text: // MIT License:
  //
  // Copyright (c) 2010-2013, Joe Walnes
  //               2013-2014, Drew Noakes
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  
  /**
   * Smoothie Charts - http://smoothiecharts.org/
   * (c) 2010-2013, Joe Walnes
   *     2013-2014, Drew Noakes
   *
   * v1.0: Main charting library, by Joe Walnes
   * v1.1: Auto scaling of axis, by Neil Dunn
   * v1.2: fps (frames per second) option, by Mathias Petterson
   * v1.3: Fix for divide by zero, by Paul Nikitochkin
   * v1.4: Set minimum, top-scale padding, remove timeseries, add optional timer to reset bounds, by Kelley Reynolds
   * v1.5: Set default frames per second to 50... smoother.
   *       .start(), .stop() methods for conserving CPU, by Dmitry Vyal
   *       options.interpolation = 'bezier' or 'line', by Dmitry Vyal
   *       options.maxValue to fix scale, by Dmitry Vyal
   * v1.6: minValue/maxValue will always get converted to floats, by Przemek Matylla
   * v1.7: options.grid.fillStyle may be a transparent color, by Dmitry A. Shashkin
   *       Smooth rescaling, by Kostas Michalopoulos
   * v1.8: Set max length to customize number of live points in the dataset with options.maxDataSetLength, by Krishna Narni
   * v1.9: Display timestamps along the bottom, by Nick and Stev-io
   *       (https://groups.google.com/forum/?fromgroups#!topic/smoothie-charts/-Ywse8FCpKI%5B1-25%5D)
   *       Refactored by Krishna Narni, to support timestamp formatting function
   * v1.10: Switch to requestAnimationFrame, removed the now obsoleted options.fps, by Gergely Imreh
   * v1.11: options.grid.sharpLines option added, by @drewnoakes
   *        Addressed warning seen in Firefox when seriesOption.fillStyle undefined, by @drewnoakes
   * v1.12: Support for horizontalLines added, by @drewnoakes
   *        Support for yRangeFunction callback added, by @drewnoakes
   * v1.13: Fixed typo (#32), by @alnikitich
   * v1.14: Timer cleared when last TimeSeries removed (#23), by @davidgaleano
   *        Fixed diagonal line on chart at start/end of data stream, by @drewnoakes
   * v1.15: Support for npm package (#18), by @dominictarr
   *        Fixed broken removeTimeSeries function (#24) by @davidgaleano
   *        Minor performance and tidying, by @drewnoakes
   * v1.16: Bug fix introduced in v1.14 relating to timer creation/clearance (#23), by @drewnoakes
   *        TimeSeries.append now deals with out-of-order timestamps, and can merge duplicates, by @zacwitte (#12)
   *        Documentation and some local variable renaming for clarity, by @drewnoakes
   * v1.17: Allow control over font size (#10), by @drewnoakes
   *        Timestamp text won't overlap, by @drewnoakes
   * v1.18: Allow control of max/min label precision, by @drewnoakes
   *        Added 'borderVisible' chart option, by @drewnoakes
   *        Allow drawing series with fill but no stroke (line), by @drewnoakes
   * v1.19: Avoid unnecessary repaints, and fixed flicker in old browsers having multiple charts in document (#40), by @asbai
   * v1.20: Add SmoothieChart.getTimeSeriesOptions and SmoothieChart.bringToFront functions, by @drewnoakes
   * v1.21: Add 'step' interpolation mode, by @drewnoakes
   * v1.22: Add support for different pixel ratios. Also add optional y limit formatters, by @copacetic
   * v1.23: Fix bug introduced in v1.22 (#44), by @drewnoakes
   * v1.24: Fix bug introduced in v1.23, re-adding parseFloat to y-axis formatter defaults, by @siggy_sf
   * v1.25: Fix bug seen when adding a data point to TimeSeries which is older than the current data, by @Nking92
   *        Draw time labels on top of series, by @comolosabia
   *        Add TimeSeries.clear function, by @drewnoakes
   * v1.26: Add support for resizing on high device pixel ratio screens, by @copacetic
   * v1.27: Fix bug introduced in v1.26 for non whole number devicePixelRatio values, by @zmbush
   * v1.28: Add 'minValueScale' option, by @megawac
   */
  
