text: /*!!
   *  Canvas 2 Svg v1.0.17
   *  A low level canvas to SVG converter. Uses a mock canvas context to build an SVG document.
   *
   *  Licensed under the MIT license:
   *  http://www.opensource.org/licenses/mit-license.php
   *
   *  Author:
   *  Kerry Liu
   *
   *  Copyright (c) 2014 Gliffy Inc.
   */
  
  ;(function() {
      "use strict";
  
      var STYLES, ctx, CanvasGradient, CanvasPattern, namedEntities;
  
      //helper function to format a string
      function format(str, args) {
          var keys = Object.keys(args), i;
          for (i=0; i<keys.length; i++) {
              str = str.replace(new RegExp("\\{" + keys[i] + "\\}", "gi"), args[keys[i]]);
          }
          return str;
      }
  
      //helper function that generates a random string
      function randomString(holder) {
          var chars, randomstring, i;
          if (!holder) {
              throw new Error("cannot create a random attribute name for an undefined object");
          }
          chars = "ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz";
          randomstring = "";
          do {
              randomstring = "";
              for (i = 0; i < 12; i++) {
                  randomstring += chars[Math.floor(Math.random() * chars.length)];
              }
          } while (holder[randomstring]);
          return randomstring;
      }
  
      //helper function to map named to numbered entities
      function createNamedToNumberedLookup(items, radix) {
          var i, entity, lookup = {}, base10, base16;
          items = items.split(',');
          radix = radix || 10;
          // Map from named to numbered entities.
          for (i = 0; i < items.length; i += 2) {
              entity = '&' + items[i + 1] + ';';
              base10 = parseInt(items[i], radix);
              lookup[entity] = '&#'+base10+';';
          }
          //FF and IE need to create a regex from hex values ie &nbsp; == \xa0
          lookup["\\xa0"] = '&#160;';
          return lookup;
      }
  
      //helper function to map canvas-textAlign to svg-textAnchor
      function getTextAnchor(textAlign) {
          //TODO: support rtl languages
          var mapping = {"left":"start", "right":"end", "center":"middle", "start":"start", "end":"end"};
          return mapping[textAlign] || mapping.start;
      }
  
      //helper function to map canvas-textBaseline to svg-dominantBaseline
      function getDominantBaseline(textBaseline) {
          //INFO: not supported in all browsers
          var mapping = {"alphabetic": "alphabetic", "hanging": "hanging", "top":"text-before-edge", "bottom":"text-after-edge", "middle":"central"};
          return mapping[textBaseline] || mapping.alphabetic;
      }
  
      // Unpack entities lookup where the numbers are in radix 32 to reduce the size
      // entity mapping courtesy of tinymce
      namedEntities = createNamedToNumberedLookup(
          '50,nbsp,51,iexcl,52,cent,53,pound,54,curren,55,yen,56,brvbar,57,sect,58,uml,59,copy,' +
          '5a,ordf,5b,laquo,5c,not,5d,shy,5e,reg,5f,macr,5g,deg,5h,plusmn,5i,sup2,5j,sup3,5k,acute,' +
          '5l,micro,5m,para,5n,middot,5o,cedil,5p,sup1,5q,ordm,5r,raquo,5s,frac14,5t,frac12,5u,frac34,' +
          '5v,iquest,60,Agrave,61,Aacute,62,Acirc,63,Atilde,64,Auml,65,Aring,66,AElig,67,Ccedil,' +
          '68,Egrave,69,Eacute,6a,Ecirc,6b,Euml,6c,Igrave,6d,Iacute,6e,Icirc,6f,Iuml,6g,ETH,6h,Ntilde,' +
          '6i,Ograve,6j,Oacute,6k,Ocirc,6l,Otilde,6m,Ouml,6n,times,6o,Oslash,6p,Ugrave,6q,Uacute,' +
          '6r,Ucirc,6s,Uuml,6t,Yacute,6u,THORN,6v,szlig,70,agrave,71,aacute,72,acirc,73,atilde,74,auml,' +
          '75,aring,76,aelig,77,ccedil,78,egrave,79,eacute,7a,ecirc,7b,euml,7c,igrave,7d,iacute,7e,icirc,' +
          '7f,iuml,7g,eth,7h,ntilde,7i,ograve,7j,oacute,7k,ocirc,7l,otilde,7m,ouml,7n,divide,7o,oslash,' +
          '7p,ugrave,7q,uacute,7r,ucirc,7s,uuml,7t,yacute,7u,thorn,7v,yuml,ci,fnof,sh,Alpha,si,Beta,' +
          'sj,Gamma,sk,Delta,sl,Epsilon,sm,Zeta,sn,Eta,so,Theta,sp,Iota,sq,Kappa,sr,Lambda,ss,Mu,' +
          'st,Nu,su,Xi,sv,Omicron,t0,Pi,t1,Rho,t3,Sigma,t4,Tau,t5,Upsilon,t6,Phi,t7,Chi,t8,Psi,' +
          't9,Omega,th,alpha,ti,beta,tj,gamma,tk,delta,tl,epsilon,tm,zeta,tn,eta,to,theta,tp,iota,' +
          'tq,kappa,tr,lambda,ts,mu,tt,nu,tu,xi,tv,omicron,u0,pi,u1,rho,u2,sigmaf,u3,sigma,u4,tau,' +
          'u5,upsilon,u6,phi,u7,chi,u8,psi,u9,omega,uh,thetasym,ui,upsih,um,piv,812,bull,816,hellip,' +
          '81i,prime,81j,Prime,81u,oline,824,frasl,88o,weierp,88h,image,88s,real,892,trade,89l,alefsym,' +
          '8cg,larr,8ch,uarr,8ci,rarr,8cj,darr,8ck,harr,8dl,crarr,8eg,lArr,8eh,uArr,8ei,rArr,8ej,dArr,' +
          '8ek,hArr,8g0,forall,8g2,part,8g3,exist,8g5,empty,8g7,nabla,8g8,isin,8g9,notin,8gb,ni,8gf,prod,' +
          '8gh,sum,8gi,minus,8gn,lowast,8gq,radic,8gt,prop,8gu,infin,8h0,ang,8h7,and,8h8,or,8h9,cap,8ha,cup,' +
          '8hb,int,8hk,there4,8hs,sim,8i5,cong,8i8,asymp,8j0,ne,8j1,equiv,8j4,le,8j5,ge,8k2,sub,8k3,sup,8k4,' +
          'nsub,8k6,sube,8k7,supe,8kl,oplus,8kn,otimes,8l5,perp,8m5,sdot,8o8,lceil,8o9,rceil,8oa,lfloor,8ob,' +
          'rfloor,8p9,lang,8pa,rang,9ea,loz,9j0,spades,9j3,clubs,9j5,hearts,9j6,diams,ai,OElig,aj,oelig,b0,' +
          'Scaron,b1,scaron,bo,Yuml,m6,circ,ms,tilde,802,ensp,803,emsp,809,thinsp,80c,zwnj,80d,zwj,80e,lrm,' +
          '80f,rlm,80j,ndash,80k,mdash,80o,lsquo,80p,rsquo,80q,sbquo,80s,ldquo,80t,rdquo,80u,bdquo,810,dagger,' +
          '811,Dagger,81g,permil,81p,lsaquo,81q,rsaquo,85c,euro', 32);
  
