concat('cropX', 'cropY'),
  
      /**
       * key used to retrieve the texture representing this image
       * @since 2.0.0
       * @type String
       * @default
       */
      cacheKey: '',
  
      /**
       * Image crop in pixels from original image size.
       * @since 2.0.0
       * @type Number
       * @default
       */
      cropX: 0,
  
      /**
       * Image crop in pixels from original image size.
       * @since 2.0.0
       * @type Number
       * @default
       */
      cropY: 0,
  
      /**
       * Constructor
       * @param {HTMLImageElement | String} element Image element
       * @param {Object} [options] Options object
       * @param {function} [callback] callback function to call after eventual filters applied.
       * @return {fabric.Image} thisArg
       */
      initialize: function(element, options) {
        options || (options = { });
        this.filters = [];
        this.cacheKey = 'texture' + fabric.Object.__uid++;
        this.callSuper('initialize', options);
        this._initElement(element, options);
      },
  
      /**
       * Returns image element which this instance if based on
       * @return {HTMLImageElement} Image element
       */
      getElement: function() {
        return this._element || {};
      },
  
      /**
       * Sets image element for this instance to a specified one.
       * If filters defined they are applied to new image.
       * You might need to call `canvas.renderAll` and `object.setCoords` after replacing, to render new image and update controls area.
       * @param {HTMLImageElement} element
       * @param {Object} [options] Options object
       * @return {fabric.Image} thisArg
       * @chainable
       */
      setElement: function(element, options) {
        this.removeTexture(this.cacheKey);
        this.removeTexture(this.cacheKey + '_filtered');
        this._element = element;
        this._originalElement = element;
        this._initConfig(options);
        if (this.filters.length !== 0) {
          this.applyFilters();
        }
        // resizeFilters work on the already filtered copy.
        // we need to apply resizeFilters AFTER normal filters.
        // applyResizeFilters is run more often than normal fiters
        // and is triggered by user interactions rather than dev code
        if (this.resizeFilter) {
          this.applyResizeFilters();
        }
        return this;
      },
  
      /**
       * Delete a single texture if in webgl mode
       */
      removeTexture: function(key) {
        var backend = fabric.filterBackend;
        if (backend && backend.evictCachesForKey) {
          backend.evictCachesForKey(key);
        }
      },
  
      /**
       * Delete textures, reference to elements and eventually JSDOM cleanup
       */
      dispose: function() {
        this.removeTexture(this.cacheKey);
        this.removeTexture(this.cacheKey + '_filtered');
        this._cacheContext = undefined;
        ['_originalElement', '_element', '_filteredEl', '_cacheCanvas'].forEach((function(element) {
          fabric.util.cleanUpJsdomNode(this[element]);
          this[element] = undefined;
        }).bind(this));
      },
  
      /**
       * Sets crossOrigin value (on an instance and corresponding image element)
       * @return {fabric.Image} thisArg
       * @chainable
       */
      setCrossOrigin: function(value) {
        this.crossOrigin = value;
        this._element.crossOrigin = value;
  
        return this;
      },
  
      /**
       * Returns original size of an image
       * @return {Object} Object with "width" and "height" properties
       */
      getOriginalSize: function() {
        var element = this.getElement();
        return {
          width: element.naturalWidth || element.width,
          height: element.naturalHeight || element.height
        };
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _stroke: function(ctx) {
        if (!this.stroke || this.strokeWidth === 0) {
          return;
        }
        var w = this.width / 2, h = this.height / 2;
        ctx.beginPath();
        ctx.moveTo(-w, -h);
        ctx.lineTo(w, -h);
        ctx.lineTo(w, h);
        ctx.lineTo(-w, h);
        ctx.lineTo(-w, -h);
        ctx.closePath();
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _renderDashedStroke: function(ctx) {
        var x = -this.width / 2,
            y = -this.height / 2,
            w = this.width,
            h = this.height;
  
        ctx.save();
        this._setStrokeStyles(ctx, this);
  
        ctx.beginPath();
        fabric.util.drawDashedLine(ctx, x, y, x + w, y, this.strokeDashArray);
        fabric.util.drawDashedLine(ctx, x + w, y, x + w, y + h, this.strokeDashArray);
        fabric.util.drawDashedLine(ctx, x + w, y + h, x, y + h, this.strokeDashArray);
        fabric.util.drawDashedLine(ctx, x, y + h, x, y, this.strokeDashArray);
        ctx.closePath();
        ctx.restore();
      },
  
      /**
       * Returns object representation of an instance
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object} Object representation of an instance
       */
      toObject: function(propertiesToInclude) {
        var filters = [];
  
        this.filters.forEach(function(filterObj) {
          if (filterObj) {
            filters.push(filterObj.toObject());
          }
        });
        var object = extend(
          this.callSuper(
            'toObject',
            ['crossOrigin', 'cropX', 'cropY'].concat(propertiesToInclude)
          ), {
            src: this.getSrc(),
            filters: filters,
          });
        if (this.resizeFilter) {
          object.resizeFilter = this.resizeFilter.toObject();
        }
        return object;
      },
  
      /**
       * Returns true if an image has crop applied, inspecting values of cropX,cropY,width,hight.
       * @return {Boolean}
       */
      hasCrop: function() {
        return this.cropX || this.cropY || this.width < this._element.width || this.height < this._element.height;
      },
  
      /* _TO_SVG_START_ */
      /**
       * Returns svg representation of an instance
       * @return {Array} an array of strings with the specific svg representation
       * of the instance
       */
      _toSVG: function() {
        var svgString = [], imageMarkup = [], strokeSvg,
            x = -this.width / 2, y = -this.height / 2, clipPath = '';
        if (this.hasCrop()) {
          var clipPathId = fabric.Object.__uid++;
          svgString.push(
            '<clipPath id="imageCrop_' + clipPathId + '">\n',
            '\t<rect x="' + x + '" y="' + y + '" width="' + this.width + '" height="' + this.height + '" />\n',
            '</clipPath>\n'
          );
          clipPath = ' clip-path="url(#imageCrop_' + clipPathId + ')" ';
        }
        imageMarkup.push('\t<image ', 'COMMON_PARTS', 'xlink:href="', this.getSvgSrc(true),
          '" x="', x - this.cropX, '" y="', y - this.cropY,
          // we're essentially moving origin of transformation from top/left corner to the center of the shape
          // by wrapping it in container <g> element with actual transformation, then offsetting object to the top/left
          // so that object's center aligns with container's left/top
          '" width="', this._element.width || this._element.naturalWidth,
          '" height="', this._element.height || this._element.height,
          '"', clipPath,
          '></image>\n');
  
        if (this.stroke || this.strokeDashArray) {
          var origFill = this.fill;
          this.fill = null;
          strokeSvg = [
            '\t<rect ',
            'x="', x, '" y="', y,
            '" width="', this.width, '" height="', this.height,
            '" style="', this.getSvgStyles(),
            '"/>\n'
          ];
          this.fill = origFill;
        }
        if (this.paintFirst !== 'fill') {
          svgString = svgString.concat(strokeSvg, imageMarkup);
        }
        else {
          svgString = svgString.concat(imageMarkup, strokeSvg);
        }
        return svgString;
      },
      /* _TO_SVG_END_ */
  
      /**
       * Returns source of an image
       * @param {Boolean} filtered indicates if the src is needed for svg
       * @return {String} Source of an image
       */
      getSrc: function(filtered) {
        var element = filtered ? this._element : this._originalElement;
        if (element) {
          if (element.toDataURL) {
            return element.toDataURL();
          }
  
          if (this.srcFromAttribute) {
            return element.getAttribute('src');
          }
          else {
            return element.src;
          }
        }
        else {
          return this.src || '';
        }
      },
  
      /**
       * Sets source of an image
       * @param {String} src Source string (URL)
       * @param {Function} [callback] Callback is invoked when image has been loaded (and all filters have been applied)
       * @param {Object} [options] Options object
       * @return {fabric.Image} thisArg
       * @chainable
       */
      setSrc: function(src, callback, options) {
        fabric.util.loadImage(src, function(img) {
          this.setElement(img, options);
          this._setWidthHeight();
          callback && callback(this);
        }, this, options && options.crossOrigin);
        return this;
      },
  
      /**
       * Returns string representation of an instance
       * @return {String} String representation of an instance
       */
      toString: function() {
        return '#<fabric.Image: { src: "' + this.getSrc() + '" }>';
      },
  
      applyResizeFilters: function() {
        var filter = this.resizeFilter,
            minimumScale = this.minimumScaleTrigger,
            objectScale = this.getTotalObjectScaling(),
            scaleX = objectScale.scaleX,
            scaleY = objectScale.scaleY,
            elementToFilter = this._filteredEl || this._originalElement;
        if (this.group) {
          this.set('dirty', true);
        }
        if (!filter || (scaleX > minimumScale && scaleY > minimumScale)) {
          this._element = elementToFilter;
          this._filterScalingX = 1;
          this._filterScalingY = 1;
          this._lastScaleX = scaleX;
          this._lastScaleY = scaleY;
          return;
        }
        if (!fabric.filterBackend) {
          fabric.filterBackend = fabric.initFilterBackend();
        }
        var canvasEl = fabric.util.createCanvasElement(),
            cacheKey = this._filteredEl ? (this.cacheKey + '_filtered') : this.cacheKey,
            sourceWidth = elementToFilter.width, sourceHeight = elementToFilter.height;
        canvasEl.width = sourceWidth;
        canvasEl.height = sourceHeight;
        this._element = canvasEl;
        this._lastScaleX = filter.scaleX = scaleX;
        this._lastScaleY = filter.scaleY = scaleY;
        fabric.filterBackend.applyFilters(
          [filter], elementToFilter, sourceWidth, sourceHeight, this._element, cacheKey);
        this._filterScalingX = canvasEl.width / this._originalElement.width;
        this._filterScalingY = canvasEl.height / this._originalElement.height;
      },
  
      /**
       * Applies filters assigned to this image (from "filters" array) or from filter param
       * @method applyFilters
       * @param {Array} filters to be applied
       * @param {Boolean} forResizing specify if the filter operation is a resize operation
       * @return {thisArg} return the fabric.Image object
       * @chainable
       */
      applyFilters: function(filters) {
  
        filters = filters || this.filters || [];
        filters = filters.filter(function(filter) { return filter && !filter.isNeutralState(); });
        this.set('dirty', true);
  
        // needs to clear out or WEBGL will not resize correctly
        this.removeTexture(this.cacheKey + '_filtered');
  
        if (filters.length === 0) {
          this._element = this._originalElement;
          this._filteredEl = null;
          this._filterScalingX = 1;
          this._filterScalingY = 1;
          return this;
        }
  
        var imgElement = this._originalElement,
            sourceWidth = imgElement.naturalWidth || imgElement.width,
            sourceHeight = imgElement.naturalHeight || imgElement.height;
  
        if (this._element === this._originalElement) {
          // if the element is the same we need to create a new element
          var canvasEl = fabric.util.createCanvasElement();
          canvasEl.width = sourceWidth;
          canvasEl.height = sourceHeight;
          this._element = canvasEl;
          this._filteredEl = canvasEl;
        }
        else {
          // clear the existing element to get new filter data
          // also dereference the eventual resized _element
          this._element = this._filteredEl;
          this._filteredEl.getContext('2d').clearRect(0, 0, sourceWidth, sourceHeight);
          // we also need to resize again at next renderAll, so remove saved _lastScaleX/Y
          this._lastScaleX = 1;
          this._lastScaleY = 1;
        }
        if (!fabric.filterBackend) {
          fabric.filterBackend = fabric.initFilterBackend();
        }
        fabric.filterBackend.applyFilters(
          filters, this._originalElement, sourceWidth, sourceHeight, this._element, this.cacheKey);
        if (this._originalElement.width !== this._element.width ||
          this._originalElement.height !== this._element.height) {
          this._filterScalingX = this._element.width / this._originalElement.width;
          this._filterScalingY = this._element.height / this._originalElement.height;
        }
        return this;
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _render: function(ctx) {
        if (this.isMoving !== true && this.resizeFilter && this._needsResize()) {
          this.applyResizeFilters();
        }
        this._stroke(ctx);
        this._renderPaintInOrder(ctx);
      },
  
      /**
       * Decide if the object should cache or not. Create its own cache level
       * needsItsOwnCache should be used when the object drawing method requires
       * a cache step. None of the fabric classes requires it.
       * Generally you do not cache objects in groups because the group outside is cached.
       * This is the special image version where we would like to avoid caching where possible.
       * Essentially images do not benefit from caching. They may require caching, and in that
       * case we do it. Also caching an image usually ends in a loss of details.
       * A full performance audit should be done.
       * @return {Boolean}
       */
      shouldCache: function() {
        return this.needsItsOwnCache();
      },
  
      _renderFill: function(ctx) {
        var elementToDraw = this._element,
            w = this.width, h = this.height,
            sW = Math.min(elementToDraw.naturalWidth || elementToDraw.width, w * this._filterScalingX),
            sH = Math.min(elementToDraw.naturalHeight || elementToDraw.height, h * this._filterScalingY),
            x = -w / 2, y = -h / 2,
            sX = Math.max(0, this.cropX * this._filterScalingX),
            sY = Math.max(0, this.cropY * this._filterScalingY);
  
        elementToDraw && ctx.drawImage(elementToDraw, sX, sY, sW, sH, x, y, w, h);
      },
  
      /**
       * needed to check if image needs resize
       * @private
       */
      _needsResize: function() {
        var scale = this.getTotalObjectScaling();
        return (scale.scaleX !== this._lastScaleX || scale.scaleY !== this._lastScaleY);
      },
  
      /**
       * @private
       */
      _resetWidthHeight: function() {
        this.set(this.getOriginalSize());
      },
  
      /**
       * The Image class's initialization method. This method is automatically
       * called by the constructor.
       * @private
       * @param {HTMLImageElement|String} element The element representing the image
       * @param {Object} [options] Options object
       */
      _initElement: function(element, options) {
        this.setElement(fabric.util.getById(element), options);
        fabric.util.addClass(this.getElement(), fabric.Image.CSS_CANVAS);
      },
  
      /**
       * @private
       * @param {Object} [options] Options object
       */
      _initConfig: function(options) {
        options || (options = { });
        this.setOptions(options);
        this._setWidthHeight(options);
        if (this._element && this.crossOrigin) {
          this._element.crossOrigin = this.crossOrigin;
        }
      },
  
      /**
       * @private
       * @param {Array} filters to be initialized
       * @param {Function} callback Callback to invoke when all fabric.Image.filters instances are created
       */
      _initFilters: function(filters, callback) {
        if (filters && filters.length) {
          fabric.util.enlivenObjects(filters, function(enlivenedObjects) {
            callback && callback(enlivenedObjects);
          }, 'fabric.Image.filters');
        }
        else {
          callback && callback();
        }
      },
  
      /**
       * @private
       * Set the width and the height of the image object, using the element or the
       * options.
       * @param {Object} [options] Object with width/height properties
       */
      _setWidthHeight: function(options) {
        options || (options = { });
        var el = this.getElement();
        this.width = options.width || el.naturalWidth || el.width || 0;
        this.height = options.height || el.naturalHeight || el.height || 0;
      },
  
      /**
       * Calculate offset for center and scale factor for the image in order to respect
       * the preserveAspectRatio attribute
       * @private
       * @return {Object}
       */
      parsePreserveAspectRatioAttribute: function() {
        var pAR = fabric.util.parsePreserveAspectRatioAttribute(this.preserveAspectRatio || ''),
            rWidth = this._element.width, rHeight = this._element.height,
            scaleX = 1, scaleY = 1, offsetLeft = 0, offsetTop = 0, cropX = 0, cropY = 0,
            offset, pWidth = this.width, pHeight = this.height, parsedAttributes = { width: pWidth, height: pHeight };
        if (pAR && (pAR.alignX !== 'none' || pAR.alignY !== 'none')) {
          if (pAR.meetOrSlice === 'meet') {
            scaleX = scaleY = fabric.util.findScaleToFit(this._element, parsedAttributes);
            offset = (pWidth - rWidth * scaleX) / 2;
            if (pAR.alignX === 'Min') {
              offsetLeft = -offset;
            }
            if (pAR.alignX === 'Max') {
              offsetLeft = offset;
            }
            offset = (pHeight - rHeight * scaleY) / 2;
            if (pAR.alignY === 'Min') {
              offsetTop = -offset;
            }
            if (pAR.alignY === 'Max') {
              offsetTop = offset;
            }
          }
          if (pAR.meetOrSlice === 'slice') {
            scaleX = scaleY = fabric.util.findScaleToCover(this._element, parsedAttributes);
            offset = rWidth - pWidth / scaleX;
            if (pAR.alignX === 'Mid') {
              cropX = offset / 2;
            }
            if (pAR.alignX === 'Max') {
              cropX = offset;
            }
            offset = rHeight - pHeight / scaleY;
            if (pAR.alignY === 'Mid') {
              cropY = offset / 2;
            }
            if (pAR.alignY === 'Max') {
              cropY = offset;
            }
            rWidth = pWidth / scaleX;
            rHeight = pHeight / scaleY;
          }
        }
        else {
          scaleX = pWidth / rWidth;
          scaleY = pHeight / rHeight;
        }
        return {
          width: rWidth,
          height: rHeight,
          scaleX: scaleX,
          scaleY: scaleY,
          offsetLeft: offsetLeft,
          offsetTop: offsetTop,
          cropX: cropX,
          cropY: cropY
        };
      }
    });
  
    /**
     * Default CSS class name for canvas
     * @static
     * @type String
     * @default
     */
    fabric.Image.CSS_CANVAS = 'canvas-img';
  
    /**
     * Alias for getSrc
     * @static
     */
    fabric.Image.prototype.getSvgSrc = fabric.Image.prototype.getSrc;
  
    /**
     * Creates an instance of fabric.Image from its object representation
     * @static
     * @param {Object} object Object to create an instance from
     * @param {Function} callback Callback to invoke when an image instance is created
     */
    fabric.Image.fromObject = function(_object, callback) {
      var object = fabric.util.object.clone(_object);
      fabric.util.loadImage(object.src, function(img, error) {
        if (error) {
          callback && callback(null, error);
          return;
        }
        fabric.Image.prototype._initFilters.call(object, object.filters, function(filters) {
          object.filters = filters || [];
          fabric.Image.prototype._initFilters.call(object, [object.resizeFilter], function(resizeFilters) {
            object.resizeFilter = resizeFilters[0];
            fabric.util.enlivenObjects([object.clipPath], function(enlivedProps) {
              object.clipPath = enlivedProps[0];
              var image = new fabric.Image(img, object);
              callback(image);
            });
          });
        });
      }, null, object.crossOrigin);
    };
  
    /**
     * Creates an instance of fabric.Image from an URL string
     * @static
     * @param {String} url URL to create an image from
     * @param {Function} [callback] Callback to invoke when image is created (newly created image is passed as a first argument)
     * @param {Object} [imgOptions] Options object
     */
    fabric.Image.fromURL = function(url, callback, imgOptions) {
      fabric.util.loadImage(url, function(img) {
        callback && callback(new fabric.Image(img, imgOptions));
      }, null, imgOptions && imgOptions.crossOrigin);
    };
  
    /* _FROM_SVG_START_ */
    /**
     * List of attribute names to account for when parsing SVG element (used by {@link fabric.Image.fromElement})
     * @static
     * @see {@link http://www.w3.org/TR/SVG/struct.html#ImageElement}
     */
    fabric.Image.ATTRIBUTE_NAMES =
      fabric.SHARED_ATTRIBUTES.concat('x y width height preserveAspectRatio xlink:href crossOrigin'.split(' '));
  
    /**
     * Returns {@link fabric.Image} instance from an SVG element
     * @static
     * @param {SVGElement} element Element to parse
     * @param {Object} [options] Options object
     * @param {Function} callback Callback to execute when fabric.Image object is created
     * @return {fabric.Image} Instance of fabric.Image
     */
    fabric.Image.fromElement = function(element, callback, options) {
      var parsedAttributes = fabric.parseAttributes(element, fabric.Image.ATTRIBUTE_NAMES);
      fabric.Image.fromURL(parsedAttributes['xlink:href'], callback,
        extend((options ? fabric.util.object.clone(options) : { }), parsedAttributes));
    };
    /* _FROM_SVG_END_ */
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  fabric.util.object.extend(fabric.Object.prototype, /** @lends fabric.Object.prototype */ {
  
    /**
     * @private
     * @return {Number} angle value
     */
    _getAngleValueForStraighten: function() {
      var angle = this.angle % 360;
      if (angle > 0) {
        return Math.round((angle - 1) / 90) * 90;
      }
      return Math.round(angle / 90) * 90;
    },
  
    /**
     * Straightens an object (rotating it from current angle to one of 0, 90, 180, 270, etc. depending on which is closer)
     * @return {fabric.Object} thisArg
     * @chainable
     */
    straighten: function() {
      this.rotate(this._getAngleValueForStraighten());
      return this;
    },
  
    /**
     * Same as {@link fabric.Object.prototype.straighten} but with animation
     * @param {Object} callbacks Object with callback functions
     * @param {Function} [callbacks.onComplete] Invoked on completion
     * @param {Function} [callbacks.onChange] Invoked on every step of animation
     * @return {fabric.Object} thisArg
     * @chainable
     */
    fxStraighten: function(callbacks) {
      callbacks = callbacks || { };
  
      var empty = function() { },
          onComplete = callbacks.onComplete || empty,
          onChange = callbacks.onChange || empty,
          _this = this;
  
      fabric.util.animate({
        startValue: this.get('angle'),
        endValue: this._getAngleValueForStraighten(),
        duration: this.FX_DURATION,
        onChange: function(value) {
          _this.rotate(value);
          onChange();
        },
        onComplete: function() {
          _this.setCoords();
          onComplete();
        },
      });
  
      return this;
    }
  });
  
  fabric.util.object.extend(fabric.StaticCanvas.prototype, /** @lends fabric.StaticCanvas.prototype */ {
  
    /**
     * Straightens object, then rerenders canvas
     * @param {fabric.Object} object Object to straighten
     * @return {fabric.Canvas} thisArg
     * @chainable
     */
    straightenObject: function (object) {
      object.straighten();
      this.requestRenderAll();
      return this;
    },
  
    /**
     * Same as {@link fabric.Canvas.prototype.straightenObject}, but animated
     * @param {fabric.Object} object Object to straighten
     * @return {fabric.Canvas} thisArg
     * @chainable
     */
    fxStraightenObject: function (object) {
      object.fxStraighten({
        onChange: this.requestRenderAllBound
      });
      return this;
    }
  });
  
  
  (function() {
  
    'use strict';
  
    /**
     * Tests if webgl supports certain precision
     * @param {WebGL} Canvas WebGL context to test on
     * @param {String} Precision to test can be any of following: 'lowp', 'mediump', 'highp'
     * @returns {Boolean} Whether the user's browser WebGL supports given precision.
     */
    function testPrecision(gl, precision){
      var fragmentSource = 'precision ' + precision + ' float;\nvoid main(){}';
      var fragmentShader = gl.createShader(gl.FRAGMENT_SHADER);
      gl.shaderSource(fragmentShader, fragmentSource);
      gl.compileShader(fragmentShader);
      if (!gl.getShaderParameter(fragmentShader, gl.COMPILE_STATUS)) {
        return false;
      }
      return true;
    }
  
    /**
     * Indicate whether this filtering backend is supported by the user's browser.
     * @param {Number} tileSize check if the tileSize is supported
     * @returns {Boolean} Whether the user's browser supports WebGL.
     */
    fabric.isWebglSupported = function(tileSize) {
      if (fabric.isLikelyNode) {
        return false;
      }
      tileSize = tileSize || fabric.WebglFilterBackend.prototype.tileSize;
      var canvas = document.createElement('canvas');
      var gl = canvas.getContext('webgl') || canvas.getContext('experimental-webgl');
      var isSupported = false;
      // eslint-disable-next-line
      if (gl) {
        fabric.maxTextureSize = gl.getParameter(gl.MAX_TEXTURE_SIZE);
        isSupported = fabric.maxTextureSize >= tileSize;
        var precisions = ['highp', 'mediump', 'lowp'];
        for (var i = 0; i < 3; i++){
          if (testPrecision(gl, precisions[i])){
            fabric.webGlPrecision = precisions[i];
            break;
          };
        }
      }
      this.isSupported = isSupported;
      return isSupported;
    };
  
    fabric.WebglFilterBackend = WebglFilterBackend;
  
    /**
     * WebGL filter backend.
     */
    function WebglFilterBackend(options) {
      if (options && options.tileSize) {
        this.tileSize = options.tileSize;
      }
      this.setupGLContext(this.tileSize, this.tileSize);
      this.captureGPUInfo();
    };
  
    WebglFilterBackend.prototype = /** @lends fabric.WebglFilterBackend.prototype */ {
  
      tileSize: 2048,
  
      /**
       * Experimental. This object is a sort of repository of help layers used to avoid
       * of recreating them during frequent filtering. If you are previewing a filter with
       * a slider you problably do not want to create help layers every filter step.
       * in this object there will be appended some canvases, created once, resized sometimes
       * cleared never. Clearing is left to the developer.
       **/
      resources: {
  
      },
  
      /**
       * Setup a WebGL context suitable for filtering, and bind any needed event handlers.
       */
      setupGLContext: function(width, height) {
        this.dispose();
        this.createWebGLCanvas(width, height);
        // eslint-disable-next-line
        this.aPosition = new Float32Array([0, 0, 0, 1, 1, 0, 1, 1]);
        this.chooseFastestCopyGLTo2DMethod(width, height);
      },
  
      /**
       * Pick a method to copy data from GL context to 2d canvas.  In some browsers using
       * putImageData is faster than drawImage for that specific operation.
       */
      chooseFastestCopyGLTo2DMethod: function(width, height) {
        var canMeasurePerf = typeof window.performance !== 'undefined', canUseImageData;
        try {
          new ImageData(1, 1);
          canUseImageData = true;
        }
        catch (e) {
          canUseImageData = false;
        }
        // eslint-disable-next-line no-undef
        var canUseArrayBuffer = typeof ArrayBuffer !== 'undefined';
        // eslint-disable-next-line no-undef
        var canUseUint8Clamped = typeof Uint8ClampedArray !== 'undefined';
  
        if (!(canMeasurePerf && canUseImageData && canUseArrayBuffer && canUseUint8Clamped)) {
          return;
        }
  
        var targetCanvas = fabric.util.createCanvasElement();
        // eslint-disable-next-line no-undef
        var imageBuffer = new ArrayBuffer(width * height * 4);
        if (fabric.forceGLPutImageData) {
          this.imageBuffer = imageBuffer;
          this.copyGLTo2D = copyGLTo2DPutImageData;
          return;
        }
        var testContext = {
          imageBuffer: imageBuffer,
          destinationWidth: width,
          destinationHeight: height,
          targetCanvas: targetCanvas
        };
        var startTime, drawImageTime, putImageDataTime;
        targetCanvas.width = width;
        targetCanvas.height = height;
  
        startTime = window.performance.now();
        copyGLTo2DDrawImage.call(testContext, this.gl, testContext);
        drawImageTime = window.performance.now() - startTime;
  
        startTime = window.performance.now();
        copyGLTo2DPutImageData.call(testContext, this.gl, testContext);
        putImageDataTime = window.performance.now() - startTime;
  
        if (drawImageTime > putImageDataTime) {
          this.imageBuffer = imageBuffer;
          this.copyGLTo2D = copyGLTo2DPutImageData;
        }
        else {
          this.copyGLTo2D = copyGLTo2DDrawImage;
        }
      },
  
      /**
       * Create a canvas element and associated WebGL context and attaches them as
       * class properties to the GLFilterBackend class.
       */
      createWebGLCanvas: function(width, height) {
        var canvas = fabric.util.createCanvasElement();
        canvas.width = width;
        canvas.height = height;
        var glOptions = {
              alpha: true,
              premultipliedAlpha: false,
              depth: false,
              stencil: false,
              antialias: false
            },
            gl = canvas.getContext('webgl', glOptions);
        if (!gl) {
          gl = canvas.getContext('experimental-webgl', glOptions);
        }
        if (!gl) {
          return;
        }
        gl.clearColor(0, 0, 0, 0);
        // this canvas can fire webglcontextlost and webglcontextrestored
        this.canvas = canvas;
        this.gl = gl;
      },
  
      /**
       * Attempts to apply the requested filters to the source provided, drawing the filtered output
       * to the provided target canvas.
       *
       * @param {Array} filters The filters to apply.
       * @param {HTMLImageElement|HTMLCanvasElement} source The source to be filtered.
       * @param {Number} width The width of the source input.
       * @param {Number} height The height of the source input.
       * @param {HTMLCanvasElement} targetCanvas The destination for filtered output to be drawn.
       * @param {String|undefined} cacheKey A key used to cache resources related to the source. If
       * omitted, caching will be skipped.
       */
      applyFilters: function(filters, source, width, height, targetCanvas, cacheKey) {
        var gl = this.gl;
        var cachedTexture;
        if (cacheKey) {
          cachedTexture = this.getCachedTexture(cacheKey, source);
        }
        var pipelineState = {
          originalWidth: source.width || source.originalWidth,
          originalHeight: source.height || source.originalHeight,
          sourceWidth: width,
          sourceHeight: height,
          destinationWidth: width,
          destinationHeight: height,
          context: gl,
          sourceTexture: this.createTexture(gl, width, height, !cachedTexture && source),
          targetTexture: this.createTexture(gl, width, height),
          originalTexture: cachedTexture ||
            this.createTexture(gl, width, height, !cachedTexture && source),
          passes: filters.length,
          webgl: true,
          aPosition: this.aPosition,
          programCache: this.programCache,
          pass: 0,
          filterBackend: this,
          targetCanvas: targetCanvas
        };
        var tempFbo = gl.createFramebuffer();
        gl.bindFramebuffer(gl.FRAMEBUFFER, tempFbo);
        filters.forEach(function(filter) { filter && filter.applyTo(pipelineState); });
        resizeCanvasIfNeeded(pipelineState);
        this.copyGLTo2D(gl, pipelineState);
        gl.bindTexture(gl.TEXTURE_2D, null);
        gl.deleteTexture(pipelineState.sourceTexture);
        gl.deleteTexture(pipelineState.targetTexture);
        gl.deleteFramebuffer(tempFbo);
        targetCanvas.getContext('2d').setTransform(1, 0, 0, 1, 0, 0);
        return pipelineState;
      },
  
      /**
       * Detach event listeners, remove references, and clean up caches.
       */
      dispose: function() {
        if (this.canvas) {
          this.canvas = null;
          this.gl = null;
        }
        this.clearWebGLCaches();
      },
  
      /**
       * Wipe out WebGL-related caches.
       */
      clearWebGLCaches: function() {
        this.programCache = {};
        this.textureCache = {};
      },
  
      /**
       * Create a WebGL texture object.
       *
       * Accepts specific dimensions to initialize the textuer to or a source image.
       *
       * @param {WebGLRenderingContext} gl The GL context to use for creating the texture.
       * @param {Number} width The width to initialize the texture at.
       * @param {Number} height The height to initialize the texture.
       * @param {HTMLImageElement|HTMLCanvasElement} textureImageSource A source for the texture data.
       * @returns {WebGLTexture}
       */
      createTexture: function(gl, width, height, textureImageSource) {
        var texture = gl.createTexture();
        gl.bindTexture(gl.TEXTURE_2D, texture);
        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
        if (textureImageSource) {
          gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, textureImageSource);
        }
        else {
          gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, width, height, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
        }
        return texture;
      },
  
      /**
       * Can be optionally used to get a texture from the cache array
       *
       * If an existing texture is not found, a new texture is created and cached.
       *
       * @param {String} uniqueId A cache key to use to find an existing texture.
       * @param {HTMLImageElement|HTMLCanvasElement} textureImageSource A source to use to create the
       * texture cache entry if one does not already exist.
       */
      getCachedTexture: function(uniqueId, textureImageSource) {
        if (this.textureCache[uniqueId]) {
          return this.textureCache[uniqueId];
        }
        else {
          var texture = this.createTexture(
            this.gl, textureImageSource.width, textureImageSource.height, textureImageSource);
          this.textureCache[uniqueId] = texture;
          return texture;
        }
      },
  
      /**
       * Clear out cached resources related to a source image that has been
       * filtered previously.
       *
       * @param {String} cacheKey The cache key provided when the source image was filtered.
       */
      evictCachesForKey: function(cacheKey) {
        if (this.textureCache[cacheKey]) {
          this.gl.deleteTexture(this.textureCache[cacheKey]);
          delete this.textureCache[cacheKey];
        }
      },
  
      copyGLTo2D: copyGLTo2DDrawImage,
  
      /**
       * Attempt to extract GPU information strings from a WebGL context.
       *
       * Useful information when debugging or blacklisting specific GPUs.
       *
       * @returns {Object} A GPU info object with renderer and vendor strings.
       */
      captureGPUInfo: function() {
        if (this.gpuInfo) {
          return this.gpuInfo;
        }
        var gl = this.gl, gpuInfo = { renderer: '', vendor: '' };
        if (!gl) {
          return gpuInfo;
        }
        var ext = gl.getExtension('WEBGL_debug_renderer_info');
        if (ext) {
          var renderer = gl.getParameter(ext.UNMASKED_RENDERER_WEBGL);
          var vendor = gl.getParameter(ext.UNMASKED_VENDOR_WEBGL);
          if (renderer) {
            gpuInfo.renderer = renderer.toLowerCase();
          }
          if (vendor) {
            gpuInfo.vendor = vendor.toLowerCase();
          }
        }
        this.gpuInfo = gpuInfo;
        return gpuInfo;
      },
    };
  })();
  
  function resizeCanvasIfNeeded(pipelineState) {
    var targetCanvas = pipelineState.targetCanvas,
        width = targetCanvas.width, height = targetCanvas.height,
        dWidth = pipelineState.destinationWidth,
        dHeight = pipelineState.destinationHeight;
  
    if (width !== dWidth || height !== dHeight) {
      targetCanvas.width = dWidth;
      targetCanvas.height = dHeight;
    }
  }
  
  /**
   * Copy an input WebGL canvas on to an output 2D canvas.
   *
   * The WebGL canvas is assumed to be upside down, with the top-left pixel of the
   * desired output image appearing in the bottom-left corner of the WebGL canvas.
   *
   * @param {WebGLRenderingContext} sourceContext The WebGL context to copy from.
   * @param {HTMLCanvasElement} targetCanvas The 2D target canvas to copy on to.
   * @param {Object} pipelineState The 2D target canvas to copy on to.
   */
  function copyGLTo2DDrawImage(gl, pipelineState) {
    var glCanvas = gl.canvas, targetCanvas = pipelineState.targetCanvas,
        ctx = targetCanvas.getContext('2d');
    ctx.translate(0, targetCanvas.height); // move it down again
    ctx.scale(1, -1); // vertical flip
    // where is my image on the big glcanvas?
    var sourceY = glCanvas.height - targetCanvas.height;
    ctx.drawImage(glCanvas, 0, sourceY, targetCanvas.width, targetCanvas.height, 0, 0,
      targetCanvas.width, targetCanvas.height);
  }
  
  /**
   * Copy an input WebGL canvas on to an output 2D canvas using 2d canvas' putImageData
   * API. Measurably faster than using ctx.drawImage in Firefox (version 54 on OSX Sierra).
   *
   * @param {WebGLRenderingContext} sourceContext The WebGL context to copy from.
   * @param {HTMLCanvasElement} targetCanvas The 2D target canvas to copy on to.
   * @param {Object} pipelineState The 2D target canvas to copy on to.
   */
  function copyGLTo2DPutImageData(gl, pipelineState) {
    var targetCanvas = pipelineState.targetCanvas, ctx = targetCanvas.getContext('2d'),
        dWidth = pipelineState.destinationWidth,
        dHeight = pipelineState.destinationHeight,
        numBytes = dWidth * dHeight * 4;
  
    // eslint-disable-next-line no-undef
    var u8 = new Uint8Array(this.imageBuffer, 0, numBytes);
    // eslint-disable-next-line no-undef
    var u8Clamped = new Uint8ClampedArray(this.imageBuffer, 0, numBytes);
  
    gl.readPixels(0, 0, dWidth, dHeight, gl.RGBA, gl.UNSIGNED_BYTE, u8);
    var imgData = new ImageData(u8Clamped, dWidth, dHeight);
    ctx.putImageData(imgData, 0, 0);
  }
  
  
  (function() {
  
    'use strict';
  
    var noop = function() {};
  
    fabric.Canvas2dFilterBackend = Canvas2dFilterBackend;
  
    /**
     * Canvas 2D filter backend.
     */
    function Canvas2dFilterBackend() {};
  
    Canvas2dFilterBackend.prototype = /** @lends fabric.Canvas2dFilterBackend.prototype */ {
      evictCachesForKey: noop,
      dispose: noop,
      clearWebGLCaches: noop,
  
      /**
       * Experimental. This object is a sort of repository of help layers used to avoid
       * of recreating them during frequent filtering. If you are previewing a filter with
       * a slider you probably do not want to create help layers every filter step.
       * in this object there will be appended some canvases, created once, resized sometimes
       * cleared never. Clearing is left to the developer.
       **/
      resources: {
  
      },
  
      /**
       * Apply a set of filters against a source image and draw the filtered output
       * to the provided destination canvas.
       *
       * @param {EnhancedFilter} filters The filter to apply.
       * @param {HTMLImageElement|HTMLCanvasElement} sourceElement The source to be filtered.
       * @param {Number} sourceWidth The width of the source input.
       * @param {Number} sourceHeight The height of the source input.
       * @param {HTMLCanvasElement} targetCanvas The destination for filtered output to be drawn.
       */
      applyFilters: function(filters, sourceElement, sourceWidth, sourceHeight, targetCanvas) {
        var ctx = targetCanvas.getContext('2d');
        ctx.drawImage(sourceElement, 0, 0, sourceWidth, sourceHeight);
        var imageData = ctx.getImageData(0, 0, sourceWidth, sourceHeight);
        var originalImageData = ctx.getImageData(0, 0, sourceWidth, sourceHeight);
        var pipelineState = {
          sourceWidth: sourceWidth,
          sourceHeight: sourceHeight,
          imageData: imageData,
          originalEl: sourceElement,
          originalImageData: originalImageData,
          canvasEl: targetCanvas,
          ctx: ctx,
          filterBackend: this,
        };
        filters.forEach(function(filter) { filter.applyTo(pipelineState); });
        if (pipelineState.imageData.width !== sourceWidth || pipelineState.imageData.height !== sourceHeight) {
          targetCanvas.width = pipelineState.imageData.width;
          targetCanvas.height = pipelineState.imageData.height;
        }
        ctx.putImageData(pipelineState.imageData, 0, 0);
        return pipelineState;
      },
  