  ;(function(exports) {
  
    var Util = {
      extend: function() {
        arguments[0] = arguments[0] || {};
        for (var i = 1; i < arguments.length; i++)
        {
          for (var key in arguments[i])
          {
            if (arguments[i].hasOwnProperty(key))
            {
              if (typeof(arguments[i][key]) === 'object') {
                if (arguments[i][key] instanceof Array) {
                  arguments[0][key] = arguments[i][key];
                } else {
                  arguments[0][key] = Util.extend(arguments[0][key], arguments[i][key]);
                }
              } else {
                arguments[0][key] = arguments[i][key];
              }
            }
          }
        }
        return arguments[0];
      }
    };
  
    /**
     * Initialises a new <code>TimeSeries</code> with optional data options.
     *
     * Options are of the form (defaults shown):
     *
     * <pre>
     * {
     *   resetBounds: true,        // enables/disables automatic scaling of the y-axis
     *   resetBoundsInterval: 3000 // the period between scaling calculations, in millis
     * }
     * </pre>
     *
     * Presentation options for TimeSeries are specified as an argument to <code>SmoothieChart.addTimeSeries</code>.
     *
     * @constructor
     */
    function TimeSeries(options) {
      this.options = Util.extend({}, TimeSeries.defaultOptions, options);
      this.clear();
    }
  
    TimeSeries.defaultOptions = {
      resetBoundsInterval: 3000,
      resetBounds: true
    };
  
    /**
     * Clears all data and state from this TimeSeries object.
     */
    TimeSeries.prototype.clear = function() {
      this.data = [];
      this.maxValue = Number.NaN; // The maximum value ever seen in this TimeSeries.
      this.minValue = Number.NaN; // The minimum value ever seen in this TimeSeries.
    };
  
    /**
     * Recalculate the min/max values for this <code>TimeSeries</code> object.
     *
     * This causes the graph to scale itself in the y-axis.
     */
    TimeSeries.prototype.resetBounds = function() {
      if (this.data.length) {
        // Walk through all data points, finding the min/max value
        this.maxValue = this.data[0][1];
        this.minValue = this.data[0][1];
        for (var i = 1; i < this.data.length; i++) {
          var value = this.data[i][1];
          if (value > this.maxValue) {
            this.maxValue = value;
          }
          if (value < this.minValue) {
            this.minValue = value;
          }
        }
      } else {
        // No data exists, so set min/max to NaN
        this.maxValue = Number.NaN;
        this.minValue = Number.NaN;
      }
    };
  
    /**
     * Adds a new data point to the <code>TimeSeries</code>, preserving chronological order.
     *
     * @param timestamp the position, in time, of this data point
     * @param value the value of this data point
     * @param sumRepeatedTimeStampValues if <code>timestamp</code> has an exact match in the series, this flag controls
     * whether it is replaced, or the values summed (defaults to false.)
     */
    TimeSeries.prototype.append = function(timestamp, value, sumRepeatedTimeStampValues) {
      // Rewind until we hit an older timestamp
      var i = this.data.length - 1;
      while (i >= 0 && this.data[i][0] > timestamp) {
        i--;
      }
  
      if (i === -1) {
        // This new item is the oldest data
        this.data.splice(0, 0, [timestamp, value]);
      } else if (this.data.length > 0 && this.data[i][0] === timestamp) {
        // Update existing values in the array
        if (sumRepeatedTimeStampValues) {
          // Sum this value into the existing 'bucket'
          this.data[i][1] += value;
          value = this.data[i][1];
        } else {
          // Replace the previous value
          this.data[i][1] = value;
        }
      } else if (i < this.data.length - 1) {
        // Splice into the correct position to keep timestamps in order
        this.data.splice(i + 1, 0, [timestamp, value]);
      } else {
        // Add to the end of the array
        this.data.push([timestamp, value]);
      }
  
      this.maxValue = isNaN(this.maxValue) ? value : Math.max(this.maxValue, value);
      this.minValue = isNaN(this.minValue) ? value : Math.min(this.minValue, value);
    };
  