  
      //Some basic mappings for attributes and default values.
      STYLES = {
          "strokeStyle":{
              svgAttr : "stroke", //corresponding svg attribute
              canvas : "#000000", //canvas default
              svg : "none",       //svg default
              apply : "stroke"    //apply on stroke() or fill()
          },
          "fillStyle":{
              svgAttr : "fill",
              canvas : "#000000",
              svg : null, //svg default is black, but we need to special case this to handle canvas stroke without fill
              apply : "fill"
          },
          "lineCap":{
              svgAttr : "stroke-linecap",
              canvas : "butt",
              svg : "butt",
              apply : "stroke"
          },
          "lineJoin":{
              svgAttr : "stroke-linejoin",
              canvas : "miter",
              svg : "miter",
              apply : "stroke"
          },
          "miterLimit":{
              svgAttr : "stroke-miterlimit",
              canvas : 10,
              svg : 4,
              apply : "stroke"
          },
          "lineWidth":{
              svgAttr : "stroke-width",
              canvas : 1,
              svg : 1,
              apply : "stroke"
          },
          "globalAlpha": {
              svgAttr : "opacity",
              canvas : 1,
              svg : 1,
              apply :  "fill stroke"
          },
          "font":{
              //font converts to multiple svg attributes, there is custom logic for this
              canvas : "10px sans-serif"
          },
          "shadowColor":{
              canvas : "#000000"
          },
          "shadowOffsetX":{
              canvas : 0
          },
          "shadowOffsetY":{
              canvas : 0
          },
          "shadowBlur":{
              canvas : 0
          },
          "textAlign":{
              canvas : "start"
          },
          "textBaseline":{
              canvas : "alphabetic"
          },
          "lineDash" : {
              svgAttr : "stroke-dasharray",
              canvas : [],
              svg : null,
              apply : "stroke"
          }
      };
  
      /**
       *
       * @param gradientNode - reference to the gradient
       * @constructor
       */
      CanvasGradient = function(gradientNode, ctx) {
          this.__root = gradientNode;
          this.__ctx = ctx;
      };
  
      /**
       * Adds a color stop to the gradient root
       */
      CanvasGradient.prototype.addColorStop = function(offset, color) {
          var stop = this.__ctx.__createElement("stop"), regex, matches;
          stop.setAttribute("offset", offset);
          if(color.indexOf("rgba") !== -1) {
              //separate alpha value, since webkit can't handle it
              regex = /rgba\(\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d?\.?\d*)\s*\)/gi;
              matches = regex.exec(color);
              stop.setAttribute("stop-color", format("rgb({r},{g},{b})", {r:matches[1], g:matches[2], b:matches[3]}));
              stop.setAttribute("stop-opacity", matches[4]);
          } else {
              stop.setAttribute("stop-color", color);
          }
          this.__root.appendChild(stop);
      };
  
      CanvasPattern = function(pattern, ctx) {
          this.__root = pattern;
          this.__ctx = ctx;
      };
  
      /**
       * The mock canvas context
       * @param o - options include:
       * width - width of your canvas (defaults to 500)
       * height - height of your canvas (defaults to 500)
       * enableMirroring - enables canvas mirroring (get image data) (defaults to false)
       * document - the document object (defaults to the current document)
       */
      ctx = function(o) {
  
          var defaultOptions = { width:500, height:500, enableMirroring : false}, options;
  
          //keep support for this way of calling C2S: new C2S(width,height)
          if(arguments.length > 1) {
              options = defaultOptions;
              options.width = arguments[0];
              options.height = arguments[1];
          } else if( !o ) {
              options = defaultOptions;
          } else {
              options = o;
          }
  
          if(!(this instanceof ctx)) {
              //did someone call this without new?
              return new ctx(options);
          }
  