    };
  })();
  
  
  /**
   * @namespace fabric.Image.filters
   * @memberOf fabric.Image
   * @tutorial {@link http://fabricjs.com/fabric-intro-part-2#image_filters}
   * @see {@link http://fabricjs.com/image-filters|ImageFilters demo}
   */
  fabric.Image = fabric.Image || { };
  fabric.Image.filters = fabric.Image.filters || { };
  
  /**
   * Root filter class from which all filter classes inherit from
   * @class fabric.Image.filters.BaseFilter
   * @memberOf fabric.Image.filters
   */
  fabric.Image.filters.BaseFilter = fabric.util.createClass(/** @lends fabric.Image.filters.BaseFilter.prototype */ {
  
    /**
     * Filter type
     * @param {String} type
     * @default
     */
    type: 'BaseFilter',
  
    /**
     * Array of attributes to send with buffers. do not modify
     * @private
     */
  
    vertexSource: 'attribute vec2 aPosition;\n' +
      'varying vec2 vTexCoord;\n' +
      'void main() {\n' +
        'vTexCoord = aPosition;\n' +
        'gl_Position = vec4(aPosition * 2.0 - 1.0, 0.0, 1.0);\n' +
      '}',
  
    fragmentSource: 'precision highp float;\n' +
      'varying vec2 vTexCoord;\n' +
      'uniform sampler2D uTexture;\n' +
      'void main() {\n' +
        'gl_FragColor = texture2D(uTexture, vTexCoord);\n' +
      '}',
  
    /**
     * Constructor
     * @param {Object} [options] Options object
     */
    initialize: function(options) {
      if (options) {
        this.setOptions(options);
      }
    },
  
    /**
     * Sets filter's properties from options
     * @param {Object} [options] Options object
     */
    setOptions: function(options) {
      for (var prop in options) {
        this[prop] = options[prop];
      }
    },
  
    /**
     * Compile this filter's shader program.
     *
     * @param {WebGLRenderingContext} gl The GL canvas context to use for shader compilation.
     * @param {String} fragmentSource fragmentShader source for compilation
     * @param {String} vertexSource vertexShader source for compilation
     */
    createProgram: function(gl, fragmentSource, vertexSource) {
      fragmentSource = fragmentSource || this.fragmentSource;
      vertexSource = vertexSource || this.vertexSource;
      if (fabric.webGlPrecision !== 'highp'){
        fragmentSource = fragmentSource.replace(
          /precision highp float/g,
          'precision ' + fabric.webGlPrecision + ' float'
        );
      }
      var vertexShader = gl.createShader(gl.VERTEX_SHADER);
      gl.shaderSource(vertexShader, vertexSource);
      gl.compileShader(vertexShader);
      if (!gl.getShaderParameter(vertexShader, gl.COMPILE_STATUS)) {
        throw new Error(
          // eslint-disable-next-line prefer-template
          'Vertex shader compile error for ' + this.type + ': ' +
          gl.getShaderInfoLog(vertexShader)
        );
      }
  
      var fragmentShader = gl.createShader(gl.FRAGMENT_SHADER);
      gl.shaderSource(fragmentShader, fragmentSource);
      gl.compileShader(fragmentShader);
      if (!gl.getShaderParameter(fragmentShader, gl.COMPILE_STATUS)) {
        throw new Error(
          // eslint-disable-next-line prefer-template
          'Fragment shader compile error for ' + this.type + ': ' +
          gl.getShaderInfoLog(fragmentShader)
        );
      }
  
      var program = gl.createProgram();
      gl.attachShader(program, vertexShader);
      gl.attachShader(program, fragmentShader);
      gl.linkProgram(program);
      if (!gl.getProgramParameter(program, gl.LINK_STATUS)) {
        throw new Error(
          // eslint-disable-next-line prefer-template
          'Shader link error for "${this.type}" ' +
          gl.getProgramInfoLog(program)
        );
      }
  
      var attributeLocations = this.getAttributeLocations(gl, program);
      var uniformLocations = this.getUniformLocations(gl, program) || { };
      uniformLocations.uStepW = gl.getUniformLocation(program, 'uStepW');
      uniformLocations.uStepH = gl.getUniformLocation(program, 'uStepH');
      return {
        program: program,
        attributeLocations: attributeLocations,
        uniformLocations: uniformLocations
      };
    },
  
    /**
     * Return a map of attribute names to WebGLAttributeLocation objects.
     *
     * @param {WebGLRenderingContext} gl The canvas context used to compile the shader program.
     * @param {WebGLShaderProgram} program The shader program from which to take attribute locations.
     * @returns {Object} A map of attribute names to attribute locations.
     */
    getAttributeLocations: function(gl, program) {
      return {
        aPosition: gl.getAttribLocation(program, 'aPosition'),
      };
    },
  
    /**
     * Return a map of uniform names to WebGLUniformLocation objects.
     *
     * Intended to be overridden by subclasses.
     *
     * @param {WebGLRenderingContext} gl The canvas context used to compile the shader program.
     * @param {WebGLShaderProgram} program The shader program from which to take uniform locations.
     * @returns {Object} A map of uniform names to uniform locations.
     */
    getUniformLocations: function (/* gl, program */) {
      // in case i do not need any special uniform i need to return an empty object
      return { };
    },
  
    /**
     * Send attribute data from this filter to its shader program on the GPU.
     *
     * @param {WebGLRenderingContext} gl The canvas context used to compile the shader program.
     * @param {Object} attributeLocations A map of shader attribute names to their locations.
     */
    sendAttributeData: function(gl, attributeLocations, aPositionData) {
      var attributeLocation = attributeLocations.aPosition;
      var buffer = gl.createBuffer();
      gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
      gl.enableVertexAttribArray(attributeLocation);
      gl.vertexAttribPointer(attributeLocation, 2, gl.FLOAT, false, 0, 0);
      gl.bufferData(gl.ARRAY_BUFFER, aPositionData, gl.STATIC_DRAW);
    },
  
    _setupFrameBuffer: function(options) {
      var gl = options.context, width, height;
      if (options.passes > 1) {
        width = options.destinationWidth;
        height = options.destinationHeight;
        if (options.sourceWidth !== width || options.sourceHeight !== height) {
          gl.deleteTexture(options.targetTexture);
          options.targetTexture = options.filterBackend.createTexture(gl, width, height);
        }
        gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D,
          options.targetTexture, 0);
      }
      else {
        // draw last filter on canvas and not to framebuffer.
        gl.bindFramebuffer(gl.FRAMEBUFFER, null);
        gl.finish();
      }
    },
  
    _swapTextures: function(options) {
      options.passes--;
      options.pass++;
      var temp = options.targetTexture;
      options.targetTexture = options.sourceTexture;
      options.sourceTexture = temp;
    },
  
    /**
     * Generic isNeutral implementation for one parameter based filters.
     * Used only in image applyFilters to discard filters that will not have an effect
     * on the image
     * Other filters may need their own verison ( ColorMatrix, HueRotation, gamma, ComposedFilter )
     * @param {Object} options
     **/
    isNeutralState: function(/* options */) {
      var main = this.mainParameter,
          _class = fabric.Image.filters[this.type].prototype;
      if (main) {
        if (Array.isArray(_class[main])) {
          for (var i = _class[main].length; i--;) {
            if (this[main][i] !== _class[main][i]) {
              return false;
            }
          }
          return true;
        }
        else {
          return _class[main] === this[main];
        }
      }
      else {
        return false;
      }
    },
  
    /**
     * Apply this filter to the input image data provided.
     *
     * Determines whether to use WebGL or Canvas2D based on the options.webgl flag.
     *
     * @param {Object} options
     * @param {Number} options.passes The number of filters remaining to be executed
     * @param {Boolean} options.webgl Whether to use webgl to render the filter.
     * @param {WebGLTexture} options.sourceTexture The texture setup as the source to be filtered.
     * @param {WebGLTexture} options.targetTexture The texture where filtered output should be drawn.
     * @param {WebGLRenderingContext} options.context The GL context used for rendering.
     * @param {Object} options.programCache A map of compiled shader programs, keyed by filter type.
     */
    applyTo: function(options) {
      if (options.webgl) {
        this._setupFrameBuffer(options);
        this.applyToWebGL(options);
        this._swapTextures(options);
      }
      else {
        this.applyTo2d(options);
      }
    },
  
    /**
     * Retrieves the cached shader.
     * @param {Object} options
     * @param {WebGLRenderingContext} options.context The GL context used for rendering.
     * @param {Object} options.programCache A map of compiled shader programs, keyed by filter type.
     */
    retrieveShader: function(options) {
      if (!options.programCache.hasOwnProperty(this.type)) {
        options.programCache[this.type] = this.createProgram(options.context);
      }
      return options.programCache[this.type];
    },
  
    /**
     * Apply this filter using webgl.
     *
     * @param {Object} options
     * @param {Number} options.passes The number of filters remaining to be executed
     * @param {Boolean} options.webgl Whether to use webgl to render the filter.
     * @param {WebGLTexture} options.originalTexture The texture of the original input image.
     * @param {WebGLTexture} options.sourceTexture The texture setup as the source to be filtered.
     * @param {WebGLTexture} options.targetTexture The texture where filtered output should be drawn.
     * @param {WebGLRenderingContext} options.context The GL context used for rendering.
     * @param {Object} options.programCache A map of compiled shader programs, keyed by filter type.
     */
    applyToWebGL: function(options) {
      var gl = options.context;
      var shader = this.retrieveShader(options);
      if (options.pass === 0 && options.originalTexture) {
        gl.bindTexture(gl.TEXTURE_2D, options.originalTexture);
      }
      else {
        gl.bindTexture(gl.TEXTURE_2D, options.sourceTexture);
      }
      gl.useProgram(shader.program);
      this.sendAttributeData(gl, shader.attributeLocations, options.aPosition);
  
      gl.uniform1f(shader.uniformLocations.uStepW, 1 / options.sourceWidth);
      gl.uniform1f(shader.uniformLocations.uStepH, 1 / options.sourceHeight);
  
      this.sendUniformData(gl, shader.uniformLocations);
      gl.viewport(0, 0, options.destinationWidth, options.destinationHeight);
      gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
    },
  
    bindAdditionalTexture: function(gl, texture, textureUnit) {
      gl.activeTexture(textureUnit);
      gl.bindTexture(gl.TEXTURE_2D, texture);
      // reset active texture to 0 as usual
      gl.activeTexture(gl.TEXTURE0);
    },
  
    unbindAdditionalTexture: function(gl, textureUnit) {
      gl.activeTexture(textureUnit);
      gl.bindTexture(gl.TEXTURE_2D, null);
      gl.activeTexture(gl.TEXTURE0);
    },
  
    getMainParameter: function() {
      return this[this.mainParameter];
    },
  
    setMainParameter: function(value) {
      this[this.mainParameter] = value;
    },
  
    /**
     * Send uniform data from this filter to its shader program on the GPU.
     *
     * Intended to be overridden by subclasses.
     *
     * @param {WebGLRenderingContext} gl The canvas context used to compile the shader program.
     * @param {Object} uniformLocations A map of shader uniform names to their locations.
     */
    sendUniformData: function(/* gl, uniformLocations */) {
      // Intentionally left blank.  Override me in subclasses.
    },
  
    /**
     * If needed by a 2d filter, this functions can create an helper canvas to be used
     * remember that options.targetCanvas is available for use till end of chain.
     */
    createHelpLayer: function(options) {
      if (!options.helpLayer) {
        var helpLayer = document.createElement('canvas');
        helpLayer.width = options.sourceWidth;
        helpLayer.height = options.sourceHeight;
        options.helpLayer = helpLayer;
      }
    },
  
    /**
     * Returns object representation of an instance
     * @return {Object} Object representation of an instance
     */
    toObject: function() {
      var object = { type: this.type }, mainP = this.mainParameter;
      if (mainP) {
        object[mainP] = this[mainP];
      }
      return object;
    },
  
    /**
     * Returns a JSON representation of an instance
     * @return {Object} JSON
     */
    toJSON: function() {
      // delegate, not alias
      return this.toObject();
    }
  });
  
  fabric.Image.filters.BaseFilter.fromObject = function(object, callback) {
    var filter = new fabric.Image.filters[object.type](object);
    callback && callback(filter);
    return filter;
  };
  
  
  (function(global) {
  
    'use strict';
  
    var fabric  = global.fabric || (global.fabric = { }),
        filters = fabric.Image.filters,
        createClass = fabric.util.createClass;
  
    /**
     * Color Matrix filter class
     * @class fabric.Image.filters.ColorMatrix
     * @memberOf fabric.Image.filters
     * @extends fabric.Image.filters.BaseFilter
     * @see {@link fabric.Image.filters.ColorMatrix#initialize} for constructor definition
     * @see {@link http://fabricjs.com/image-filters|ImageFilters demo}
     * @see {@Link http://www.webwasp.co.uk/tutorials/219/Color_Matrix_Filter.php}
     * @see {@Link http://phoboslab.org/log/2013/11/fast-image-filters-with-webgl}
     * @example <caption>Kodachrome filter</caption>
     * var filter = new fabric.Image.filters.ColorMatrix({
     *  matrix: [
         1.1285582396593525, -0.3967382283601348, -0.03992559172921793, 0, 63.72958762196502,
         -0.16404339962244616, 1.0835251566291304, -0.05498805115633132, 0, 24.732407896706203,
         -0.16786010706155763, -0.5603416277695248, 1.6014850761964943, 0, 35.62982807460946,
         0, 0, 0, 1, 0
        ]
     * });
     * object.filters.push(filter);
     * object.applyFilters();
     */
    filters.ColorMatrix = createClass(filters.BaseFilter, /** @lends fabric.Image.filters.ColorMatrix.prototype */ {
  
      /**
       * Filter type
       * @param {String} type
       * @default
       */
      type: 'ColorMatrix',
  
      fragmentSource: 'precision highp float;\n' +
        'uniform sampler2D uTexture;\n' +
        'varying vec2 vTexCoord;\n' +
        'uniform mat4 uColorMatrix;\n' +
        'uniform vec4 uConstants;\n' +
        'void main() {\n' +
          'vec4 color = texture2D(uTexture, vTexCoord);\n' +
          'color *= uColorMatrix;\n' +
          'color += uConstants;\n' +
          'gl_FragColor = color;\n' +
        '}',
  
      /**
       * Colormatrix for pixels.
       * array of 20 floats. Numbers in positions 4, 9, 14, 19 loose meaning
       * outside the -1, 1 range.
       * 0.0039215686 is the part of 1 that get translated to 1 in 2d
       * @param {Array} matrix array of 20 numbers.
       * @default
       */
      matrix: [
        1, 0, 0, 0, 0,
        0, 1, 0, 0, 0,
        0, 0, 1, 0, 0,
        0, 0, 0, 1, 0
      ],
  
      mainParameter: 'matrix',
  
      /**
       * Lock the colormatrix on the color part, skipping alpha, manly for non webgl scenario
       * to save some calculation
       */
      colorsOnly: true,
  
      /**
       * Constructor
       * @param {Object} [options] Options object
       */
      initialize: function(options) {
        this.callSuper('initialize', options);
        // create a new array instead mutating the prototype with push
        this.matrix = this.matrix.slice(0);
      },
  
      /**
       * Apply the ColorMatrix operation to a Uint8Array representing the pixels of an image.
       *
       * @param {Object} options
       * @param {ImageData} options.imageData The Uint8Array to be filtered.
       */
      applyTo2d: function(options) {
        var imageData = options.imageData,
            data = imageData.data,
            iLen = data.length,
            m = this.matrix,
            r, g, b, a, i, colorsOnly = this.colorsOnly;
  
        for (i = 0; i < iLen; i += 4) {
          r = data[i];
          g = data[i + 1];
          b = data[i + 2];
          if (colorsOnly) {
            data[i] = r * m[0] + g * m[1] + b * m[2] + m[4] * 255;
            data[i + 1] = r * m[5] + g * m[6] + b * m[7] + m[9] * 255;
            data[i + 2] = r * m[10] + g * m[11] + b * m[12] + m[14] * 255;
          }
          else {
            a = data[i + 3];
            data[i] = r * m[0] + g * m[1] + b * m[2] + a * m[3] + m[4] * 255;
            data[i + 1] = r * m[5] + g * m[6] + b * m[7] + a * m[8] + m[9] * 255;
            data[i + 2] = r * m[10] + g * m[11] + b * m[12] + a * m[13] + m[14] * 255;
            data[i + 3] = r * m[15] + g * m[16] + b * m[17] + a * m[18] + m[19] * 255;
          }
        }
      },
  
      /**
       * Return WebGL uniform locations for this filter's shader.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {WebGLShaderProgram} program This filter's compiled shader program.
       */
      getUniformLocations: function(gl, program) {
        return {
          uColorMatrix: gl.getUniformLocation(program, 'uColorMatrix'),
          uConstants: gl.getUniformLocation(program, 'uConstants'),
        };
      },
  
      /**
       * Send data from this filter to its shader program's uniforms.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {Object} uniformLocations A map of string uniform names to WebGLUniformLocation objects
       */
      sendUniformData: function(gl, uniformLocations) {
        var m = this.matrix,
            matrix = [
              m[0], m[1], m[2], m[3],
              m[5], m[6], m[7], m[8],
              m[10], m[11], m[12], m[13],
              m[15], m[16], m[17], m[18]
            ],
            constants = [m[4], m[9], m[14], m[19]];
        gl.uniformMatrix4fv(uniformLocations.uColorMatrix, false, matrix);
        gl.uniform4fv(uniformLocations.uConstants, constants);
      },
    });
  
    /**
     * Returns filter instance from an object representation
     * @static
     * @param {Object} object Object to create an instance from
     * @param {function} [callback] function to invoke after filter creation
     * @return {fabric.Image.filters.ColorMatrix} Instance of fabric.Image.filters.ColorMatrix
     */
    fabric.Image.filters.ColorMatrix.fromObject = fabric.Image.filters.BaseFilter.fromObject;
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric  = global.fabric || (global.fabric = { }),
        filters = fabric.Image.filters,
        createClass = fabric.util.createClass;
  
    /**
     * Brightness filter class
     * @class fabric.Image.filters.Brightness
     * @memberOf fabric.Image.filters
     * @extends fabric.Image.filters.BaseFilter
     * @see {@link fabric.Image.filters.Brightness#initialize} for constructor definition
     * @see {@link http://fabricjs.com/image-filters|ImageFilters demo}
     * @example
     * var filter = new fabric.Image.filters.Brightness({
     *   brightness: 0.05
     * });
     * object.filters.push(filter);
     * object.applyFilters();
     */
    filters.Brightness = createClass(filters.BaseFilter, /** @lends fabric.Image.filters.Brightness.prototype */ {
  
      /**
       * Filter type
       * @param {String} type
       * @default
       */
      type: 'Brightness',
  
      /**
       * Fragment source for the brightness program
       */
      fragmentSource: 'precision highp float;\n' +
        'uniform sampler2D uTexture;\n' +
        'uniform float uBrightness;\n' +
        'varying vec2 vTexCoord;\n' +
        'void main() {\n' +
          'vec4 color = texture2D(uTexture, vTexCoord);\n' +
          'color.rgb += uBrightness;\n' +
          'gl_FragColor = color;\n' +
        '}',
  
      /**
       * Brightness value, from -1 to 1.
       * translated to -255 to 255 for 2d
       * 0.0039215686 is the part of 1 that get translated to 1 in 2d
       * @param {Number} brightness
       * @default
       */
      brightness: 0,
  
      /**
       * Describe the property that is the filter parameter
       * @param {String} m
       * @default
       */
      mainParameter: 'brightness',
  
      /**
      * Apply the Brightness operation to a Uint8ClampedArray representing the pixels of an image.
      *
      * @param {Object} options
      * @param {ImageData} options.imageData The Uint8ClampedArray to be filtered.
      */
      applyTo2d: function(options) {
        if (this.brightness === 0) {
          return;
        }
        var imageData = options.imageData,
            data = imageData.data, i, len = data.length,
            brightness = Math.round(this.brightness * 255);
        for (i = 0; i < len; i += 4) {
          data[i] = data[i] + brightness;
          data[i + 1] = data[i + 1] + brightness;
          data[i + 2] = data[i + 2] + brightness;
        }
      },
  
      /**
       * Return WebGL uniform locations for this filter's shader.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {WebGLShaderProgram} program This filter's compiled shader program.
       */
      getUniformLocations: function(gl, program) {
        return {
          uBrightness: gl.getUniformLocation(program, 'uBrightness'),
        };
      },
  
      /**
       * Send data from this filter to its shader program's uniforms.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {Object} uniformLocations A map of string uniform names to WebGLUniformLocation objects
       */
      sendUniformData: function(gl, uniformLocations) {
        gl.uniform1f(uniformLocations.uBrightness, this.brightness);
      },
    });
  
    /**
     * Returns filter instance from an object representation
     * @static
     * @param {Object} object Object to create an instance from
     * @param {function} [callback] to be invoked after filter creation
     * @return {fabric.Image.filters.Brightness} Instance of fabric.Image.filters.Brightness
     */
    fabric.Image.filters.Brightness.fromObject = fabric.Image.filters.BaseFilter.fromObject;
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric  = global.fabric || (global.fabric = { }),
        extend = fabric.util.object.extend,
        filters = fabric.Image.filters,
        createClass = fabric.util.createClass;
  
    /**
     * Adapted from <a href="http://www.html5rocks.com/en/tutorials/canvas/imagefilters/">html5rocks article</a>
     * @class fabric.Image.filters.Convolute
     * @memberOf fabric.Image.filters
     * @extends fabric.Image.filters.BaseFilter
     * @see {@link fabric.Image.filters.Convolute#initialize} for constructor definition
     * @see {@link http://fabricjs.com/image-filters|ImageFilters demo}
     * @example <caption>Sharpen filter</caption>
     * var filter = new fabric.Image.filters.Convolute({
     *   matrix: [ 0, -1,  0,
     *            -1,  5, -1,
     *             0, -1,  0 ]
     * });
     * object.filters.push(filter);
     * object.applyFilters();
     * canvas.renderAll();
     * @example <caption>Blur filter</caption>
     * var filter = new fabric.Image.filters.Convolute({
     *   matrix: [ 1/9, 1/9, 1/9,
     *             1/9, 1/9, 1/9,
     *             1/9, 1/9, 1/9 ]
     * });
     * object.filters.push(filter);
     * object.applyFilters();
     * canvas.renderAll();
     * @example <caption>Emboss filter</caption>
     * var filter = new fabric.Image.filters.Convolute({
     *   matrix: [ 1,   1,  1,
     *             1, 0.7, -1,
     *            -1,  -1, -1 ]
     * });
     * object.filters.push(filter);
     * object.applyFilters();
     * canvas.renderAll();
     * @example <caption>Emboss filter with opaqueness</caption>
     * var filter = new fabric.Image.filters.Convolute({
     *   opaque: true,
     *   matrix: [ 1,   1,  1,
     *             1, 0.7, -1,
     *            -1,  -1, -1 ]
     * });
     * object.filters.push(filter);
     * object.applyFilters();
     * canvas.renderAll();
     */
    filters.Convolute = createClass(filters.BaseFilter, /** @lends fabric.Image.filters.Convolute.prototype */ {
  
      /**
       * Filter type
       * @param {String} type
       * @default
       */
      type: 'Convolute',
  
      /*
       * Opaque value (true/false)
       */
      opaque: false,
  
      /*
       * matrix for the filter, max 9x9
       */
      matrix: [0, 0, 0, 0, 1, 0, 0, 0, 0],
  
      /**
       * Fragment source for the brightness program
       */
      fragmentSource: {
        Convolute_3_1: 'precision highp float;\n' +
          'uniform sampler2D uTexture;\n' +
          'uniform float uMatrix[9];\n' +
          'uniform float uStepW;\n' +
          'uniform float uStepH;\n' +
          'varying vec2 vTexCoord;\n' +
          'void main() {\n' +
            'vec4 color = vec4(0, 0, 0, 0);\n' +
            'for (float h = 0.0; h < 3.0; h+=1.0) {\n' +
              'for (float w = 0.0; w < 3.0; w+=1.0) {\n' +
                'vec2 matrixPos = vec2(uStepW * (w - 1), uStepH * (h - 1));\n' +
                'color += texture2D(uTexture, vTexCoord + matrixPos) * uMatrix[int(h * 3.0 + w)];\n' +
              '}\n' +
            '}\n' +
            'gl_FragColor = color;\n' +
          '}',
        Convolute_3_0: 'precision highp float;\n' +
          'uniform sampler2D uTexture;\n' +
          'uniform float uMatrix[9];\n' +
          'uniform float uStepW;\n' +
          'uniform float uStepH;\n' +
          'varying vec2 vTexCoord;\n' +
          'void main() {\n' +
            'vec4 color = vec4(0, 0, 0, 1);\n' +
            'for (float h = 0.0; h < 3.0; h+=1.0) {\n' +
              'for (float w = 0.0; w < 3.0; w+=1.0) {\n' +
                'vec2 matrixPos = vec2(uStepW * (w - 1.0), uStepH * (h - 1.0));\n' +
                'color.rgb += texture2D(uTexture, vTexCoord + matrixPos).rgb * uMatrix[int(h * 3.0 + w)];\n' +
              '}\n' +
            '}\n' +
            'float alpha = texture2D(uTexture, vTexCoord).a;\n' +
            'gl_FragColor = color;\n' +
            'gl_FragColor.a = alpha;\n' +
          '}',
        Convolute_5_1: 'precision highp float;\n' +
          'uniform sampler2D uTexture;\n' +
          'uniform float uMatrix[25];\n' +
          'uniform float uStepW;\n' +
          'uniform float uStepH;\n' +
          'varying vec2 vTexCoord;\n' +
          'void main() {\n' +
            'vec4 color = vec4(0, 0, 0, 0);\n' +
            'for (float h = 0.0; h < 5.0; h+=1.0) {\n' +
              'for (float w = 0.0; w < 5.0; w+=1.0) {\n' +
                'vec2 matrixPos = vec2(uStepW * (w - 2.0), uStepH * (h - 2.0));\n' +
                'color += texture2D(uTexture, vTexCoord + matrixPos) * uMatrix[int(h * 5.0 + w)];\n' +
              '}\n' +
            '}\n' +
            'gl_FragColor = color;\n' +
          '}',
        Convolute_5_0: 'precision highp float;\n' +
          'uniform sampler2D uTexture;\n' +
          'uniform float uMatrix[25];\n' +
          'uniform float uStepW;\n' +
          'uniform float uStepH;\n' +
          'varying vec2 vTexCoord;\n' +
          'void main() {\n' +
            'vec4 color = vec4(0, 0, 0, 1);\n' +
            'for (float h = 0.0; h < 5.0; h+=1.0) {\n' +
              'for (float w = 0.0; w < 5.0; w+=1.0) {\n' +
                'vec2 matrixPos = vec2(uStepW * (w - 2.0), uStepH * (h - 2.0));\n' +
                'color.rgb += texture2D(uTexture, vTexCoord + matrixPos).rgb * uMatrix[int(h * 5.0 + w)];\n' +
              '}\n' +
            '}\n' +
            'float alpha = texture2D(uTexture, vTexCoord).a;\n' +
            'gl_FragColor = color;\n' +
            'gl_FragColor.a = alpha;\n' +
          '}',
        Convolute_7_1: 'precision highp float;\n' +
          'uniform sampler2D uTexture;\n' +
          'uniform float uMatrix[49];\n' +
          'uniform float uStepW;\n' +
          'uniform float uStepH;\n' +
          'varying vec2 vTexCoord;\n' +
          'void main() {\n' +
            'vec4 color = vec4(0, 0, 0, 0);\n' +
            'for (float h = 0.0; h < 7.0; h+=1.0) {\n' +
              'for (float w = 0.0; w < 7.0; w+=1.0) {\n' +
                'vec2 matrixPos = vec2(uStepW * (w - 3.0), uStepH * (h - 3.0));\n' +
                'color += texture2D(uTexture, vTexCoord + matrixPos) * uMatrix[int(h * 7.0 + w)];\n' +
              '}\n' +
            '}\n' +
            'gl_FragColor = color;\n' +
          '}',
        Convolute_7_0: 'precision highp float;\n' +
          'uniform sampler2D uTexture;\n' +
          'uniform float uMatrix[49];\n' +
          'uniform float uStepW;\n' +
          'uniform float uStepH;\n' +
          'varying vec2 vTexCoord;\n' +
          'void main() {\n' +
            'vec4 color = vec4(0, 0, 0, 1);\n' +
            'for (float h = 0.0; h < 7.0; h+=1.0) {\n' +
              'for (float w = 0.0; w < 7.0; w+=1.0) {\n' +
                'vec2 matrixPos = vec2(uStepW * (w - 3.0), uStepH * (h - 3.0));\n' +
                'color.rgb += texture2D(uTexture, vTexCoord + matrixPos).rgb * uMatrix[int(h * 7.0 + w)];\n' +
              '}\n' +
            '}\n' +
            'float alpha = texture2D(uTexture, vTexCoord).a;\n' +
            'gl_FragColor = color;\n' +
            'gl_FragColor.a = alpha;\n' +
          '}',
        Convolute_9_1: 'precision highp float;\n' +
          'uniform sampler2D uTexture;\n' +
          'uniform float uMatrix[81];\n' +
          'uniform float uStepW;\n' +
          'uniform float uStepH;\n' +
          'varying vec2 vTexCoord;\n' +
          'void main() {\n' +
            'vec4 color = vec4(0, 0, 0, 0);\n' +
            'for (float h = 0.0; h < 9.0; h+=1.0) {\n' +
              'for (float w = 0.0; w < 9.0; w+=1.0) {\n' +
                'vec2 matrixPos = vec2(uStepW * (w - 4.0), uStepH * (h - 4.0));\n' +
                'color += texture2D(uTexture, vTexCoord + matrixPos) * uMatrix[int(h * 9.0 + w)];\n' +
              '}\n' +
            '}\n' +
            'gl_FragColor = color;\n' +
          '}',
        Convolute_9_0: 'precision highp float;\n' +
          'uniform sampler2D uTexture;\n' +
          'uniform float uMatrix[81];\n' +
          'uniform float uStepW;\n' +
          'uniform float uStepH;\n' +
          'varying vec2 vTexCoord;\n' +
          'void main() {\n' +
            'vec4 color = vec4(0, 0, 0, 1);\n' +
            'for (float h = 0.0; h < 9.0; h+=1.0) {\n' +
              'for (float w = 0.0; w < 9.0; w+=1.0) {\n' +
                'vec2 matrixPos = vec2(uStepW * (w - 4.0), uStepH * (h - 4.0));\n' +
                'color.rgb += texture2D(uTexture, vTexCoord + matrixPos).rgb * uMatrix[int(h * 9.0 + w)];\n' +
              '}\n' +
            '}\n' +
            'float alpha = texture2D(uTexture, vTexCoord).a;\n' +
            'gl_FragColor = color;\n' +
            'gl_FragColor.a = alpha;\n' +
          '}',
      },
  
      /**
       * Constructor
       * @memberOf fabric.Image.filters.Convolute.prototype
       * @param {Object} [options] Options object
       * @param {Boolean} [options.opaque=false] Opaque value (true/false)
       * @param {Array} [options.matrix] Filter matrix
       */
  
  
      /**
      * Retrieves the cached shader.
      * @param {Object} options
      * @param {WebGLRenderingContext} options.context The GL context used for rendering.
      * @param {Object} options.programCache A map of compiled shader programs, keyed by filter type.
      */
      retrieveShader: function(options) {
        var size = Math.sqrt(this.matrix.length);
        var cacheKey = this.type + '_' + size + '_' + (this.opaque ? 1 : 0);
        var shaderSource = this.fragmentSource[cacheKey];
        if (!options.programCache.hasOwnProperty(cacheKey)) {
          options.programCache[cacheKey] = this.createProgram(options.context, shaderSource);
        }
        return options.programCache[cacheKey];
      },
  
      /**
       * Apply the Brightness operation to a Uint8ClampedArray representing the pixels of an image.
       *
       * @param {Object} options
       * @param {ImageData} options.imageData The Uint8ClampedArray to be filtered.
       */
      applyTo2d: function(options) {
        var imageData = options.imageData,
            data = imageData.data,
            weights = this.matrix,
            side = Math.round(Math.sqrt(weights.length)),
            halfSide = Math.floor(side / 2),
            sw = imageData.width,
            sh = imageData.height,
            output = options.ctx.createImageData(sw, sh),
            dst = output.data,
            // go through the destination image pixels
            alphaFac = this.opaque ? 1 : 0,
            r, g, b, a, dstOff,
            scx, scy, srcOff, wt,
            x, y, cx, cy;
  
        for (y = 0; y < sh; y++) {
          for (x = 0; x < sw; x++) {
            dstOff = (y * sw + x) * 4;
            // calculate the weighed sum of the source image pixels that
            // fall under the convolution matrix
            r = 0; g = 0; b = 0; a = 0;
  
            for (cy = 0; cy < side; cy++) {
              for (cx = 0; cx < side; cx++) {
                scy = y + cy - halfSide;
                scx = x + cx - halfSide;
  
                // eslint-disable-next-line max-depth
                if (scy < 0 || scy > sh || scx < 0 || scx > sw) {
                  continue;
                }
  
                srcOff = (scy * sw + scx) * 4;
                wt = weights[cy * side + cx];
  
                r += data[srcOff] * wt;
                g += data[srcOff + 1] * wt;
                b += data[srcOff + 2] * wt;
                // eslint-disable-next-line max-depth
                if (!alphaFac) {
                  a += data[srcOff + 3] * wt;
                }
              }
            }
            dst[dstOff] = r;
            dst[dstOff + 1] = g;
            dst[dstOff + 2] = b;
            if (!alphaFac) {
              dst[dstOff + 3] = a;
            }
            else {
              dst[dstOff + 3] = data[dstOff + 3];
            }
          }
        }
        options.imageData = output;
      },
  
      /**
       * Return WebGL uniform locations for this filter's shader.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {WebGLShaderProgram} program This filter's compiled shader program.
       */
      getUniformLocations: function(gl, program) {
        return {
          uMatrix: gl.getUniformLocation(program, 'uMatrix'),
          uOpaque: gl.getUniformLocation(program, 'uOpaque'),
          uHalfSize: gl.getUniformLocation(program, 'uHalfSize'),
          uSize: gl.getUniformLocation(program, 'uSize'),
        };
      },
  
      /**
       * Send data from this filter to its shader program's uniforms.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {Object} uniformLocations A map of string uniform names to WebGLUniformLocation objects
       */
      sendUniformData: function(gl, uniformLocations) {
        gl.uniform1fv(uniformLocations.uMatrix, this.matrix);
      },
  
      /**
       * Returns object representation of an instance
       * @return {Object} Object representation of an instance
       */
      toObject: function() {
        return extend(this.callSuper('toObject'), {
          opaque: this.opaque,
          matrix: this.matrix
        });
      }
    });
  
    /**
     * Returns filter instance from an object representation
     * @static
     * @param {Object} object Object to create an instance from
     * @param {function} [callback] to be invoked after filter creation
     * @return {fabric.Image.filters.Convolute} Instance of fabric.Image.filters.Convolute
     */
    fabric.Image.filters.Convolute.fromObject = fabric.Image.filters.BaseFilter.fromObject;
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric  = global.fabric || (global.fabric = { }),
        filters = fabric.Image.filters,
        createClass = fabric.util.createClass;
  
    /**
     * Grayscale image filter class
     * @class fabric.Image.filters.Grayscale
     * @memberOf fabric.Image.filters
     * @extends fabric.Image.filters.BaseFilter
     * @see {@link http://fabricjs.com/image-filters|ImageFilters demo}
     * @example
     * var filter = new fabric.Image.filters.Grayscale();
     * object.filters.push(filter);
     * object.applyFilters();
     */
    filters.Grayscale = createClass(filters.BaseFilter, /** @lends fabric.Image.filters.Grayscale.prototype */ {
  
      /**
       * Filter type
       * @param {String} type
       * @default
       */
      type: 'Grayscale',
  
      fragmentSource: {
        average: 'precision highp float;\n' +
          'uniform sampler2D uTexture;\n' +
          'varying vec2 vTexCoord;\n' +
          'void main() {\n' +
            'vec4 color = texture2D(uTexture, vTexCoord);\n' +
            'float average = (color.r + color.b + color.g) / 3.0;\n' +
            'gl_FragColor = vec4(average, average, average, color.a);\n' +
          '}',
        lightness: 'precision highp float;\n' +
          'uniform sampler2D uTexture;\n' +
          'uniform int uMode;\n' +
          'varying vec2 vTexCoord;\n' +
          'void main() {\n' +
            'vec4 col = texture2D(uTexture, vTexCoord);\n' +
            'float average = (max(max(col.r, col.g),col.b) + min(min(col.r, col.g),col.b)) / 2.0;\n' +
            'gl_FragColor = vec4(average, average, average, col.a);\n' +
          '}',
        luminosity: 'precision highp float;\n' +
          'uniform sampler2D uTexture;\n' +
          'uniform int uMode;\n' +
          'varying vec2 vTexCoord;\n' +
          'void main() {\n' +
            'vec4 col = texture2D(uTexture, vTexCoord);\n' +
            'float average = 0.21 * col.r + 0.72 * col.g + 0.07 * col.b;\n' +
            'gl_FragColor = vec4(average, average, average, col.a);\n' +
          '}',
      },
  