    TimeSeries.prototype.dropOldData = function(oldestValidTime, maxDataSetLength) {
      // We must always keep one expired data point as we need this to draw the
      // line that comes into the chart from the left, but any points prior to that can be removed.
      var removeCount = 0;
      while (this.data.length - removeCount >= maxDataSetLength && this.data[removeCount + 1][0] < oldestValidTime) {
        removeCount++;
      }
      if (removeCount !== 0) {
        this.data.splice(0, removeCount);
      }
    };
  
    /**
     * Initialises a new <code>SmoothieChart</code>.
     *
     * Options are optional, and should be of the form below. Just specify the values you
     * need and the rest will be given sensible defaults as shown:
     *
     * <pre>
     * {
     *   minValue: undefined,                      // specify to clamp the lower y-axis to a given value
     *   maxValue: undefined,                      // specify to clamp the upper y-axis to a given value
     *   maxValueScale: 1,                         // allows proportional padding to be added above the chart. for 10% padding, specify 1.1.
     *   minValueScale: 1,                         // allows proportional padding to be added below the chart. for 10% padding, specify 1.1.
     *   yRangeFunction: undefined,                // function({min: , max: }) { return {min: , max: }; }
     *   scaleSmoothing: 0.125,                    // controls the rate at which y-value zoom animation occurs
     *   millisPerPixel: 20,                       // sets the speed at which the chart pans by
     *   enableDpiScaling: true,                   // support rendering at different DPI depending on the device
     *   yMinFormatter: function(min, precision) { // callback function that formats the min y value label
     *     return parseFloat(min).toFixed(precision);
     *   },
     *   yMaxFormatter: function(max, precision) { // callback function that formats the max y value label
     *     return parseFloat(max).toFixed(precision);
     *   },
     *   maxDataSetLength: 2,
     *   interpolation: 'bezier'                   // one of 'bezier', 'linear', or 'step'
     *   timestampFormatter: null,                 // optional function to format time stamps for bottom of chart
     *                                             // you may use SmoothieChart.timeFormatter, or your own: function(date) { return ''; }
     *   scrollBackwards: false,                   // reverse the scroll direction of the chart
     *   horizontalLines: [],                      // [ { value: 0, color: '#ffffff', lineWidth: 1 } ]
     *   grid:
     *   {
     *     fillStyle: '#000000',                   // the background colour of the chart
     *     lineWidth: 1,                           // the pixel width of grid lines
     *     strokeStyle: '#777777',                 // colour of grid lines
     *     millisPerLine: 1000,                    // distance between vertical grid lines
     *     sharpLines: false,                      // controls whether grid lines are 1px sharp, or softened
     *     verticalSections: 2,                    // number of vertical sections marked out by horizontal grid lines
     *     borderVisible: true                     // whether the grid lines trace the border of the chart or not
     *   },
     *   labels
     *   {
     *     disabled: false,                        // enables/disables labels showing the min/max values
     *     fillStyle: '#ffffff',                   // colour for text of labels,
     *     fontSize: 15,
     *     fontFamily: 'sans-serif',
     *     precision: 2
     *   }
     * }
     * </pre>
     *
     * @constructor
     */
    function SmoothieChart(options) {
      this.options = Util.extend({}, SmoothieChart.defaultChartOptions, options);
      this.seriesSet = [];
      this.currentValueRange = 1;
      this.currentVisMinValue = 0;
      this.lastRenderTimeMillis = 0;
    }
  
    SmoothieChart.defaultChartOptions = {
      millisPerPixel: 20,
      enableDpiScaling: true,
      yMinFormatter: function(min, precision) {
        return parseFloat(min).toFixed(precision);
      },
      yMaxFormatter: function(max, precision) {
        return parseFloat(max).toFixed(precision);
      },
      maxValueScale: 1,
      minValueScale: 1,
      interpolation: 'bezier',
      scaleSmoothing: 0.125,
      maxDataSetLength: 2,
      scrollBackwards: false,
      grid: {
        fillStyle: '#000000',
        strokeStyle: '#777777',
        lineWidth: 1,
        sharpLines: false,
        millisPerLine: 1000,
        verticalSections: 2,
        borderVisible: true
      },
      labels: {
        fillStyle: '#ffffff',
        disabled: false,
        fontSize: 10,
        fontFamily: 'monospace',
        precision: 2
      },
      horizontalLines: []
    };
  