          //setup options
          this.width = options.width || defaultOptions.width;
          this.height = options.height || defaultOptions.height;
          this.enableMirroring = options.enableMirroring !== undefined ? options.enableMirroring : defaultOptions.enableMirroring;
  
          this.canvas = this;   ///point back to this instance!
          this.__document = options.document || document;
          this.__canvas = this.__document.createElement("canvas");
          this.__ctx = this.__canvas.getContext("2d");
  
          this.__setDefaultStyles();
          this.__stack = [this.__getStyleState()];
          this.__groupStack = [];
  
          //the root svg element
          this.__root = this.__document.createElementNS("http://www.w3.org/2000/svg", "svg");
          this.__root.setAttribute("version", 1.1);
          this.__root.setAttribute("xmlns", "http://www.w3.org/2000/svg");
          this.__root.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns:xlink", "http://www.w3.org/1999/xlink");
          this.__root.setAttribute("width", this.width);
          this.__root.setAttribute("height", this.height);
  
          //make sure we don't generate the same ids in defs
          this.__ids = {};
  
          //defs tag
          this.__defs = this.__document.createElementNS("http://www.w3.org/2000/svg", "defs");
          this.__root.appendChild(this.__defs);
  
          //also add a group child. the svg element can't use the transform attribute
          this.__currentElement = this.__document.createElementNS("http://www.w3.org/2000/svg", "g");
          this.__root.appendChild(this.__currentElement);
      };
  
  
      /**
       * Creates the specified svg element
       * @private
       */
      ctx.prototype.__createElement = function (elementName, properties, resetFill) {
          if (typeof properties === "undefined") {
              properties = {};
          }
  
          var element = this.__document.createElementNS("http://www.w3.org/2000/svg", elementName),
              keys = Object.keys(properties), i, key;
          if(resetFill) {
              //if fill or stroke is not specified, the svg element should not display. By default SVG's fill is black.
              element.setAttribute("fill", "none");
              element.setAttribute("stroke", "none");
          }
          for(i=0; i<keys.length; i++) {
              key = keys[i];
              element.setAttribute(key, properties[key]);
          }
          return element;
      };
  
      /**
       * Applies default canvas styles to the context
       * @private
       */
      ctx.prototype.__setDefaultStyles = function() {
          //default 2d canvas context properties see:http://www.w3.org/TR/2dcontext/
          var keys = Object.keys(STYLES), i, key;
          for(i=0; i<keys.length; i++) {
              key = keys[i];
              this[key] = STYLES[key].canvas;
          }
      };
  
      /**
       * Applies styles on restore
       * @param styleState
       * @private
       */
      ctx.prototype.__applyStyleState = function(styleState) {
          var keys = Object.keys(styleState), i, key;
          for(i=0; i<keys.length; i++) {
              key = keys[i];
              this[key] = styleState[key];
          }
      };
  
      /**
       * Gets the current style state
       * @return {Object}
       * @private
       */
      ctx.prototype.__getStyleState = function() {
          var i, styleState = {}, keys = Object.keys(STYLES), key;
          for(i=0; i<keys.length; i++) {
              key = keys[i];
              styleState[key] = this[key];
          }
          return styleState;
      };
  
      /**
       * Apples the current styles to the current SVG element. On "ctx.fill" or "ctx.stroke"
       * @param type
       * @private
       */
      ctx.prototype.__applyStyleToCurrentElement = function(type) {
          var keys = Object.keys(STYLES), i, style, value, id, regex, matches;
          for(i=0; i<keys.length; i++) {
              style = STYLES[keys[i]];
              value = this[keys[i]];
              if(style.apply) {
                  //is this a gradient or pattern?
                  if(style.apply.indexOf("fill")!==-1 && value instanceof CanvasPattern) {
                      //pattern
                      if(value.__ctx) {
                          //copy over defs
                          while(value.__ctx.__defs.childNodes.length) {
                              id = value.__ctx.__defs.childNodes[0].getAttribute("id");
                              this.__ids[id] = id;
                              this.__defs.appendChild(value.__ctx.__defs.childNodes[0]);
                          }
                      }
                      this.__currentElement.setAttribute("fill", format("url(#{id})", {id:value.__root.getAttribute("id")}));
                  }
                  else if(style.apply.indexOf("fill")!==-1 && value instanceof CanvasGradient) {
                      //gradient
                      this.__currentElement.setAttribute("fill", format("url(#{id})", {id:value.__root.getAttribute("id")}));
                  } else if(style.apply.indexOf(type)!==-1 && style.svg !== value) {
                      if((style.svgAttr === "stroke" || style.svgAttr === "fill") && value.indexOf("rgba") !== -1) {
                          //separate alpha value, since illustrator can't handle it
                          regex = /rgba\(\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d?\.?\d*)\s*\)/gi;
                          matches = regex.exec(value);
                          this.__currentElement.setAttribute(style.svgAttr, format("rgb({r},{g},{b})", {r:matches[1], g:matches[2], b:matches[3]}));
                          //should take globalAlpha here
                          var opacity = matches[4];
                          var globalAlpha = this.globalAlpha;
                          if (globalAlpha != null) {
                              opacity *= globalAlpha;
                          }
                          this.__currentElement.setAttribute(style.svgAttr+"-opacity", opacity);
                      } else {
                          var attr = style.svgAttr;
                          if (keys[i] === 'globalAlpha') {
                              attr = type+'-'+style.svgAttr;
                              if (this.__currentElement.getAttribute(attr)) {
                                  //fill-opacity or stroke-opacity has already been set by stroke or fill.
                                  continue;
                              }
                          }
                          //otherwise only update attribute if right type, and not svg default
                          this.__currentElement.setAttribute(attr, value);
  