  
      /**
       * Grayscale mode, between 'average', 'lightness', 'luminosity'
       * @param {String} type
       * @default
       */
      mode: 'average',
  
      mainParameter: 'mode',
  
      /**
       * Apply the Grayscale operation to a Uint8Array representing the pixels of an image.
       *
       * @param {Object} options
       * @param {ImageData} options.imageData The Uint8Array to be filtered.
       */
      applyTo2d: function(options) {
        var imageData = options.imageData,
            data = imageData.data, i,
            len = data.length, value,
            mode = this.mode;
        for (i = 0; i < len; i += 4) {
          if (mode === 'average') {
            value = (data[i] + data[i + 1] + data[i + 2]) / 3;
          }
          else if (mode === 'lightness') {
            value = (Math.min(data[i], data[i + 1], data[i + 2]) +
              Math.max(data[i], data[i + 1], data[i + 2])) / 2;
          }
          else if (mode === 'luminosity') {
            value = 0.21 * data[i] + 0.72 * data[i + 1] + 0.07 * data[i + 2];
          }
          data[i] = value;
          data[i + 1] = value;
          data[i + 2] = value;
        }
      },
  
      /**
       * Retrieves the cached shader.
       * @param {Object} options
       * @param {WebGLRenderingContext} options.context The GL context used for rendering.
       * @param {Object} options.programCache A map of compiled shader programs, keyed by filter type.
       */
      retrieveShader: function(options) {
        var cacheKey = this.type + '_' + this.mode;
        if (!options.programCache.hasOwnProperty(cacheKey)) {
          var shaderSource = this.fragmentSource[this.mode];
          options.programCache[cacheKey] = this.createProgram(options.context, shaderSource);
        }
        return options.programCache[cacheKey];
      },
  
      /**
       * Return WebGL uniform locations for this filter's shader.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {WebGLShaderProgram} program This filter's compiled shader program.
       */
      getUniformLocations: function(gl, program) {
        return {
          uMode: gl.getUniformLocation(program, 'uMode'),
        };
      },
  
      /**
       * Send data from this filter to its shader program's uniforms.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {Object} uniformLocations A map of string uniform names to WebGLUniformLocation objects
       */
      sendUniformData: function(gl, uniformLocations) {
        // default average mode.
        var mode = 1;
        gl.uniform1i(uniformLocations.uMode, mode);
      },
  
      /**
       * Grayscale filter isNeutralState implementation
       * The filter is never neutral
       * on the image
       **/
      isNeutralState: function() {
        return false;
      },
    });
  
    /**
     * Returns filter instance from an object representation
     * @static
     * @param {Object} object Object to create an instance from
     * @param {function} [callback] to be invoked after filter creation
     * @return {fabric.Image.filters.Grayscale} Instance of fabric.Image.filters.Grayscale
     */
    fabric.Image.filters.Grayscale.fromObject = fabric.Image.filters.BaseFilter.fromObject;
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric  = global.fabric || (global.fabric = { }),
        filters = fabric.Image.filters,
        createClass = fabric.util.createClass;
  
    /**
     * Invert filter class
     * @class fabric.Image.filters.Invert
     * @memberOf fabric.Image.filters
     * @extends fabric.Image.filters.BaseFilter
     * @see {@link http://fabricjs.com/image-filters|ImageFilters demo}
     * @example
     * var filter = new fabric.Image.filters.Invert();
     * object.filters.push(filter);
     * object.applyFilters(canvas.renderAll.bind(canvas));
     */
    filters.Invert = createClass(filters.BaseFilter, /** @lends fabric.Image.filters.Invert.prototype */ {
  
      /**
       * Filter type
       * @param {String} type
       * @default
       */
      type: 'Invert',
  
      fragmentSource: 'precision highp float;\n' +
        'uniform sampler2D uTexture;\n' +
        'uniform int uInvert;\n' +
        'varying vec2 vTexCoord;\n' +
        'void main() {\n' +
          'vec4 color = texture2D(uTexture, vTexCoord);\n' +
          'if (uInvert == 1) {\n' +
            'gl_FragColor = vec4(1.0 - color.r,1.0 -color.g,1.0 -color.b,color.a);\n' +
          '} else {\n' +
            'gl_FragColor = color;\n' +
          '}\n' +
        '}',
  
      /**
       * Filter invert. if false, does nothing
       * @param {Boolean} invert
       * @default
       */
      invert: true,
  
      mainParameter: 'invert',
  
      /**
       * Apply the Invert operation to a Uint8Array representing the pixels of an image.
       *
       * @param {Object} options
       * @param {ImageData} options.imageData The Uint8Array to be filtered.
       */
      applyTo2d: function(options) {
        var imageData = options.imageData,
            data = imageData.data, i,
            len = data.length;
        for (i = 0; i < len; i += 4) {
          data[i] = 255 - data[i];
          data[i + 1] = 255 - data[i + 1];
          data[i + 2] = 255 - data[i + 2];
        }
      },
  
      /**
       * Invert filter isNeutralState implementation
       * Used only in image applyFilters to discard filters that will not have an effect
       * on the image
       * @param {Object} options
       **/
      isNeutralState: function() {
        return !this.invert;
      },
  
      /**
       * Return WebGL uniform locations for this filter's shader.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {WebGLShaderProgram} program This filter's compiled shader program.
       */
      getUniformLocations: function(gl, program) {
        return {
          uInvert: gl.getUniformLocation(program, 'uInvert'),
        };
      },
  
      /**
       * Send data from this filter to its shader program's uniforms.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {Object} uniformLocations A map of string uniform names to WebGLUniformLocation objects
       */
      sendUniformData: function(gl, uniformLocations) {
        gl.uniform1i(uniformLocations.uInvert, this.invert);
      },
    });
  
    /**
     * Returns filter instance from an object representation
     * @static
     * @param {Object} object Object to create an instance from
     * @param {function} [callback] to be invoked after filter creation
     * @return {fabric.Image.filters.Invert} Instance of fabric.Image.filters.Invert
     */
    fabric.Image.filters.Invert.fromObject = fabric.Image.filters.BaseFilter.fromObject;
  
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric  = global.fabric || (global.fabric = { }),
        extend = fabric.util.object.extend,
        filters = fabric.Image.filters,
        createClass = fabric.util.createClass;
  
    /**
     * Noise filter class
     * @class fabric.Image.filters.Noise
     * @memberOf fabric.Image.filters
     * @extends fabric.Image.filters.BaseFilter
     * @see {@link fabric.Image.filters.Noise#initialize} for constructor definition
     * @see {@link http://fabricjs.com/image-filters|ImageFilters demo}
     * @example
     * var filter = new fabric.Image.filters.Noise({
     *   noise: 700
     * });
     * object.filters.push(filter);
     * object.applyFilters();
     * canvas.renderAll();
     */
    filters.Noise = createClass(filters.BaseFilter, /** @lends fabric.Image.filters.Noise.prototype */ {
  
      /**
       * Filter type
       * @param {String} type
       * @default
       */
      type: 'Noise',
  
      /**
       * Fragment source for the noise program
       */
      fragmentSource: 'precision highp float;\n' +
        'uniform sampler2D uTexture;\n' +
        'uniform float uStepH;\n' +
        'uniform float uNoise;\n' +
        'uniform float uSeed;\n' +
        'varying vec2 vTexCoord;\n' +
        'float rand(vec2 co, float seed, float vScale) {\n' +
          'return fract(sin(dot(co.xy * vScale ,vec2(12.9898 , 78.233))) * 43758.5453 * (seed + 0.01) / 2.0);\n' +
        '}\n' +
        'void main() {\n' +
          'vec4 color = texture2D(uTexture, vTexCoord);\n' +
          'color.rgb += (0.5 - rand(vTexCoord, uSeed, 0.1 / uStepH)) * uNoise;\n' +
          'gl_FragColor = color;\n' +
        '}',
  
      /**
       * Describe the property that is the filter parameter
       * @param {String} m
       * @default
       */
      mainParameter: 'noise',
  
      /**
       * Noise value, from
       * @param {Number} noise
       * @default
       */
      noise: 0,
  
      /**
       * Apply the Brightness operation to a Uint8ClampedArray representing the pixels of an image.
       *
       * @param {Object} options
       * @param {ImageData} options.imageData The Uint8ClampedArray to be filtered.
       */
      applyTo2d: function(options) {
        if (this.noise === 0) {
          return;
        }
        var imageData = options.imageData,
            data = imageData.data, i, len = data.length,
            noise = this.noise, rand;
  
        for (i = 0, len = data.length; i < len; i += 4) {
  
          rand = (0.5 - Math.random()) * noise;
  
          data[i] += rand;
          data[i + 1] += rand;
          data[i + 2] += rand;
        }
      },
  
      /**
       * Return WebGL uniform locations for this filter's shader.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {WebGLShaderProgram} program This filter's compiled shader program.
       */
      getUniformLocations: function(gl, program) {
        return {
          uNoise: gl.getUniformLocation(program, 'uNoise'),
          uSeed: gl.getUniformLocation(program, 'uSeed'),
        };
      },
  
      /**
       * Send data from this filter to its shader program's uniforms.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {Object} uniformLocations A map of string uniform names to WebGLUniformLocation objects
       */
      sendUniformData: function(gl, uniformLocations) {
        gl.uniform1f(uniformLocations.uNoise, this.noise / 255);
        gl.uniform1f(uniformLocations.uSeed, Math.random());
      },
  
      /**
       * Returns object representation of an instance
       * @return {Object} Object representation of an instance
       */
      toObject: function() {
        return extend(this.callSuper('toObject'), {
          noise: this.noise
        });
      }
    });
  
    /**
     * Returns filter instance from an object representation
     * @static
     * @param {Object} object Object to create an instance from
     * @param {Function} [callback] to be invoked after filter creation
     * @return {fabric.Image.filters.Noise} Instance of fabric.Image.filters.Noise
     */
    fabric.Image.filters.Noise.fromObject = fabric.Image.filters.BaseFilter.fromObject;
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric  = global.fabric || (global.fabric = { }),
        filters = fabric.Image.filters,
        createClass = fabric.util.createClass;
  
    /**
     * Pixelate filter class
     * @class fabric.Image.filters.Pixelate
     * @memberOf fabric.Image.filters
     * @extends fabric.Image.filters.BaseFilter
     * @see {@link fabric.Image.filters.Pixelate#initialize} for constructor definition
     * @see {@link http://fabricjs.com/image-filters|ImageFilters demo}
     * @example
     * var filter = new fabric.Image.filters.Pixelate({
     *   blocksize: 8
     * });
     * object.filters.push(filter);
     * object.applyFilters();
     */
    filters.Pixelate = createClass(filters.BaseFilter, /** @lends fabric.Image.filters.Pixelate.prototype */ {
  
      /**
       * Filter type
       * @param {String} type
       * @default
       */
      type: 'Pixelate',
  
      blocksize: 4,
  
      mainParameter: 'blocksize',
  
      /**
       * Fragment source for the Pixelate program
       */
      fragmentSource: 'precision highp float;\n' +
        'uniform sampler2D uTexture;\n' +
        'uniform float uBlocksize;\n' +
        'uniform float uStepW;\n' +
        'uniform float uStepH;\n' +
        'varying vec2 vTexCoord;\n' +
        'void main() {\n' +
          'float blockW = uBlocksize * uStepW;\n' +
          'float blockH = uBlocksize * uStepW;\n' +
          'int posX = int(vTexCoord.x / blockW);\n' +
          'int posY = int(vTexCoord.y / blockH);\n' +
          'float fposX = float(posX);\n' +
          'float fposY = float(posY);\n' +
          'vec2 squareCoords = vec2(fposX * blockW, fposY * blockH);\n' +
          'vec4 color = texture2D(uTexture, squareCoords);\n' +
          'gl_FragColor = color;\n' +
        '}',
  
      /**
       * Apply the Pixelate operation to a Uint8ClampedArray representing the pixels of an image.
       *
       * @param {Object} options
       * @param {ImageData} options.imageData The Uint8ClampedArray to be filtered.
       */
      applyTo2d: function(options) {
        var imageData = options.imageData,
            data = imageData.data,
            iLen = imageData.height,
            jLen = imageData.width,
            index, i, j, r, g, b, a,
            _i, _j, _iLen, _jLen;
  
        for (i = 0; i < iLen; i += this.blocksize) {
          for (j = 0; j < jLen; j += this.blocksize) {
  
            index = (i * 4) * jLen + (j * 4);
  
            r = data[index];
            g = data[index + 1];
            b = data[index + 2];
            a = data[index + 3];
  
            _iLen = Math.min(i + this.blocksize, iLen);
            _jLen = Math.min(j + this.blocksize, jLen);
            for (_i = i; _i < _iLen; _i++) {
              for (_j = j; _j < _jLen; _j++) {
                index = (_i * 4) * jLen + (_j * 4);
                data[index] = r;
                data[index + 1] = g;
                data[index + 2] = b;
                data[index + 3] = a;
              }
            }
          }
        }
      },
  
      /**
       * Indicate when the filter is not gonna apply changes to the image
       **/
      isNeutralState: function() {
        return this.blocksize === 1;
      },
  
      /**
       * Return WebGL uniform locations for this filter's shader.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {WebGLShaderProgram} program This filter's compiled shader program.
       */
      getUniformLocations: function(gl, program) {
        return {
          uBlocksize: gl.getUniformLocation(program, 'uBlocksize'),
          uStepW: gl.getUniformLocation(program, 'uStepW'),
          uStepH: gl.getUniformLocation(program, 'uStepH'),
        };
      },
  
      /**
       * Send data from this filter to its shader program's uniforms.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {Object} uniformLocations A map of string uniform names to WebGLUniformLocation objects
       */
      sendUniformData: function(gl, uniformLocations) {
        gl.uniform1f(uniformLocations.uBlocksize, this.blocksize);
      },
    });
  
    /**
     * Returns filter instance from an object representation
     * @static
     * @param {Object} object Object to create an instance from
     * @param {Function} [callback] to be invoked after filter creation
     * @return {fabric.Image.filters.Pixelate} Instance of fabric.Image.filters.Pixelate
     */
    fabric.Image.filters.Pixelate.fromObject = fabric.Image.filters.BaseFilter.fromObject;
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric  = global.fabric || (global.fabric = { }),
        extend = fabric.util.object.extend,
        filters = fabric.Image.filters,
        createClass = fabric.util.createClass;
  
    /**
     * Remove white filter class
     * @class fabric.Image.filters.RemoveColor
     * @memberOf fabric.Image.filters
     * @extends fabric.Image.filters.BaseFilter
     * @see {@link fabric.Image.filters.RemoveColor#initialize} for constructor definition
     * @see {@link http://fabricjs.com/image-filters|ImageFilters demo}
     * @example
     * var filter = new fabric.Image.filters.RemoveColor({
     *   threshold: 0.2,
     * });
     * object.filters.push(filter);
     * object.applyFilters();
     * canvas.renderAll();
     */
    filters.RemoveColor = createClass(filters.BaseFilter, /** @lends fabric.Image.filters.RemoveColor.prototype */ {
  
      /**
       * Filter type
       * @param {String} type
       * @default
       */
      type: 'RemoveColor',
  
      /**
       * Color to remove, in any format understood by fabric.Color.
       * @param {String} type
       * @default
       */
      color: '#FFFFFF',
  
      /**
       * Fragment source for the brightness program
       */
      fragmentSource: 'precision highp float;\n' +
        'uniform sampler2D uTexture;\n' +
        'uniform vec4 uLow;\n' +
        'uniform vec4 uHigh;\n' +
        'varying vec2 vTexCoord;\n' +
        'void main() {\n' +
          'gl_FragColor = texture2D(uTexture, vTexCoord);\n' +
          'if(all(greaterThan(gl_FragColor.rgb,uLow.rgb)) && all(greaterThan(uHigh.rgb,gl_FragColor.rgb))) {\n' +
            'gl_FragColor.a = 0.0;\n' +
          '}\n' +
        '}',
  
      /**
       * distance to actual color, as value up or down from each r,g,b
       * between 0 and 1
       **/
      distance: 0.02,
  
      /**
       * For color to remove inside distance, use alpha channel for a smoother deletion
       * NOT IMPLEMENTED YET
       **/
      useAlpha: false,
  
      /**
       * Constructor
       * @memberOf fabric.Image.filters.RemoveWhite.prototype
       * @param {Object} [options] Options object
       * @param {Number} [options.color=#RRGGBB] Threshold value
       * @param {Number} [options.distance=10] Distance value
       */
  
      /**
       * Applies filter to canvas element
       * @param {Object} canvasEl Canvas element to apply filter to
       */
      applyTo2d: function(options) {
        var imageData = options.imageData,
            data = imageData.data, i,
            distance = this.distance * 255,
            r, g, b,
            source = new fabric.Color(this.color).getSource(),
            lowC = [
              source[0] - distance,
              source[1] - distance,
              source[2] - distance,
            ],
            highC = [
              source[0] + distance,
              source[1] + distance,
              source[2] + distance,
            ];
  
  
        for (i = 0; i < data.length; i += 4) {
          r = data[i];
          g = data[i + 1];
          b = data[i + 2];
  
          if (r > lowC[0] &&
              g > lowC[1] &&
              b > lowC[2] &&
              r < highC[0] &&
              g < highC[1] &&
              b < highC[2]) {
            data[i + 3] = 0;
          }
        }
      },
  
      /**
       * Return WebGL uniform locations for this filter's shader.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {WebGLShaderProgram} program This filter's compiled shader program.
       */
      getUniformLocations: function(gl, program) {
        return {
          uLow: gl.getUniformLocation(program, 'uLow'),
          uHigh: gl.getUniformLocation(program, 'uHigh'),
        };
      },
  
      /**
       * Send data from this filter to its shader program's uniforms.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {Object} uniformLocations A map of string uniform names to WebGLUniformLocation objects
       */
      sendUniformData: function(gl, uniformLocations) {
        var source = new fabric.Color(this.color).getSource(),
            distance = parseFloat(this.distance),
            lowC = [
              0 + source[0] / 255 - distance,
              0 + source[1] / 255 - distance,
              0 + source[2] / 255 - distance,
              1
            ],
            highC = [
              source[0] / 255 + distance,
              source[1] / 255 + distance,
              source[2] / 255 + distance,
              1
            ];
        gl.uniform4fv(uniformLocations.uLow, lowC);
        gl.uniform4fv(uniformLocations.uHigh, highC);
      },
  
      /**
       * Returns object representation of an instance
       * @return {Object} Object representation of an instance
       */
      toObject: function() {
        return extend(this.callSuper('toObject'), {
          color: this.color,
          distance: this.distance
        });
      }
    });
  
    /**
     * Returns filter instance from an object representation
     * @static
     * @param {Object} object Object to create an instance from
     * @param {Function} [callback] to be invoked after filter creation
     * @return {fabric.Image.filters.RemoveColor} Instance of fabric.Image.filters.RemoveWhite
     */
    fabric.Image.filters.RemoveColor.fromObject = fabric.Image.filters.BaseFilter.fromObject;
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric  = global.fabric || (global.fabric = { }),
        filters = fabric.Image.filters,
        createClass = fabric.util.createClass;
  
    var matrices = {
      Brownie: [
        0.59970,0.34553,-0.27082,0,0.186,
        -0.03770,0.86095,0.15059,0,-0.1449,
        0.24113,-0.07441,0.44972,0,-0.02965,
        0,0,0,1,0
      ],
      Vintage: [
        0.62793,0.32021,-0.03965,0,0.03784,
        0.02578,0.64411,0.03259,0,0.02926,
        0.04660,-0.08512,0.52416,0,0.02023,
        0,0,0,1,0
      ],
      Kodachrome: [
        1.12855,-0.39673,-0.03992,0,0.24991,
        -0.16404,1.08352,-0.05498,0,0.09698,
        -0.16786,-0.56034,1.60148,0,0.13972,
        0,0,0,1,0
      ],
      Technicolor: [
        1.91252,-0.85453,-0.09155,0,0.04624,
        -0.30878,1.76589,-0.10601,0,-0.27589,
        -0.23110,-0.75018,1.84759,0,0.12137,
        0,0,0,1,0
      ],
      Polaroid: [
        1.438,-0.062,-0.062,0,0,
        -0.122,1.378,-0.122,0,0,
        -0.016,-0.016,1.483,0,0,
        0,0,0,1,0
      ],
      Sepia: [
        0.393, 0.769, 0.189, 0, 0,
        0.349, 0.686, 0.168, 0, 0,
        0.272, 0.534, 0.131, 0, 0,
        0, 0, 0, 1, 0
      ],
      BlackWhite: [
        1.5, 1.5, 1.5, 0, -1,
        1.5, 1.5, 1.5, 0, -1,
        1.5, 1.5, 1.5, 0, -1,
        0, 0, 0, 1, 0,
      ]
    };
  
    for (var key in matrices) {
      filters[key] = createClass(filters.ColorMatrix, /** @lends fabric.Image.filters.Sepia.prototype */ {
  
        /**
         * Filter type
         * @param {String} type
         * @default
         */
        type: key,
  
        /**
         * Colormatrix for the effect
         * array of 20 floats. Numbers in positions 4, 9, 14, 19 loose meaning
         * outside the -1, 1 range.
         * @param {Array} matrix array of 20 numbers.
         * @default
         */
        matrix: matrices[key],
  
        /**
         * Lock the matrix export for this kind of static, parameter less filters.
         */
        mainParameter: false,
        /**
         * Lock the colormatrix on the color part, skipping alpha
         */
        colorsOnly: true,
  
      });
      fabric.Image.filters[key].fromObject = fabric.Image.filters.BaseFilter.fromObject;
    }
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
    'use strict';
  
    var fabric = global.fabric,
        filters = fabric.Image.filters,
        createClass = fabric.util.createClass;
  
    /**
     * Color Blend filter class
     * @class fabric.Image.filter.BlendColor
     * @memberOf fabric.Image.filters
     * @extends fabric.Image.filters.BaseFilter
     * @example
     * var filter = new fabric.Image.filters.BlendColor({
     *  color: '#000',
     *  mode: 'multiply'
     * });
     *
     * var filter = new fabric.Image.filters.BlendImage({
     *  image: fabricImageObject,
     *  mode: 'multiply',
     *  alpha: 0.5
     * });
     * object.filters.push(filter);
     * object.applyFilters();
     * canvas.renderAll();
     */
  
    filters.BlendColor = createClass(filters.BaseFilter, /** @lends fabric.Image.filters.Blend.prototype */ {
      type: 'BlendColor',
  
      /**
       * Color to make the blend operation with. default to a reddish color since black or white
       * gives always strong result.
       **/
      color: '#F95C63',
  
      /**
       * Blend mode for the filter: one of multiply, add, diff, screen, subtract,
       * darken, lighten, overlay, exclusion, tint.
       **/
      mode: 'multiply',
  
      /**
       * alpha value. represent the strength of the blend color operation.
       **/
      alpha: 1,
  
      /**
       * Fragment source for the Multiply program
       */
      fragmentSource: {
        multiply: 'gl_FragColor.rgb *= uColor.rgb;\n',
        screen: 'gl_FragColor.rgb = 1.0 - (1.0 - gl_FragColor.rgb) * (1.0 - uColor.rgb);\n',
        add: 'gl_FragColor.rgb += uColor.rgb;\n',
        diff: 'gl_FragColor.rgb = abs(gl_FragColor.rgb - uColor.rgb);\n',
        subtract: 'gl_FragColor.rgb -= uColor.rgb;\n',
        lighten: 'gl_FragColor.rgb = max(gl_FragColor.rgb, uColor.rgb);\n',
        darken: 'gl_FragColor.rgb = min(gl_FragColor.rgb, uColor.rgb);\n',
        exclusion: 'gl_FragColor.rgb += uColor.rgb - 2.0 * (uColor.rgb * gl_FragColor.rgb);\n',
        overlay: 'if (uColor.r < 0.5) {\n' +
            'gl_FragColor.r *= 2.0 * uColor.r;\n' +
          '} else {\n' +
            'gl_FragColor.r = 1.0 - 2.0 * (1.0 - gl_FragColor.r) * (1.0 - uColor.r);\n' +
          '}\n' +
          'if (uColor.g < 0.5) {\n' +
            'gl_FragColor.g *= 2.0 * uColor.g;\n' +
          '} else {\n' +
            'gl_FragColor.g = 1.0 - 2.0 * (1.0 - gl_FragColor.g) * (1.0 - uColor.g);\n' +
          '}\n' +
          'if (uColor.b < 0.5) {\n' +
            'gl_FragColor.b *= 2.0 * uColor.b;\n' +
          '} else {\n' +
            'gl_FragColor.b = 1.0 - 2.0 * (1.0 - gl_FragColor.b) * (1.0 - uColor.b);\n' +
          '}\n',
        tint: 'gl_FragColor.rgb *= (1.0 - uColor.a);\n' +
          'gl_FragColor.rgb += uColor.rgb;\n',
      },
  
      /**
       * build the fragment source for the filters, joining the common part with
       * the specific one.
       * @param {String} mode the mode of the filter, a key of this.fragmentSource
       * @return {String} the source to be compiled
       * @private
       */
      buildSource: function(mode) {
        return 'precision highp float;\n' +
          'uniform sampler2D uTexture;\n' +
          'uniform vec4 uColor;\n' +
          'varying vec2 vTexCoord;\n' +
          'void main() {\n' +
            'vec4 color = texture2D(uTexture, vTexCoord);\n' +
            'gl_FragColor = color;\n' +
            'if (color.a > 0.0) {\n' +
              this.fragmentSource[mode] +
            '}\n' +
          '}';
      },
  
      /**
       * Retrieves the cached shader.
       * @param {Object} options
       * @param {WebGLRenderingContext} options.context The GL context used for rendering.
       * @param {Object} options.programCache A map of compiled shader programs, keyed by filter type.
       */
      retrieveShader: function(options) {
        var cacheKey = this.type + '_' + this.mode, shaderSource;
        if (!options.programCache.hasOwnProperty(cacheKey)) {
          shaderSource = this.buildSource(this.mode);
          options.programCache[cacheKey] = this.createProgram(options.context, shaderSource);
        }
        return options.programCache[cacheKey];
      },
  
      /**
       * Apply the Blend operation to a Uint8ClampedArray representing the pixels of an image.
       *
       * @param {Object} options
       * @param {ImageData} options.imageData The Uint8ClampedArray to be filtered.
       */
      applyTo2d: function(options) {
        var imageData = options.imageData,
            data = imageData.data, iLen = data.length,
            tr, tg, tb,
            r, g, b,
            source, alpha1 = 1 - this.alpha;
  
        source = new fabric.Color(this.color).getSource();
        tr = source[0] * this.alpha;
        tg = source[1] * this.alpha;
        tb = source[2] * this.alpha;
  
        for (var i = 0; i < iLen; i += 4) {
  
          r = data[i];
          g = data[i + 1];
          b = data[i + 2];
  
          switch (this.mode) {
            case 'multiply':
              data[i] = r * tr / 255;
              data[i + 1] = g * tg / 255;
              data[i + 2] = b * tb / 255;
              break;
            case 'screen':
              data[i] = 255 - (255 - r) * (255 - tr) / 255;
              data[i + 1] = 255 - (255 - g) * (255 - tg) / 255;
              data[i + 2] = 255 - (255 - b) * (255 - tb) / 255;
              break;
            case 'add':
              data[i] = r + tr;
              data[i + 1] = g + tg;
              data[i + 2] = b + tb;
              break;
            case 'diff':
            case 'difference':
              data[i] = Math.abs(r - tr);
              data[i + 1] = Math.abs(g - tg);
              data[i + 2] = Math.abs(b - tb);
              break;
            case 'subtract':
              data[i] = r - tr;
              data[i + 1] = g - tg;
              data[i + 2] = b - tb;
              break;
            case 'darken':
              data[i] = Math.min(r, tr);
              data[i + 1] = Math.min(g, tg);
              data[i + 2] = Math.min(b, tb);
              break;
            case 'lighten':
              data[i] = Math.max(r, tr);
              data[i + 1] = Math.max(g, tg);
              data[i + 2] = Math.max(b, tb);
              break;
            case 'overlay':
              data[i] = tr < 128 ? (2 * r * tr / 255) : (255 - 2 * (255 - r) * (255 - tr) / 255);
              data[i + 1] = tg < 128 ? (2 * g * tg / 255) : (255 - 2 * (255 - g) * (255 - tg) / 255);
              data[i + 2] = tb < 128 ? (2 * b * tb / 255) : (255 - 2 * (255 - b) * (255 - tb) / 255);
              break;
            case 'exclusion':
              data[i] = tr + r - ((2 * tr * r) / 255);
              data[i + 1] = tg + g - ((2 * tg * g) / 255);
              data[i + 2] = tb + b - ((2 * tb * b) / 255);
              break;
            case 'tint':
              data[i] = tr + r * alpha1;
              data[i + 1] = tg + g * alpha1;
              data[i + 2] = tb + b * alpha1;
          }
        }
      },
  
      /**
       * Return WebGL uniform locations for this filter's shader.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {WebGLShaderProgram} program This filter's compiled shader program.
       */
      getUniformLocations: function(gl, program) {
        return {
          uColor: gl.getUniformLocation(program, 'uColor'),
        };
      },
  
      /**
       * Send data from this filter to its shader program's uniforms.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {Object} uniformLocations A map of string uniform names to WebGLUniformLocation objects
       */
      sendUniformData: function(gl, uniformLocations) {
        var source = new fabric.Color(this.color).getSource();
        source[0] = this.alpha * source[0] / 255;
        source[1] = this.alpha * source[1] / 255;
        source[2] = this.alpha * source[2] / 255;
        source[3] = this.alpha;
        gl.uniform4fv(uniformLocations.uColor, source);
      },
  
      /**
       * Returns object representation of an instance
       * @return {Object} Object representation of an instance
       */
      toObject: function() {
        return {
          type: this.type,
          color: this.color,
          mode: this.mode,
          alpha: this.alpha
        };
      }
    });
  
    /**
     * Returns filter instance from an object representation
     * @static
     * @param {Object} object Object to create an instance from
     * @param {function} [callback] to be invoked after filter creation
     * @return {fabric.Image.filters.BlendColor} Instance of fabric.Image.filters.BlendColor
     */
    fabric.Image.filters.BlendColor.fromObject = fabric.Image.filters.BaseFilter.fromObject;
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
    'use strict';
  
    var fabric = global.fabric,
        filters = fabric.Image.filters,
        createClass = fabric.util.createClass;
  
    /**
     * Image Blend filter class
     * @class fabric.Image.filter.BlendImage
     * @memberOf fabric.Image.filters
     * @extends fabric.Image.filters.BaseFilter
     * @example
     * var filter = new fabric.Image.filters.BlendColor({
     *  color: '#000',
     *  mode: 'multiply'
     * });
     *
     * var filter = new fabric.Image.filters.BlendImage({
     *  image: fabricImageObject,
     *  mode: 'multiply',
     *  alpha: 0.5
     * });
     * object.filters.push(filter);
     * object.applyFilters();
     * canvas.renderAll();
     */
  
    filters.BlendImage = createClass(filters.BaseFilter, /** @lends fabric.Image.filters.BlendImage.prototype */ {
      type: 'BlendImage',
  
      /**
       * Color to make the blend operation with. default to a reddish color since black or white
       * gives always strong result.
       **/
      image: null,
  
      /**
       * Blend mode for the filter: one of multiply, add, diff, screen, subtract,
       * darken, lighten, overlay, exclusion, tint.
       **/
      mode: 'multiply',
  
      /**
       * alpha value. represent the strength of the blend image operation.
       * not implemented.
       **/
      alpha: 1,
  
      vertexSource: 'attribute vec2 aPosition;\n' +
        'varying vec2 vTexCoord;\n' +
        'varying vec2 vTexCoord2;\n' +
        'uniform mat3 uTransformMatrix;\n' +
        'void main() {\n' +
          'vTexCoord = aPosition;\n' +
          'vTexCoord2 = (uTransformMatrix * vec3(aPosition, 1.0)).xy;\n' +
          'gl_Position = vec4(aPosition * 2.0 - 1.0, 0.0, 1.0);\n' +
        '}',
  
      /**
       * Fragment source for the Multiply program
       */
      fragmentSource: {
        multiply: 'precision highp float;\n' +
          'uniform sampler2D uTexture;\n' +
          'uniform sampler2D uImage;\n' +
          'uniform vec4 uColor;\n' +
          'varying vec2 vTexCoord;\n' +
          'varying vec2 vTexCoord2;\n' +
          'void main() {\n' +
            'vec4 color = texture2D(uTexture, vTexCoord);\n' +
            'vec4 color2 = texture2D(uImage, vTexCoord2);\n' +
            'color.rgba *= color2.rgba;\n' +
            'gl_FragColor = color;\n' +
          '}',
        mask: 'precision highp float;\n' +
          'uniform sampler2D uTexture;\n' +
          'uniform sampler2D uImage;\n' +
          'uniform vec4 uColor;\n' +
          'varying vec2 vTexCoord;\n' +
          'varying vec2 vTexCoord2;\n' +
          'void main() {\n' +
            'vec4 color = texture2D(uTexture, vTexCoord);\n' +
            'vec4 color2 = texture2D(uImage, vTexCoord2);\n' +
            'color.a = color2.a;\n' +
            'gl_FragColor = color;\n' +
          '}',
      },
  
      /**
       * Retrieves the cached shader.
       * @param {Object} options
       * @param {WebGLRenderingContext} options.context The GL context used for rendering.
       * @param {Object} options.programCache A map of compiled shader programs, keyed by filter type.
       */
      retrieveShader: function(options) {
        var cacheKey = this.type + '_' + this.mode;
        var shaderSource = this.fragmentSource[this.mode];
        if (!options.programCache.hasOwnProperty(cacheKey)) {
          options.programCache[cacheKey] = this.createProgram(options.context, shaderSource);
        }
        return options.programCache[cacheKey];
      },
  
      applyToWebGL: function(options) {
        // load texture to blend.
        var gl = options.context,
            texture = this.createTexture(options.filterBackend, this.image);
        this.bindAdditionalTexture(gl, texture, gl.TEXTURE1);
        this.callSuper('applyToWebGL', options);
        this.unbindAdditionalTexture(gl, gl.TEXTURE1);
      },
  
      createTexture: function(backend, image) {
        return backend.getCachedTexture(image.cacheKey, image._element);
      },
  
      /**
       * Calculate a transformMatrix to adapt the image to blend over
       * @param {Object} options
       * @param {WebGLRenderingContext} options.context The GL context used for rendering.
       * @param {Object} options.programCache A map of compiled shader programs, keyed by filter type.
       */
      calculateMatrix: function() {
        var image = this.image,
            width = image._element.width,
            height = image._element.height;
        return [
          1 / image.scaleX, 0, 0,
          0, 1 / image.scaleY, 0,
          -image.left / width, -image.top / height, 1
        ];
      },
  
      /**
       * Apply the Blend operation to a Uint8ClampedArray representing the pixels of an image.
       *
       * @param {Object} options
       * @param {ImageData} options.imageData The Uint8ClampedArray to be filtered.
       */
      applyTo2d: function(options) {
        var imageData = options.imageData,
            resources = options.filterBackend.resources,
            data = imageData.data, iLen = data.length,
            width = imageData.width,
            height = imageData.height,
            tr, tg, tb, ta,
            r, g, b, a,
            canvas1, context, image = this.image, blendData;
  
        if (!resources.blendImage) {
          resources.blendImage = fabric.util.createCanvasElement();
        }
        canvas1 = resources.blendImage;
        context = canvas1.getContext('2d');
        if (canvas1.width !== width || canvas1.height !== height) {
          canvas1.width = width;
          canvas1.height = height;
        }
        else {
          context.clearRect(0, 0, width, height);
        }
        context.setTransform(image.scaleX, 0, 0, image.scaleY, image.left, image.top);
        context.drawImage(image._element, 0, 0, width, height);
        blendData = context.getImageData(0, 0, width, height).data;
        for (var i = 0; i < iLen; i += 4) {
  
          r = data[i];
          g = data[i + 1];
          b = data[i + 2];
          a = data[i + 3];
  
          tr = blendData[i];
          tg = blendData[i + 1];
          tb = blendData[i + 2];
          ta = blendData[i + 3];
  
          switch (this.mode) {
            case 'multiply':
              data[i] = r * tr / 255;
              data[i + 1] = g * tg / 255;
              data[i + 2] = b * tb / 255;
              data[i + 3] = a * ta / 255;
              break;
            case 'mask':
              data[i + 3] = ta;
              break;
          }
        }
      },
  
      /**
       * Return WebGL uniform locations for this filter's shader.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {WebGLShaderProgram} program This filter's compiled shader program.
       */
      getUniformLocations: function(gl, program) {
        return {
          uTransformMatrix: gl.getUniformLocation(program, 'uTransformMatrix'),
          uImage: gl.getUniformLocation(program, 'uImage'),
        };
      },
  
      /**
       * Send data from this filter to its shader program's uniforms.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {Object} uniformLocations A map of string uniform names to WebGLUniformLocation objects
       */
      sendUniformData: function(gl, uniformLocations) {
        var matrix = this.calculateMatrix();
        gl.uniform1i(uniformLocations.uImage, 1); // texture unit 1.
        gl.uniformMatrix3fv(uniformLocations.uTransformMatrix, false, matrix);
      },
  
      /**
       * Returns object representation of an instance
       * @return {Object} Object representation of an instance
       */
      toObject: function() {
        return {
          type: this.type,
          image: this.image && this.image.toObject(),
          mode: this.mode,
          alpha: this.alpha
        };
      }
    });
  