    // Based on http://inspirit.github.com/jsfeat/js/compatibility.js
    SmoothieChart.AnimateCompatibility = (function() {
      var requestAnimationFrame = function(callback, element) {
            var requestAnimationFrame =
              window.requestAnimationFrame        ||
              window.webkitRequestAnimationFrame  ||
              window.mozRequestAnimationFrame     ||
              window.oRequestAnimationFrame       ||
              window.msRequestAnimationFrame      ||
              function(callback) {
                return window.setTimeout(function() {
                  callback(new Date().getTime());
                }, 16);
              };
            return requestAnimationFrame.call(window, callback, element);
          },
          cancelAnimationFrame = function(id) {
            var cancelAnimationFrame =
              window.cancelAnimationFrame ||
              function(id) {
                clearTimeout(id);
              };
            return cancelAnimationFrame.call(window, id);
          };
  
      return {
        requestAnimationFrame: requestAnimationFrame,
        cancelAnimationFrame: cancelAnimationFrame
      };
    })();
  
    SmoothieChart.defaultSeriesPresentationOptions = {
      lineWidth: 1,
      strokeStyle: '#ffffff'
    };
  
    /**
     * Adds a <code>TimeSeries</code> to this chart, with optional presentation options.
     *
     * Presentation options should be of the form (defaults shown):
     *
     * <pre>
     * {
     *   lineWidth: 1,
     *   strokeStyle: '#ffffff',
     *   fillStyle: undefined
     * }
     * </pre>
     */
    SmoothieChart.prototype.addTimeSeries = function(timeSeries, options) {
      this.seriesSet.push({timeSeries: timeSeries, options: Util.extend({}, SmoothieChart.defaultSeriesPresentationOptions, options)});
      if (timeSeries.options.resetBounds && timeSeries.options.resetBoundsInterval > 0) {
        timeSeries.resetBoundsTimerId = setInterval(
          function() {
            timeSeries.resetBounds();
          },
          timeSeries.options.resetBoundsInterval
        );
      }
    };
  
    /**
     * Removes the specified <code>TimeSeries</code> from the chart.
     */
    SmoothieChart.prototype.removeTimeSeries = function(timeSeries) {
      // Find the correct timeseries to remove, and remove it
      var numSeries = this.seriesSet.length;
      for (var i = 0; i < numSeries; i++) {
        if (this.seriesSet[i].timeSeries === timeSeries) {
          this.seriesSet.splice(i, 1);
          break;
        }
      }
      // If a timer was operating for that timeseries, remove it
      if (timeSeries.resetBoundsTimerId) {
        // Stop resetting the bounds, if we were
        clearInterval(timeSeries.resetBoundsTimerId);
      }
    };
  
    /**
     * Gets render options for the specified <code>TimeSeries</code>.
     *
     * As you may use a single <code>TimeSeries</code> in multiple charts with different formatting in each usage,
     * these settings are stored in the chart.
     */
    SmoothieChart.prototype.getTimeSeriesOptions = function(timeSeries) {
      // Find the correct timeseries to remove, and remove it
      var numSeries = this.seriesSet.length;
      for (var i = 0; i < numSeries; i++) {
        if (this.seriesSet[i].timeSeries === timeSeries) {
          return this.seriesSet[i].options;
        }
      }
    };
  
    /**
     * Brings the specified <code>TimeSeries</code> to the top of the chart. It will be rendered last.
     */
    SmoothieChart.prototype.bringToFront = function(timeSeries) {
      // Find the correct timeseries to remove, and remove it
      var numSeries = this.seriesSet.length;
      for (var i = 0; i < numSeries; i++) {
        if (this.seriesSet[i].timeSeries === timeSeries) {
          var set = this.seriesSet.splice(i, 1);
          this.seriesSet.push(set[0]);
          break;
        }
      }
    };
  