  
                      }
                  }
              }
          }
  
      };
  
      /**
       * Will return the closest group or svg node. May return the current element.
       * @private
       */
      ctx.prototype.__closestGroupOrSvg = function(node) {
          node = node || this.__currentElement;
          if(node.nodeName === "g" || node.nodeName === "svg") {
              return node;
          } else {
              return this.__closestGroupOrSvg(node.parentNode);
          }
      };
  
      /**
       * Returns the serialized value of the svg so far
       * @param fixNamedEntities - Standalone SVG doesn't support named entities, which document.createTextNode encodes.
       *                           If true, we attempt to find all named entities and encode it as a numeric entity.
       * @return serialized svg
       */
      ctx.prototype.getSerializedSvg = function(fixNamedEntities) {
          var serialized = new XMLSerializer().serializeToString(this.__root),
              keys, i, key, value, regexp, xmlns;
  
          //IE search for a duplicate xmnls because they didn't implement setAttributeNS correctly
          xmlns = /xmlns="http:\/\/www\.w3\.org\/2000\/svg".+xmlns="http:\/\/www\.w3\.org\/2000\/svg/gi;
          if(xmlns.test(serialized)) {
              serialized = serialized.replace('xmlns="http://www.w3.org/2000/svg','xmlns:xlink="http://www.w3.org/1999/xlink');
          }
  
          if(fixNamedEntities) {
              keys = Object.keys(namedEntities);
              //loop over each named entity and replace with the proper equivalent.
              for(i=0; i<keys.length; i++) {
                  key = keys[i];
                  value = namedEntities[key];
                  regexp = new RegExp(key, "gi");
                  if(regexp.test(serialized)) {
                      serialized = serialized.replace(regexp, value);
                  }
              }
          }
  
          return serialized;
      };
  
  
      /**
       * Returns the root svg
       * @return
       */
      ctx.prototype.getSvg = function() {
          return this.__root;
      };
      /**
       * Will generate a group tag.
       */
      ctx.prototype.save = function() {
          var group = this.__createElement("g"), parent = this.__closestGroupOrSvg();
          this.__groupStack.push(parent);
          parent.appendChild(group);
          this.__currentElement = group;
          this.__stack.push(this.__getStyleState());
      };
      /**
       * Sets current element to parent, or just root if already root
       */
      ctx.prototype.restore = function(){
          this.__currentElement = this.__groupStack.pop();
          //Clearing canvas will make the poped group invalid, currentElement is set to the root group node.
          if (!this.__currentElement) {
              this.__currentElement = this.__root.childNodes[1];
          }
          var state = this.__stack.pop();
          this.__applyStyleState(state);
  
      };
  
      /**
       * Helper method to add transform
       * @private
       */
      ctx.prototype.__addTransform = function(t) {
  
          //if the current element has siblings, add another group
          var parent = this.__closestGroupOrSvg();
          if(parent.childNodes.length > 0) {
              var group = this.__createElement("g");
              parent.appendChild(group);
              this.__currentElement = group;
          }
  
          var transform = this.__currentElement.getAttribute("transform");
          if(transform) {
              transform += " ";
          } else {
              transform = "";
          }
          transform += t;
          this.__currentElement.setAttribute("transform", transform);
      };
  
      /**
       *  scales the current element
       */
      ctx.prototype.scale = function(x, y) {
          if(y === undefined) {
              y = x;
          }
          this.__addTransform(format("scale({x},{y})", {x:x, y:y}));
      };
  
      /**
       * rotates the current element
       */
      ctx.prototype.rotate = function(angle){
          var degrees = (angle * 180 / Math.PI);
          this.__addTransform(format("rotate({angle},{cx},{cy})", {angle:degrees, cx:0, cy:0}));
      };
  
      /**
       * translates the current element
       */
      ctx.prototype.translate = function(x, y){
          this.__addTransform(format("translate({x},{y})", {x:x,y:y}));
      };
  
      /**
       * applies a transform to the current element
       */
      ctx.prototype.transform = function(a, b, c, d, e, f){
          this.__addTransform(format("matrix({a},{b},{c},{d},{e},{f})", {a:a, b:b, c:c, d:d, e:e, f:f}));
      };
  
      /**
       * Create a new Path Element
       */
      ctx.prototype.beginPath = function(){
          var path, parent;
  
          // Note that there is only one current default path, it is not part of the drawing state.
          // See also: https://html.spec.whatwg.org/multipage/scripting.html#current-default-path
          this.__currentDefaultPath = "";
          this.__currentPosition = {};
  
          path = this.__createElement("path", {}, true);
          parent = this.__closestGroupOrSvg();
          parent.appendChild(path);
          this.__currentElement = path;
      };
  
      /**
       * Helper function to apply currentDefaultPath to current path element
       * @private
       */
      ctx.prototype.__applyCurrentDefaultPath = function() {
          if(this.__currentElement.nodeName === "path") {
              var d = this.__currentDefaultPath;
              this.__currentElement.setAttribute("d", d);
          } else {
              throw new Error("Attempted to apply path command to node " + this.__currentElement.nodeName);
          }
      };
  
      /**
       * Helper function to add path command
       * @private
       */
      ctx.prototype.__addPathCommand = function(command){
          this.__currentDefaultPath += " ";
          this.__currentDefaultPath += command;
      };
  