    /**
     * Returns filter instance from an object representation
     * @static
     * @param {Object} object Object to create an instance from
     * @param {function} callback to be invoked after filter creation
     * @return {fabric.Image.filters.BlendImage} Instance of fabric.Image.filters.BlendImage
     */
    fabric.Image.filters.BlendImage.fromObject = function(object, callback) {
      fabric.Image.fromObject(object.image, function(image) {
        var options = fabric.util.object.clone(object);
        options.image = image;
        callback(new fabric.Image.filters.BlendImage(options));
      });
    };
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric  = global.fabric || (global.fabric = { }), pow = Math.pow, floor = Math.floor,
        sqrt = Math.sqrt, abs = Math.abs, round = Math.round, sin = Math.sin,
        ceil = Math.ceil,
        filters = fabric.Image.filters,
        createClass = fabric.util.createClass;
  
    /**
     * Resize image filter class
     * @class fabric.Image.filters.Resize
     * @memberOf fabric.Image.filters
     * @extends fabric.Image.filters.BaseFilter
     * @see {@link http://fabricjs.com/image-filters|ImageFilters demo}
     * @example
     * var filter = new fabric.Image.filters.Resize();
     * object.filters.push(filter);
     * object.applyFilters(canvas.renderAll.bind(canvas));
     */
    filters.Resize = createClass(filters.BaseFilter, /** @lends fabric.Image.filters.Resize.prototype */ {
  
      /**
       * Filter type
       * @param {String} type
       * @default
       */
      type: 'Resize',
  
      /**
       * Resize type
       * for webgl resizeType is just lanczos, for canvas2d can be:
       * bilinear, hermite, sliceHack, lanczos.
       * @param {String} resizeType
       * @default
       */
      resizeType: 'hermite',
  
      /**
       * Scale factor for resizing, x axis
       * @param {Number} scaleX
       * @default
       */
      scaleX: 1,
  
      /**
       * Scale factor for resizing, y axis
       * @param {Number} scaleY
       * @default
       */
      scaleY: 1,
  
      /**
       * LanczosLobes parameter for lanczos filter, valid for resizeType lanczos
       * @param {Number} lanczosLobes
       * @default
       */
      lanczosLobes: 3,
  
  
      /**
       * Return WebGL uniform locations for this filter's shader.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {WebGLShaderProgram} program This filter's compiled shader program.
       */
      getUniformLocations: function(gl, program) {
        return {
          uDelta: gl.getUniformLocation(program, 'uDelta'),
          uTaps: gl.getUniformLocation(program, 'uTaps'),
        };
      },
  
      /**
       * Send data from this filter to its shader program's uniforms.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {Object} uniformLocations A map of string uniform names to WebGLUniformLocation objects
       */
      sendUniformData: function(gl, uniformLocations) {
        gl.uniform2fv(uniformLocations.uDelta, this.horizontal ? [1 / this.width, 0] : [0, 1 / this.height]);
        gl.uniform1fv(uniformLocations.uTaps, this.taps);
      },
  
      /**
       * Retrieves the cached shader.
       * @param {Object} options
       * @param {WebGLRenderingContext} options.context The GL context used for rendering.
       * @param {Object} options.programCache A map of compiled shader programs, keyed by filter type.
       */
      retrieveShader: function(options) {
        var filterWindow = this.getFilterWindow(), cacheKey = this.type + '_' + filterWindow;
        if (!options.programCache.hasOwnProperty(cacheKey)) {
          var fragmentShader = this.generateShader(filterWindow);
          options.programCache[cacheKey] = this.createProgram(options.context, fragmentShader);
        }
        return options.programCache[cacheKey];
      },
  
      getFilterWindow: function() {
        var scale = this.tempScale;
        return Math.ceil(this.lanczosLobes / scale);
      },
  
      getTaps: function() {
        var lobeFunction = this.lanczosCreate(this.lanczosLobes), scale = this.tempScale,
            filterWindow = this.getFilterWindow(), taps = new Array(filterWindow);
        for (var i = 1; i <= filterWindow; i++) {
          taps[i - 1] = lobeFunction(i * scale);
        }
        return taps;
      },
  
      /**
       * Generate vertex and shader sources from the necessary steps numbers
       * @param {Number} filterWindow
       */
      generateShader: function(filterWindow) {
        var offsets = new Array(filterWindow),
            fragmentShader = this.fragmentSourceTOP, filterWindow;
  
        for (var i = 1; i <= filterWindow; i++) {
          offsets[i - 1] = i + '.0 * uDelta';
        }
  
        fragmentShader += 'uniform float uTaps[' + filterWindow + '];\n';
        fragmentShader += 'void main() {\n';
        fragmentShader += '  vec4 color = texture2D(uTexture, vTexCoord);\n';
        fragmentShader += '  float sum = 1.0;\n';
  
        offsets.forEach(function(offset, i) {
          fragmentShader += '  color += texture2D(uTexture, vTexCoord + ' + offset + ') * uTaps[' + i + '];\n';
          fragmentShader += '  color += texture2D(uTexture, vTexCoord - ' + offset + ') * uTaps[' + i + '];\n';
          fragmentShader += '  sum += 2.0 * uTaps[' + i + '];\n';
        });
        fragmentShader += '  gl_FragColor = color / sum;\n';
        fragmentShader += '}';
        return fragmentShader;
      },
  
      fragmentSourceTOP: 'precision highp float;\n' +
        'uniform sampler2D uTexture;\n' +
        'uniform vec2 uDelta;\n' +
        'varying vec2 vTexCoord;\n',
  
      /**
       * Apply the resize filter to the image
       * Determines whether to use WebGL or Canvas2D based on the options.webgl flag.
       *
       * @param {Object} options
       * @param {Number} options.passes The number of filters remaining to be executed
       * @param {Boolean} options.webgl Whether to use webgl to render the filter.
       * @param {WebGLTexture} options.sourceTexture The texture setup as the source to be filtered.
       * @param {WebGLTexture} options.targetTexture The texture where filtered output should be drawn.
       * @param {WebGLRenderingContext} options.context The GL context used for rendering.
       * @param {Object} options.programCache A map of compiled shader programs, keyed by filter type.
       */
      applyTo: function(options) {
        if (options.webgl) {
          options.passes++;
          this.width = options.sourceWidth;
          this.horizontal = true;
          this.dW = Math.round(this.width * this.scaleX);
          this.dH = options.sourceHeight;
          this.tempScale = this.dW / this.width;
          this.taps = this.getTaps();
          options.destinationWidth = this.dW;
          this._setupFrameBuffer(options);
          this.applyToWebGL(options);
          this._swapTextures(options);
          options.sourceWidth = options.destinationWidth;
  
          this.height = options.sourceHeight;
          this.horizontal = false;
          this.dH = Math.round(this.height * this.scaleY);
          this.tempScale = this.dH / this.height;
          this.taps = this.getTaps();
          options.destinationHeight = this.dH;
          this._setupFrameBuffer(options);
          this.applyToWebGL(options);
          this._swapTextures(options);
          options.sourceHeight = options.destinationHeight;
        }
        else {
          this.applyTo2d(options);
        }
      },
  
      isNeutralState: function() {
        return this.scaleX === 1 && this.scaleY === 1;
      },
  
      lanczosCreate: function(lobes) {
        return function(x) {
          if (x >= lobes || x <= -lobes) {
            return 0.0;
          }
          if (x < 1.19209290E-07 && x > -1.19209290E-07) {
            return 1.0;
          }
          x *= Math.PI;
          var xx = x / lobes;
          return (sin(x) / x) * sin(xx) / xx;
        };
      },
  
      /**
       * Applies filter to canvas element
       * @memberOf fabric.Image.filters.Resize.prototype
       * @param {Object} canvasEl Canvas element to apply filter to
       * @param {Number} scaleX
       * @param {Number} scaleY
       */
      applyTo2d: function(options) {
        var imageData = options.imageData,
            scaleX = this.scaleX,
            scaleY = this.scaleY;
  
        this.rcpScaleX = 1 / scaleX;
        this.rcpScaleY = 1 / scaleY;
  
        var oW = imageData.width, oH = imageData.height,
            dW = round(oW * scaleX), dH = round(oH * scaleY),
            newData;
  
        if (this.resizeType === 'sliceHack') {
          newData = this.sliceByTwo(options, oW, oH, dW, dH);
        }
        else if (this.resizeType === 'hermite') {
          newData = this.hermiteFastResize(options, oW, oH, dW, dH);
        }
        else if (this.resizeType === 'bilinear') {
          newData = this.bilinearFiltering(options, oW, oH, dW, dH);
        }
        else if (this.resizeType === 'lanczos') {
          newData = this.lanczosResize(options, oW, oH, dW, dH);
        }
        options.imageData = newData;
      },
  
      /**
       * Filter sliceByTwo
       * @param {Object} canvasEl Canvas element to apply filter to
       * @param {Number} oW Original Width
       * @param {Number} oH Original Height
       * @param {Number} dW Destination Width
       * @param {Number} dH Destination Height
       * @returns {ImageData}
       */
      sliceByTwo: function(options, oW, oH, dW, dH) {
        var imageData = options.imageData,
            mult = 0.5, doneW = false, doneH = false, stepW = oW * mult,
            stepH = oH * mult, resources = fabric.filterBackend.resources,
            tmpCanvas, ctx, sX = 0, sY = 0, dX = oW, dY = 0;
        if (!resources.sliceByTwo) {
          resources.sliceByTwo = document.createElement('canvas');
        }
        tmpCanvas = resources.sliceByTwo;
        if (tmpCanvas.width < oW * 1.5 || tmpCanvas.height < oH) {
          tmpCanvas.width = oW * 1.5;
          tmpCanvas.height = oH;
        }
        ctx = tmpCanvas.getContext('2d');
        ctx.clearRect(0, 0, oW * 1.5, oH);
        ctx.putImageData(imageData, 0, 0);
  
        dW = floor(dW);
        dH = floor(dH);
  
        while (!doneW || !doneH) {
          oW = stepW;
          oH = stepH;
          if (dW < floor(stepW * mult)) {
            stepW = floor(stepW * mult);
          }
          else {
            stepW = dW;
            doneW = true;
          }
          if (dH < floor(stepH * mult)) {
            stepH = floor(stepH * mult);
          }
          else {
            stepH = dH;
            doneH = true;
          }
          ctx.drawImage(tmpCanvas, sX, sY, oW, oH, dX, dY, stepW, stepH);
          sX = dX;
          sY = dY;
          dY += stepH;
        }
        return ctx.getImageData(sX, sY, dW, dH);
      },
  
      /**
       * Filter lanczosResize
       * @param {Object} canvasEl Canvas element to apply filter to
       * @param {Number} oW Original Width
       * @param {Number} oH Original Height
       * @param {Number} dW Destination Width
       * @param {Number} dH Destination Height
       * @returns {ImageData}
       */
      lanczosResize: function(options, oW, oH, dW, dH) {
  
        function process(u) {
          var v, i, weight, idx, a, red, green,
              blue, alpha, fX, fY;
          center.x = (u + 0.5) * ratioX;
          icenter.x = floor(center.x);
          for (v = 0; v < dH; v++) {
            center.y = (v + 0.5) * ratioY;
            icenter.y = floor(center.y);
            a = 0; red = 0; green = 0; blue = 0; alpha = 0;
            for (i = icenter.x - range2X; i <= icenter.x + range2X; i++) {
              if (i < 0 || i >= oW) {
                continue;
              }
              fX = floor(1000 * abs(i - center.x));
              if (!cacheLanc[fX]) {
                cacheLanc[fX] = { };
              }
              for (var j = icenter.y - range2Y; j <= icenter.y + range2Y; j++) {
                if (j < 0 || j >= oH) {
                  continue;
                }
                fY = floor(1000 * abs(j - center.y));
                if (!cacheLanc[fX][fY]) {
                  cacheLanc[fX][fY] = lanczos(sqrt(pow(fX * rcpRatioX, 2) + pow(fY * rcpRatioY, 2)) / 1000);
                }
                weight = cacheLanc[fX][fY];
                if (weight > 0) {
                  idx = (j * oW + i) * 4;
                  a += weight;
                  red += weight * srcData[idx];
                  green += weight * srcData[idx + 1];
                  blue += weight * srcData[idx + 2];
                  alpha += weight * srcData[idx + 3];
                }
              }
            }
            idx = (v * dW + u) * 4;
            destData[idx] = red / a;
            destData[idx + 1] = green / a;
            destData[idx + 2] = blue / a;
            destData[idx + 3] = alpha / a;
          }
  
          if (++u < dW) {
            return process(u);
          }
          else {
            return destImg;
          }
        }
  
        var srcData = options.imageData.data,
            destImg = options.ctx.createImageData(dW, dH),
            destData = destImg.data,
            lanczos = this.lanczosCreate(this.lanczosLobes),
            ratioX = this.rcpScaleX, ratioY = this.rcpScaleY,
            rcpRatioX = 2 / this.rcpScaleX, rcpRatioY = 2 / this.rcpScaleY,
            range2X = ceil(ratioX * this.lanczosLobes / 2),
            range2Y = ceil(ratioY * this.lanczosLobes / 2),
            cacheLanc = { }, center = { }, icenter = { };
  
        return process(0);
      },
  
      /**
       * bilinearFiltering
       * @param {Object} canvasEl Canvas element to apply filter to
       * @param {Number} oW Original Width
       * @param {Number} oH Original Height
       * @param {Number} dW Destination Width
       * @param {Number} dH Destination Height
       * @returns {ImageData}
       */
      bilinearFiltering: function(options, oW, oH, dW, dH) {
        var a, b, c, d, x, y, i, j, xDiff, yDiff, chnl,
            color, offset = 0, origPix, ratioX = this.rcpScaleX,
            ratioY = this.rcpScaleY,
            w4 = 4 * (oW - 1), img = options.imageData,
            pixels = img.data, destImage = options.ctx.createImageData(dW, dH),
            destPixels = destImage.data;
        for (i = 0; i < dH; i++) {
          for (j = 0; j < dW; j++) {
            x = floor(ratioX * j);
            y = floor(ratioY * i);
            xDiff = ratioX * j - x;
            yDiff = ratioY * i - y;
            origPix = 4 * (y * oW + x);
  
            for (chnl = 0; chnl < 4; chnl++) {
              a = pixels[origPix + chnl];
              b = pixels[origPix + 4 + chnl];
              c = pixels[origPix + w4 + chnl];
              d = pixels[origPix + w4 + 4 + chnl];
              color = a * (1 - xDiff) * (1 - yDiff) + b * xDiff * (1 - yDiff) +
                      c * yDiff * (1 - xDiff) + d * xDiff * yDiff;
              destPixels[offset++] = color;
            }
          }
        }
        return destImage;
      },
  
      /**
       * hermiteFastResize
       * @param {Object} canvasEl Canvas element to apply filter to
       * @param {Number} oW Original Width
       * @param {Number} oH Original Height
       * @param {Number} dW Destination Width
       * @param {Number} dH Destination Height
       * @returns {ImageData}
       */
      hermiteFastResize: function(options, oW, oH, dW, dH) {
        var ratioW = this.rcpScaleX, ratioH = this.rcpScaleY,
            ratioWHalf = ceil(ratioW / 2),
            ratioHHalf = ceil(ratioH / 2),
            img = options.imageData, data = img.data,
            img2 = options.ctx.createImageData(dW, dH), data2 = img2.data;
        for (var j = 0; j < dH; j++) {
          for (var i = 0; i < dW; i++) {
            var x2 = (i + j * dW) * 4, weight = 0, weights = 0, weightsAlpha = 0,
                gxR = 0, gxG = 0, gxB = 0, gxA = 0, centerY = (j + 0.5) * ratioH;
            for (var yy = floor(j * ratioH); yy < (j + 1) * ratioH; yy++) {
              var dy = abs(centerY - (yy + 0.5)) / ratioHHalf,
                  centerX = (i + 0.5) * ratioW, w0 = dy * dy;
              for (var xx = floor(i * ratioW); xx < (i + 1) * ratioW; xx++) {
                var dx = abs(centerX - (xx + 0.5)) / ratioWHalf,
                    w = sqrt(w0 + dx * dx);
                /* eslint-disable max-depth */
                if (w > 1 && w < -1) {
                  continue;
                }
                //hermite filter
                weight = 2 * w * w * w - 3 * w * w + 1;
                if (weight > 0) {
                  dx = 4 * (xx + yy * oW);
                  //alpha
                  gxA += weight * data[dx + 3];
                  weightsAlpha += weight;
                  //colors
                  if (data[dx + 3] < 255) {
                    weight = weight * data[dx + 3] / 250;
                  }
                  gxR += weight * data[dx];
                  gxG += weight * data[dx + 1];
                  gxB += weight * data[dx + 2];
                  weights += weight;
                }
                /* eslint-enable max-depth */
              }
            }
            data2[x2] = gxR / weights;
            data2[x2 + 1] = gxG / weights;
            data2[x2 + 2] = gxB / weights;
            data2[x2 + 3] = gxA / weightsAlpha;
          }
        }
        return img2;
      },
  
      /**
       * Returns object representation of an instance
       * @return {Object} Object representation of an instance
       */
      toObject: function() {
        return {
          type: this.type,
          scaleX: this.scaleX,
          scaleY: this.scaleY,
          resizeType: this.resizeType,
          lanczosLobes: this.lanczosLobes
        };
      }
    });
  
    /**
     * Returns filter instance from an object representation
     * @static
     * @param {Object} object Object to create an instance from
     * @param {Function} [callback] to be invoked after filter creation
     * @return {fabric.Image.filters.Resize} Instance of fabric.Image.filters.Resize
     */
    fabric.Image.filters.Resize.fromObject = fabric.Image.filters.BaseFilter.fromObject;
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric  = global.fabric || (global.fabric = { }),
        filters = fabric.Image.filters,
        createClass = fabric.util.createClass;
  
    /**
     * Contrast filter class
     * @class fabric.Image.filters.Contrast
     * @memberOf fabric.Image.filters
     * @extends fabric.Image.filters.BaseFilter
     * @see {@link fabric.Image.filters.Contrast#initialize} for constructor definition
     * @see {@link http://fabricjs.com/image-filters|ImageFilters demo}
     * @example
     * var filter = new fabric.Image.filters.Contrast({
     *   contrast: 40
     * });
     * object.filters.push(filter);
     * object.applyFilters();
     */
    filters.Contrast = createClass(filters.BaseFilter, /** @lends fabric.Image.filters.Contrast.prototype */ {
  
      /**
       * Filter type
       * @param {String} type
       * @default
       */
      type: 'Contrast',
  
      fragmentSource: 'precision highp float;\n' +
        'uniform sampler2D uTexture;\n' +
        'uniform float uContrast;\n' +
        'varying vec2 vTexCoord;\n' +
        'void main() {\n' +
          'vec4 color = texture2D(uTexture, vTexCoord);\n' +
          'float contrastF = 1.015 * (uContrast + 1.0) / (1.0 * (1.015 - uContrast));\n' +
          'color.rgb = contrastF * (color.rgb - 0.5) + 0.5;\n' +
          'gl_FragColor = color;\n' +
        '}',
  
      contrast: 0,
  
      mainParameter: 'contrast',
  
      /**
       * Constructor
       * @memberOf fabric.Image.filters.Contrast.prototype
       * @param {Object} [options] Options object
       * @param {Number} [options.contrast=0] Value to contrast the image up (-1...1)
       */
  
      /**
        * Apply the Contrast operation to a Uint8Array representing the pixels of an image.
        *
        * @param {Object} options
        * @param {ImageData} options.imageData The Uint8Array to be filtered.
        */
      applyTo2d: function(options) {
        if (this.contrast === 0) {
          return;
        }
        var imageData = options.imageData, i, len,
            data = imageData.data, len = data.length,
            contrast = Math.floor(this.contrast * 255),
            contrastF = 259 * (contrast + 255) / (255 * (259 - contrast));
  
        for (i = 0; i < len; i += 4) {
          data[i] = contrastF * (data[i] - 128) + 128;
          data[i + 1] = contrastF * (data[i + 1] - 128) + 128;
          data[i + 2] = contrastF * (data[i + 2] - 128) + 128;
        }
      },
  
      /**
       * Return WebGL uniform locations for this filter's shader.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {WebGLShaderProgram} program This filter's compiled shader program.
       */
      getUniformLocations: function(gl, program) {
        return {
          uContrast: gl.getUniformLocation(program, 'uContrast'),
        };
      },
  
      /**
       * Send data from this filter to its shader program's uniforms.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {Object} uniformLocations A map of string uniform names to WebGLUniformLocation objects
       */
      sendUniformData: function(gl, uniformLocations) {
        gl.uniform1f(uniformLocations.uContrast, this.contrast);
      },
    });
  
    /**
     * Returns filter instance from an object representation
     * @static
     * @param {Object} object Object to create an instance from
     * @param {function} [callback] to be invoked after filter creation
     * @return {fabric.Image.filters.Contrast} Instance of fabric.Image.filters.Contrast
     */
    fabric.Image.filters.Contrast.fromObject = fabric.Image.filters.BaseFilter.fromObject;
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric  = global.fabric || (global.fabric = { }),
        filters = fabric.Image.filters,
        createClass = fabric.util.createClass;
  
    /**
     * Saturate filter class
     * @class fabric.Image.filters.Saturation
     * @memberOf fabric.Image.filters
     * @extends fabric.Image.filters.BaseFilter
     * @see {@link fabric.Image.filters.Saturation#initialize} for constructor definition
     * @see {@link http://fabricjs.com/image-filters|ImageFilters demo}
     * @example
     * var filter = new fabric.Image.filters.Saturation({
     *   saturation: 100
     * });
     * object.filters.push(filter);
     * object.applyFilters();
     */
    filters.Saturation = createClass(filters.BaseFilter, /** @lends fabric.Image.filters.Saturation.prototype */ {
  
      /**
       * Filter type
       * @param {String} type
       * @default
       */
      type: 'Saturation',
  
      fragmentSource: 'precision highp float;\n' +
        'uniform sampler2D uTexture;\n' +
        'uniform float uSaturation;\n' +
        'varying vec2 vTexCoord;\n' +
        'void main() {\n' +
          'vec4 color = texture2D(uTexture, vTexCoord);\n' +
          'float rgMax = max(color.r, color.g);\n' +
          'float rgbMax = max(rgMax, color.b);\n' +
          'color.r += rgbMax != color.r ? (rgbMax - color.r) * uSaturation : 0.00;\n' +
          'color.g += rgbMax != color.g ? (rgbMax - color.g) * uSaturation : 0.00;\n' +
          'color.b += rgbMax != color.b ? (rgbMax - color.b) * uSaturation : 0.00;\n' +
          'gl_FragColor = color;\n' +
        '}',
  
      saturation: 0,
  
      mainParameter: 'saturation',
  
      /**
       * Constructor
       * @memberOf fabric.Image.filters.Saturate.prototype
       * @param {Object} [options] Options object
       * @param {Number} [options.saturate=0] Value to saturate the image (-1...1)
       */
  
      /**
       * Apply the Saturation operation to a Uint8ClampedArray representing the pixels of an image.
       *
       * @param {Object} options
       * @param {ImageData} options.imageData The Uint8ClampedArray to be filtered.
       */
      applyTo2d: function(options) {
        if (this.saturation === 0) {
          return;
        }
        var imageData = options.imageData,
            data = imageData.data, len = data.length,
            adjust = -this.saturation, i, max;
  
        for (i = 0; i < len; i += 4) {
          max = Math.max(data[i], data[i + 1], data[i + 2]);
          data[i] += max !== data[i] ? (max - data[i]) * adjust : 0;
          data[i + 1] += max !== data[i + 1] ? (max - data[i + 1]) * adjust : 0;
          data[i + 2] += max !== data[i + 2] ? (max - data[i + 2]) * adjust : 0;
        }
      },
  
      /**
       * Return WebGL uniform locations for this filter's shader.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {WebGLShaderProgram} program This filter's compiled shader program.
       */
      getUniformLocations: function(gl, program) {
        return {
          uSaturation: gl.getUniformLocation(program, 'uSaturation'),
        };
      },
  
      /**
       * Send data from this filter to its shader program's uniforms.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {Object} uniformLocations A map of string uniform names to WebGLUniformLocation objects
       */
      sendUniformData: function(gl, uniformLocations) {
        gl.uniform1f(uniformLocations.uSaturation, -this.saturation);
      },
    });
  
    /**
     * Returns filter instance from an object representation
     * @static
     * @param {Object} object Object to create an instance from
     * @param {Function} [callback] to be invoked after filter creation
     * @return {fabric.Image.filters.Saturation} Instance of fabric.Image.filters.Saturate
     */
    fabric.Image.filters.Saturation.fromObject = fabric.Image.filters.BaseFilter.fromObject;
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric  = global.fabric || (global.fabric = { }),
        filters = fabric.Image.filters,
        createClass = fabric.util.createClass;
  
    /**
     * Blur filter class
     * @class fabric.Image.filters.Blur
     * @memberOf fabric.Image.filters
     * @extends fabric.Image.filters.BaseFilter
     * @see {@link fabric.Image.filters.Blur#initialize} for constructor definition
     * @see {@link http://fabricjs.com/image-filters|ImageFilters demo}
     * @example
     * var filter = new fabric.Image.filters.Blur({
     *   blur: 0.5
     * });
     * object.filters.push(filter);
     * object.applyFilters();
     * canvas.renderAll();
     */
    filters.Blur = createClass(filters.BaseFilter, /** @lends fabric.Image.filters.Blur.prototype */ {
  
      type: 'Blur',
  
      /*
  'gl_FragColor = vec4(0.0);',
  'gl_FragColor += texture2D(texture, vTexCoord + -7 * uDelta)*0.0044299121055113265;',
  'gl_FragColor += texture2D(texture, vTexCoord + -6 * uDelta)*0.00895781211794;',
  'gl_FragColor += texture2D(texture, vTexCoord + -5 * uDelta)*0.0215963866053;',
  'gl_FragColor += texture2D(texture, vTexCoord + -4 * uDelta)*0.0443683338718;',
  'gl_FragColor += texture2D(texture, vTexCoord + -3 * uDelta)*0.0776744219933;',
  'gl_FragColor += texture2D(texture, vTexCoord + -2 * uDelta)*0.115876621105;',
  'gl_FragColor += texture2D(texture, vTexCoord + -1 * uDelta)*0.147308056121;',
  'gl_FragColor += texture2D(texture, vTexCoord              )*0.159576912161;',
  'gl_FragColor += texture2D(texture, vTexCoord + 1 * uDelta)*0.147308056121;',
  'gl_FragColor += texture2D(texture, vTexCoord + 2 * uDelta)*0.115876621105;',
  'gl_FragColor += texture2D(texture, vTexCoord + 3 * uDelta)*0.0776744219933;',
  'gl_FragColor += texture2D(texture, vTexCoord + 4 * uDelta)*0.0443683338718;',
  'gl_FragColor += texture2D(texture, vTexCoord + 5 * uDelta)*0.0215963866053;',
  'gl_FragColor += texture2D(texture, vTexCoord + 6 * uDelta)*0.00895781211794;',
  'gl_FragColor += texture2D(texture, vTexCoord + 7 * uDelta)*0.0044299121055113265;',
  */
  
      /* eslint-disable max-len */
      fragmentSource: 'precision highp float;\n' +
        'uniform sampler2D uTexture;\n' +
        'uniform vec2 uDelta;\n' +
        'varying vec2 vTexCoord;\n' +
        'const float nSamples = 15.0;\n' +
        'vec3 v3offset = vec3(12.9898, 78.233, 151.7182);\n' +
        'float random(vec3 scale) {\n' +
          /* use the fragment position for a different seed per-pixel */
          'return fract(sin(dot(gl_FragCoord.xyz, scale)) * 43758.5453);\n' +
        '}\n' +
        'void main() {\n' +
          'vec4 color = vec4(0.0);\n' +
          'float total = 0.0;\n' +
          'float offset = random(v3offset);\n' +
          'for (float t = -nSamples; t <= nSamples; t++) {\n' +
            'float percent = (t + offset - 0.5) / nSamples;\n' +
            'float weight = 1.0 - abs(percent);\n' +
            'color += texture2D(uTexture, vTexCoord + uDelta * percent) * weight;\n' +
            'total += weight;\n' +
          '}\n' +
          'gl_FragColor = color / total;\n' +
        '}',
      /* eslint-enable max-len */
  
      /**
       * blur value, in percentage of image dimensions.
       * specific to keep the image blur constant at different resolutions
       * range bewteen 0 and 1.
       */
      blur: 0,
  
      mainParameter: 'blur',
  
      applyTo: function(options) {
        if (options.webgl) {
          // this aspectRatio is used to give the same blur to vertical and horizontal
          this.aspectRatio = options.sourceWidth / options.sourceHeight;
          options.passes++;
          this._setupFrameBuffer(options);
          this.horizontal = true;
          this.applyToWebGL(options);
          this._swapTextures(options);
          this._setupFrameBuffer(options);
          this.horizontal = false;
          this.applyToWebGL(options);
          this._swapTextures(options);
        }
        else {
          this.applyTo2d(options);
        }
      },
  
      applyTo2d: function(options) {
        // paint canvasEl with current image data.
        //options.ctx.putImageData(options.imageData, 0, 0);
        options.imageData = this.simpleBlur(options);
      },
  
      simpleBlur: function(options) {
        var resources = options.filterBackend.resources, canvas1, canvas2,
            width = options.imageData.width,
            height = options.imageData.height;
  
        if (!resources.blurLayer1) {
          resources.blurLayer1 = fabric.util.createCanvasElement();
          resources.blurLayer2 = fabric.util.createCanvasElement();
        }
        canvas1 = resources.blurLayer1;
        canvas2 = resources.blurLayer2;
        if (canvas1.width !== width || canvas1.height !== height) {
          canvas2.width = canvas1.width = width;
          canvas2.height = canvas1.height = height;
        }
        var ctx1 = canvas1.getContext('2d'),
            ctx2 = canvas2.getContext('2d'),
            nSamples = 15,
            random, percent, j, i,
            blur = this.blur * 0.06 * 0.5;
  
        // load first canvas
        ctx1.putImageData(options.imageData, 0, 0);
        ctx2.clearRect(0, 0, width, height);
  
        for (i = -nSamples; i <= nSamples; i++) {
          random = (Math.random() - 0.5) / 4;
          percent = i / nSamples;
          j = blur * percent * width + random;
          ctx2.globalAlpha = 1 - Math.abs(percent);
          ctx2.drawImage(canvas1, j, random);
          ctx1.drawImage(canvas2, 0, 0);
          ctx2.globalAlpha = 1;
          ctx2.clearRect(0, 0, canvas2.width, canvas2.height);
        }
        for (i = -nSamples; i <= nSamples; i++) {
          random = (Math.random() - 0.5) / 4;
          percent = i / nSamples;
          j = blur * percent * height + random;
          ctx2.globalAlpha = 1 - Math.abs(percent);
          ctx2.drawImage(canvas1, random, j);
          ctx1.drawImage(canvas2, 0, 0);
          ctx2.globalAlpha = 1;
          ctx2.clearRect(0, 0, canvas2.width, canvas2.height);
        }
        options.ctx.drawImage(canvas1, 0, 0);
        var newImageData = options.ctx.getImageData(0, 0, canvas1.width, canvas1.height);
        ctx1.globalAlpha = 1;
        ctx1.clearRect(0, 0, canvas1.width, canvas1.height);
        return newImageData;
      },
  
      /**
       * Return WebGL uniform locations for this filter's shader.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {WebGLShaderProgram} program This filter's compiled shader program.
       */
      getUniformLocations: function(gl, program) {
        return {
          delta: gl.getUniformLocation(program, 'uDelta'),
        };
      },
  
      /**
       * Send data from this filter to its shader program's uniforms.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {Object} uniformLocations A map of string uniform names to WebGLUniformLocation objects
       */
      sendUniformData: function(gl, uniformLocations) {
        var delta = this.chooseRightDelta();
        gl.uniform2fv(uniformLocations.delta, delta);
      },
  
      /**
       * choose right value of image percentage to blur with
       * @returns {Array} a numeric array with delta values
       */
      chooseRightDelta: function() {
        var blurScale = 1, delta = [0, 0], blur;
        if (this.horizontal) {
          if (this.aspectRatio > 1) {
            // image is wide, i want to shrink radius horizontal
            blurScale = 1 / this.aspectRatio;
          }
        }
        else {
          if (this.aspectRatio < 1) {
            // image is tall, i want to shrink radius vertical
            blurScale = this.aspectRatio;
          }
        }
        blur = blurScale * this.blur * 0.12;
        if (this.horizontal) {
          delta[0] = blur;
        }
        else {
          delta[1] = blur;
        }
        return delta;
      },
    });
  
    /**
     * Deserialize a JSON definition of a BlurFilter into a concrete instance.
     */
    filters.Blur.fromObject = fabric.Image.filters.BaseFilter.fromObject;
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric  = global.fabric || (global.fabric = { }),
        filters = fabric.Image.filters,
        createClass = fabric.util.createClass;
  
    /**
     * Gamma filter class
     * @class fabric.Image.filters.Gamma
     * @memberOf fabric.Image.filters
     * @extends fabric.Image.filters.BaseFilter
     * @see {@link fabric.Image.filters.Gamma#initialize} for constructor definition
     * @see {@link http://fabricjs.com/image-filters|ImageFilters demo}
     * @example
     * var filter = new fabric.Image.filters.Gamma({
     *   brightness: 200
     * });
     * object.filters.push(filter);
     * object.applyFilters();
     */
    filters.Gamma = createClass(filters.BaseFilter, /** @lends fabric.Image.filters.Gamma.prototype */ {
  
      /**
       * Filter type
       * @param {String} type
       * @default
       */
      type: 'Gamma',
  
      fragmentSource: 'precision highp float;\n' +
        'uniform sampler2D uTexture;\n' +
        'uniform vec3 uGamma;\n' +
        'varying vec2 vTexCoord;\n' +
        'void main() {\n' +
          'vec4 color = texture2D(uTexture, vTexCoord);\n' +
          'vec3 correction = (1.0 / uGamma);\n' +
          'color.r = pow(color.r, correction.r);\n' +
          'color.g = pow(color.g, correction.g);\n' +
          'color.b = pow(color.b, correction.b);\n' +
          'gl_FragColor = color;\n' +
          'gl_FragColor.rgb *= color.a;\n' +
        '}',
  
      /**
       * Gamma array value, from 0.01 to 2.2.
       * @param {Array} gamma
       * @default
       */
      gamma: [1, 1, 1],
  
      /**
       * Describe the property that is the filter parameter
       * @param {String} m
       * @default
       */
      mainParameter: 'gamma',
  
      /**
       * Constructor
       * @param {Object} [options] Options object
       */
      initialize: function(options) {
        this.gamma = [1, 1, 1];
        filters.BaseFilter.prototype.initialize.call(this, options);
      },
  
      /**
       * Apply the Gamma operation to a Uint8Array representing the pixels of an image.
       *
       * @param {Object} options
       * @param {ImageData} options.imageData The Uint8Array to be filtered.
       */
      applyTo2d: function(options) {
        var imageData = options.imageData, data = imageData.data,
            gamma = this.gamma, len = data.length,
            rInv = 1 / gamma[0], gInv = 1 / gamma[1],
            bInv = 1 / gamma[2], i;
  
        if (!this.rVals) {
          // eslint-disable-next-line
          this.rVals = new Uint8Array(256);
          // eslint-disable-next-line
          this.gVals = new Uint8Array(256);
          // eslint-disable-next-line
          this.bVals = new Uint8Array(256);
        }
  
        // This is an optimization - pre-compute a look-up table for each color channel
        // instead of performing these pow calls for each pixel in the image.
        for (i = 0, len = 256; i < len; i++) {
          this.rVals[i] = Math.pow(i / 255, rInv) * 255;
          this.gVals[i] = Math.pow(i / 255, gInv) * 255;
          this.bVals[i] = Math.pow(i / 255, bInv) * 255;
        }
        for (i = 0, len = data.length; i < len; i += 4) {
          data[i] = this.rVals[data[i]];
          data[i + 1] = this.gVals[data[i + 1]];
          data[i + 2] = this.bVals[data[i + 2]];
        }
      },
  
      /**
       * Return WebGL uniform locations for this filter's shader.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {WebGLShaderProgram} program This filter's compiled shader program.
       */
      getUniformLocations: function(gl, program) {
        return {
          uGamma: gl.getUniformLocation(program, 'uGamma'),
        };
      },
  
      /**
       * Send data from this filter to its shader program's uniforms.
       *
       * @param {WebGLRenderingContext} gl The GL canvas context used to compile this filter's shader.
       * @param {Object} uniformLocations A map of string uniform names to WebGLUniformLocation objects
       */
      sendUniformData: function(gl, uniformLocations) {
        gl.uniform3fv(uniformLocations.uGamma, this.gamma);
      },
    });
  
    /**
     * Returns filter instance from an object representation
     * @static
     * @param {Object} object Object to create an instance from
     * @param {function} [callback] to be invoked after filter creation
     * @return {fabric.Image.filters.Gamma} Instance of fabric.Image.filters.Gamma
     */
    fabric.Image.filters.Gamma.fromObject = fabric.Image.filters.BaseFilter.fromObject;
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric  = global.fabric || (global.fabric = { }),
        filters = fabric.Image.filters,
        createClass = fabric.util.createClass;
  
    /**
     * A container class that knows how to apply a sequence of filters to an input image.
     */
    filters.Composed = createClass(filters.BaseFilter, /** @lends fabric.Image.filters.Composed.prototype */ {
  
      type: 'Composed',
  
      /**
       * A non sparse array of filters to apply
       */
      subFilters: [],
  
      /**
       * Constructor
       * @param {Object} [options] Options object
       */
      initialize: function(options) {
        this.callSuper('initialize', options);
        // create a new array instead mutating the prototype with push
        this.subFilters = this.subFilters.slice(0);
      },
  
      /**
       * Apply this container's filters to the input image provided.
       *
       * @param {Object} options
       * @param {Number} options.passes The number of filters remaining to be applied.
       */
      applyTo: function(options) {
        options.passes += this.subFilters.length - 1;
        this.subFilters.forEach(function(filter) {
          filter.applyTo(options);
        });
      },
  