    /**
     * Instructs the <code>SmoothieChart</code> to start rendering to the provided canvas, with specified delay.
     *
     * @param canvas the target canvas element
     * @param delayMillis an amount of time to wait before a data point is shown. This can prevent the end of the series
     * from appearing on screen, with new values flashing into view, at the expense of some latency.
     */
    SmoothieChart.prototype.streamTo = function(canvas, delayMillis) {
      this.canvas = canvas;
      this.delay = delayMillis;
      this.start();
    };
  
    /**
     * Make sure the canvas has the optimal resolution for the device's pixel ratio.
     */
    SmoothieChart.prototype.resize = function() {
      // TODO this function doesn't handle the value of enableDpiScaling changing during execution
      if (!this.options.enableDpiScaling || !window || window.devicePixelRatio === 1)
        return;
  
      var dpr = window.devicePixelRatio;
      var width = parseInt(this.canvas.getAttribute('width'));
      var height = parseInt(this.canvas.getAttribute('height'));
  
      if (!this.originalWidth || (Math.floor(this.originalWidth * dpr) !== width)) {
        this.originalWidth = width;
        this.canvas.setAttribute('width', (Math.floor(width * dpr)).toString());
        this.canvas.style.width = width + 'px';
        this.canvas.getContext('2d').scale(dpr, dpr);
      }
  
      if (!this.originalHeight || (Math.floor(this.originalHeight * dpr) !== height)) {
        this.originalHeight = height;
        this.canvas.setAttribute('height', (Math.floor(height * dpr)).toString());
        this.canvas.style.height = height + 'px';
        this.canvas.getContext('2d').scale(dpr, dpr);
      }
    };
  
    /**
     * Starts the animation of this chart.
     */
    SmoothieChart.prototype.start = function() {
      if (this.frame) {
        // We're already running, so just return
        return;
      }
  
      // Renders a frame, and queues the next frame for later rendering
      var animate = function() {
        this.frame = SmoothieChart.AnimateCompatibility.requestAnimationFrame(function() {
          this.render();
          animate();
        }.bind(this));
      }.bind(this);
  
      animate();
    };
  
    /**
     * Stops the animation of this chart.
     */
    SmoothieChart.prototype.stop = function() {
      if (this.frame) {
        SmoothieChart.AnimateCompatibility.cancelAnimationFrame(this.frame);
        delete this.frame;
      }
    };
  
    SmoothieChart.prototype.updateValueRange = function() {
      // Calculate the current scale of the chart, from all time series.
      var chartOptions = this.options,
          chartMaxValue = Number.NaN,
          chartMinValue = Number.NaN;
  
      for (var d = 0; d < this.seriesSet.length; d++) {
        // TODO(ndunn): We could calculate / track these values as they stream in.
        var timeSeries = this.seriesSet[d].timeSeries;
        if (!isNaN(timeSeries.maxValue)) {
          chartMaxValue = !isNaN(chartMaxValue) ? Math.max(chartMaxValue, timeSeries.maxValue) : timeSeries.maxValue;
        }
  
        if (!isNaN(timeSeries.minValue)) {
          chartMinValue = !isNaN(chartMinValue) ? Math.min(chartMinValue, timeSeries.minValue) : timeSeries.minValue;
        }
      }
  
      // Scale the chartMaxValue to add padding at the top if required
      if (chartOptions.maxValue != null) {
        chartMaxValue = chartOptions.maxValue;
      } else {
        chartMaxValue *= chartOptions.maxValueScale;
      }
  
      // Set the minimum if we've specified one
      if (chartOptions.minValue != null) {
        chartMinValue = chartOptions.minValue;
      } else {
        chartMinValue -= Math.abs(chartMinValue * chartOptions.minValueScale - chartMinValue);
      }
  