      /**
       * Adds the move command to the current path element,
       * if the currentPathElement is not empty create a new path element
       */
      ctx.prototype.moveTo = function(x,y){
          if(this.__currentElement.nodeName !== "path") {
              this.beginPath();
          }
  
          // creates a new subpath with the given point
          this.__currentPosition = {x: x, y: y};
          this.__addPathCommand(format("M {x} {y}", {x:x, y:y}));
      };
  
      /**
       * Closes the current path
       */
      ctx.prototype.closePath = function(){
          this.__addPathCommand("Z");
      };
  
      /**
       * Adds a line to command
       */
      ctx.prototype.lineTo = function(x, y){
          this.__currentPosition = {x: x, y: y};
          if (this.__currentDefaultPath.indexOf('M') > -1) {
              this.__addPathCommand(format("L {x} {y}", {x:x, y:y}));
          } else {
              this.__addPathCommand(format("M {x} {y}", {x:x, y:y}));
          }
      };
  
      /**
       * Add a bezier command
       */
      ctx.prototype.bezierCurveTo = function(cp1x, cp1y, cp2x, cp2y, x, y) {
          this.__currentPosition = {x: x, y: y};
          this.__addPathCommand(format("C {cp1x} {cp1y} {cp2x} {cp2y} {x} {y}",
              {cp1x:cp1x, cp1y:cp1y, cp2x:cp2x, cp2y:cp2y, x:x, y:y}));
      };
  
      /**
       * Adds a quadratic curve to command
       */
      ctx.prototype.quadraticCurveTo = function(cpx, cpy, x, y){
          this.__currentPosition = {x: x, y: y};
          this.__addPathCommand(format("Q {cpx} {cpy} {x} {y}", {cpx:cpx, cpy:cpy, x:x, y:y}));
      };
  
  
      /**
       * Return a new normalized vector of given vector
       */
      var normalize = function(vector) {
          var len = Math.sqrt(vector[0] * vector[0] + vector[1] * vector[1]);
          return [vector[0] / len, vector[1] / len];
      };
  
      /**
       * Adds the arcTo to the current path
       *
       * @see http://www.w3.org/TR/2015/WD-2dcontext-20150514/#dom-context-2d-arcto
       */
      ctx.prototype.arcTo = function(x1, y1, x2, y2, radius) {
          // Let the point (x0, y0) be the last point in the subpath.
          var x0 = this.__currentPosition && this.__currentPosition.x;
          var y0 = this.__currentPosition && this.__currentPosition.y;
  
          // First ensure there is a subpath for (x1, y1).
          if (typeof x0 == "undefined" || typeof y0 == "undefined") {
              return;
          }
  
          // Negative values for radius must cause the implementation to throw an IndexSizeError exception.
          if (radius < 0) {
              throw new Error("IndexSizeError: The radius provided (" + radius + ") is negative.");
          }
  
          // If the point (x0, y0) is equal to the point (x1, y1),
          // or if the point (x1, y1) is equal to the point (x2, y2),
          // or if the radius radius is zero,
          // then the method must add the point (x1, y1) to the subpath,
          // and connect that point to the previous point (x0, y0) by a straight line.
          if (((x0 === x1) && (y0 === y1))
              || ((x1 === x2) && (y1 === y2))
              || (radius === 0)) {
              this.lineTo(x1, y1);
              return;
          }
  
          // Otherwise, if the points (x0, y0), (x1, y1), and (x2, y2) all lie on a single straight line,
          // then the method must add the point (x1, y1) to the subpath,
          // and connect that point to the previous point (x0, y0) by a straight line.
          var unit_vec_p1_p0 = normalize([x0 - x1, y0 - y1]);
          var unit_vec_p1_p2 = normalize([x2 - x1, y2 - y1]);
          if (unit_vec_p1_p0[0] * unit_vec_p1_p2[1] === unit_vec_p1_p0[1] * unit_vec_p1_p2[0]) {
              this.lineTo(x1, y1);
              return;
          }
  
          // Otherwise, let The Arc be the shortest arc given by circumference of the circle that has radius radius,
          // and that has one point tangent to the half-infinite line that crosses the point (x0, y0) and ends at the point (x1, y1),
          // and that has a different point tangent to the half-infinite line that ends at the point (x1, y1), and crosses the point (x2, y2).
          // The points at which this circle touches these two lines are called the start and end tangent points respectively.
  
          // note that both vectors are unit vectors, so the length is 1
          var cos = (unit_vec_p1_p0[0] * unit_vec_p1_p2[0] + unit_vec_p1_p0[1] * unit_vec_p1_p2[1]);
          var theta = Math.acos(Math.abs(cos));
  
          // Calculate origin
          var unit_vec_p1_origin = normalize([
              unit_vec_p1_p0[0] + unit_vec_p1_p2[0],
              unit_vec_p1_p0[1] + unit_vec_p1_p2[1]
          ]);
          var len_p1_origin = radius / Math.sin(theta / 2);
          var x = x1 + len_p1_origin * unit_vec_p1_origin[0];
          var y = y1 + len_p1_origin * unit_vec_p1_origin[1];
  