      /**
       * Serialize this filter into JSON.
       *
       * @returns {Object} A JSON representation of this filter.
       */
      toObject: function() {
        return fabric.util.object.extend(this.callSuper('toObject'), {
          subFilters: this.subFilters.map(function(filter) { return filter.toObject(); }),
        });
      },
  
      isNeutralState: function() {
        return !this.subFilters.some(function(filter) { return !filter.isNeutralState(); });
      }
    });
  
    /**
     * Deserialize a JSON definition of a ComposedFilter into a concrete instance.
     */
    fabric.Image.filters.Composed.fromObject = function(object, callback) {
      var filters = object.subFilters || [],
          subFilters = filters.map(function(filter) {
            return new fabric.Image.filters[filter.type](filter);
          }),
          instance = new fabric.Image.filters.Composed({ subFilters: subFilters });
      callback && callback(instance);
      return instance;
    };
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric  = global.fabric || (global.fabric = { }),
        filters = fabric.Image.filters,
        createClass = fabric.util.createClass;
  
    /**
     * HueRotation filter class
     * @class fabric.Image.filters.HueRotation
     * @memberOf fabric.Image.filters
     * @extends fabric.Image.filters.BaseFilter
     * @see {@link fabric.Image.filters.HueRotation#initialize} for constructor definition
     * @see {@link http://fabricjs.com/image-filters|ImageFilters demo}
     * @example
     * var filter = new fabric.Image.filters.HueRotation({
     *   rotation: -0.5
     * });
     * object.filters.push(filter);
     * object.applyFilters();
     */
    filters.HueRotation = createClass(filters.ColorMatrix, /** @lends fabric.Image.filters.HueRotation.prototype */ {
  
      /**
       * Filter type
       * @param {String} type
       * @default
       */
      type: 'HueRotation',
  
      /**
       * HueRotation value, from -1 to 1.
       * the unit is radians
       * @param {Number} myParameter
       * @default
       */
      rotation: 0,
  
      /**
       * Describe the property that is the filter parameter
       * @param {String} m
       * @default
       */
      mainParameter: 'rotation',
  
      calculateMatrix: function() {
        var rad = this.rotation * Math.PI, cos = fabric.util.cos(rad), sin = fabric.util.sin(rad),
            aThird = 1 / 3, aThirdSqtSin = Math.sqrt(aThird) * sin, OneMinusCos = 1 - cos;
        this.matrix = [
          1, 0, 0, 0, 0,
          0, 1, 0, 0, 0,
          0, 0, 1, 0, 0,
          0, 0, 0, 1, 0
        ];
        this.matrix[0] = cos + OneMinusCos / 3;
        this.matrix[1] = aThird * OneMinusCos - aThirdSqtSin;
        this.matrix[2] = aThird * OneMinusCos + aThirdSqtSin;
        this.matrix[5] = aThird * OneMinusCos + aThirdSqtSin;
        this.matrix[6] = cos + aThird * OneMinusCos;
        this.matrix[7] = aThird * OneMinusCos - aThirdSqtSin;
        this.matrix[10] = aThird * OneMinusCos - aThirdSqtSin;
        this.matrix[11] = aThird * OneMinusCos + aThirdSqtSin;
        this.matrix[12] = cos + aThird * OneMinusCos;
      },
  
      /**
       * HueRotation isNeutralState implementation
       * Used only in image applyFilters to discard filters that will not have an effect
       * on the image
       * @param {Object} options
       **/
      isNeutralState: function(options) {
        this.calculateMatrix();
        return filters.BaseFilter.prototype.isNeutralState.call(this, options);
      },
  
      /**
       * Apply this filter to the input image data provided.
       *
       * Determines whether to use WebGL or Canvas2D based on the options.webgl flag.
       *
       * @param {Object} options
       * @param {Number} options.passes The number of filters remaining to be executed
       * @param {Boolean} options.webgl Whether to use webgl to render the filter.
       * @param {WebGLTexture} options.sourceTexture The texture setup as the source to be filtered.
       * @param {WebGLTexture} options.targetTexture The texture where filtered output should be drawn.
       * @param {WebGLRenderingContext} options.context The GL context used for rendering.
       * @param {Object} options.programCache A map of compiled shader programs, keyed by filter type.
       */
      applyTo: function(options) {
        this.calculateMatrix();
        filters.BaseFilter.prototype.applyTo.call(this, options);
      },
  
    });
  
    /**
     * Returns filter instance from an object representation
     * @static
     * @param {Object} object Object to create an instance from
     * @param {function} [callback] to be invoked after filter creation
     * @return {fabric.Image.filters.HueRotation} Instance of fabric.Image.filters.HueRotation
     */
    fabric.Image.filters.HueRotation.fromObject = fabric.Image.filters.BaseFilter.fromObject;
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function(global) {
  
    'use strict';
  
    var fabric = global.fabric || (global.fabric = { }),
        clone = fabric.util.object.clone;
  
    if (fabric.Text) {
      fabric.warn('fabric.Text is already defined');
      return;
    }
  
    /**
     * Text class
     * @class fabric.Text
     * @extends fabric.Object
     * @return {fabric.Text} thisArg
     * @tutorial {@link http://fabricjs.com/fabric-intro-part-2#text}
     * @see {@link fabric.Text#initialize} for constructor definition
     */
    fabric.Text = fabric.util.createClass(fabric.Object, /** @lends fabric.Text.prototype */ {
  
      /**
       * Properties which when set cause object to change dimensions
       * @type Array
       * @private
       */
      _dimensionAffectingProps: [
        'fontSize',
        'fontWeight',
        'fontFamily',
        'fontStyle',
        'lineHeight',
        'text',
        'charSpacing',
        'textAlign',
        'styles',
      ],
  
      /**
       * @private
       */
      _reNewline: /\r?\n/,
  
      /**
       * Use this regular expression to filter for whitespaces that is not a new line.
       * Mostly used when text is 'justify' aligned.
       * @private
       */
      _reSpacesAndTabs: /[ \t\r]/g,
  
      /**
       * Use this regular expression to filter for whitespace that is not a new line.
       * Mostly used when text is 'justify' aligned.
       * @private
       */
      _reSpaceAndTab: /[ \t\r]/,
  
      /**
       * Use this regular expression to filter consecutive groups of non spaces.
       * Mostly used when text is 'justify' aligned.
       * @private
       */
      _reWords: /\S+/g,
  
      /**
       * Type of an object
       * @type String
       * @default
       */
      type:                 'text',
  
      /**
       * Font size (in pixels)
       * @type Number
       * @default
       */
      fontSize:             40,
  
      /**
       * Font weight (e.g. bold, normal, 400, 600, 800)
       * @type {(Number|String)}
       * @default
       */
      fontWeight:           'normal',
  
      /**
       * Font family
       * @type String
       * @default
       */
      fontFamily:           'Times New Roman',
  
      /**
       * Text decoration underline.
       * @type Boolean
       * @default
       */
      underline:       false,
  
      /**
       * Text decoration overline.
       * @type Boolean
       * @default
       */
      overline:       false,
  
      /**
       * Text decoration linethrough.
       * @type Boolean
       * @default
       */
      linethrough:       false,
  
      /**
       * Text alignment. Possible values: "left", "center", "right", "justify",
       * "justify-left", "justify-center" or "justify-right".
       * @type String
       * @default
       */
      textAlign:            'left',
  
      /**
       * Font style . Possible values: "", "normal", "italic" or "oblique".
       * @type String
       * @default
       */
      fontStyle:            'normal',
  
      /**
       * Line height
       * @type Number
       * @default
       */
      lineHeight:           1.16,
  
      /**
       * Superscript schema object (minimum overlap)
       * @type {Object}
       * @default
       */
      superscript: {
        size:      0.60, // fontSize factor
        baseline: -0.35  // baseline-shift factor (upwards)
      },
  
      /**
       * Subscript schema object (minimum overlap)
       * @type {Object}
       * @default
       */
      subscript: {
        size:      0.60, // fontSize factor
        baseline:  0.11  // baseline-shift factor (downwards)
      },
  
      /**
       * Background color of text lines
       * @type String
       * @default
       */
      textBackgroundColor:  '',
  
      /**
       * List of properties to consider when checking if
       * state of an object is changed ({@link fabric.Object#hasStateChanged})
       * as well as for history (undo/redo) purposes
       * @type Array
       */
      stateProperties: fabric.Object.prototype.stateProperties.concat('fontFamily',
        'fontWeight',
        'fontSize',
        'text',
        'underline',
        'overline',
        'linethrough',
        'textAlign',
        'fontStyle',
        'lineHeight',
        'textBackgroundColor',
        'charSpacing',
        'styles'),
  
      /**
       * List of properties to consider when checking if cache needs refresh
       * @type Array
       */
      cacheProperties: fabric.Object.prototype.cacheProperties.concat('fontFamily',
        'fontWeight',
        'fontSize',
        'text',
        'underline',
        'overline',
        'linethrough',
        'textAlign',
        'fontStyle',
        'lineHeight',
        'textBackgroundColor',
        'charSpacing',
        'styles'),
  
      /**
       * When defined, an object is rendered via stroke and this property specifies its color.
       * <b>Backwards incompatibility note:</b> This property was named "strokeStyle" until v1.1.6
       * @type String
       * @default
       */
      stroke:               null,
  
      /**
       * Shadow object representing shadow of this shape.
       * <b>Backwards incompatibility note:</b> This property was named "textShadow" (String) until v1.2.11
       * @type fabric.Shadow
       * @default
       */
      shadow:               null,
  
      /**
       * @private
       */
      _fontSizeFraction: 0.222,
  
      /**
       * @private
       */
      offsets: {
        underline: 0.10,
        linethrough: -0.315,
        overline: -0.88
      },
  
      /**
       * Text Line proportion to font Size (in pixels)
       * @type Number
       * @default
       */
      _fontSizeMult:             1.13,
  
      /**
       * additional space between characters
       * expressed in thousands of em unit
       * @type Number
       * @default
       */
      charSpacing:             0,
  
      /**
       * Object containing character styles - top-level properties -> line numbers,
       * 2nd-level properties - charater numbers
       * @type Object
       * @default
       */
      styles: null,
  
      /**
       * Reference to a context to measure text char or couple of chars
       * the cacheContext of the canvas will be used or a freshly created one if the object is not on canvas
       * once created it will be referenced on fabric._measuringContext to avoide creating a canvas for every
       * text object created.
       * @type {CanvasRenderingContext2D}
       * @default
       */
      _measuringContext: null,
  
      /**
       * Baseline shift, stlyes only, keep at 0 for the main text object
       * @type {Number}
       * @default
       */
      deltaY: 0,
  
      /**
       * Array of properties that define a style unit (of 'styles').
       * @type {Array}
       * @default
       */
      _styleProperties: [
        'stroke',
        'strokeWidth',
        'fill',
        'fontFamily',
        'fontSize',
        'fontWeight',
        'fontStyle',
        'underline',
        'overline',
        'linethrough',
        'deltaY',
        'textBackgroundColor',
      ],
  
      /**
       * contains characters bounding boxes
       */
      __charBounds: [],
  
      /**
       * use this size when measuring text. To avoid IE11 rounding errors
       * @type {Number}
       * @default
       * @readonly
       * @private
       */
      CACHE_FONT_SIZE: 400,
  
      /**
       * contains the min text width to avoid getting 0
       * @type {Number}
       * @default
       */
      MIN_TEXT_WIDTH: 2,
  
      /**
       * Constructor
       * @param {String} text Text string
       * @param {Object} [options] Options object
       * @return {fabric.Text} thisArg
       */
      initialize: function(text, options) {
        this.styles = options ? (options.styles || { }) : { };
        this.text = text;
        this.__skipDimension = true;
        this.callSuper('initialize', options);
        this.__skipDimension = false;
        this.initDimensions();
        this.setCoords();
        this.setupState({ propertySet: '_dimensionAffectingProps' });
      },
  
      /**
       * Return a contex for measurement of text string.
       * if created it gets stored for reuse
       * @param {String} text Text string
       * @param {Object} [options] Options object
       * @return {fabric.Text} thisArg
       */
      getMeasuringContext: function() {
        // if we did not return we have to measure something.
        if (!fabric._measuringContext) {
          fabric._measuringContext = this.canvas && this.canvas.contextCache ||
            fabric.util.createCanvasElement().getContext('2d');
        }
        return fabric._measuringContext;
      },
  
      /**
       * @private
       * Divides text into lines of text and lines of graphemes.
       */
      _splitText: function() {
        var newLines = this._splitTextIntoLines(this.text);
        this.textLines = newLines.lines;
        this._textLines = newLines.graphemeLines;
        this._unwrappedTextLines = newLines._unwrappedLines;
        this._text = newLines.graphemeText;
        return newLines;
      },
  
      /**
       * Initialize or update text dimensions.
       * Updates this.width and this.height with the proper values.
       * Does not return dimensions.
       */
      initDimensions: function() {
        if (this.__skipDimension) {
          return;
        }
        this._splitText();
        this._clearCache();
        this.width = this.calcTextWidth() || this.cursorWidth || this.MIN_TEXT_WIDTH;
        if (this.textAlign.indexOf('justify') !== -1) {
          // once text is measured we need to make space fatter to make justified text.
          this.enlargeSpaces();
        }
        this.height = this.calcTextHeight();
        this.saveState({ propertySet: '_dimensionAffectingProps' });
      },
  
      /**
       * Enlarge space boxes and shift the others
       */
      enlargeSpaces: function() {
        var diffSpace, currentLineWidth, numberOfSpaces, accumulatedSpace, line, charBound, spaces;
        for (var i = 0, len = this._textLines.length; i < len; i++) {
          if (this.textAlign !== 'justify' && (i === len - 1 || this.isEndOfWrapping(i))) {
            continue;
          }
          accumulatedSpace = 0;
          line = this._textLines[i];
          currentLineWidth = this.getLineWidth(i);
          if (currentLineWidth < this.width && (spaces = this.textLines[i].match(this._reSpacesAndTabs))) {
            numberOfSpaces = spaces.length;
            diffSpace = (this.width - currentLineWidth) / numberOfSpaces;
            for (var j = 0, jlen = line.length; j <= jlen; j++) {
              charBound = this.__charBounds[i][j];
              if (this._reSpaceAndTab.test(line[j])) {
                charBound.width += diffSpace;
                charBound.kernedWidth += diffSpace;
                charBound.left += accumulatedSpace;
                accumulatedSpace += diffSpace;
              }
              else {
                charBound.left += accumulatedSpace;
              }
            }
          }
        }
      },
  
      /**
       * Detect if the text line is ended with an hard break
       * text and itext do not have wrapping, return false
       * @return {Boolean}
       */
      isEndOfWrapping: function(lineIndex) {
        return lineIndex === this._textLines.length - 1;
      },
  
      /**
       * Detect if a line has a linebreak and so we need to account for it when moving
       * and counting style.
       * It return always for text and Itext.
       * @return Number
       */
      missingNewlineOffset: function() {
        return 1;
      },
  
      /**
       * Returns string representation of an instance
       * @return {String} String representation of text object
       */
      toString: function() {
        return '#<fabric.Text (' + this.complexity() +
          '): { "text": "' + this.text + '", "fontFamily": "' + this.fontFamily + '" }>';
      },
  
      /**
       * Return the dimension and the zoom level needed to create a cache canvas
       * big enough to host the object to be cached.
       * @private
       * @param {Object} dim.x width of object to be cached
       * @param {Object} dim.y height of object to be cached
       * @return {Object}.width width of canvas
       * @return {Object}.height height of canvas
       * @return {Object}.zoomX zoomX zoom value to unscale the canvas before drawing cache
       * @return {Object}.zoomY zoomY zoom value to unscale the canvas before drawing cache
       */
      _getCacheCanvasDimensions: function() {
        var dims = this.callSuper('_getCacheCanvasDimensions');
        var fontSize = this.fontSize;
        dims.width += fontSize * dims.zoomX;
        dims.height += fontSize * dims.zoomY;
        return dims;
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _render: function(ctx) {
        this._setTextStyles(ctx);
        this._renderTextLinesBackground(ctx);
        this._renderTextDecoration(ctx, 'underline');
        this._renderText(ctx);
        this._renderTextDecoration(ctx, 'overline');
        this._renderTextDecoration(ctx, 'linethrough');
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _renderText: function(ctx) {
        if (this.paintFirst === 'stroke') {
          this._renderTextStroke(ctx);
          this._renderTextFill(ctx);
        }
        else {
          this._renderTextFill(ctx);
          this._renderTextStroke(ctx);
        }
      },
  
      /**
       * Set the font parameter of the context with the object properties or with charStyle
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       * @param {Object} [charStyle] object with font style properties
       * @param {String} [charStyle.fontFamily] Font Family
       * @param {Number} [charStyle.fontSize] Font size in pixels. ( without px suffix )
       * @param {String} [charStyle.fontWeight] Font weight
       * @param {String} [charStyle.fontStyle] Font style (italic|normal)
       */
      _setTextStyles: function(ctx, charStyle, forMeasuring) {
        ctx.textBaseline = 'alphabetic';
        ctx.font = this._getFontDeclaration(charStyle, forMeasuring);
      },
  
      /**
       * calculate and return the text Width measuring each line.
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       * @return {Number} Maximum width of fabric.Text object
       */
      calcTextWidth: function() {
        var maxWidth = this.getLineWidth(0);
  
        for (var i = 1, len = this._textLines.length; i < len; i++) {
          var currentLineWidth = this.getLineWidth(i);
          if (currentLineWidth > maxWidth) {
            maxWidth = currentLineWidth;
          }
        }
        return maxWidth;
      },
  
      /**
       * @private
       * @param {String} method Method name ("fillText" or "strokeText")
       * @param {CanvasRenderingContext2D} ctx Context to render on
       * @param {String} line Text to render
       * @param {Number} left Left position of text
       * @param {Number} top Top position of text
       * @param {Number} lineIndex Index of a line in a text
       */
      _renderTextLine: function(method, ctx, line, left, top, lineIndex) {
        this._renderChars(method, ctx, line, left, top, lineIndex);
      },
  
      /**
       * Renders the text background for lines, taking care of style
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _renderTextLinesBackground: function(ctx) {
        if (!this.textBackgroundColor && !this.styleHas('textBackgroundColor')) {
          return;
        }
        var lineTopOffset = 0, heightOfLine,
            lineLeftOffset, originalFill = ctx.fillStyle,
            line, lastColor,
            leftOffset = this._getLeftOffset(),
            topOffset = this._getTopOffset(),
            boxStart = 0, boxWidth = 0, charBox, currentColor;
  
        for (var i = 0, len = this._textLines.length; i < len; i++) {
          heightOfLine = this.getHeightOfLine(i);
          if (!this.textBackgroundColor && !this.styleHas('textBackgroundColor', i)) {
            lineTopOffset += heightOfLine;
            continue;
          }
          line = this._textLines[i];
          lineLeftOffset = this._getLineLeftOffset(i);
          boxWidth = 0;
          boxStart = 0;
          lastColor = this.getValueOfPropertyAt(i, 0, 'textBackgroundColor');
          for (var j = 0, jlen = line.length; j < jlen; j++) {
            charBox = this.__charBounds[i][j];
            currentColor = this.getValueOfPropertyAt(i, j, 'textBackgroundColor');
            if (currentColor !== lastColor) {
              ctx.fillStyle = lastColor;
              lastColor && ctx.fillRect(
                leftOffset + lineLeftOffset + boxStart,
                topOffset + lineTopOffset,
                boxWidth,
                heightOfLine / this.lineHeight
              );
              boxStart = charBox.left;
              boxWidth = charBox.width;
              lastColor = currentColor;
            }
            else {
              boxWidth += charBox.kernedWidth;
            }
          }
          if (currentColor) {
            ctx.fillStyle = currentColor;
            ctx.fillRect(
              leftOffset + lineLeftOffset + boxStart,
              topOffset + lineTopOffset,
              boxWidth,
              heightOfLine / this.lineHeight
            );
          }
          lineTopOffset += heightOfLine;
        }
        ctx.fillStyle = originalFill;
        // if there is text background color no
        // other shadows should be casted
        this._removeShadow(ctx);
      },
  
      /**
       * @private
       * @param {Object} decl style declaration for cache
       * @param {String} decl.fontFamily fontFamily
       * @param {String} decl.fontStyle fontStyle
       * @param {String} decl.fontWeight fontWeight
       * @return {Object} reference to cache
       */
      getFontCache: function(decl) {
        var fontFamily = decl.fontFamily.toLowerCase();
        if (!fabric.charWidthsCache[fontFamily]) {
          fabric.charWidthsCache[fontFamily] = { };
        }
        var cache = fabric.charWidthsCache[fontFamily],
            cacheProp = decl.fontStyle.toLowerCase() + '_' + (decl.fontWeight + '').toLowerCase();
        if (!cache[cacheProp]) {
          cache[cacheProp] = { };
        }
        return cache[cacheProp];
      },
  
      /**
       * apply all the character style to canvas for rendering
       * @private
       * @param {String} _char
       * @param {Number} lineIndex
       * @param {Number} charIndex
       * @param {Object} [decl]
       */
      _applyCharStyles: function(method, ctx, lineIndex, charIndex, styleDeclaration) {
  
        this._setFillStyles(ctx, styleDeclaration);
        this._setStrokeStyles(ctx, styleDeclaration);
  
        ctx.font = this._getFontDeclaration(styleDeclaration);
      },
  
      /**
       * measure and return the width of a single character.
       * possibly overridden to accommodate different measure logic or
       * to hook some external lib for character measurement
       * @private
       * @param {String} _char, char to be measured
       * @param {Object} charStyle style of char to be measured
       * @param {String} [previousChar] previous char
       * @param {Object} [prevCharStyle] style of previous char
       */
      _measureChar: function(_char, charStyle, previousChar, prevCharStyle) {
        // first i try to return from cache
        var fontCache = this.getFontCache(charStyle), fontDeclaration = this._getFontDeclaration(charStyle),
            previousFontDeclaration = this._getFontDeclaration(prevCharStyle), couple = previousChar + _char,
            stylesAreEqual = fontDeclaration === previousFontDeclaration, width, coupleWidth, previousWidth,
            fontMultiplier = charStyle.fontSize / this.CACHE_FONT_SIZE, kernedWidth;
  
        if (previousChar && fontCache[previousChar] !== undefined) {
          previousWidth = fontCache[previousChar];
        }
        if (fontCache[_char] !== undefined) {
          kernedWidth = width = fontCache[_char];
        }
        if (stylesAreEqual && fontCache[couple] !== undefined) {
          coupleWidth = fontCache[couple];
          kernedWidth = coupleWidth - previousWidth;
        }
        if (width === undefined || previousWidth === undefined || coupleWidth === undefined) {
          var ctx = this.getMeasuringContext();
          // send a TRUE to specify measuring font size CACHE_FONT_SIZE
          this._setTextStyles(ctx, charStyle, true);
        }
        if (width === undefined) {
          kernedWidth = width = ctx.measureText(_char).width;
          fontCache[_char] = width;
        }
        if (previousWidth === undefined && stylesAreEqual && previousChar) {
          previousWidth = ctx.measureText(previousChar).width;
          fontCache[previousChar] = previousWidth;
        }
        if (stylesAreEqual && coupleWidth === undefined) {
          // we can measure the kerning couple and subtract the width of the previous character
          coupleWidth = ctx.measureText(couple).width;
          fontCache[couple] = coupleWidth;
          kernedWidth = coupleWidth - previousWidth;
        }
        return { width: width * fontMultiplier, kernedWidth: kernedWidth * fontMultiplier };
      },
  
      /**
       * Computes height of character at given position
       * @param {Number} line the line index number
       * @param {Number} _char the character index number
       * @return {Number} fontSize of the character
       */
      getHeightOfChar: function(line, _char) {
        return this.getValueOfPropertyAt(line, _char, 'fontSize');
      },
  
      /**
       * measure a text line measuring all characters.
       * @param {Number} lineIndex line number
       * @return {Number} Line width
       */
      measureLine: function(lineIndex) {
        var lineInfo = this._measureLine(lineIndex);
        if (this.charSpacing !== 0) {
          lineInfo.width -= this._getWidthOfCharSpacing();
        }
        if (lineInfo.width < 0) {
          lineInfo.width = 0;
        }
        return lineInfo;
      },
  
      /**
       * measure every grapheme of a line, populating __charBounds
       * @param {Number} lineIndex
       * @return {Object} object.width total width of characters
       * @return {Object} object.widthOfSpaces length of chars that match this._reSpacesAndTabs
       */
      _measureLine: function(lineIndex) {
        var width = 0, i, grapheme, line = this._textLines[lineIndex], prevGrapheme,
            graphemeInfo, numOfSpaces = 0, lineBounds = new Array(line.length);
  
        this.__charBounds[lineIndex] = lineBounds;
        for (i = 0; i < line.length; i++) {
          grapheme = line[i];
          graphemeInfo = this._getGraphemeBox(grapheme, lineIndex, i, prevGrapheme);
          lineBounds[i] = graphemeInfo;
          width += graphemeInfo.kernedWidth;
          prevGrapheme = grapheme;
        }
        // this latest bound box represent the last character of the line
        // to simplify cursor handling in interactive mode.
        lineBounds[i] = {
          left: graphemeInfo ? graphemeInfo.left + graphemeInfo.width : 0,
          width: 0,
          kernedWidth: 0,
          height: this.fontSize
        };
        return { width: width, numOfSpaces: numOfSpaces };
      },
  
      /**
       * Measure and return the info of a single grapheme.
       * needs the the info of previous graphemes already filled
       * @private
       * @param {String} grapheme to be measured
       * @param {Number} lineIndex index of the line where the char is
       * @param {Number} charIndex position in the line
       * @param {String} [prevGrapheme] character preceding the one to be measured
       */
      _getGraphemeBox: function(grapheme, lineIndex, charIndex, prevGrapheme, skipLeft) {
        var style = this.getCompleteStyleDeclaration(lineIndex, charIndex),
            prevStyle = prevGrapheme ? this.getCompleteStyleDeclaration(lineIndex, charIndex - 1) : { },
            info = this._measureChar(grapheme, style, prevGrapheme, prevStyle),
            kernedWidth = info.kernedWidth,
            width = info.width, charSpacing;
  
        if (this.charSpacing !== 0) {
          charSpacing = this._getWidthOfCharSpacing();
          width += charSpacing;
          kernedWidth += charSpacing;
        }
  
        var box = {
          width: width,
          left: 0,
          height: style.fontSize,
          kernedWidth: kernedWidth,
          deltaY: style.deltaY,
        };
        if (charIndex > 0 && !skipLeft) {
          var previousBox = this.__charBounds[lineIndex][charIndex - 1];
          box.left = previousBox.left + previousBox.width + info.kernedWidth - info.width;
        }
        return box;
      },
  
      /**
       * Calculate height of line at 'lineIndex'
       * @param {Number} lineIndex index of line to calculate
       * @return {Number}
       */
      getHeightOfLine: function(lineIndex) {
        if (this.__lineHeights[lineIndex]) {
          return this.__lineHeights[lineIndex];
        }
  
        var line = this._textLines[lineIndex],
            // char 0 is measured before the line cycle because it nneds to char
            // emptylines
            maxHeight = this.getHeightOfChar(lineIndex, 0);
        for (var i = 1, len = line.length; i < len; i++) {
          maxHeight = Math.max(this.getHeightOfChar(lineIndex, i), maxHeight);
        }
  
        return this.__lineHeights[lineIndex] = maxHeight * this.lineHeight * this._fontSizeMult;
      },
  
      /**
       * Calculate text box height
       */
      calcTextHeight: function() {
        var lineHeight, height = 0;
        for (var i = 0, len = this._textLines.length; i < len; i++) {
          lineHeight = this.getHeightOfLine(i);
          height += (i === len - 1 ? lineHeight / this.lineHeight : lineHeight);
        }
        return height;
      },
  
      /**
       * @private
       * @return {Number} Left offset
       */
      _getLeftOffset: function() {
        return -this.width / 2;
      },
  
      /**
       * @private
       * @return {Number} Top offset
       */
      _getTopOffset: function() {
        return -this.height / 2;
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       * @param {String} method Method name ("fillText" or "strokeText")
       */
      _renderTextCommon: function(ctx, method) {
        ctx.save();
        var lineHeights = 0, left = this._getLeftOffset(), top = this._getTopOffset(),
            offsets = this._applyPatternGradientTransform(ctx, method === 'fillText' ? this.fill : this.stroke);
        for (var i = 0, len = this._textLines.length; i < len; i++) {
          var heightOfLine = this.getHeightOfLine(i),
              maxHeight = heightOfLine / this.lineHeight,
              leftOffset = this._getLineLeftOffset(i);
          this._renderTextLine(
            method,
            ctx,
            this._textLines[i],
            left + leftOffset - offsets.offsetX,
            top + lineHeights + maxHeight - offsets.offsetY,
            i
          );
          lineHeights += heightOfLine;
        }
        ctx.restore();
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _renderTextFill: function(ctx) {
        if (!this.fill && !this.styleHas('fill')) {
          return;
        }
  
        this._renderTextCommon(ctx, 'fillText');
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _renderTextStroke: function(ctx) {
        if ((!this.stroke || this.strokeWidth === 0) && this.isEmptyStyles()) {
          return;
        }
  
        if (this.shadow && !this.shadow.affectStroke) {
          this._removeShadow(ctx);
        }
  
        ctx.save();
        this._setLineDash(ctx, this.strokeDashArray);
        ctx.beginPath();
        this._renderTextCommon(ctx, 'strokeText');
        ctx.closePath();
        ctx.restore();
      },
  
      /**
       * @private
       * @param {String} method
       * @param {CanvasRenderingContext2D} ctx Context to render on
       * @param {String} line Content of the line
       * @param {Number} left
       * @param {Number} top
       * @param {Number} lineIndex
       * @param {Number} charOffset
       */
      _renderChars: function(method, ctx, line, left, top, lineIndex) {
        // set proper line offset
        var lineHeight = this.getHeightOfLine(lineIndex),
            isJustify = this.textAlign.indexOf('justify') !== -1,
            actualStyle,
            nextStyle,
            charsToRender = '',
            charBox,
            boxWidth = 0,
            timeToRender,
            shortCut = !isJustify && this.charSpacing === 0 && this.isEmptyStyles(lineIndex);
  
        ctx.save();
        top -= lineHeight * this._fontSizeFraction / this.lineHeight;
        if (shortCut) {
          // render all the line in one pass without checking
          this._renderChar(method, ctx, lineIndex, 0, this.textLines[lineIndex], left, top, lineHeight);
          ctx.restore();
          return;
        }
        for (var i = 0, len = line.length - 1; i <= len; i++) {
          timeToRender = i === len || this.charSpacing;
          charsToRender += line[i];
          charBox = this.__charBounds[lineIndex][i];
          if (boxWidth === 0) {
            left += charBox.kernedWidth - charBox.width;
            boxWidth += charBox.width;
          }
          else {
            boxWidth += charBox.kernedWidth;
          }
          if (isJustify && !timeToRender) {
            if (this._reSpaceAndTab.test(line[i])) {
              timeToRender = true;
            }
          }
          if (!timeToRender) {
            // if we have charSpacing, we render char by char
            actualStyle = actualStyle || this.getCompleteStyleDeclaration(lineIndex, i);
            nextStyle = this.getCompleteStyleDeclaration(lineIndex, i + 1);
            timeToRender = this._hasStyleChanged(actualStyle, nextStyle);
          }
          if (timeToRender) {
            this._renderChar(method, ctx, lineIndex, i, charsToRender, left, top, lineHeight);
            charsToRender = '';
            actualStyle = nextStyle;
            left += boxWidth;
            boxWidth = 0;
          }
        }
        ctx.restore();
      },
  
      /**
       * @private
       * @param {String} method
       * @param {CanvasRenderingContext2D} ctx Context to render on
       * @param {Number} lineIndex
       * @param {Number} charIndex
       * @param {String} _char
       * @param {Number} left Left coordinate
       * @param {Number} top Top coordinate
       * @param {Number} lineHeight Height of the line
       */
      _renderChar: function(method, ctx, lineIndex, charIndex, _char, left, top) {
        var decl = this._getStyleDeclaration(lineIndex, charIndex),
            fullDecl = this.getCompleteStyleDeclaration(lineIndex, charIndex),
            shouldFill = method === 'fillText' && fullDecl.fill,
            shouldStroke = method === 'strokeText' && fullDecl.stroke && fullDecl.strokeWidth;
  
        if (!shouldStroke && !shouldFill) {
          return;
        }
        decl && ctx.save();
  
        this._applyCharStyles(method, ctx, lineIndex, charIndex, fullDecl);
  
        if (decl && decl.textBackgroundColor) {
          this._removeShadow(ctx);
        }
        if (decl && decl.deltaY) {
          top += decl.deltaY;
        }
  
        shouldFill && ctx.fillText(_char, left, top);
        shouldStroke && ctx.strokeText(_char, left, top);
        decl && ctx.restore();
      },
  
      /**
       * Turns the character into a 'superior figure' (i.e. 'superscript')
       * @param {Number} start selection start
       * @param {Number} end selection end
       * @returns {fabric.Text} thisArg
       * @chainable
       */
      setSuperscript: function(start, end) {
        return this._setScript(start, end, this.superscript);
      },
  
      /**
       * Turns the character into an 'inferior figure' (i.e. 'subscript')
       * @param {Number} start selection start
       * @param {Number} end selection end
       * @returns {fabric.Text} thisArg
       * @chainable
       */
      setSubscript: function(start, end) {
        return this._setScript(start, end, this.subscript);
      },
  
      /**
       * Applies 'schema' at given position
       * @private
       * @param {Number} start selection start
       * @param {Number} end selection end
       * @param {Number} schema
       * @returns {fabric.Text} thisArg
       * @chainable
       */
      _setScript: function(start, end, schema) {
        var loc = this.get2DCursorLocation(start, true),
            fontSize = this.getValueOfPropertyAt(loc.lineIndex, loc.charIndex, 'fontSize'),
            dy = this.getValueOfPropertyAt(loc.lineIndex, loc.charIndex, 'deltaY'),
            style = { fontSize: fontSize * schema.size, deltaY: dy + fontSize * schema.baseline };
        this.setSelectionStyles(style, start, end);
        return this;
      },
  
      /**
       * @private
       * @param {Object} prevStyle
       * @param {Object} thisStyle
       */
      _hasStyleChanged: function(prevStyle, thisStyle) {
        return prevStyle.fill !== thisStyle.fill ||
                prevStyle.stroke !== thisStyle.stroke ||
                prevStyle.strokeWidth !== thisStyle.strokeWidth ||
                prevStyle.fontSize !== thisStyle.fontSize ||
                prevStyle.fontFamily !== thisStyle.fontFamily ||
                prevStyle.fontWeight !== thisStyle.fontWeight ||
                prevStyle.fontStyle !== thisStyle.fontStyle ||
                prevStyle.deltaY !== thisStyle.deltaY;
      },
  
      /**
       * @private
       * @param {Object} prevStyle
       * @param {Object} thisStyle
       */
      _hasStyleChangedForSvg: function(prevStyle, thisStyle) {
        return this._hasStyleChanged(prevStyle, thisStyle) ||
          prevStyle.overline !== thisStyle.overline ||
          prevStyle.underline !== thisStyle.underline ||
          prevStyle.linethrough !== thisStyle.linethrough;
      },
  
      /**
       * @private
       * @param {Number} lineIndex index text line
       * @return {Number} Line left offset
       */
      _getLineLeftOffset: function(lineIndex) {
        var lineWidth = this.getLineWidth(lineIndex);
        if (this.textAlign === 'center') {
          return (this.width - lineWidth) / 2;
        }
        if (this.textAlign === 'right') {
          return this.width - lineWidth;
        }
        if (this.textAlign === 'justify-center' && this.isEndOfWrapping(lineIndex)) {
          return (this.width - lineWidth) / 2;
        }
        if (this.textAlign === 'justify-right' && this.isEndOfWrapping(lineIndex)) {
          return this.width - lineWidth;
        }
        return 0;
      },
  
      /**
       * @private
       */
      _clearCache: function() {
        this.__lineWidths = [];
        this.__lineHeights = [];
        this.__charBounds = [];
      },
  
      /**
       * @private
       */
      _shouldClearDimensionCache: function() {
        var shouldClear = this._forceClearCache;
        shouldClear || (shouldClear = this.hasStateChanged('_dimensionAffectingProps'));
        if (shouldClear) {
          this.dirty = true;
          this._forceClearCache = false;
        }
        return shouldClear;
      },
  
      /**
       * Measure a single line given its index. Used to calculate the initial
       * text bounding box. The values are calculated and stored in __lineWidths cache.
       * @private
       * @param {Number} lineIndex line number
       * @return {Number} Line width
       */
      getLineWidth: function(lineIndex) {
        if (this.__lineWidths[lineIndex]) {
          return this.__lineWidths[lineIndex];
        }
  
        var width, line = this._textLines[lineIndex], lineInfo;
  
        if (line === '') {
          width = 0;
        }
        else {
          lineInfo = this.measureLine(lineIndex);
          width = lineInfo.width;
        }
        this.__lineWidths[lineIndex] = width;
        return width;
      },
  
      _getWidthOfCharSpacing: function() {
        if (this.charSpacing !== 0) {
          return this.fontSize * this.charSpacing / 1000;
        }
        return 0;
      },
  
      /**
       * Retrieves the value of property at given character position
       * @param {Number} lineIndex the line number
       * @param {Number} charIndex the charater number
       * @param {String} property the property name
       * @returns the value of 'property'
       */
      getValueOfPropertyAt: function(lineIndex, charIndex, property) {
        var charStyle = this._getStyleDeclaration(lineIndex, charIndex);
        if (charStyle && typeof charStyle[property] !== 'undefined') {
          return charStyle[property];
        }
        return this[property];
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _renderTextDecoration: function(ctx, type) {
        if (!this[type] && !this.styleHas(type)) {
          return;
        }
        var heightOfLine, size, _size,
            lineLeftOffset, dy, _dy,
            line, lastDecoration,
            leftOffset = this._getLeftOffset(),
            topOffset = this._getTopOffset(), top,
            boxStart, boxWidth, charBox, currentDecoration,
            maxHeight, currentFill, lastFill,
            charSpacing = this._getWidthOfCharSpacing();
  
        for (var i = 0, len = this._textLines.length; i < len; i++) {
          heightOfLine = this.getHeightOfLine(i);
          if (!this[type] && !this.styleHas(type, i)) {
            topOffset += heightOfLine;
            continue;
          }
          line = this._textLines[i];
          maxHeight = heightOfLine / this.lineHeight;
          lineLeftOffset = this._getLineLeftOffset(i);
          boxStart = 0;
          boxWidth = 0;
          lastDecoration = this.getValueOfPropertyAt(i, 0, type);
          lastFill = this.getValueOfPropertyAt(i, 0, 'fill');
          top = topOffset + maxHeight * (1 - this._fontSizeFraction);
          size = this.getHeightOfChar(i, 0);
          dy = this.getValueOfPropertyAt(i, 0, 'deltaY');
          for (var j = 0, jlen = line.length; j < jlen; j++) {
            charBox = this.__charBounds[i][j];
            currentDecoration = this.getValueOfPropertyAt(i, j, type);
            currentFill = this.getValueOfPropertyAt(i, j, 'fill');
            _size = this.getHeightOfChar(i, j);
            _dy = this.getValueOfPropertyAt(i, j, 'deltaY');
            if ((currentDecoration !== lastDecoration || currentFill !== lastFill || _size !== size || _dy !== dy) &&
                boxWidth > 0) {
              ctx.fillStyle = lastFill;
              lastDecoration && lastFill && ctx.fillRect(
                leftOffset + lineLeftOffset + boxStart,
                top + this.offsets[type] * size + dy,
                boxWidth,
                this.fontSize / 15
              );
              boxStart = charBox.left;
              boxWidth = charBox.width;
              lastDecoration = currentDecoration;
              lastFill = currentFill;
              size = _size;
              dy = _dy;
            }
            else {
              boxWidth += charBox.kernedWidth;
            }
          }
          ctx.fillStyle = currentFill;
          currentDecoration && currentFill && ctx.fillRect(
            leftOffset + lineLeftOffset + boxStart,
            top + this.offsets[type] * size + dy,
            boxWidth - charSpacing,
            this.fontSize / 15
          );
          topOffset += heightOfLine;
        }
        // if there is text background color no
        // other shadows should be casted
        this._removeShadow(ctx);
      },
  
      /**
       * return font declaration string for canvas context
       * @param {Object} [styleObject] object
       * @returns {String} font declaration formatted for canvas context.
       */
      _getFontDeclaration: function(styleObject, forMeasuring) {
        var style = styleObject || this, family = this.fontFamily,
            fontIsGeneric = fabric.Text.genericFonts.indexOf(family.toLowerCase()) > -1;
        var fontFamily = family === undefined ||
        family.indexOf('\'') > -1 || family.indexOf(',') > -1 ||
        family.indexOf('"') > -1 || fontIsGeneric
          ? style.fontFamily : '"' + style.fontFamily + '"';
        return [
          // node-canvas needs "weight style", while browsers need "style weight"
          // verify if this can be fixed in JSDOM
          (fabric.isLikelyNode ? style.fontWeight : style.fontStyle),
          (fabric.isLikelyNode ? style.fontStyle : style.fontWeight),
          forMeasuring ? this.CACHE_FONT_SIZE + 'px' : style.fontSize + 'px',
          fontFamily
        ].join(' ');
      },
  
      /**
       * Renders text instance on a specified context
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      render: function(ctx) {
        // do not render if object is not visible
        if (!this.visible) {
          return;
        }
        if (this.canvas && this.canvas.skipOffscreen && !this.group && !this.isOnScreen()) {
          return;
        }
        if (this._shouldClearDimensionCache()) {
          this.initDimensions();
        }
        this.callSuper('render', ctx);
      },
  
      /**
       * Returns the text as an array of lines.
       * @param {String} text text to split
       * @returns {Array} Lines in the text
       */
      _splitTextIntoLines: function(text) {
        var lines = text.split(this._reNewline),
            newLines = new Array(lines.length),
            newLine = ['\n'],
            newText = [];
        for (var i = 0; i < lines.length; i++) {
          newLines[i] = fabric.util.string.graphemeSplit(lines[i]);
          newText = newText.concat(newLines[i], newLine);
        }
        newText.pop();
        return { _unwrappedLines: newLines, lines: lines, graphemeText: newText, graphemeLines: newLines };
      },
  
      /**
       * Returns object representation of an instance
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object} Object representation of an instance
       */
      toObject: function(propertiesToInclude) {
        var additionalProperties = [
          'text',
          'fontSize',
          'fontWeight',
          'fontFamily',
          'fontStyle',
          'lineHeight',
          'underline',
          'overline',
          'linethrough',
          'textAlign',
          'textBackgroundColor',
          'charSpacing',
        ].concat(propertiesToInclude);
        var obj = this.callSuper('toObject', additionalProperties);
        obj.styles = clone(this.styles, true);
        return obj;
      },
  
      /**
       * Sets property to a given value. When changing position/dimension -related properties (left, top, scale, angle, etc.) `set` does not update position of object's borders/controls. If you need to update those, call `setCoords()`.
       * @param {String|Object} key Property name or object (if object, iterate over the object properties)
       * @param {Object|Function} value Property value (if function, the value is passed into it and its return value is used as a new one)
       * @return {fabric.Object} thisArg
       * @chainable
       */
      set: function(key, value) {
        this.callSuper('set', key, value);
        var needsDims = false;
        if (typeof key === 'object') {
          for (var _key in key) {
            needsDims = needsDims || this._dimensionAffectingProps.indexOf(_key) !== -1;
          }
        }
        else {
          needsDims = this._dimensionAffectingProps.indexOf(key) !== -1;
        }
        if (needsDims) {
          this.initDimensions();
          this.setCoords();
        }
        return this;
      },
  
      /**
       * Returns complexity of an instance
       * @return {Number} complexity
       */
      complexity: function() {
        return 1;
      }
    });
  
    /* _FROM_SVG_START_ */
    /**
     * List of attribute names to account for when parsing SVG element (used by {@link fabric.Text.fromElement})
     * @static
     * @memberOf fabric.Text
     * @see: http://www.w3.org/TR/SVG/text.html#TextElement
     */
    fabric.Text.ATTRIBUTE_NAMES = fabric.SHARED_ATTRIBUTES.concat(
      'x y dx dy font-family font-style font-weight font-size letter-spacing text-decoration text-anchor'.split(' '));
  
    /**
     * Default SVG font size
     * @static
     * @memberOf fabric.Text
     */
    fabric.Text.DEFAULT_SVG_FONT_SIZE = 16;
  
    /**
     * Returns fabric.Text instance from an SVG element (<b>not yet implemented</b>)
     * @static
     * @memberOf fabric.Text
     * @param {SVGElement} element Element to parse
     * @param {Function} callback callback function invoked after parsing
     * @param {Object} [options] Options object
     */
    fabric.Text.fromElement = function(element, callback, options) {
      if (!element) {
        return callback(null);
      }
  
      var parsedAttributes = fabric.parseAttributes(element, fabric.Text.ATTRIBUTE_NAMES),
          parsedAnchor = parsedAttributes.textAnchor || 'left';
      options = fabric.util.object.extend((options ? clone(options) : { }), parsedAttributes);
  
      options.top = options.top || 0;
      options.left = options.left || 0;
      if (parsedAttributes.textDecoration) {
        var textDecoration = parsedAttributes.textDecoration;
        if (textDecoration.indexOf('underline') !== -1) {
          options.underline = true;
        }
        if (textDecoration.indexOf('overline') !== -1) {
          options.overline = true;
        }
        if (textDecoration.indexOf('line-through') !== -1) {
          options.linethrough = true;
        }
        delete options.textDecoration;
      }
      if ('dx' in parsedAttributes) {
        options.left += parsedAttributes.dx;
      }
      if ('dy' in parsedAttributes) {
        options.top += parsedAttributes.dy;
      }
      if (!('fontSize' in options)) {
        options.fontSize = fabric.Text.DEFAULT_SVG_FONT_SIZE;
      }
  
      var textContent = '';
  
      // The XML is not properly parsed in IE9 so a workaround to get
      // textContent is through firstChild.data. Another workaround would be
      // to convert XML loaded from a file to be converted using DOMParser (same way loadSVGFromString() does)
      if (!('textContent' in element)) {
        if ('firstChild' in element && element.firstChild !== null) {
          if ('data' in element.firstChild && element.firstChild.data !== null) {
            textContent = element.firstChild.data;
          }
        }
      }
      else {
        textContent = element.textContent;
      }
  
      textContent = textContent.replace(/^\s+|\s+$|\n+/g, '').replace(/\s+/g, ' ');
      var originalStrokeWidth = options.strokeWidth;
      options.strokeWidth = 0;
  
      var text = new fabric.Text(textContent, options),
          textHeightScaleFactor = text.getScaledHeight() / text.height,
          lineHeightDiff = (text.height + text.strokeWidth) * text.lineHeight - text.height,
          scaledDiff = lineHeightDiff * textHeightScaleFactor,
          textHeight = text.getScaledHeight() + scaledDiff,
          offX = 0;
      /*
        Adjust positioning:
          x/y attributes in SVG correspond to the bottom-left corner of text bounding box
          fabric output by default at top, left.
      */
      if (parsedAnchor === 'center') {
        offX = text.getScaledWidth() / 2;
      }
      if (parsedAnchor === 'right') {
        offX = text.getScaledWidth();
      }
      text.set({
        left: text.left - offX,
        top: text.top - (textHeight - text.fontSize * (0.07 + text._fontSizeFraction)) / text.lineHeight,
        strokeWidth: typeof originalStrokeWidth !== 'undefined' ? originalStrokeWidth : 1,
      });
      callback(text);
    };
    /* _FROM_SVG_END_ */
  
    /**
     * Returns fabric.Text instance from an object representation
     * @static
     * @memberOf fabric.Text
     * @param {Object} object Object to create an instance from
     * @param {Function} [callback] Callback to invoke when an fabric.Text instance is created
     */
    fabric.Text.fromObject = function(object, callback) {
      return fabric.Object._fromObject('Text', object, callback, 'text');
    };
  
    fabric.Text.genericFonts = ['sans-serif', 'serif', 'cursive', 'fantasy', 'monospace'];
  
    fabric.util.createAccessors && fabric.util.createAccessors(fabric.Text);
  
  })(typeof exports !== 'undefined' ? exports : this);
  
  
  (function() {
    fabric.util.object.extend(fabric.Text.prototype, /** @lends fabric.Text.prototype */ {
      /**
       * Returns true if object has no styling or no styling in a line
       * @param {Number} lineIndex , lineIndex is on wrapped lines.
       * @return {Boolean}
       */
      isEmptyStyles: function(lineIndex) {
        if (!this.styles) {
          return true;
        }
        if (typeof lineIndex !== 'undefined' && !this.styles[lineIndex]) {
          return true;
        }
        var obj = typeof lineIndex === 'undefined' ? this.styles : { line: this.styles[lineIndex] };
        for (var p1 in obj) {
          for (var p2 in obj[p1]) {
            // eslint-disable-next-line no-unused-vars
            for (var p3 in obj[p1][p2]) {
              return false;
            }
          }
        }
        return true;
      },
  
      /**
       * Returns true if object has a style property or has it ina specified line
       * This function is used to detect if a text will use a particular property or not.
       * @param {String} property to check for
       * @param {Number} lineIndex to check the style on
       * @return {Boolean}
       */
      styleHas: function(property, lineIndex) {
        if (!this.styles || !property || property === '') {
          return false;
        }
        if (typeof lineIndex !== 'undefined' && !this.styles[lineIndex]) {
          return false;
        }
        var obj = typeof lineIndex === 'undefined' ? this.styles : { 0: this.styles[lineIndex] };
        // eslint-disable-next-line
        for (var p1 in obj) {
          // eslint-disable-next-line
          for (var p2 in obj[p1]) {
            if (typeof obj[p1][p2][property] !== 'undefined') {
              return true;
            }
          }
        }
        return false;
      },
  
      /**
       * Check if characters in a text have a value for a property
       * whose value matches the textbox's value for that property.  If so,
       * the character-level property is deleted.  If the character
       * has no other properties, then it is also deleted.  Finally,
       * if the line containing that character has no other characters
       * then it also is deleted.
       *
       * @param {string} property The property to compare between characters and text.
       */
      cleanStyle: function(property) {
        if (!this.styles || !property || property === '') {
          return false;
        }
        var obj = this.styles, stylesCount = 0, letterCount, stylePropertyValue,
            allStyleObjectPropertiesMatch = true, graphemeCount = 0, styleObject;
        // eslint-disable-next-line
        for (var p1 in obj) {
          letterCount = 0;
          // eslint-disable-next-line
          for (var p2 in obj[p1]) {
            var styleObject = obj[p1][p2],
                stylePropertyHasBeenSet = styleObject.hasOwnProperty(property);
  
            stylesCount++;
  
            if (stylePropertyHasBeenSet) {
              if (!stylePropertyValue) {
                stylePropertyValue = styleObject[property];
              }
              else if (styleObject[property] !== stylePropertyValue) {
                allStyleObjectPropertiesMatch = false;
              }
  
              if (styleObject[property] === this[property]) {
                delete styleObject[property];
              }
            }
            else {
              allStyleObjectPropertiesMatch = false;
            }
  
            if (Object.keys(styleObject).length !== 0) {
              letterCount++;
            }
            else {
              delete obj[p1][p2];
            }
          }
  
          if (letterCount === 0) {
            delete obj[p1];
          }
        }
        // if every grapheme has the same style set then
        // delete those styles and set it on the parent
        for (var i = 0; i < this._textLines.length; i++) {
          graphemeCount += this._textLines[i].length;
        }
        if (allStyleObjectPropertiesMatch && stylesCount === graphemeCount) {
          this[property] = stylePropertyValue;
          this.removeStyle(property);
        }
      },
  
      /**
       * Remove a style property or properties from all individual character styles
       * in a text object.  Deletes the character style object if it contains no other style
       * props.  Deletes a line style object if it contains no other character styles.
       *
       * @param {String} props The property to remove from character styles.
       */
      removeStyle: function(property) {
        if (!this.styles || !property || property === '') {
          return;
        }
        var obj = this.styles, line, lineNum, charNum;
        for (lineNum in obj) {
          line = obj[lineNum];
          for (charNum in line) {
            delete line[charNum][property];
            if (Object.keys(line[charNum]).length === 0) {
              delete line[charNum];
            }
          }
          if (Object.keys(line).length === 0) {
            delete obj[lineNum];
          }
        }
      },
  
      /**
       * @private
       */
      _extendStyles: function(index, styles) {
        var loc = this.get2DCursorLocation(index);
  
        if (!this._getLineStyle(loc.lineIndex)) {
          this._setLineStyle(loc.lineIndex);
        }
  
        if (!this._getStyleDeclaration(loc.lineIndex, loc.charIndex)) {
          this._setStyleDeclaration(loc.lineIndex, loc.charIndex, {});
        }
  
        fabric.util.object.extend(this._getStyleDeclaration(loc.lineIndex, loc.charIndex), styles);
      },
  
      /**
       * Returns 2d representation (lineIndex and charIndex) of cursor (or selection start)
       * @param {Number} [selectionStart] Optional index. When not given, current selectionStart is used.
       * @param {Boolean} [skipWrapping] consider the location for unwrapped lines. usefull to manage styles.
       */
      get2DCursorLocation: function(selectionStart, skipWrapping) {
        if (typeof selectionStart === 'undefined') {
          selectionStart = this.selectionStart;
        }
        var lines = skipWrapping ? this._unwrappedTextLines : this._textLines,
            len = lines.length;
        for (var i = 0; i < len; i++) {
          if (selectionStart <= lines[i].length) {
            return {
              lineIndex: i,
              charIndex: selectionStart
            };
          }
          selectionStart -= lines[i].length + this.missingNewlineOffset(i);
        }
        return {
          lineIndex: i - 1,
          charIndex: lines[i - 1].length < selectionStart ? lines[i - 1].length : selectionStart
        };
      },
  
      /**
       * Gets style of a current selection/cursor (at the start position)
       * if startIndex or endIndex are not provided, slectionStart or selectionEnd will be used.
       * @param {Number} [startIndex] Start index to get styles at
       * @param {Number} [endIndex] End index to get styles at, if not specified selectionEnd or startIndex + 1
       * @param {Boolean} [complete] get full style or not
       * @return {Array} styles an array with one, zero or more Style objects
       */
      getSelectionStyles: function(startIndex, endIndex, complete) {
        if (typeof startIndex === 'undefined') {
          startIndex = this.selectionStart || 0;
        }
        if (typeof endIndex === 'undefined') {
          endIndex = this.selectionEnd || startIndex;
        }
        var styles = [];
        for (var i = startIndex; i < endIndex; i++) {
          styles.push(this.getStyleAtPosition(i, complete));
        }
        return styles;
      },
  
      /**
       * Gets style of a current selection/cursor position
       * @param {Number} position  to get styles at
       * @param {Boolean} [complete] full style if true
       * @return {Object} style Style object at a specified index
       * @private
       */
      getStyleAtPosition: function(position, complete) {
        var loc = this.get2DCursorLocation(position),
            style = complete ? this.getCompleteStyleDeclaration(loc.lineIndex, loc.charIndex) :
              this._getStyleDeclaration(loc.lineIndex, loc.charIndex);
        return style || {};
      },
  
      /**
       * Sets style of a current selection, if no selection exist, do not set anything.
       * @param {Object} [styles] Styles object
       * @param {Number} [startIndex] Start index to get styles at
       * @param {Number} [endIndex] End index to get styles at, if not specified selectionEnd or startIndex + 1
       * @return {fabric.IText} thisArg
       * @chainable
       */
      setSelectionStyles: function(styles, startIndex, endIndex) {
        if (typeof startIndex === 'undefined') {
          startIndex = this.selectionStart || 0;
        }
        if (typeof endIndex === 'undefined') {
          endIndex = this.selectionEnd || startIndex;
        }
        for (var i = startIndex; i < endIndex; i++) {
          this._extendStyles(i, styles);
        }
        /* not included in _extendStyles to avoid clearing cache more than once */
        this._forceClearCache = true;
        return this;
      },
  
      /**
       * get the reference, not a clone, of the style object for a given character
       * @param {Number} lineIndex
       * @param {Number} charIndex
       * @return {Object} style object
       */
      _getStyleDeclaration: function(lineIndex, charIndex) {
        var lineStyle = this.styles && this.styles[lineIndex];
        if (!lineStyle) {
          return null;
        }
        return lineStyle[charIndex];
      },
  
      /**
       * return a new object that contains all the style property for a character
       * the object returned is newly created
       * @param {Number} lineIndex of the line where the character is
       * @param {Number} charIndex position of the character on the line
       * @return {Object} style object
       */
      getCompleteStyleDeclaration: function(lineIndex, charIndex) {
        var style = this._getStyleDeclaration(lineIndex, charIndex) || { },
            styleObject = { }, prop;
        for (var i = 0; i < this._styleProperties.length; i++) {
          prop = this._styleProperties[i];
          styleObject[prop] = typeof style[prop] === 'undefined' ? this[prop] : style[prop];
        }
        return styleObject;
      },
  
      /**
       * @param {Number} lineIndex
       * @param {Number} charIndex
       * @param {Object} style
       * @private
       */
      _setStyleDeclaration: function(lineIndex, charIndex, style) {
        this.styles[lineIndex][charIndex] = style;
      },
  
      /**
       *
       * @param {Number} lineIndex
       * @param {Number} charIndex
       * @private
       */
      _deleteStyleDeclaration: function(lineIndex, charIndex) {
        delete this.styles[lineIndex][charIndex];
      },
  
      /**
       * @param {Number} lineIndex
       * @return {Boolean} if the line exists or not
       * @private
       */
      _getLineStyle: function(lineIndex) {
        return !!this.styles[lineIndex];
      },
  
      /**
       * Set the line style to an empty object so that is initialized
       * @param {Number} lineIndex
       * @private
       */
      _setLineStyle: function(lineIndex) {
        this.styles[lineIndex] = {};
      },
  
      /**
       * @param {Number} lineIndex
       * @private
       */
      _deleteLineStyle: function(lineIndex) {
        delete this.styles[lineIndex];
      }
    });
  })();
  
  
  (function() {
  
    function parseDecoration(object) {
      if (object.textDecoration) {
        object.textDecoration.indexOf('underline') > -1 && (object.underline = true);
        object.textDecoration.indexOf('line-through') > -1 && (object.linethrough = true);
        object.textDecoration.indexOf('overline') > -1 && (object.overline = true);
        delete object.textDecoration;
      }
    }
  
    /**
     * IText class (introduced in <b>v1.4</b>) Events are also fired with "text:"
     * prefix when observing canvas.
     * @class fabric.IText
     * @extends fabric.Text
     * @mixes fabric.Observable
     *
     * @fires changed
     * @fires selection:changed
     * @fires editing:entered
     * @fires editing:exited
     *
     * @return {fabric.IText} thisArg
     * @see {@link fabric.IText#initialize} for constructor definition
     *
     * <p>Supported key combinations:</p>
     * <pre>
     *   Move cursor:                    left, right, up, down
     *   Select character:               shift + left, shift + right
     *   Select text vertically:         shift + up, shift + down
     *   Move cursor by word:            alt + left, alt + right
     *   Select words:                   shift + alt + left, shift + alt + right
     *   Move cursor to line start/end:  cmd + left, cmd + right or home, end
     *   Select till start/end of line:  cmd + shift + left, cmd + shift + right or shift + home, shift + end
     *   Jump to start/end of text:      cmd + up, cmd + down
     *   Select till start/end of text:  cmd + shift + up, cmd + shift + down or shift + pgUp, shift + pgDown
     *   Delete character:               backspace
     *   Delete word:                    alt + backspace
     *   Delete line:                    cmd + backspace
     *   Forward delete:                 delete
     *   Copy text:                      ctrl/cmd + c
     *   Paste text:                     ctrl/cmd + v
     *   Cut text:                       ctrl/cmd + x
     *   Select entire text:             ctrl/cmd + a
     *   Quit editing                    tab or esc
     * </pre>
     *
     * <p>Supported mouse/touch combination</p>
     * <pre>
     *   Position cursor:                click/touch
     *   Create selection:               click/touch & drag
     *   Create selection:               click & shift + click
     *   Select word:                    double click
     *   Select line:                    triple click
     * </pre>
     */
    fabric.IText = fabric.util.createClass(fabric.Text, fabric.Observable, /** @lends fabric.IText.prototype */ {
  
      /**
       * Type of an object
       * @type String
       * @default
       */
      type: 'i-text',
  
      /**
       * Index where text selection starts (or where cursor is when there is no selection)
       * @type Number
       * @default
       */
      selectionStart: 0,
  
      /**
       * Index where text selection ends
       * @type Number
       * @default
       */
      selectionEnd: 0,
  
      /**
       * Color of text selection
       * @type String
       * @default
       */
      selectionColor: 'rgba(17,119,255,0.3)',
  
      /**
       * Indicates whether text is in editing mode
       * @type Boolean
       * @default
       */
      isEditing: false,
  
      /**
       * Indicates whether a text can be edited
       * @type Boolean
       * @default
       */
      editable: true,
  
      /**
       * Border color of text object while it's in editing mode
       * @type String
       * @default
       */
      editingBorderColor: 'rgba(102,153,255,0.25)',
  
      /**
       * Width of cursor (in px)
       * @type Number
       * @default
       */
      cursorWidth: 2,
  
      /**
       * Color of default cursor (when not overwritten by character style)
       * @type String
       * @default
       */
      cursorColor: '#333',
  
      /**
       * Delay between cursor blink (in ms)
       * @type Number
       * @default
       */
      cursorDelay: 1000,
  
      /**
       * Duration of cursor fadein (in ms)
       * @type Number
       * @default
       */
      cursorDuration: 600,
  
      /**
       * Indicates whether internal text char widths can be cached
       * @type Boolean
       * @default
       */
      caching: true,
  
      /**
       * @private
       */
      _reSpace: /\s|\n/,
  
      /**
       * @private
       */
      _currentCursorOpacity: 0,
  
      /**
       * @private
       */
      _selectionDirection: null,
  
      /**
       * @private
       */
      _abortCursorAnimation: false,
  
      /**
       * @private
       */
      __widthOfSpace: [],
  
      /**
       * Helps determining when the text is in composition, so that the cursor
       * rendering is altered.
       */
      inCompositionMode: false,
  
      /**
       * Constructor
       * @param {String} text Text string
       * @param {Object} [options] Options object
       * @return {fabric.IText} thisArg
       */
      initialize: function(text, options) {
        this.callSuper('initialize', text, options);
        this.initBehavior();
      },
  
      /**
       * Sets selection start (left boundary of a selection)
       * @param {Number} index Index to set selection start to
       */
      setSelectionStart: function(index) {
        index = Math.max(index, 0);
        this._updateAndFire('selectionStart', index);
      },
  
      /**
       * Sets selection end (right boundary of a selection)
       * @param {Number} index Index to set selection end to
       */
      setSelectionEnd: function(index) {
        index = Math.min(index, this.text.length);
        this._updateAndFire('selectionEnd', index);
      },
  
      /**
       * @private
       * @param {String} property 'selectionStart' or 'selectionEnd'
       * @param {Number} index new position of property
       */
      _updateAndFire: function(property, index) {
        if (this[property] !== index) {
          this._fireSelectionChanged();
          this[property] = index;
        }
        this._updateTextarea();
      },
  
      /**
       * Fires the even of selection changed
       * @private
       */
      _fireSelectionChanged: function() {
        this.fire('selection:changed');
        this.canvas && this.canvas.fire('text:selection:changed', { target: this });
      },
  
      /**
       * Initialize text dimensions. Render all text on given context
       * or on a offscreen canvas to get the text width with measureText.
       * Updates this.width and this.height with the proper values.
       * Does not return dimensions.
       * @private
       */
      initDimensions: function() {
        this.isEditing && this.initDelayedCursor();
        this.clearContextTop();
        this.callSuper('initDimensions');
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      render: function(ctx) {
        this.clearContextTop();
        this.callSuper('render', ctx);
        // clear the cursorOffsetCache, so we ensure to calculate once per renderCursor
        // the correct position but not at every cursor animation.
        this.cursorOffsetCache = { };
        this.renderCursorOrSelection();
      },
  
      /**
       * @private
       * @param {CanvasRenderingContext2D} ctx Context to render on
       */
      _render: function(ctx) {
        this.callSuper('_render', ctx);
      },
  
      /**
       * Prepare and clean the contextTop
       */
      clearContextTop: function(skipRestore) {
        if (!this.isEditing || !this.canvas || !this.canvas.contextTop) {
          return;
        }
        var ctx = this.canvas.contextTop, v = this.canvas.viewportTransform;
        ctx.save();
        ctx.transform(v[0], v[1], v[2], v[3], v[4], v[5]);
        this.transform(ctx);
        this.transformMatrix && ctx.transform.apply(ctx, this.transformMatrix);
        this._clearTextArea(ctx);
        skipRestore || ctx.restore();
      },
  
      /**
       * Renders cursor or selection (depending on what exists)
       * it does on the contextTop. If contextTop is not available, do nothing.
       */
      renderCursorOrSelection: function() {
        if (!this.isEditing || !this.canvas || !this.canvas.contextTop) {
          return;
        }
        var boundaries = this._getCursorBoundaries(),
            ctx = this.canvas.contextTop;
        this.clearContextTop(true);
        if (this.selectionStart === this.selectionEnd) {
          this.renderCursor(boundaries, ctx);
        }
        else {
          this.renderSelection(boundaries, ctx);
        }
        ctx.restore();
      },
  
      _clearTextArea: function(ctx) {
        // we add 4 pixel, to be sure to do not leave any pixel out
        var width = this.width + 4, height = this.height + 4;
        ctx.clearRect(-width / 2, -height / 2, width, height);
      },
  
      /**
       * Returns cursor boundaries (left, top, leftOffset, topOffset)
       * @private
       * @param {Array} chars Array of characters
       * @param {String} typeOfBoundaries
       */
      _getCursorBoundaries: function(position) {
  
        // left/top are left/top of entire text box
        // leftOffset/topOffset are offset from that left/top point of a text box
  
        if (typeof position === 'undefined') {
          position = this.selectionStart;
        }
  
        var left = this._getLeftOffset(),
            top = this._getTopOffset(),
            offsets = this._getCursorBoundariesOffsets(position);
  
        return {
          left: left,
          top: top,
          leftOffset: offsets.left,
          topOffset: offsets.top
        };
      },
  
      /**
       * @private
       */
      _getCursorBoundariesOffsets: function(position) {
        if (this.cursorOffsetCache && 'top' in this.cursorOffsetCache) {
          return this.cursorOffsetCache;
        }
        var lineLeftOffset,
            lineIndex,
            charIndex,
            topOffset = 0,
            leftOffset = 0,
            boundaries,
            cursorPosition = this.get2DCursorLocation(position);
        charIndex = cursorPosition.charIndex;
        lineIndex = cursorPosition.lineIndex;
        for (var i = 0; i < lineIndex; i++) {
          topOffset += this.getHeightOfLine(i);
        }
        lineLeftOffset = this._getLineLeftOffset(lineIndex);
        var bound = this.__charBounds[lineIndex][charIndex];
        bound && (leftOffset = bound.left);
        if (this.charSpacing !== 0 && charIndex === this._textLines[lineIndex].length) {
          leftOffset -= this._getWidthOfCharSpacing();
        }
        boundaries = {
          top: topOffset,
          left: lineLeftOffset + (leftOffset > 0 ? leftOffset : 0),
        };
        this.cursorOffsetCache = boundaries;
        return this.cursorOffsetCache;
      },
  
      /**
       * Renders cursor
       * @param {Object} boundaries
       * @param {CanvasRenderingContext2D} ctx transformed context to draw on
       */
      renderCursor: function(boundaries, ctx) {
        var cursorLocation = this.get2DCursorLocation(),
            lineIndex = cursorLocation.lineIndex,
            charIndex = cursorLocation.charIndex > 0 ? cursorLocation.charIndex - 1 : 0,
            charHeight = this.getValueOfPropertyAt(lineIndex, charIndex, 'fontSize'),
            multiplier = this.scaleX * this.canvas.getZoom(),
            cursorWidth = this.cursorWidth / multiplier,
            topOffset = boundaries.topOffset,
            dy = this.getValueOfPropertyAt(lineIndex, charIndex, 'deltaY');
  
        topOffset += (1 - this._fontSizeFraction) * this.getHeightOfLine(lineIndex) / this.lineHeight
          - charHeight * (1 - this._fontSizeFraction);
  
        if (this.inCompositionMode) {
          this.renderSelection(boundaries, ctx);
        }
  
        ctx.fillStyle = this.getValueOfPropertyAt(lineIndex, charIndex, 'fill');
        ctx.globalAlpha = this.__isMousedown ? 1 : this._currentCursorOpacity;
        ctx.fillRect(
          boundaries.left + boundaries.leftOffset - cursorWidth / 2,
          topOffset + boundaries.top + dy,
          cursorWidth,
          charHeight);
      },
  
      /**
       * Renders text selection
       * @param {Object} boundaries Object with left/top/leftOffset/topOffset
       * @param {CanvasRenderingContext2D} ctx transformed context to draw on
       */
      renderSelection: function(boundaries, ctx) {
  
        var selectionStart = this.inCompositionMode ? this.hiddenTextarea.selectionStart : this.selectionStart,
            selectionEnd = this.inCompositionMode ? this.hiddenTextarea.selectionEnd : this.selectionEnd,
            isJustify = this.textAlign.indexOf('justify') !== -1,
            start = this.get2DCursorLocation(selectionStart),
            end = this.get2DCursorLocation(selectionEnd),
            startLine = start.lineIndex,
            endLine = end.lineIndex,
            startChar = start.charIndex < 0 ? 0 : start.charIndex,
            endChar = end.charIndex < 0 ? 0 : end.charIndex;
  
        for (var i = startLine; i <= endLine; i++) {
          var lineOffset = this._getLineLeftOffset(i) || 0,
              lineHeight = this.getHeightOfLine(i),
              realLineHeight = 0, boxStart = 0, boxEnd = 0;
  
          if (i === startLine) {
            boxStart = this.__charBounds[startLine][startChar].left;
          }
          if (i >= startLine && i < endLine) {
            boxEnd = isJustify && !this.isEndOfWrapping(i) ? this.width : this.getLineWidth(i) || 5; // WTF is this 5?
          }
          else if (i === endLine) {
            if (endChar === 0) {
              boxEnd = this.__charBounds[endLine][endChar].left;
            }
            else {
              var charSpacing = this._getWidthOfCharSpacing();
              boxEnd = this.__charBounds[endLine][endChar - 1].left
                + this.__charBounds[endLine][endChar - 1].width - charSpacing;
            }
          }
          realLineHeight = lineHeight;
          if (this.lineHeight < 1 || (i === endLine && this.lineHeight > 1)) {
            lineHeight /= this.lineHeight;
          }
          if (this.inCompositionMode) {
            ctx.fillStyle = this.compositionColor || 'black';
            ctx.fillRect(
              boundaries.left + lineOffset + boxStart,
              boundaries.top + boundaries.topOffset + lineHeight,
              boxEnd - boxStart,
              1);
          }
          else {
            ctx.fillStyle = this.selectionColor;
            ctx.fillRect(
              boundaries.left + lineOffset + boxStart,
              boundaries.top + boundaries.topOffset,
              boxEnd - boxStart,
              lineHeight);
          }
  
  
          boundaries.topOffset += realLineHeight;
        }
      },
  
      /**
       * High level function to know the height of the cursor.
       * the currentChar is the one that precedes the cursor
       * Returns fontSize of char at the current cursor
       * @return {Number} Character font size
       */
      getCurrentCharFontSize: function() {
        var cp = this._getCurrentCharIndex();
        return this.getValueOfPropertyAt(cp.l, cp.c, 'fontSize');
      },
  
      /**
       * High level function to know the color of the cursor.
       * the currentChar is the one that precedes the cursor
       * Returns color (fill) of char at the current cursor
       * @return {String} Character color (fill)
       */
      getCurrentCharColor: function() {
        var cp = this._getCurrentCharIndex();
        return this.getValueOfPropertyAt(cp.l, cp.c, 'fill');
      },
  
      /**
       * Returns the cursor position for the getCurrent.. functions
       * @private
       */
      _getCurrentCharIndex: function() {
        var cursorPosition = this.get2DCursorLocation(this.selectionStart, true),
            charIndex = cursorPosition.charIndex > 0 ? cursorPosition.charIndex - 1 : 0;
        return { l: cursorPosition.lineIndex, c: charIndex };
      }
    });
  
    /**
     * Returns fabric.IText instance from an object representation
     * @static
     * @memberOf fabric.IText
     * @param {Object} object Object to create an instance from
     * @param {function} [callback] invoked with new instance as argument
     */
    fabric.IText.fromObject = function(object, callback) {
      parseDecoration(object);
      if (object.styles) {
        for (var i in object.styles) {
          for (var j in object.styles[i]) {
            parseDecoration(object.styles[i][j]);
          }
        }
      }
      fabric.Object._fromObject('IText', object, callback, 'text');
    };
  })();
  
  
  (function() {
  
    var clone = fabric.util.object.clone;
  
    fabric.util.object.extend(fabric.IText.prototype, /** @lends fabric.IText.prototype */ {
  
      /**
       * Initializes all the interactive behavior of IText
       */
      initBehavior: function() {
        this.initAddedHandler();
        this.initRemovedHandler();
        this.initCursorSelectionHandlers();
        this.initDoubleClickSimulation();
        this.mouseMoveHandler = this.mouseMoveHandler.bind(this);
      },
  
      onDeselect: function() {
        this.isEditing && this.exitEditing();
        this.selected = false;
      },
  
      /**
       * Initializes "added" event handler
       */
      initAddedHandler: function() {
        var _this = this;
        this.on('added', function() {
          var canvas = _this.canvas;
          if (canvas) {
            if (!canvas._hasITextHandlers) {
              canvas._hasITextHandlers = true;
              _this._initCanvasHandlers(canvas);
            }
            canvas._iTextInstances = canvas._iTextInstances || [];
            canvas._iTextInstances.push(_this);
          }
        });
      },
  
      initRemovedHandler: function() {
        var _this = this;
        this.on('removed', function() {
          var canvas = _this.canvas;
          if (canvas) {
            canvas._iTextInstances = canvas._iTextInstances || [];
            fabric.util.removeFromArray(canvas._iTextInstances, _this);
            if (canvas._iTextInstances.length === 0) {
              canvas._hasITextHandlers = false;
              _this._removeCanvasHandlers(canvas);
            }
          }
        });
      },
  
      /**
       * register canvas event to manage exiting on other instances
       * @private
       */
      _initCanvasHandlers: function(canvas) {
        canvas._mouseUpITextHandler = function() {
          if (canvas._iTextInstances) {
            canvas._iTextInstances.forEach(function(obj) {
              obj.__isMousedown = false;
            });
          }
        };
        canvas.on('mouse:up', canvas._mouseUpITextHandler);
      },
  
      /**
       * remove canvas event to manage exiting on other instances
       * @private
       */
      _removeCanvasHandlers: function(canvas) {
        canvas.off('mouse:up', canvas._mouseUpITextHandler);
      },
  
      /**
       * @private
       */
      _tick: function() {
        this._currentTickState = this._animateCursor(this, 1, this.cursorDuration, '_onTickComplete');
      },
  