          // Calculate start angle and end angle
          // rotate 90deg clockwise (note that y axis points to its down)
          var unit_vec_origin_start_tangent = [
              -unit_vec_p1_p0[1],
              unit_vec_p1_p0[0]
          ];
          // rotate 90deg counter clockwise (note that y axis points to its down)
          var unit_vec_origin_end_tangent = [
              unit_vec_p1_p2[1],
              -unit_vec_p1_p2[0]
          ];
          var getAngle = function(vector) {
              // get angle (clockwise) between vector and (1, 0)
              var x = vector[0];
              var y = vector[1];
              if (y >= 0) { // note that y axis points to its down
                  return Math.acos(x);
              } else {
                  return -Math.acos(x);
              }
          };
          var startAngle = getAngle(unit_vec_origin_start_tangent);
          var endAngle = getAngle(unit_vec_origin_end_tangent);
  
          // Connect the point (x0, y0) to the start tangent point by a straight line
          this.lineTo(x + unit_vec_origin_start_tangent[0] * radius,
              y + unit_vec_origin_start_tangent[1] * radius);
  
          // Connect the start tangent point to the end tangent point by arc
          // and adding the end tangent point to the subpath.
          this.arc(x, y, radius, startAngle, endAngle);
      };
  
      /**
       * Sets the stroke property on the current element
       */
      ctx.prototype.stroke = function(){
          if(this.__currentElement.nodeName === "path") {
              this.__currentElement.setAttribute("paint-order", "fill stroke markers");
          }
          this.__applyCurrentDefaultPath();
          this.__applyStyleToCurrentElement("stroke");
      };
  
      /**
       * Sets fill properties on the current element
       */
      ctx.prototype.fill = function(){
          if(this.__currentElement.nodeName === "path") {
              this.__currentElement.setAttribute("paint-order", "stroke fill markers");
          }
          this.__applyCurrentDefaultPath();
          this.__applyStyleToCurrentElement("fill");
      };
  
      /**
       *  Adds a rectangle to the path.
       */
      ctx.prototype.rect = function(x, y, width, height){
          if(this.__currentElement.nodeName !== "path") {
              this.beginPath();
          }
          this.moveTo(x, y);
          this.lineTo(x+width, y);
          this.lineTo(x+width, y+height);
          this.lineTo(x, y+height);
          this.lineTo(x, y);
          this.closePath();
      };
  
  
      /**
       * adds a rectangle element
       */
      ctx.prototype.fillRect = function(x, y, width, height){
          var rect, parent;
          rect = this.__createElement("rect", {
              x : x,
              y : y,
              width : width,
              height : height
          }, true);
          parent = this.__closestGroupOrSvg();
          parent.appendChild(rect);
          this.__currentElement = rect;
          this.__applyStyleToCurrentElement("fill");
      };
  
      /**
       * Draws a rectangle with no fill
       * @param x
       * @param y
       * @param width
       * @param height
       */
      ctx.prototype.strokeRect = function(x, y, width, height){
          var rect, parent;
          rect = this.__createElement("rect", {
              x : x,
              y : y,
              width : width,
              height : height
          }, true);
          parent = this.__closestGroupOrSvg();
          parent.appendChild(rect);
          this.__currentElement = rect;
          this.__applyStyleToCurrentElement("stroke");
      };
  
  
      /**
       * Clear entire canvas:
       * 1. save current transforms
       * 2. remove all the childNodes of the root g element
       */
      ctx.prototype.__clearCanvas = function() {
          var current = this.__closestGroupOrSvg(),
              transform = current.getAttribute("transform");
          var rootGroup = this.__root.childNodes[1];
          var childNodes = rootGroup.childNodes;
          for (var i = childNodes.length - 1; i >= 0; i--) {
              if (childNodes[i]) {
                  rootGroup.removeChild(childNodes[i]);
              }
          }
          this.__currentElement = rootGroup;
          //reset __groupStack as all the child group nodes are all removed.
          this.__groupStack = [];
          if (transform) {
              this.__addTransform(transform);
          }
      };
  
      /**
       * "Clears" a canvas by just drawing a white rectangle in the current group.
       */
      ctx.prototype.clearRect = function(x, y, width, height) {
          //clear entire canvas
          if (x === 0 && y === 0 && width === this.width && height === this.height) {
              this.__clearCanvas();
              return;
          }
          var rect, parent = this.__closestGroupOrSvg();
          rect = this.__createElement("rect", {
              x : x,
              y : y,
              width : width,
              height : height,
              fill : "#FFFFFF"
          }, true);
          parent.appendChild(rect);
      };
  
      /**
       * Adds a linear gradient to a defs tag.
       * Returns a canvas gradient object that has a reference to it's parent def
       */
      ctx.prototype.createLinearGradient = function(x1, y1, x2, y2){
          var grad = this.__createElement("linearGradient", {
              id : randomString(this.__ids),
              x1 : x1+"px",
              x2 : x2+"px",
              y1 : y1+"px",
              y2 : y2+"px",
              "gradientUnits" : "userSpaceOnUse"
          }, false);
          this.__defs.appendChild(grad);
          return new CanvasGradient(grad, this);
      };
  
      /**
       * Adds a radial gradient to a defs tag.
       * Returns a canvas gradient object that has a reference to it's parent def
       */
      ctx.prototype.createRadialGradient = function(x0, y0, r0, x1, y1, r1){
          var grad = this.__createElement("radialGradient", {
              id : randomString(this.__ids),
              cx : x1+"px",
              cy : y1+"px",
              r  : r1+"px",
              fx : x0+"px",
              fy : y0+"px",
              "gradientUnits" : "userSpaceOnUse"
          }, false);
          this.__defs.appendChild(grad);
          return new CanvasGradient(grad, this);
  
      };
  
      /**
       * Parses the font string and returns svg mapping
       * @private
       */
      ctx.prototype.__parseFont = function() {
          var regex = /^\s*(?=(?:(?:[-a-z]+\s*){0,2}(italic|oblique))?)(?=(?:(?:[-a-z]+\s*){0,2}(small-caps))?)(?=(?:(?:[-a-z]+\s*){0,2}(bold(?:er)?|lighter|[1-9]00))?)(?:(?:normal|\1|\2|\3)\s*){0,3}((?:xx?-)?(?:small|large)|medium|smaller|larger|[.\d]+(?:\%|in|[cem]m|ex|p[ctx]))(?:\s*\/\s*(normal|[.\d]+(?:\%|in|[cem]m|ex|p[ctx])))?\s*([-,\"\sa-z]+?)\s*$/i;
          var fontPart = regex.exec( this.font );
          var data = {
              style : fontPart[1] || 'normal',
              size : fontPart[4] || '10px',
              family : fontPart[6] || 'sans-serif',
              weight: fontPart[3] || 'normal',
              decoration : fontPart[2] || 'normal',
              href : null
          };
  
          //canvas doesn't support underline natively, but we can pass this attribute
          if(this.__fontUnderline === "underline") {
              data.decoration = "underline";
          }
  
          //canvas also doesn't support linking, but we can pass this as well
          if(this.__fontHref) {
              data.href = this.__fontHref;
          }
  
          return data;
      };
  
      /**
       * Helper to link text fragments
       * @param font
       * @param element
       * @return {*}
       * @private
       */
      ctx.prototype.__wrapTextLink = function(font, element) {
          if(font.href) {
              var a = this.__createElement("a");
              a.setAttributeNS("http://www.w3.org/1999/xlink", "xlink:href", font.href);
              a.appendChild(element);
              return a;
          }
          return element;
      };
  
      /**
       * Fills or strokes text
       * @param text
       * @param x
       * @param y
       * @param action - stroke or fill
       * @private
       */
      ctx.prototype.__applyText = function(text, x, y, action) {
          var font = this.__parseFont(),
              parent = this.__closestGroupOrSvg(),
              textElement = this.__createElement("text", {
                  "font-family" : font.family,
                  "font-size" : font.size,
                  "font-style" : font.style,
                  "font-weight" : font.weight,
                  "text-decoration" : font.decoration,
                  "x" : x,
                  "y" : y,
                  "text-anchor": getTextAnchor(this.textAlign),
                  "dominant-baseline": getDominantBaseline(this.textBaseline)
              }, true);
  
          textElement.appendChild(this.__document.createTextNode(text));
          this.__currentElement = textElement;
          this.__applyStyleToCurrentElement(action);
          parent.appendChild(this.__wrapTextLink(font,textElement));
      };
  
      /**
       * Creates a text element
       * @param text
       * @param x
       * @param y
       */
      ctx.prototype.fillText = function(text, x, y){
          this.__applyText(text, x, y, "fill");
      };
  
      /**
       * Strokes text
       * @param text
       * @param x
       * @param y
       */
      ctx.prototype.strokeText = function(text, x, y){
          this.__applyText(text, x, y, "stroke");
      };
  
      /**
       * No need to implement this for svg.
       * @param text
       * @return {TextMetrics}
       */
      ctx.prototype.measureText = function(text){
          this.__ctx.font = this.font;
          return this.__ctx.measureText(text);
      };
  
      /**
       *  Arc command!
       */
      ctx.prototype.arc = function(x, y, radius, startAngle, endAngle, counterClockwise) {
          // in canvas no circle is drawn if no angle is provided.
          if (startAngle === endAngle) {
              return;
          }
          startAngle = startAngle % (2*Math.PI);
          endAngle = endAngle % (2*Math.PI);
          if(startAngle === endAngle) {
              //circle time! subtract some of the angle so svg is happy (svg elliptical arc can't draw a full circle)
              endAngle = ((endAngle + (2*Math.PI)) - 0.001 * (counterClockwise ? -1 : 1)) % (2*Math.PI);
          }
          var endX = x+radius*Math.cos(endAngle),
              endY = y+radius*Math.sin(endAngle),
              startX = x+radius*Math.cos(startAngle),
              startY = y+radius*Math.sin(startAngle),
              sweepFlag = counterClockwise ? 0 : 1,
              largeArcFlag = 0,
              diff = endAngle - startAngle;
  
          // https://github.com/gliffy/canvas2svg/issues/4
          if(diff < 0) {
              diff += 2*Math.PI;
          }
  
          if(counterClockwise) {
              largeArcFlag = diff > Math.PI ? 0 : 1;
          } else {
              largeArcFlag = diff > Math.PI ? 1 : 0;
          }
  
          this.lineTo(startX, startY);
          this.__addPathCommand(format("A {rx} {ry} {xAxisRotation} {largeArcFlag} {sweepFlag} {endX} {endY}",
              {rx:radius, ry:radius, xAxisRotation:0, largeArcFlag:largeArcFlag, sweepFlag:sweepFlag, endX:endX, endY:endY}));
  
          this.__currentPosition = {x: endX, y: endY};
      };
  
      /**
       * Generates a ClipPath from the clip command.
       */
      ctx.prototype.clip = function(){
          var group = this.__closestGroupOrSvg(),
              clipPath = this.__createElement("clipPath"),
              id =  randomString(this.__ids),
              newGroup = this.__createElement("g");
  
          group.removeChild(this.__currentElement);
          clipPath.setAttribute("id", id);
          clipPath.appendChild(this.__currentElement);
  
          this.__defs.appendChild(clipPath);
  