      /**
       * @private
       */
      _animateCursor: function(obj, targetOpacity, duration, completeMethod) {
  
        var tickState;
  
        tickState = {
          isAborted: false,
          abort: function() {
            this.isAborted = true;
          },
        };
  
        obj.animate('_currentCursorOpacity', targetOpacity, {
          duration: duration,
          onComplete: function() {
            if (!tickState.isAborted) {
              obj[completeMethod]();
            }
          },
          onChange: function() {
            // we do not want to animate a selection, only cursor
            if (obj.canvas && obj.selectionStart === obj.selectionEnd) {
              obj.renderCursorOrSelection();
            }
          },
          abort: function() {
            return tickState.isAborted;
          }
        });
        return tickState;
      },
  
      /**
       * @private
       */
      _onTickComplete: function() {
  
        var _this = this;
  
        if (this._cursorTimeout1) {
          clearTimeout(this._cursorTimeout1);
        }
        this._cursorTimeout1 = setTimeout(function() {
          _this._currentTickCompleteState = _this._animateCursor(_this, 0, this.cursorDuration / 2, '_tick');
        }, 100);
      },
  
      /**
       * Initializes delayed cursor
       */
      initDelayedCursor: function(restart) {
        var _this = this,
            delay = restart ? 0 : this.cursorDelay;
  
        this.abortCursorAnimation();
        this._currentCursorOpacity = 1;
        this._cursorTimeout2 = setTimeout(function() {
          _this._tick();
        }, delay);
      },
  
      /**
       * Aborts cursor animation and clears all timeouts
       */
      abortCursorAnimation: function() {
        var shouldClear = this._currentTickState || this._currentTickCompleteState,
            canvas = this.canvas;
        this._currentTickState && this._currentTickState.abort();
        this._currentTickCompleteState && this._currentTickCompleteState.abort();
  
        clearTimeout(this._cursorTimeout1);
        clearTimeout(this._cursorTimeout2);
  
        this._currentCursorOpacity = 0;
        // to clear just itext area we need to transform the context
        // it may not be worth it
        if (shouldClear && canvas) {
          canvas.clearContext(canvas.contextTop || canvas.contextContainer);
        }
  
      },
  
      /**
       * Selects entire text
       * @return {fabric.IText} thisArg
       * @chainable
       */
      selectAll: function() {
        this.selectionStart = 0;
        this.selectionEnd = this._text.length;
        this._fireSelectionChanged();
        this._updateTextarea();
        return this;
      },
  
      /**
       * Returns selected text
       * @return {String}
       */
      getSelectedText: function() {
        return this._text.slice(this.selectionStart, this.selectionEnd).join('');
      },
  
      /**
       * Find new selection index representing start of current word according to current selection index
       * @param {Number} startFrom Current selection index
       * @return {Number} New selection index
       */
      findWordBoundaryLeft: function(startFrom) {
        var offset = 0, index = startFrom - 1;
  
        // remove space before cursor first
        if (this._reSpace.test(this._text[index])) {
          while (this._reSpace.test(this._text[index])) {
            offset++;
            index--;
          }
        }
        while (/\S/.test(this._text[index]) && index > -1) {
          offset++;
          index--;
        }
  
        return startFrom - offset;
      },
  
      /**
       * Find new selection index representing end of current word according to current selection index
       * @param {Number} startFrom Current selection index
       * @return {Number} New selection index
       */
      findWordBoundaryRight: function(startFrom) {
        var offset = 0, index = startFrom;
  
        // remove space after cursor first
        if (this._reSpace.test(this._text[index])) {
          while (this._reSpace.test(this._text[index])) {
            offset++;
            index++;
          }
        }
        while (/\S/.test(this._text[index]) && index < this._text.length) {
          offset++;
          index++;
        }
  
        return startFrom + offset;
      },
  
      /**
       * Find new selection index representing start of current line according to current selection index
       * @param {Number} startFrom Current selection index
       * @return {Number} New selection index
       */
      findLineBoundaryLeft: function(startFrom) {
        var offset = 0, index = startFrom - 1;
  
        while (!/\n/.test(this._text[index]) && index > -1) {
          offset++;
          index--;
        }
  
        return startFrom - offset;
      },
  
      /**
       * Find new selection index representing end of current line according to current selection index
       * @param {Number} startFrom Current selection index
       * @return {Number} New selection index
       */
      findLineBoundaryRight: function(startFrom) {
        var offset = 0, index = startFrom;
  
        while (!/\n/.test(this._text[index]) && index < this._text.length) {
          offset++;
          index++;
        }
  
        return startFrom + offset;
      },
  
      /**
       * Finds index corresponding to beginning or end of a word
       * @param {Number} selectionStart Index of a character
       * @param {Number} direction 1 or -1
       * @return {Number} Index of the beginning or end of a word
       */
      searchWordBoundary: function(selectionStart, direction) {
        var index     = this._reSpace.test(this._text[selectionStart]) ? selectionStart - 1 : selectionStart,
            _char     = this._text[index],
            reNonWord = /[ \n\.,;!\?\-]/;
  
        while (!reNonWord.test(_char) && index > 0 && index < this._text.length) {
          index += direction;
          _char = this._text[index];
        }
        if (reNonWord.test(_char) && _char !== '\n') {
          index += direction === 1 ? 0 : 1;
        }
        return index;
      },
  
      /**
       * Selects a word based on the index
       * @param {Number} selectionStart Index of a character
       */
      selectWord: function(selectionStart) {
        selectionStart = selectionStart || this.selectionStart;
        var newSelectionStart = this.searchWordBoundary(selectionStart, -1), /* search backwards */
            newSelectionEnd = this.searchWordBoundary(selectionStart, 1); /* search forward */
  
        this.selectionStart = newSelectionStart;
        this.selectionEnd = newSelectionEnd;
        this._fireSelectionChanged();
        this._updateTextarea();
        this.renderCursorOrSelection();
      },
  
      /**
       * Selects a line based on the index
       * @param {Number} selectionStart Index of a character
       * @return {fabric.IText} thisArg
       * @chainable
       */
      selectLine: function(selectionStart) {
        selectionStart = selectionStart || this.selectionStart;
        var newSelectionStart = this.findLineBoundaryLeft(selectionStart),
            newSelectionEnd = this.findLineBoundaryRight(selectionStart);
  
        this.selectionStart = newSelectionStart;
        this.selectionEnd = newSelectionEnd;
        this._fireSelectionChanged();
        this._updateTextarea();
        return this;
      },
  
      /**
       * Enters editing state
       * @return {fabric.IText} thisArg
       * @chainable
       */
      enterEditing: function(e) {
        if (this.isEditing || !this.editable) {
          return;
        }
  
        if (this.canvas) {
          this.canvas.calcOffset();
          this.exitEditingOnOthers(this.canvas);
        }
  
        this.isEditing = true;
  
        this.initHiddenTextarea(e);
        this.hiddenTextarea.focus();
        this.hiddenTextarea.value = this.text;
        this._updateTextarea();
        this._saveEditingProps();
        this._setEditingProps();
        this._textBeforeEdit = this.text;
  
        this._tick();
        this.fire('editing:entered');
        this._fireSelectionChanged();
        if (!this.canvas) {
          return this;
        }
        this.canvas.fire('text:editing:entered', { target: this });
        this.initMouseMoveHandler();
        this.canvas.requestRenderAll();
        return this;
      },
  
      exitEditingOnOthers: function(canvas) {
        if (canvas._iTextInstances) {
          canvas._iTextInstances.forEach(function(obj) {
            obj.selected = false;
            if (obj.isEditing) {
              obj.exitEditing();
            }
          });
        }
      },
  
      /**
       * Initializes "mousemove" event handler
       */
      initMouseMoveHandler: function() {
        this.canvas.on('mouse:move', this.mouseMoveHandler);
      },
  
      /**
       * @private
       */
      mouseMoveHandler: function(options) {
        if (!this.__isMousedown || !this.isEditing) {
          return;
        }
  
        var newSelectionStart = this.getSelectionStartFromPointer(options.e),
            currentStart = this.selectionStart,
            currentEnd = this.selectionEnd;
        if (
          (newSelectionStart !== this.__selectionStartOnMouseDown || currentStart === currentEnd)
          &&
          (currentStart === newSelectionStart || currentEnd === newSelectionStart)
        ) {
          return;
        }
        if (newSelectionStart > this.__selectionStartOnMouseDown) {
          this.selectionStart = this.__selectionStartOnMouseDown;
          this.selectionEnd = newSelectionStart;
        }
        else {
          this.selectionStart = newSelectionStart;
          this.selectionEnd = this.__selectionStartOnMouseDown;
        }
        if (this.selectionStart !== currentStart || this.selectionEnd !== currentEnd) {
          this.restartCursorIfNeeded();
          this._fireSelectionChanged();
          this._updateTextarea();
          this.renderCursorOrSelection();
        }
      },
  
      /**
       * @private
       */
      _setEditingProps: function() {
        this.hoverCursor = 'text';
  
        if (this.canvas) {
          this.canvas.defaultCursor = this.canvas.moveCursor = 'text';
        }
  
        this.borderColor = this.editingBorderColor;
        this.hasControls = this.selectable = false;
        this.lockMovementX = this.lockMovementY = true;
      },
  
      /**
       * convert from textarea to grapheme indexes
       */
      fromStringToGraphemeSelection: function(start, end, text) {
        var smallerTextStart = text.slice(0, start),
            graphemeStart = fabric.util.string.graphemeSplit(smallerTextStart).length;
        if (start === end) {
          return { selectionStart: graphemeStart, selectionEnd: graphemeStart };
        }
        var smallerTextEnd = text.slice(start, end),
            graphemeEnd = fabric.util.string.graphemeSplit(smallerTextEnd).length;
        return { selectionStart: graphemeStart, selectionEnd: graphemeStart + graphemeEnd };
      },
  
      /**
       * convert from fabric to textarea values
       */
      fromGraphemeToStringSelection: function(start, end, _text) {
        var smallerTextStart = _text.slice(0, start),
            graphemeStart = smallerTextStart.join('').length;
        if (start === end) {
          return { selectionStart: graphemeStart, selectionEnd: graphemeStart };
        }
        var smallerTextEnd = _text.slice(start, end),
            graphemeEnd = smallerTextEnd.join('').length;
        return { selectionStart: graphemeStart, selectionEnd: graphemeStart + graphemeEnd };
      },
  
      /**
       * @private
       */
      _updateTextarea: function() {
        this.cursorOffsetCache = { };
        if (!this.hiddenTextarea) {
          return;
        }
        if (!this.inCompositionMode) {
          var newSelection = this.fromGraphemeToStringSelection(this.selectionStart, this.selectionEnd, this._text);
          this.hiddenTextarea.selectionStart = newSelection.selectionStart;
          this.hiddenTextarea.selectionEnd = newSelection.selectionEnd;
        }
        this.updateTextareaPosition();
      },
  
      /**
       * @private
       */
      updateFromTextArea: function() {
        if (!this.hiddenTextarea) {
          return;
        }
        this.cursorOffsetCache = { };
        this.text = this.hiddenTextarea.value;
        if (this._shouldClearDimensionCache()) {
          this.initDimensions();
          this.setCoords();
        }
        var newSelection = this.fromStringToGraphemeSelection(
          this.hiddenTextarea.selectionStart, this.hiddenTextarea.selectionEnd, this.hiddenTextarea.value);
        this.selectionEnd = this.selectionStart = newSelection.selectionEnd;
        if (!this.inCompositionMode) {
          this.selectionStart = newSelection.selectionStart;
        }
        this.updateTextareaPosition();
      },
  
      /**
       * @private
       */
      updateTextareaPosition: function() {
        if (this.selectionStart === this.selectionEnd) {
          var style = this._calcTextareaPosition();
          this.hiddenTextarea.style.left = style.left;
          this.hiddenTextarea.style.top = style.top;
        }
      },
  
      /**
       * @private
       * @return {Object} style contains style for hiddenTextarea
       */
      _calcTextareaPosition: function() {
        if (!this.canvas) {
          return { x: 1, y: 1 };
        }
        var desiredPosition = this.inCompositionMode ? this.compositionStart : this.selectionStart,
            boundaries = this._getCursorBoundaries(desiredPosition),
            cursorLocation = this.get2DCursorLocation(desiredPosition),
            lineIndex = cursorLocation.lineIndex,
            charIndex = cursorLocation.charIndex,
            charHeight = this.getValueOfPropertyAt(lineIndex, charIndex, 'fontSize') * this.lineHeight,
            leftOffset = boundaries.leftOffset,
            m = this.calcTransformMatrix(),
            p = {
              x: boundaries.left + leftOffset,
              y: boundaries.top + boundaries.topOffset + charHeight
            },
            upperCanvas = this.canvas.upperCanvasEl,
            upperCanvasWidth = upperCanvas.width,
            upperCanvasHeight = upperCanvas.height,
            maxWidth = upperCanvasWidth - charHeight,
            maxHeight = upperCanvasHeight - charHeight,
            scaleX = upperCanvas.clientWidth / upperCanvasWidth,
            scaleY = upperCanvas.clientHeight / upperCanvasHeight;
  
        p = fabric.util.transformPoint(p, m);
        p = fabric.util.transformPoint(p, this.canvas.viewportTransform);
        p.x *= scaleX;
        p.y *= scaleY;
        if (p.x < 0) {
          p.x = 0;
        }
        if (p.x > maxWidth) {
          p.x = maxWidth;
        }
        if (p.y < 0) {
          p.y = 0;
        }
        if (p.y > maxHeight) {
          p.y = maxHeight;
        }
  
        // add canvas offset on document
        p.x += this.canvas._offset.left;
        p.y += this.canvas._offset.top;
  
        return { left: p.x + 'px', top: p.y + 'px', fontSize: charHeight + 'px', charHeight: charHeight };
      },
  
      /**
       * @private
       */
      _saveEditingProps: function() {
        this._savedProps = {
          hasControls: this.hasControls,
          borderColor: this.borderColor,
          lockMovementX: this.lockMovementX,
          lockMovementY: this.lockMovementY,
          hoverCursor: this.hoverCursor,
          selectable: this.selectable,
          defaultCursor: this.canvas && this.canvas.defaultCursor,
          moveCursor: this.canvas && this.canvas.moveCursor
        };
      },
  
      /**
       * @private
       */
      _restoreEditingProps: function() {
        if (!this._savedProps) {
          return;
        }
  
        this.hoverCursor = this._savedProps.hoverCursor;
        this.hasControls = this._savedProps.hasControls;
        this.borderColor = this._savedProps.borderColor;
        this.selectable = this._savedProps.selectable;
        this.lockMovementX = this._savedProps.lockMovementX;
        this.lockMovementY = this._savedProps.lockMovementY;
  
        if (this.canvas) {
          this.canvas.defaultCursor = this._savedProps.defaultCursor;
          this.canvas.moveCursor = this._savedProps.moveCursor;
        }
      },
  
      /**
       * Exits from editing state
       * @return {fabric.IText} thisArg
       * @chainable
       */
      exitEditing: function() {
        var isTextChanged = (this._textBeforeEdit !== this.text);
        this.selected = false;
        this.isEditing = false;
  
        this.selectionEnd = this.selectionStart;
  
        if (this.hiddenTextarea) {
          this.hiddenTextarea.blur && this.hiddenTextarea.blur();
          this.canvas && this.hiddenTextarea.parentNode.removeChild(this.hiddenTextarea);
          this.hiddenTextarea = null;
        }
  
        this.abortCursorAnimation();
        this._restoreEditingProps();
        this._currentCursorOpacity = 0;
        if (this._shouldClearDimensionCache()) {
          this.initDimensions();
          this.setCoords();
        }
        this.fire('editing:exited');
        isTextChanged && this.fire('modified');
        if (this.canvas) {
          this.canvas.off('mouse:move', this.mouseMoveHandler);
          this.canvas.fire('text:editing:exited', { target: this });
          isTextChanged && this.canvas.fire('object:modified', { target: this });
        }
        return this;
      },
  
      /**
       * @private
       */
      _removeExtraneousStyles: function() {
        for (var prop in this.styles) {
          if (!this._textLines[prop]) {
            delete this.styles[prop];
          }
        }
      },
  
      /**
       * remove and reflow a style block from start to end.
       * @param {Number} start linear start position for removal (included in removal)
       * @param {Number} end linear end position for removal ( excluded from removal )
       */
      removeStyleFromTo: function(start, end) {
        var cursorStart = this.get2DCursorLocation(start, true),
            cursorEnd = this.get2DCursorLocation(end, true),
            lineStart = cursorStart.lineIndex,
            charStart = cursorStart.charIndex,
            lineEnd = cursorEnd.lineIndex,
            charEnd = cursorEnd.charIndex,
            i, styleObj;
        if (lineStart !== lineEnd) {
          // step1 remove the trailing of lineStart
          if (this.styles[lineStart]) {
            for (i = charStart; i < this._unwrappedTextLines[lineStart].length; i++) {
              delete this.styles[lineStart][i];
            }
          }
          // step2 move the trailing of lineEnd to lineStart if needed
          if (this.styles[lineEnd]) {
            for (i = charEnd; i < this._unwrappedTextLines[lineEnd].length; i++) {
              styleObj = this.styles[lineEnd][i];
              if (styleObj) {
                this.styles[lineStart] || (this.styles[lineStart] = { });
                this.styles[lineStart][charStart + i - charEnd] = styleObj;
              }
            }
          }
          // step3 detects lines will be completely removed.
          for (i = lineStart + 1; i <= lineEnd; i++) {
            delete this.styles[i];
          }
          // step4 shift remaining lines.
          this.shiftLineStyles(lineEnd, lineStart - lineEnd);
        }
        else {
          // remove and shift left on the same line
          if (this.styles[lineStart]) {
            styleObj = this.styles[lineStart];
            var diff = charEnd - charStart, numericChar, _char;
            for (i = charStart; i < charEnd; i++) {
              delete styleObj[i];
            }
            for (_char in this.styles[lineStart]) {
              numericChar = parseInt(_char, 10);
              if (numericChar >= charEnd) {
                styleObj[numericChar - diff] = styleObj[_char];
                delete styleObj[_char];
              }
            }
          }
        }
      },
  
      /**
       * Shifts line styles up or down
       * @param {Number} lineIndex Index of a line
       * @param {Number} offset Can any number?
       */
      shiftLineStyles: function(lineIndex, offset) {
        // shift all line styles by offset upward or downward
        // do not clone deep. we need new array, not new style objects
        var clonedStyles = clone(this.styles);
        for (var line in this.styles) {
          var numericLine = parseInt(line, 10);
          if (numericLine > lineIndex) {
            this.styles[numericLine + offset] = clonedStyles[numericLine];
            if (!clonedStyles[numericLine - offset]) {
              delete this.styles[numericLine];
            }
          }
        }
      },
  
      restartCursorIfNeeded: function() {
        if (!this._currentTickState || this._currentTickState.isAborted
          || !this._currentTickCompleteState || this._currentTickCompleteState.isAborted
        ) {
          this.initDelayedCursor();
        }
      },
  
      /**
       * Inserts new style object
       * @param {Number} lineIndex Index of a line
       * @param {Number} charIndex Index of a char
       * @param {Number} qty number of lines to add
       * @param {Array} copiedStyle Array of objects styles
       */
      insertNewlineStyleObject: function(lineIndex, charIndex, qty, copiedStyle) {
        var currentCharStyle,
            newLineStyles = {},
            somethingAdded = false;
  
        qty || (qty = 1);
        this.shiftLineStyles(lineIndex, qty);
        if (this.styles[lineIndex]) {
          currentCharStyle = this.styles[lineIndex][charIndex === 0 ? charIndex : charIndex - 1];
        }
  
        // we clone styles of all chars
        // after cursor onto the current line
        for (var index in this.styles[lineIndex]) {
          var numIndex = parseInt(index, 10);
          if (numIndex >= charIndex) {
            somethingAdded = true;
            newLineStyles[numIndex - charIndex] = this.styles[lineIndex][index];
            // remove lines from the previous line since they're on a new line now
            delete this.styles[lineIndex][index];
          }
        }
        if (somethingAdded) {
          this.styles[lineIndex + qty] = newLineStyles;
        }
        else {
          delete this.styles[lineIndex + qty];
        }
        // for the other lines
        // we clone current char style onto the next (otherwise empty) line
        while (qty > 1) {
          qty--;
          if (copiedStyle && copiedStyle[qty]) {
            this.styles[lineIndex + qty] = { 0: clone(copiedStyle[qty]) };
          }
          else if (currentCharStyle) {
            this.styles[lineIndex + qty] = { 0: clone(currentCharStyle) };
          }
          else {
            delete this.styles[lineIndex + qty];
          }
        }
        this._forceClearCache = true;
      },
  
      /**
       * Inserts style object for a given line/char index
       * @param {Number} lineIndex Index of a line
       * @param {Number} charIndex Index of a char
       * @param {Number} quantity number Style object to insert, if given
       * @param {Array} copiedStyle array of style objects
       */
      insertCharStyleObject: function(lineIndex, charIndex, quantity, copiedStyle) {
        if (!this.styles) {
          this.styles = {};
        }
        var currentLineStyles       = this.styles[lineIndex],
            currentLineStylesCloned = currentLineStyles ? clone(currentLineStyles) : {};
  
        quantity || (quantity = 1);
        // shift all char styles by quantity forward
        // 0,1,2,3 -> (charIndex=2) -> 0,1,3,4 -> (insert 2) -> 0,1,2,3,4
        for (var index in currentLineStylesCloned) {
          var numericIndex = parseInt(index, 10);
          if (numericIndex >= charIndex) {
            currentLineStyles[numericIndex + quantity] = currentLineStylesCloned[numericIndex];
            // only delete the style if there was nothing moved there
            if (!currentLineStylesCloned[numericIndex - quantity]) {
              delete currentLineStyles[numericIndex];
            }
          }
        }
        this._forceClearCache = true;
        if (copiedStyle) {
          while (quantity--) {
            if (!Object.keys(copiedStyle[quantity]).length) {
              continue;
            }
            if (!this.styles[lineIndex]) {
              this.styles[lineIndex] = {};
            }
            this.styles[lineIndex][charIndex + quantity] = clone(copiedStyle[quantity]);
          }
          return;
        }
        if (!currentLineStyles) {
          return;
        }
        var newStyle = currentLineStyles[charIndex ? charIndex - 1 : 1];
        while (newStyle && quantity--) {
          this.styles[lineIndex][charIndex + quantity] = clone(newStyle);
        }
      },
  
      /**
       * Inserts style object(s)
       * @param {Array} insertedText Characters at the location where style is inserted
       * @param {Number} start cursor index for inserting style
       * @param {Array} [copiedStyle] array of style objects to insert.
       */
      insertNewStyleBlock: function(insertedText, start, copiedStyle) {
        var cursorLoc = this.get2DCursorLocation(start, true),
            addedLines = [0], linesLength = 0;
        for (var i = 0; i < insertedText.length; i++) {
          if (insertedText[i] === '\n') {
            linesLength++;
            addedLines[linesLength] = 0;
          }
          else {
            addedLines[linesLength]++;
          }
        }
        if (addedLines[0] > 0) {
          this.insertCharStyleObject(cursorLoc.lineIndex, cursorLoc.charIndex, addedLines[0], copiedStyle);
          copiedStyle = copiedStyle && copiedStyle.slice(addedLines[0] + 1);
        }
        linesLength && this.insertNewlineStyleObject(
          cursorLoc.lineIndex, cursorLoc.charIndex + addedLines[0], linesLength);
        for (var i = 1; i < linesLength; i++) {
          if (addedLines[i] > 0) {
            this.insertCharStyleObject(cursorLoc.lineIndex + i, 0, addedLines[i], copiedStyle);
          }
          else if (copiedStyle) {
            this.styles[cursorLoc.lineIndex + i][0] = copiedStyle[0];
          }
          copiedStyle = copiedStyle && copiedStyle.slice(addedLines[i] + 1);
        }
        // we use i outside the loop to get it like linesLength
        if (addedLines[i] > 0) {
          this.insertCharStyleObject(cursorLoc.lineIndex + i, 0, addedLines[i], copiedStyle);
        }
      },
  
      /**
       * Set the selectionStart and selectionEnd according to the new position of cursor
       * mimic the key - mouse navigation when shift is pressed.
       */
      setSelectionStartEndWithShift: function(start, end, newSelection) {
        if (newSelection <= start) {
          if (end === start) {
            this._selectionDirection = 'left';
          }
          else if (this._selectionDirection === 'right') {
            this._selectionDirection = 'left';
            this.selectionEnd = start;
          }
          this.selectionStart = newSelection;
        }
        else if (newSelection > start && newSelection < end) {
          if (this._selectionDirection === 'right') {
            this.selectionEnd = newSelection;
          }
          else {
            this.selectionStart = newSelection;
          }
        }
        else {
          // newSelection is > selection start and end
          if (end === start) {
            this._selectionDirection = 'right';
          }
          else if (this._selectionDirection === 'left') {
            this._selectionDirection = 'right';
            this.selectionStart = end;
          }
          this.selectionEnd = newSelection;
        }
      },
  
      setSelectionInBoundaries: function() {
        var length = this.text.length;
        if (this.selectionStart > length) {
          this.selectionStart = length;
        }
        else if (this.selectionStart < 0) {
          this.selectionStart = 0;
        }
        if (this.selectionEnd > length) {
          this.selectionEnd = length;
        }
        else if (this.selectionEnd < 0) {
          this.selectionEnd = 0;
        }
      }
    });
  })();
  
  
  fabric.util.object.extend(fabric.IText.prototype, /** @lends fabric.IText.prototype */ {
    /**
     * Initializes "dbclick" event handler
     */
    initDoubleClickSimulation: function() {
  
      // for double click
      this.__lastClickTime = +new Date();
  
      // for triple click
      this.__lastLastClickTime = +new Date();
  
      this.__lastPointer = { };
  
      this.on('mousedown', this.onMouseDown);
    },
  
    /**
     * Default event handler to simulate triple click
     * @private
     */
    onMouseDown: function(options) {
      if (!this.canvas) {
        return;
      }
      this.__newClickTime = +new Date();
      var newPointer = options.pointer;
      if (this.isTripleClick(newPointer)) {
        this.fire('tripleclick', options);
        this._stopEvent(options.e);
      }
      this.__lastLastClickTime = this.__lastClickTime;
      this.__lastClickTime = this.__newClickTime;
      this.__lastPointer = newPointer;
      this.__lastIsEditing = this.isEditing;
      this.__lastSelected = this.selected;
    },
  
    isTripleClick: function(newPointer) {
      return this.__newClickTime - this.__lastClickTime < 500 &&
          this.__lastClickTime - this.__lastLastClickTime < 500 &&
          this.__lastPointer.x === newPointer.x &&
          this.__lastPointer.y === newPointer.y;
    },
  
    /**
     * @private
     */
    _stopEvent: function(e) {
      e.preventDefault && e.preventDefault();
      e.stopPropagation && e.stopPropagation();
    },
  
    /**
     * Initializes event handlers related to cursor or selection
     */
    initCursorSelectionHandlers: function() {
      this.initMousedownHandler();
      this.initMouseupHandler();
      this.initClicks();
    },
  
    /**
     * Initializes double and triple click event handlers
     */
    initClicks: function() {
      this.on('mousedblclick', function(options) {
        this.selectWord(this.getSelectionStartFromPointer(options.e));
      });
      this.on('tripleclick', function(options) {
        this.selectLine(this.getSelectionStartFromPointer(options.e));
      });
    },
  
    /**
     * Default event handler for the basic functionalities needed on _mouseDown
     * can be overridden to do something different.
     * Scope of this implementation is: find the click position, set selectionStart
     * find selectionEnd, initialize the drawing of either cursor or selection area
     */
    _mouseDownHandler: function(options) {
      if (!this.canvas || !this.editable || (options.e.button && options.e.button !== 1)) {
        return;
      }
  
      this.__isMousedown = true;
  
      if (this.selected) {
        this.setCursorByClick(options.e);
      }
  
      if (this.isEditing) {
        this.__selectionStartOnMouseDown = this.selectionStart;
        if (this.selectionStart === this.selectionEnd) {
          this.abortCursorAnimation();
        }
        this.renderCursorOrSelection();
      }
    },
  
    /**
     * Default event handler for the basic functionalities needed on mousedown:before
     * can be overridden to do something different.
     * Scope of this implementation is: verify the object is already selected when mousing down
     */
    _mouseDownHandlerBefore: function(options) {
      if (!this.canvas || !this.editable || (options.e.button && options.e.button !== 1)) {
        return;
      }
      if (this === this.canvas._activeObject) {
        this.selected = true;
      }
    },
  
    /**
     * Initializes "mousedown" event handler
     */
    initMousedownHandler: function() {
      this.on('mousedown', this._mouseDownHandler);
      this.on('mousedown:before', this._mouseDownHandlerBefore);
    },
  
    /**
     * Initializes "mouseup" event handler
     */
    initMouseupHandler: function() {
      this.on('mouseup', this.mouseUpHandler);
    },
  
    /**
     * standard hander for mouse up, overridable
     * @private
     */
    mouseUpHandler: function(options) {
      this.__isMousedown = false;
      if (!this.editable || this.group ||
        (options.transform && options.transform.actionPerformed) ||
        (options.e.button && options.e.button !== 1)) {
        return;
      }
  
      if (this.canvas) {
        var currentActive = this.canvas._activeObject;
        if (currentActive && currentActive !== this) {
          // avoid running this logic when there is an active object
          // this because is possible with shift click and fast clicks,
          // to rapidly deselect and reselect this object and trigger an enterEdit
          return;
        }
      }
  
      if (this.__lastSelected && !this.__corner) {
        this.selected = false;
        this.__lastSelected = false;
        this.enterEditing(options.e);
        if (this.selectionStart === this.selectionEnd) {
          this.initDelayedCursor(true);
        }
        else {
          this.renderCursorOrSelection();
        }
      }
      else {
        this.selected = true;
      }
    },
  
    /**
     * Changes cursor location in a text depending on passed pointer (x/y) object
     * @param {Event} e Event object
     */
    setCursorByClick: function(e) {
      var newSelection = this.getSelectionStartFromPointer(e),
          start = this.selectionStart, end = this.selectionEnd;
      if (e.shiftKey) {
        this.setSelectionStartEndWithShift(start, end, newSelection);
      }
      else {
        this.selectionStart = newSelection;
        this.selectionEnd = newSelection;
      }
      if (this.isEditing) {
        this._fireSelectionChanged();
        this._updateTextarea();
      }
    },
  
    /**
     * Returns index of a character corresponding to where an object was clicked
     * @param {Event} e Event object
     * @return {Number} Index of a character
     */
    getSelectionStartFromPointer: function(e) {
      var mouseOffset = this.getLocalPointer(e),
          prevWidth = 0,
          width = 0,
          height = 0,
          charIndex = 0,
          lineIndex = 0,
          lineLeftOffset,
          line;
  
      for (var i = 0, len = this._textLines.length; i < len; i++) {
        if (height <= mouseOffset.y) {
          height += this.getHeightOfLine(i) * this.scaleY;
          lineIndex = i;
          if (i > 0) {
            charIndex += this._textLines[i - 1].length + this.missingNewlineOffset(i - 1);
          }
        }
        else {
          break;
        }
      }
      lineLeftOffset = this._getLineLeftOffset(lineIndex);
      width = lineLeftOffset * this.scaleX;
      line = this._textLines[lineIndex];
      for (var j = 0, jlen = line.length; j < jlen; j++) {
        prevWidth = width;
        // i removed something about flipX here, check.
        width += this.__charBounds[lineIndex][j].kernedWidth * this.scaleX;
        if (width <= mouseOffset.x) {
          charIndex++;
        }
        else {
          break;
        }
      }
      return this._getNewSelectionStartFromOffset(mouseOffset, prevWidth, width, charIndex, jlen);
    },
  
    /**
     * @private
     */
    _getNewSelectionStartFromOffset: function(mouseOffset, prevWidth, width, index, jlen) {
      // we need Math.abs because when width is after the last char, the offset is given as 1, while is 0
      var distanceBtwLastCharAndCursor = mouseOffset.x - prevWidth,
          distanceBtwNextCharAndCursor = width - mouseOffset.x,
          offset = distanceBtwNextCharAndCursor > distanceBtwLastCharAndCursor ||
            distanceBtwNextCharAndCursor < 0 ? 0 : 1,
          newSelectionStart = index + offset;
      // if object is horizontally flipped, mirror cursor location from the end
      if (this.flipX) {
        newSelectionStart = jlen - newSelectionStart;
      }
  
      if (newSelectionStart > this._text.length) {
        newSelectionStart = this._text.length;
      }
  
      return newSelectionStart;
    }
  });
  
  
  fabric.util.object.extend(fabric.IText.prototype, /** @lends fabric.IText.prototype */ {
  
    /**
     * Initializes hidden textarea (needed to bring up keyboard in iOS)
     */
    initHiddenTextarea: function() {
      this.hiddenTextarea = fabric.document.createElement('textarea');
      this.hiddenTextarea.setAttribute('autocapitalize', 'off');
      this.hiddenTextarea.setAttribute('autocorrect', 'off');
      this.hiddenTextarea.setAttribute('autocomplete', 'off');
      this.hiddenTextarea.setAttribute('spellcheck', 'false');
      this.hiddenTextarea.setAttribute('data-fabric-hiddentextarea', '');
      this.hiddenTextarea.setAttribute('wrap', 'off');
      var style = this._calcTextareaPosition();
      // line-height: 1px; was removed from the style to fix this:
      // https://bugs.chromium.org/p/chromium/issues/detail?id=870966
      this.hiddenTextarea.style.cssText = 'position: absolute; top: ' + style.top +
      '; left: ' + style.left + '; z-index: -999; opacity: 0; width: 1px; height: 1px; font-size: 1px;' +
      ' paddingｰtop: ' + style.fontSize + ';';
      fabric.document.body.appendChild(this.hiddenTextarea);
  
      fabric.util.addListener(this.hiddenTextarea, 'keydown', this.onKeyDown.bind(this));
      fabric.util.addListener(this.hiddenTextarea, 'keyup', this.onKeyUp.bind(this));
      fabric.util.addListener(this.hiddenTextarea, 'input', this.onInput.bind(this));
      fabric.util.addListener(this.hiddenTextarea, 'copy', this.copy.bind(this));
      fabric.util.addListener(this.hiddenTextarea, 'cut', this.copy.bind(this));
      fabric.util.addListener(this.hiddenTextarea, 'paste', this.paste.bind(this));
      fabric.util.addListener(this.hiddenTextarea, 'compositionstart', this.onCompositionStart.bind(this));
      fabric.util.addListener(this.hiddenTextarea, 'compositionupdate', this.onCompositionUpdate.bind(this));
      fabric.util.addListener(this.hiddenTextarea, 'compositionend', this.onCompositionEnd.bind(this));
  
      if (!this._clickHandlerInitialized && this.canvas) {
        fabric.util.addListener(this.canvas.upperCanvasEl, 'click', this.onClick.bind(this));
        this._clickHandlerInitialized = true;
      }
    },
  
    /**
     * For functionalities on keyDown
     * Map a special key to a function of the instance/prototype
     * If you need different behaviour for ESC or TAB or arrows, you have to change
     * this map setting the name of a function that you build on the fabric.Itext or
     * your prototype.
     * the map change will affect all Instances unless you need for only some text Instances
     * in that case you have to clone this object and assign your Instance.
     * this.keysMap = fabric.util.object.clone(this.keysMap);
     * The function must be in fabric.Itext.prototype.myFunction And will receive event as args[0]
     */
    keysMap: {
      9:  'exitEditing',
      27: 'exitEditing',
      33: 'moveCursorUp',
      34: 'moveCursorDown',
      35: 'moveCursorRight',
      36: 'moveCursorLeft',
      37: 'moveCursorLeft',
      38: 'moveCursorUp',
      39: 'moveCursorRight',
      40: 'moveCursorDown',
    },
  
    /**
     * For functionalities on keyUp + ctrl || cmd
     */
    ctrlKeysMapUp: {
      67: 'copy',
      88: 'cut'
    },
  
    /**
     * For functionalities on keyDown + ctrl || cmd
     */
    ctrlKeysMapDown: {
      65: 'selectAll'
    },
  
    onClick: function() {
      // No need to trigger click event here, focus is enough to have the keyboard appear on Android
      this.hiddenTextarea && this.hiddenTextarea.focus();
    },
  
    /**
     * Handles keyup event
     * @param {Event} e Event object
     */
    onKeyDown: function(e) {
      if (!this.isEditing || this.inCompositionMode) {
        return;
      }
      if (e.keyCode in this.keysMap) {
        this[this.keysMap[e.keyCode]](e);
      }
      else if ((e.keyCode in this.ctrlKeysMapDown) && (e.ctrlKey || e.metaKey)) {
        this[this.ctrlKeysMapDown[e.keyCode]](e);
      }
      else {
        return;
      }
      e.stopImmediatePropagation();
      e.preventDefault();
      if (e.keyCode >= 33 && e.keyCode <= 40) {
        // if i press an arrow key just update selection
        this.clearContextTop();
        this.renderCursorOrSelection();
      }
      else {
        this.canvas && this.canvas.requestRenderAll();
      }
    },
  
    /**
     * Handles keyup event
     * We handle KeyUp because ie11 and edge have difficulties copy/pasting
     * if a copy/cut event fired, keyup is dismissed
     * @param {Event} e Event object
     */
    onKeyUp: function(e) {
      if (!this.isEditing || this._copyDone || this.inCompositionMode) {
        this._copyDone = false;
        return;
      }
      if ((e.keyCode in this.ctrlKeysMapUp) && (e.ctrlKey || e.metaKey)) {
        this[this.ctrlKeysMapUp[e.keyCode]](e);
      }
      else {
        return;
      }
      e.stopImmediatePropagation();
      e.preventDefault();
      this.canvas && this.canvas.requestRenderAll();
    },
  