          //set the clip path to this group
          group.setAttribute("clip-path", format("url(#{id})", {id:id}));
  
          //clip paths can be scaled and transformed, we need to add another wrapper group to avoid later transformations
          // to this path
          group.appendChild(newGroup);
  
          this.__currentElement = newGroup;
  
      };
  
      /**
       * Draws a canvas, image or mock context to this canvas.
       * Note that all svg dom manipulation uses node.childNodes rather than node.children for IE support.
       * http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html#dom-context-2d-drawimage
       */
      ctx.prototype.drawImage = function(){
          //convert arguments to a real array
          var args = Array.prototype.slice.call(arguments),
              image=args[0],
              dx, dy, dw, dh, sx=0, sy=0, sw, sh, parent, svg, defs, group,
              currentElement, svgImage, canvas, context, id;
  
          if(args.length === 3) {
              dx = args[1];
              dy = args[2];
              sw = image.width;
              sh = image.height;
              dw = sw;
              dh = sh;
          } else if(args.length === 5) {
              dx = args[1];
              dy = args[2];
              dw = args[3];
              dh = args[4];
              sw = image.width;
              sh = image.height;
          } else if(args.length === 9) {
              sx = args[1];
              sy = args[2];
              sw = args[3];
              sh = args[4];
              dx = args[5];
              dy = args[6];
              dw = args[7];
              dh = args[8];
          } else {
              throw new Error("Inavlid number of arguments passed to drawImage: " + arguments.length);
          }
  
          parent = this.__closestGroupOrSvg();
          currentElement = this.__currentElement;
          var translateDirective = "translate(" + dx + ", " + dy + ")";
          if(image instanceof ctx) {
              //canvas2svg mock canvas context. In the future we may want to clone nodes instead.
              //also I'm currently ignoring dw, dh, sw, sh, sx, sy for a mock context.
              svg = image.getSvg().cloneNode(true);
              if (svg.childNodes && svg.childNodes.length > 1) {
                  defs = svg.childNodes[0];
                  while(defs.childNodes.length) {
                      id = defs.childNodes[0].getAttribute("id");
                      this.__ids[id] = id;
                      this.__defs.appendChild(defs.childNodes[0]);
                  }
                  group = svg.childNodes[1];
                  if (group) {
                      //save original transform
                      var originTransform = group.getAttribute("transform");
                      var transformDirective;
                      if (originTransform) {
                          transformDirective = originTransform+" "+translateDirective;
                      } else {
                          transformDirective = translateDirective;
                      }
                      group.setAttribute("transform", transformDirective);
                      parent.appendChild(group);
                  }
              }
          } else if(image.nodeName === "CANVAS" || image.nodeName === "IMG") {
              //canvas or image
              svgImage = this.__createElement("image");
              svgImage.setAttribute("width", dw);
              svgImage.setAttribute("height", dh);
              svgImage.setAttribute("preserveAspectRatio", "none");
  
              if(sx || sy || sw !== image.width || sh !== image.height) {
                  //crop the image using a temporary canvas
                  canvas = this.__document.createElement("canvas");
                  canvas.width = dw;
                  canvas.height = dh;
                  context = canvas.getContext("2d");
                  context.drawImage(image, sx, sy, sw, sh, 0, 0, dw, dh);
                  image = canvas;
              }
              svgImage.setAttribute("transform", translateDirective);
              svgImage.setAttributeNS("http://www.w3.org/1999/xlink", "xlink:href",
                  image.nodeName === "CANVAS" ? image.toDataURL() : image.getAttribute("src"));
              parent.appendChild(svgImage);
          }
      };
  
      /**
       * Generates a pattern tag
       */
      ctx.prototype.createPattern = function(image, repetition){
          var pattern = this.__document.createElementNS("http://www.w3.org/2000/svg", "pattern"), id = randomString(this.__ids),
              img;
          pattern.setAttribute("id", id);
          pattern.setAttribute("width", image.width);
          pattern.setAttribute("height", image.height);
          if(image.nodeName === "CANVAS" || image.nodeName === "IMG") {
              img = this.__document.createElementNS("http://www.w3.org/2000/svg", "image");
              img.setAttribute("width", image.width);
              img.setAttribute("height", image.height);
              img.setAttributeNS("http://www.w3.org/1999/xlink", "xlink:href",
                  image.nodeName === "CANVAS" ? image.toDataURL() : image.getAttribute("src"));
              pattern.appendChild(img);
              this.__defs.appendChild(pattern);
          } else if(image instanceof ctx) {
              pattern.appendChild(image.__root.childNodes[1]);
              this.__defs.appendChild(pattern);
          }
          return new CanvasPattern(pattern, this);
      };
  
      ctx.prototype.setLineDash = function(dashArray) {
          if (dashArray && dashArray.length > 0) {
              this.lineDash = dashArray.join(",");
          } else {
              this.lineDash = null;
          }
      };
  
      /**
       * Not yet implemented
       */
      ctx.prototype.drawFocusRing = function(){};
      ctx.prototype.createImageData = function(){};
      ctx.prototype.getImageData = function(){};
      ctx.prototype.putImageData = function(){};
      ctx.prototype.globalCompositeOperation = function(){};
      ctx.prototype.setTransform = function(){};
  
      //add options for alternative namespace
      if (typeof window === "object") {
          window.C2S = ctx;
      }
  
      // CommonJS/Browserify
      if (typeof module === "object" && typeof module.exports === "object") {
          module.exports = ctx;
      }
  
  }());