    /**
     * Handles onInput event
     * @param {Event} e Event object
     */
    onInput: function(e) {
      var fromPaste = this.fromPaste;
      this.fromPaste = false;
      e && e.stopPropagation();
      if (!this.isEditing) {
        return;
      }
      // decisions about style changes.
      var nextText = this._splitTextIntoLines(this.hiddenTextarea.value).graphemeText,
          charCount = this._text.length,
          nextCharCount = nextText.length,
          removedText, insertedText,
          charDiff = nextCharCount - charCount;
      if (this.hiddenTextarea.value === '') {
        this.styles = { };
        this.updateFromTextArea();
        this.fire('changed');
        if (this.canvas) {
          this.canvas.fire('text:changed', { target: this });
          this.canvas.requestRenderAll();
        }
        return;
      }
  
      var textareaSelection = this.fromStringToGraphemeSelection(
        this.hiddenTextarea.selectionStart,
        this.hiddenTextarea.selectionEnd,
        this.hiddenTextarea.value
      );
      var backDelete = this.selectionStart > textareaSelection.selectionStart;
  
      if (this.selectionStart !== this.selectionEnd) {
        removedText = this._text.slice(this.selectionStart, this.selectionEnd);
        charDiff += this.selectionEnd - this.selectionStart;
      }
      else if (nextCharCount < charCount) {
        if (backDelete) {
          removedText = this._text.slice(this.selectionEnd + charDiff, this.selectionEnd);
        }
        else {
          removedText = this._text.slice(this.selectionStart, this.selectionStart - charDiff);
        }
      }
      insertedText = nextText.slice(textareaSelection.selectionEnd - charDiff, textareaSelection.selectionEnd);
      if (removedText && removedText.length) {
        if (this.selectionStart !== this.selectionEnd) {
          this.removeStyleFromTo(this.selectionStart, this.selectionEnd);
        }
        else if (backDelete) {
          // detect differencies between forwardDelete and backDelete
          this.removeStyleFromTo(this.selectionEnd - removedText.length, this.selectionEnd);
        }
        else {
          this.removeStyleFromTo(this.selectionEnd, this.selectionEnd + removedText.length);
        }
      }
      if (insertedText.length) {
        if (fromPaste && insertedText.join('') === fabric.copiedText && !fabric.disableStyleCopyPaste) {
          this.insertNewStyleBlock(insertedText, this.selectionStart, fabric.copiedTextStyle);
        }
        else {
          this.insertNewStyleBlock(insertedText, this.selectionStart);
        }
      }
      this.updateFromTextArea();
      this.fire('changed');
      if (this.canvas) {
        this.canvas.fire('text:changed', { target: this });
        this.canvas.requestRenderAll();
      }
    },
    /**
     * Composition start
     */
    onCompositionStart: function() {
      this.inCompositionMode = true;
    },
  
    /**
     * Composition end
     */
    onCompositionEnd: function() {
      this.inCompositionMode = false;
    },
  
    // /**
    //  * Composition update
    //  */
    onCompositionUpdate: function(e) {
      this.compositionStart = e.target.selectionStart;
      this.compositionEnd = e.target.selectionEnd;
      this.updateTextareaPosition();
    },
  
    /**
     * Copies selected text
     * @param {Event} e Event object
     */
    copy: function() {
      if (this.selectionStart === this.selectionEnd) {
        //do not cut-copy if no selection
        return;
      }
  
      fabric.copiedText = this.getSelectedText();
      if (!fabric.disableStyleCopyPaste) {
        fabric.copiedTextStyle = this.getSelectionStyles(this.selectionStart, this.selectionEnd, true);
      }
      else {
        fabric.copiedTextStyle = null;
      }
      this._copyDone = true;
    },
  
    /**
     * Pastes text
     * @param {Event} e Event object
     */
    paste: function() {
      this.fromPaste = true;
    },
  
    /**
     * @private
     * @param {Event} e Event object
     * @return {Object} Clipboard data object
     */
    _getClipboardData: function(e) {
      return (e && e.clipboardData) || fabric.window.clipboardData;
    },
  
    /**
     * Finds the width in pixels before the cursor on the same line
     * @private
     * @param {Number} lineIndex
     * @param {Number} charIndex
     * @return {Number} widthBeforeCursor width before cursor
     */
    _getWidthBeforeCursor: function(lineIndex, charIndex) {
      var widthBeforeCursor = this._getLineLeftOffset(lineIndex), bound;
  
      if (charIndex > 0) {
        bound = this.__charBounds[lineIndex][charIndex - 1];
        widthBeforeCursor += bound.left + bound.width;
      }
      return widthBeforeCursor;
    },
  
    /**
     * Gets start offset of a selection
     * @param {Event} e Event object
     * @param {Boolean} isRight
     * @return {Number}
     */
    getDownCursorOffset: function(e, isRight) {
      var selectionProp = this._getSelectionForOffset(e, isRight),
          cursorLocation = this.get2DCursorLocation(selectionProp),
          lineIndex = cursorLocation.lineIndex;
      // if on last line, down cursor goes to end of line
      if (lineIndex === this._textLines.length - 1 || e.metaKey || e.keyCode === 34) {
        // move to the end of a text
        return this._text.length - selectionProp;
      }
      var charIndex = cursorLocation.charIndex,
          widthBeforeCursor = this._getWidthBeforeCursor(lineIndex, charIndex),
          indexOnOtherLine = this._getIndexOnLine(lineIndex + 1, widthBeforeCursor),
          textAfterCursor = this._textLines[lineIndex].slice(charIndex);
      return textAfterCursor.length + indexOnOtherLine + 1 + this.missingNewlineOffset(lineIndex);
    },
  
    /**
     * private
     * Helps finding if the offset should be counted from Start or End
     * @param {Event} e Event object
     * @param {Boolean} isRight
     * @return {Number}
     */
    _getSelectionForOffset: function(e, isRight) {
      if (e.shiftKey && this.selectionStart !== this.selectionEnd && isRight) {
        return this.selectionEnd;
      }
      else {
        return this.selectionStart;
      }
    },
  
    /**
     * @param {Event} e Event object
     * @param {Boolean} isRight
     * @return {Number}
     */
    getUpCursorOffset: function(e, isRight) {
      var selectionProp = this._getSelectionForOffset(e, isRight),
          cursorLocation = this.get2DCursorLocation(selectionProp),
          lineIndex = cursorLocation.lineIndex;
      if (lineIndex === 0 || e.metaKey || e.keyCode === 33) {
        // if on first line, up cursor goes to start of line
        return -selectionProp;
      }
      var charIndex = cursorLocation.charIndex,
          widthBeforeCursor = this._getWidthBeforeCursor(lineIndex, charIndex),
          indexOnOtherLine = this._getIndexOnLine(lineIndex - 1, widthBeforeCursor),
          textBeforeCursor = this._textLines[lineIndex].slice(0, charIndex),
          missingNewlineOffset = this.missingNewlineOffset(lineIndex - 1);
      // return a negative offset
      return -this._textLines[lineIndex - 1].length
       + indexOnOtherLine - textBeforeCursor.length + (1 - missingNewlineOffset);
    },
  
    /**
     * for a given width it founds the matching character.
     * @private
     */
    _getIndexOnLine: function(lineIndex, width) {
  
      var line = this._textLines[lineIndex],
          lineLeftOffset = this._getLineLeftOffset(lineIndex),
          widthOfCharsOnLine = lineLeftOffset,
          indexOnLine = 0, charWidth, foundMatch;
  
      for (var j = 0, jlen = line.length; j < jlen; j++) {
        charWidth = this.__charBounds[lineIndex][j].width;
        widthOfCharsOnLine += charWidth;
        if (widthOfCharsOnLine > width) {
          foundMatch = true;
          var leftEdge = widthOfCharsOnLine - charWidth,
              rightEdge = widthOfCharsOnLine,
              offsetFromLeftEdge = Math.abs(leftEdge - width),
              offsetFromRightEdge = Math.abs(rightEdge - width);
  
          indexOnLine = offsetFromRightEdge < offsetFromLeftEdge ? j : (j - 1);
          break;
        }
      }
  
      // reached end
      if (!foundMatch) {
        indexOnLine = line.length - 1;
      }
  
      return indexOnLine;
    },
  
  
    /**
     * Moves cursor down
     * @param {Event} e Event object
     */
    moveCursorDown: function(e) {
      if (this.selectionStart >= this._text.length && this.selectionEnd >= this._text.length) {
        return;
      }
      this._moveCursorUpOrDown('Down', e);
    },
  
    /**
     * Moves cursor up
     * @param {Event} e Event object
     */
    moveCursorUp: function(e) {
      if (this.selectionStart === 0 && this.selectionEnd === 0) {
        return;
      }
      this._moveCursorUpOrDown('Up', e);
    },
  
    /**
     * Moves cursor up or down, fires the events
     * @param {String} direction 'Up' or 'Down'
     * @param {Event} e Event object
     */
    _moveCursorUpOrDown: function(direction, e) {
      // getUpCursorOffset
      // getDownCursorOffset
      var action = 'get' + direction + 'CursorOffset',
          offset = this[action](e, this._selectionDirection === 'right');
      if (e.shiftKey) {
        this.moveCursorWithShift(offset);
      }
      else {
        this.moveCursorWithoutShift(offset);
      }
      if (offset !== 0) {
        this.setSelectionInBoundaries();
        this.abortCursorAnimation();
        this._currentCursorOpacity = 1;
        this.initDelayedCursor();
        this._fireSelectionChanged();
        this._updateTextarea();
      }
    },
  
    /**
     * Moves cursor with shift
     * @param {Number} offset
     */
    moveCursorWithShift: function(offset) {
      var newSelection = this._selectionDirection === 'left'
        ? this.selectionStart + offset
        : this.selectionEnd + offset;
      this.setSelectionStartEndWithShift(this.selectionStart, this.selectionEnd, newSelection);
      return offset !== 0;
    },
  
    /**
     * Moves cursor up without shift
     * @param {Number} offset
     */
    moveCursorWithoutShift: function(offset) {
      if (offset < 0) {
        this.selectionStart += offset;
        this.selectionEnd = this.selectionStart;
      }
      else {
        this.selectionEnd += offset;
        this.selectionStart = this.selectionEnd;
      }
      return offset !== 0;
    },
  
    /**
     * Moves cursor left
     * @param {Event} e Event object
     */
    moveCursorLeft: function(e) {
      if (this.selectionStart === 0 && this.selectionEnd === 0) {
        return;
      }
      this._moveCursorLeftOrRight('Left', e);
    },
  
    /**
     * @private
     * @return {Boolean} true if a change happened
     */
    _move: function(e, prop, direction) {
      var newValue;
      if (e.altKey) {
        newValue = this['findWordBoundary' + direction](this[prop]);
      }
      else if (e.metaKey || e.keyCode === 35 ||  e.keyCode === 36 ) {
        newValue = this['findLineBoundary' + direction](this[prop]);
      }
      else {
        this[prop] += direction === 'Left' ? -1 : 1;
        return true;
      }
      if (typeof newValue !== undefined && this[prop] !== newValue) {
        this[prop] = newValue;
        return true;
      }
    },
  
    /**
     * @private
     */
    _moveLeft: function(e, prop) {
      return this._move(e, prop, 'Left');
    },
  
    /**
     * @private
     */
    _moveRight: function(e, prop) {
      return this._move(e, prop, 'Right');
    },
  
    /**
     * Moves cursor left without keeping selection
     * @param {Event} e
     */
    moveCursorLeftWithoutShift: function(e) {
      var change = true;
      this._selectionDirection = 'left';
  
      // only move cursor when there is no selection,
      // otherwise we discard it, and leave cursor on same place
      if (this.selectionEnd === this.selectionStart && this.selectionStart !== 0) {
        change = this._moveLeft(e, 'selectionStart');
  
      }
      this.selectionEnd = this.selectionStart;
      return change;
    },
  
    /**
     * Moves cursor left while keeping selection
     * @param {Event} e
     */
    moveCursorLeftWithShift: function(e) {
      if (this._selectionDirection === 'right' && this.selectionStart !== this.selectionEnd) {
        return this._moveLeft(e, 'selectionEnd');
      }
      else if (this.selectionStart !== 0){
        this._selectionDirection = 'left';
        return this._moveLeft(e, 'selectionStart');
      }
    },
  
    /**
     * Moves cursor right
     * @param {Event} e Event object
     */
    moveCursorRight: function(e) {
      if (this.selectionStart >= this._text.length && this.selectionEnd >= this._text.length) {
        return;
      }
      this._moveCursorLeftOrRight('Right', e);
    },
  
    /**
     * Moves cursor right or Left, fires event
     * @param {String} direction 'Left', 'Right'
     * @param {Event} e Event object
     */
    _moveCursorLeftOrRight: function(direction, e) {
      var actionName = 'moveCursor' + direction + 'With';
      this._currentCursorOpacity = 1;
  
      if (e.shiftKey) {
        actionName += 'Shift';
      }
      else {
        actionName += 'outShift';
      }
      if (this[actionName](e)) {
        this.abortCursorAnimation();
        this.initDelayedCursor();
        this._fireSelectionChanged();
        this._updateTextarea();
      }
    },
  
    /**
     * Moves cursor right while keeping selection
     * @param {Event} e
     */
    moveCursorRightWithShift: function(e) {
      if (this._selectionDirection === 'left' && this.selectionStart !== this.selectionEnd) {
        return this._moveRight(e, 'selectionStart');
      }
      else if (this.selectionEnd !== this._text.length) {
        this._selectionDirection = 'right';
        return this._moveRight(e, 'selectionEnd');
      }
    },
  
    /**
     * Moves cursor right without keeping selection
     * @param {Event} e Event object
     */
    moveCursorRightWithoutShift: function(e) {
      var changed = true;
      this._selectionDirection = 'right';
  
      if (this.selectionStart === this.selectionEnd) {
        changed = this._moveRight(e, 'selectionStart');
        this.selectionEnd = this.selectionStart;
      }
      else {
        this.selectionStart = this.selectionEnd;
      }
      return changed;
    },
  
    /**
     * Removes characters from start/end
     * start/end ar per grapheme position in _text array.
     *
     * @param {Number} start
     * @param {Number} end default to start + 1
     */
    removeChars: function(start, end) {
      if (typeof end === 'undefined') {
        end = start + 1;
      }
      this.removeStyleFromTo(start, end);
      this._text.splice(start, end - start);
      this.text = this._text.join('');
      this.set('dirty', true);
      if (this._shouldClearDimensionCache()) {
        this.initDimensions();
        this.setCoords();
      }
      this._removeExtraneousStyles();
    },
  
    /**
     * insert characters at start position, before start position.
     * start  equal 1 it means the text get inserted between actual grapheme 0 and 1
     * if style array is provided, it must be as the same length of text in graphemes
     * if end is provided and is bigger than start, old text is replaced.
     * start/end ar per grapheme position in _text array.
     *
     * @param {String} text text to insert
     * @param {Array} style array of style objects
     * @param {Number} start
     * @param {Number} end default to start + 1
     */
    insertChars: function(text, style, start, end) {
      if (typeof end === 'undefined') {
        end = start;
      }
      if (end > start) {
        this.removeStyleFromTo(start, end);
      }
      var graphemes = fabric.util.string.graphemeSplit(text);
      this.insertNewStyleBlock(graphemes, start, style);
      this._text = [].concat(this._text.slice(0, start), graphemes, this._text.slice(end));
      this.text = this._text.join('');
      this.set('dirty', true);
      if (this._shouldClearDimensionCache()) {
        this.initDimensions();
        this.setCoords();
      }
      this._removeExtraneousStyles();
    },
  
  });
  
  
  /* _TO_SVG_START_ */
  (function() {
    var toFixed = fabric.util.toFixed,
        multipleSpacesRegex = /  +/g;
  
    fabric.util.object.extend(fabric.Text.prototype, /** @lends fabric.Text.prototype */ {
  
      /**
       * Returns SVG representation of an instance
       * @param {Function} [reviver] Method for further parsing of svg representation.
       * @return {String} svg representation of an instance
       */
      _toSVG: function() {
        var offsets = this._getSVGLeftTopOffsets(),
            textAndBg = this._getSVGTextAndBg(offsets.textTop, offsets.textLeft);
        return this._wrapSVGTextAndBg(textAndBg);
      },
  
      /**
       * Returns svg representation of an instance
       * @param {Function} [reviver] Method for further parsing of svg representation.
       * @return {String} svg representation of an instance
       */
      toSVG: function(reviver) {
        return this._createBaseSVGMarkup(
          this._toSVG(),
          { reviver: reviver, noStyle: true, withShadow: true }
        );
      },
  
      /**
       * @private
       */
      _getSVGLeftTopOffsets: function() {
        return {
          textLeft: -this.width / 2,
          textTop: -this.height / 2,
          lineTop: this.getHeightOfLine(0)
        };
      },
  
      /**
       * @private
       */
      _wrapSVGTextAndBg: function(textAndBg) {
        var noShadow = true,
            textDecoration = this.getSvgTextDecoration(this);
        return [
          textAndBg.textBgRects.join(''),
          '\t\t<text xml:space="preserve" ',
          (this.fontFamily ? 'font-family="' + this.fontFamily.replace(/"/g, '\'') + '" ' : ''),
          (this.fontSize ? 'font-size="' + this.fontSize + '" ' : ''),
          (this.fontStyle ? 'font-style="' + this.fontStyle + '" ' : ''),
          (this.fontWeight ? 'font-weight="' + this.fontWeight + '" ' : ''),
          (textDecoration ? 'text-decoration="' + textDecoration + '" ' : ''),
          'style="', this.getSvgStyles(noShadow), '"', this.addPaintOrder(), ' >',
          textAndBg.textSpans.join(''),
          '</text>\n'
        ];
      },
  
      /**
       * @private
       * @param {Number} textTopOffset Text top offset
       * @param {Number} textLeftOffset Text left offset
       * @return {Object}
       */
      _getSVGTextAndBg: function(textTopOffset, textLeftOffset) {
        var textSpans = [],
            textBgRects = [],
            height = textTopOffset, lineOffset;
        // bounding-box background
        this._setSVGBg(textBgRects);
  
        // text and text-background
        for (var i = 0, len = this._textLines.length; i < len; i++) {
          lineOffset = this._getLineLeftOffset(i);
          if (this.textBackgroundColor || this.styleHas('textBackgroundColor', i)) {
            this._setSVGTextLineBg(textBgRects, i, textLeftOffset + lineOffset, height);
          }
          this._setSVGTextLineText(textSpans, i, textLeftOffset + lineOffset, height);
          height += this.getHeightOfLine(i);
        }
  
        return {
          textSpans: textSpans,
          textBgRects: textBgRects
        };
      },
  
      /**
       * @private
       */
      _createTextCharSpan: function(_char, styleDecl, left, top) {
        var shouldUseWhitespace = _char !== _char.trim() || _char.match(multipleSpacesRegex),
            styleProps = this.getSvgSpanStyles(styleDecl, shouldUseWhitespace),
            fillStyles = styleProps ? 'style="' + styleProps + '"' : '',
            dy = styleDecl.deltaY, dySpan = '',
            NUM_FRACTION_DIGITS = fabric.Object.NUM_FRACTION_DIGITS;
        if (dy) {
          dySpan = ' dy="' + toFixed(dy, NUM_FRACTION_DIGITS) + '" ';
        }
        return [
          '<tspan x="', toFixed(left, NUM_FRACTION_DIGITS), '" y="',
          toFixed(top, NUM_FRACTION_DIGITS), '" ', dySpan,
          fillStyles, '>',
          fabric.util.string.escapeXml(_char),
          '</tspan>'
        ].join('');
      },
  
      _setSVGTextLineText: function(textSpans, lineIndex, textLeftOffset, textTopOffset) {
        // set proper line offset
        var lineHeight = this.getHeightOfLine(lineIndex),
            isJustify = this.textAlign.indexOf('justify') !== -1,
            actualStyle,
            nextStyle,
            charsToRender = '',
            charBox, style,
            boxWidth = 0,
            line = this._textLines[lineIndex],
            timeToRender;
  
        textTopOffset += lineHeight * (1 - this._fontSizeFraction) / this.lineHeight;
        for (var i = 0, len = line.length - 1; i <= len; i++) {
          timeToRender = i === len || this.charSpacing;
          charsToRender += line[i];
          charBox = this.__charBounds[lineIndex][i];
          if (boxWidth === 0) {
            textLeftOffset += charBox.kernedWidth - charBox.width;
            boxWidth += charBox.width;
          }
          else {
            boxWidth += charBox.kernedWidth;
          }
          if (isJustify && !timeToRender) {
            if (this._reSpaceAndTab.test(line[i])) {
              timeToRender = true;
            }
          }
          if (!timeToRender) {
            // if we have charSpacing, we render char by char
            actualStyle = actualStyle || this.getCompleteStyleDeclaration(lineIndex, i);
            nextStyle = this.getCompleteStyleDeclaration(lineIndex, i + 1);
            timeToRender = this._hasStyleChangedForSvg(actualStyle, nextStyle);
          }
          if (timeToRender) {
            style = this._getStyleDeclaration(lineIndex, i) || { };
            textSpans.push(this._createTextCharSpan(charsToRender, style, textLeftOffset, textTopOffset));
            charsToRender = '';
            actualStyle = nextStyle;
            textLeftOffset += boxWidth;
            boxWidth = 0;
          }
        }
      },
  
      _pushTextBgRect: function(textBgRects, color, left, top, width, height) {
        var NUM_FRACTION_DIGITS = fabric.Object.NUM_FRACTION_DIGITS;
        textBgRects.push(
          '\t\t<rect ',
          this._getFillAttributes(color),
          ' x="',
          toFixed(left, NUM_FRACTION_DIGITS),
          '" y="',
          toFixed(top, NUM_FRACTION_DIGITS),
          '" width="',
          toFixed(width, NUM_FRACTION_DIGITS),
          '" height="',
          toFixed(height, NUM_FRACTION_DIGITS),
          '"></rect>\n');
      },
  
      _setSVGTextLineBg: function(textBgRects, i, leftOffset, textTopOffset) {
        var line = this._textLines[i],
            heightOfLine = this.getHeightOfLine(i) / this.lineHeight,
            boxWidth = 0,
            boxStart = 0,
            charBox, currentColor,
            lastColor = this.getValueOfPropertyAt(i, 0, 'textBackgroundColor');
        for (var j = 0, jlen = line.length; j < jlen; j++) {
          charBox = this.__charBounds[i][j];
          currentColor = this.getValueOfPropertyAt(i, j, 'textBackgroundColor');
          if (currentColor !== lastColor) {
            lastColor && this._pushTextBgRect(textBgRects, lastColor, leftOffset + boxStart,
              textTopOffset, boxWidth, heightOfLine);
            boxStart = charBox.left;
            boxWidth = charBox.width;
            lastColor = currentColor;
          }
          else {
            boxWidth += charBox.kernedWidth;
          }
        }
        currentColor && this._pushTextBgRect(textBgRects, currentColor, leftOffset + boxStart,
          textTopOffset, boxWidth, heightOfLine);
      },
  
      /**
       * Adobe Illustrator (at least CS5) is unable to render rgba()-based fill values
       * we work around it by "moving" alpha channel into opacity attribute and setting fill's alpha to 1
       *
       * @private
       * @param {*} value
       * @return {String}
       */
      _getFillAttributes: function(value) {
        var fillColor = (value && typeof value === 'string') ? new fabric.Color(value) : '';
        if (!fillColor || !fillColor.getSource() || fillColor.getAlpha() === 1) {
          return 'fill="' + value + '"';
        }
        return 'opacity="' + fillColor.getAlpha() + '" fill="' + fillColor.setAlpha(1).toRgb() + '"';
      },
  
      /**
       * @private
       */
      _getSVGLineTopOffset: function(lineIndex) {
        var lineTopOffset = 0, lastHeight = 0;
        for (var j = 0; j < lineIndex; j++) {
          lineTopOffset += this.getHeightOfLine(j);
        }
        lastHeight = this.getHeightOfLine(j);
        return {
          lineTop: lineTopOffset,
          offset: (this._fontSizeMult - this._fontSizeFraction) * lastHeight / (this.lineHeight * this._fontSizeMult)
        };
      },
  
      /**
       * Returns styles-string for svg-export
       * @param {Boolean} skipShadow a boolean to skip shadow filter output
       * @return {String}
       */
      getSvgStyles: function(skipShadow) {
        var svgStyle = fabric.Object.prototype.getSvgStyles.call(this, skipShadow);
        return svgStyle + ' white-space: pre;';
      },
    });
  })();
  /* _TO_SVG_END_ */
  
  
  (function(global) {
  
    'use strict';
  
    var fabric = global.fabric || (global.fabric = {});
  
    /**
     * Textbox class, based on IText, allows the user to resize the text rectangle
     * and wraps lines automatically. Textboxes have their Y scaling locked, the
     * user can only change width. Height is adjusted automatically based on the
     * wrapping of lines.
     * @class fabric.Textbox
     * @extends fabric.IText
     * @mixes fabric.Observable
     * @return {fabric.Textbox} thisArg
     * @see {@link fabric.Textbox#initialize} for constructor definition
     */
    fabric.Textbox = fabric.util.createClass(fabric.IText, fabric.Observable, {
  
      /**
       * Type of an object
       * @type String
       * @default
       */
      type: 'textbox',
  
      /**
       * Minimum width of textbox, in pixels.
       * @type Number
       * @default
       */
      minWidth: 20,
  
      /**
       * Minimum calculated width of a textbox, in pixels.
       * fixed to 2 so that an empty textbox cannot go to 0
       * and is still selectable without text.
       * @type Number
       * @default
       */
      dynamicMinWidth: 2,
  
      /**
       * Cached array of text wrapping.
       * @type Array
       */
      __cachedLines: null,
  
      /**
       * Override standard Object class values
       */
      lockScalingFlip: true,
  
      /**
       * Override standard Object class values
       * Textbox needs this on false
       */
      noScaleCache: false,
  
      /**
       * Properties which when set cause object to change dimensions
       * @type Object
       * @private
       */
      _dimensionAffectingProps: fabric.Text.prototype._dimensionAffectingProps.concat('width'),
  
      /**
       * Use this regular expression to split strings in breakable lines
       * @private
       */
      _wordJoiners: /[ \t\r]/,
  
      /**
       * Use this boolean property in order to split strings that have no white space concept.
       * this is a cheap way to help with chinese/japaense
       * @type Boolean
       * @since 2.6.0
       */
      splitByGrapheme: false,
  
      /**
       * Unlike superclass's version of this function, Textbox does not update
       * its width.
       * @private
       * @override
       */
      initDimensions: function() {
        if (this.__skipDimension) {
          return;
        }
        this.isEditing && this.initDelayedCursor();
        this.clearContextTop();
        this._clearCache();
        // clear dynamicMinWidth as it will be different after we re-wrap line
        this.dynamicMinWidth = 0;
        // wrap lines
        this._styleMap = this._generateStyleMap(this._splitText());
        // if after wrapping, the width is smaller than dynamicMinWidth, change the width and re-wrap
        if (this.dynamicMinWidth > this.width) {
          this._set('width', this.dynamicMinWidth);
        }
        if (this.textAlign.indexOf('justify') !== -1) {
          // once text is measured we need to make space fatter to make justified text.
          this.enlargeSpaces();
        }
        // clear cache and re-calculate height
        this.height = this.calcTextHeight();
        this.saveState({ propertySet: '_dimensionAffectingProps' });
      },
  
      /**
       * Generate an object that translates the style object so that it is
       * broken up by visual lines (new lines and automatic wrapping).
       * The original text styles object is broken up by actual lines (new lines only),
       * which is only sufficient for Text / IText
       * @private
       */
      _generateStyleMap: function(textInfo) {
        var realLineCount     = 0,
            realLineCharCount = 0,
            charCount         = 0,
            map               = {};
  
        for (var i = 0; i < textInfo.graphemeLines.length; i++) {
          if (textInfo.graphemeText[charCount] === '\n' && i > 0) {
            realLineCharCount = 0;
            charCount++;
            realLineCount++;
          }
          else if (!this.splitByGrapheme && this._reSpaceAndTab.test(textInfo.graphemeText[charCount]) && i > 0) {
            // this case deals with space's that are removed from end of lines when wrapping
            realLineCharCount++;
            charCount++;
          }
  
          map[i] = { line: realLineCount, offset: realLineCharCount };
  
          charCount += textInfo.graphemeLines[i].length;
          realLineCharCount += textInfo.graphemeLines[i].length;
        }
  
        return map;
      },
  
      /**
       * Returns true if object has a style property or has it on a specified line
       * @param {Number} lineIndex
       * @return {Boolean}
       */
      styleHas: function(property, lineIndex) {
        if (this._styleMap && !this.isWrapping) {
          var map = this._styleMap[lineIndex];
          if (map) {
            lineIndex = map.line;
          }
        }
        return fabric.Text.prototype.styleHas.call(this, property, lineIndex);
      },
  
      /**
       * Returns true if object has no styling or no styling in a line
       * @param {Number} lineIndex , lineIndex is on wrapped lines.
       * @return {Boolean}
       */
      isEmptyStyles: function(lineIndex) {
        if (!this.styles) {
          return true;
        }
        var offset = 0, nextLineIndex = lineIndex + 1, nextOffset, obj, shouldLimit = false,
            map = this._styleMap[lineIndex], mapNextLine = this._styleMap[lineIndex + 1];
        if (map) {
          lineIndex = map.line;
          offset = map.offset;
        }
        if (mapNextLine) {
          nextLineIndex = mapNextLine.line;
          shouldLimit = nextLineIndex === lineIndex;
          nextOffset = mapNextLine.offset;
        }
        obj = typeof lineIndex === 'undefined' ? this.styles : { line: this.styles[lineIndex] };
        for (var p1 in obj) {
          for (var p2 in obj[p1]) {
            if (p2 >= offset && (!shouldLimit || p2 < nextOffset)) {
              // eslint-disable-next-line no-unused-vars
              for (var p3 in obj[p1][p2]) {
                return false;
              }
            }
          }
        }
        return true;
      },
  
      /**
       * @param {Number} lineIndex
       * @param {Number} charIndex
       * @private
       */
      _getStyleDeclaration: function(lineIndex, charIndex) {
        if (this._styleMap && !this.isWrapping) {
          var map = this._styleMap[lineIndex];
          if (!map) {
            return null;
          }
          lineIndex = map.line;
          charIndex = map.offset + charIndex;
        }
        return this.callSuper('_getStyleDeclaration', lineIndex, charIndex);
      },
  
      /**
       * @param {Number} lineIndex
       * @param {Number} charIndex
       * @param {Object} style
       * @private
       */
      _setStyleDeclaration: function(lineIndex, charIndex, style) {
        var map = this._styleMap[lineIndex];
        lineIndex = map.line;
        charIndex = map.offset + charIndex;
  
        this.styles[lineIndex][charIndex] = style;
      },
  
      /**
       * @param {Number} lineIndex
       * @param {Number} charIndex
       * @private
       */
      _deleteStyleDeclaration: function(lineIndex, charIndex) {
        var map = this._styleMap[lineIndex];
        lineIndex = map.line;
        charIndex = map.offset + charIndex;
        delete this.styles[lineIndex][charIndex];
      },
  
      /**
       * probably broken need a fix
       * Returns the real style line that correspond to the wrapped lineIndex line
       * Used just to verify if the line does exist or not.
       * @param {Number} lineIndex
       * @returns {Boolean} if the line exists or not
       * @private
       */
      _getLineStyle: function(lineIndex) {
        var map = this._styleMap[lineIndex];
        return !!this.styles[map.line];
      },
  
      /**
       * Set the line style to an empty object so that is initialized
       * @param {Number} lineIndex
       * @param {Object} style
       * @private
       */
      _setLineStyle: function(lineIndex) {
        var map = this._styleMap[lineIndex];
        this.styles[map.line] = {};
      },
  
      /**
       * Wraps text using the 'width' property of Textbox. First this function
       * splits text on newlines, so we preserve newlines entered by the user.
       * Then it wraps each line using the width of the Textbox by calling
       * _wrapLine().
       * @param {Array} lines The string array of text that is split into lines
       * @param {Number} desiredWidth width you want to wrap to
       * @returns {Array} Array of lines
       */
      _wrapText: function(lines, desiredWidth) {
        var wrapped = [], i;
        this.isWrapping = true;
        for (i = 0; i < lines.length; i++) {
          wrapped = wrapped.concat(this._wrapLine(lines[i], i, desiredWidth));
        }
        this.isWrapping = false;
        return wrapped;
      },
  
      /**
       * Helper function to measure a string of text, given its lineIndex and charIndex offset
       * it gets called when charBounds are not available yet.
       * @param {CanvasRenderingContext2D} ctx
       * @param {String} text
       * @param {number} lineIndex
       * @param {number} charOffset
       * @returns {number}
       * @private
       */
      _measureWord: function(word, lineIndex, charOffset) {
        var width = 0, prevGrapheme, skipLeft = true;
        charOffset = charOffset || 0;
        for (var i = 0, len = word.length; i < len; i++) {
          var box = this._getGraphemeBox(word[i], lineIndex, i + charOffset, prevGrapheme, skipLeft);
          width += box.kernedWidth;
          prevGrapheme = word[i];
        }
        return width;
      },
  
      /**
       * Wraps a line of text using the width of the Textbox and a context.
       * @param {Array} line The grapheme array that represent the line
       * @param {Number} lineIndex
       * @param {Number} desiredWidth width you want to wrap the line to
       * @param {Number} reservedSpace space to remove from wrapping for custom functionalities
       * @returns {Array} Array of line(s) into which the given text is wrapped
       * to.
       */
      _wrapLine: function(_line, lineIndex, desiredWidth, reservedSpace) {
        var lineWidth = 0,
            splitByGrapheme = this.splitByGrapheme,
            graphemeLines = [],
            line = [],
            // spaces in different languges?
            words = splitByGrapheme ? fabric.util.string.graphemeSplit(_line) : _line.split(this._wordJoiners),
            word = '',
            offset = 0,
            infix = splitByGrapheme ? '' : ' ',
            wordWidth = 0,
            infixWidth = 0,
            largestWordWidth = 0,
            lineJustStarted = true,
            additionalSpace = splitByGrapheme ? 0 : this._getWidthOfCharSpacing(),
            reservedSpace = reservedSpace || 0;
        // fix a difference between split and graphemeSplit
        if (words.length === 0) {
          words.push([]);
        }
        desiredWidth -= reservedSpace;
        for (var i = 0; i < words.length; i++) {
          // if using splitByGrapheme words are already in graphemes.
          word = splitByGrapheme ? words[i] : fabric.util.string.graphemeSplit(words[i]);
          wordWidth = this._measureWord(word, lineIndex, offset);
          offset += word.length;
  
          lineWidth += infixWidth + wordWidth - additionalSpace;
  
          if (lineWidth >= desiredWidth && !lineJustStarted) {
            graphemeLines.push(line);
            line = [];
            lineWidth = wordWidth;
            lineJustStarted = true;
          }
          else {
            lineWidth += additionalSpace;
          }
  
          if (!lineJustStarted && !splitByGrapheme) {
            line.push(infix);
          }
          line = line.concat(word);
  
          infixWidth = this._measureWord([infix], lineIndex, offset);
          offset++;
          lineJustStarted = false;
          // keep track of largest word
          if (wordWidth > largestWordWidth) {
            largestWordWidth = wordWidth;
          }
        }
  
        i && graphemeLines.push(line);
  
        if (largestWordWidth + reservedSpace > this.dynamicMinWidth) {
          this.dynamicMinWidth = largestWordWidth - additionalSpace + reservedSpace;
        }
  
        return graphemeLines;
      },
  
      /**
       * Detect if the text line is ended with an hard break
       * text and itext do not have wrapping, return false
       * @param {Number} lineIndex text to split
       * @return {Boolean}
       */
      isEndOfWrapping: function(lineIndex) {
        if (!this._styleMap[lineIndex + 1]) {
          // is last line, return true;
          return true;
        }
        if (this._styleMap[lineIndex + 1].line !== this._styleMap[lineIndex].line) {
          // this is last line before a line break, return true;
          return true;
        }
        return false;
      },
  
      /**
       * Detect if a line has a linebreak and so we need to account for it when moving
       * and counting style.
       * @return Number
       */
      missingNewlineOffset: function(lineIndex) {
        if (this.splitByGrapheme) {
          return this.isEndOfWrapping(lineIndex) ? 1 : 0;
        }
        return 1;
      },
  
      /**
      * Gets lines of text to render in the Textbox. This function calculates
      * text wrapping on the fly every time it is called.
      * @param {String} text text to split
      * @returns {Array} Array of lines in the Textbox.
      * @override
      */
      _splitTextIntoLines: function(text) {
        var newText = fabric.Text.prototype._splitTextIntoLines.call(this, text),
            graphemeLines = this._wrapText(newText.lines, this.width),
            lines = new Array(graphemeLines.length);
        for (var i = 0; i < graphemeLines.length; i++) {
          lines[i] = graphemeLines[i].join('');
        }
        newText.lines = lines;
        newText.graphemeLines = graphemeLines;
        return newText;
      },
  
      getMinWidth: function() {
        return Math.max(this.minWidth, this.dynamicMinWidth);
      },
  
      _removeExtraneousStyles: function() {
        var linesToKeep = {};
        for (var prop in this._styleMap) {
          if (this._textLines[prop]) {
            linesToKeep[this._styleMap[prop].line] = 1;
          }
        }
        for (var prop in this.styles) {
          if (!linesToKeep[prop]) {
            delete this.styles[prop];
          }
        }
      },
  
      /**
       * Returns object representation of an instance
       * @method toObject
       * @param {Array} [propertiesToInclude] Any properties that you might want to additionally include in the output
       * @return {Object} object representation of an instance
       */
      toObject: function(propertiesToInclude) {
        return this.callSuper('toObject', ['minWidth', 'splitByGrapheme'].concat(propertiesToInclude));
      }
    });
  
    /**
     * Returns fabric.Textbox instance from an object representation
     * @static
     * @memberOf fabric.Textbox
     * @param {Object} object Object to create an instance from
     * @param {Function} [callback] Callback to invoke when an fabric.Textbox instance is created
     */
    fabric.Textbox.fromObject = function(object, callback) {
      return fabric.Object._fromObject('Textbox', object, callback, 'text');
    };
  })(typeof exports !== 'undefined' ? exports : this);
  
  