      // If a custom range function is set, call it
      if (this.options.yRangeFunction) {
        var range = this.options.yRangeFunction({min: chartMinValue, max: chartMaxValue});
        chartMinValue = range.min;
        chartMaxValue = range.max;
      }
  
      if (!isNaN(chartMaxValue) && !isNaN(chartMinValue)) {
        var targetValueRange = chartMaxValue - chartMinValue;
        var valueRangeDiff = (targetValueRange - this.currentValueRange);
        var minValueDiff = (chartMinValue - this.currentVisMinValue);
        this.isAnimatingScale = Math.abs(valueRangeDiff) > 0.1 || Math.abs(minValueDiff) > 0.1;
        this.currentValueRange += chartOptions.scaleSmoothing * valueRangeDiff;
        this.currentVisMinValue += chartOptions.scaleSmoothing * minValueDiff;
      }
  
      this.valueRange = { min: chartMinValue, max: chartMaxValue };
    };
  
    SmoothieChart.prototype.render = function(canvas, time) {
      var nowMillis = new Date().getTime();
  
      if (!this.isAnimatingScale) {
        // We're not animating. We can use the last render time and the scroll speed to work out whether
        // we actually need to paint anything yet. If not, we can return immediately.
  
        // Render at least every 1/6th of a second. The canvas may be resized, which there is
        // no reliable way to detect.
        var maxIdleMillis = Math.min(1000/6, this.options.millisPerPixel);
  
        if (nowMillis - this.lastRenderTimeMillis < maxIdleMillis) {
          return;
        }
      }
  
      this.resize();
  
      this.lastRenderTimeMillis = nowMillis;
  
      canvas = canvas || this.canvas;
      time = time || nowMillis - (this.delay || 0);
  
      // Round time down to pixel granularity, so motion appears smoother.
      time -= time % this.options.millisPerPixel;
  
      var context = canvas.getContext('2d'),
          chartOptions = this.options,
          dimensions = { top: 0, left: 0, width: canvas.clientWidth, height: canvas.clientHeight },
          // Calculate the threshold time for the oldest data points.
          oldestValidTime = time - (dimensions.width * chartOptions.millisPerPixel),
          valueToYPixel = function(value) {
            var offset = value - this.currentVisMinValue;
            return this.currentValueRange === 0
              ? dimensions.height
              : dimensions.height - (Math.round((offset / this.currentValueRange) * dimensions.height));
          }.bind(this),
          timeToXPixel = function(t) {
            if(chartOptions.scrollBackwards) {
              return Math.round((time - t) / chartOptions.millisPerPixel);
            }
            return Math.round(dimensions.width - ((time - t) / chartOptions.millisPerPixel));
          };
  
      this.updateValueRange();
  
      context.font = chartOptions.labels.fontSize + 'px ' + chartOptions.labels.fontFamily;
  
      // Save the state of the canvas context, any transformations applied in this method
      // will get removed from the stack at the end of this method when .restore() is called.
      context.save();
  
      // Move the origin.
      context.translate(dimensions.left, dimensions.top);
  
      // Create a clipped rectangle - anything we draw will be constrained to this rectangle.
      // This prevents the occasional pixels from curves near the edges overrunning and creating
      // screen cheese (that phrase should need no explanation).
      context.beginPath();
      context.rect(0, 0, dimensions.width, dimensions.height);
      context.clip();
  
      // Clear the working area.
      context.save();
      context.fillStyle = chartOptions.grid.fillStyle;
      context.clearRect(0, 0, dimensions.width, dimensions.height);
      context.fillRect(0, 0, dimensions.width, dimensions.height);
      context.restore();
  
      // Grid lines...
      context.save();
      context.lineWidth = chartOptions.grid.lineWidth;
      context.strokeStyle = chartOptions.grid.strokeStyle;
      // Vertical (time) dividers.
      if (chartOptions.grid.millisPerLine > 0) {
        context.beginPath();
        for (var t = time - (time % chartOptions.grid.millisPerLine);
             t >= oldestValidTime;
             t -= chartOptions.grid.millisPerLine) {
          var gx = timeToXPixel(t);
          if (chartOptions.grid.sharpLines) {
            gx -= 0.5;
          }
          context.moveTo(gx, 0);
          context.lineTo(gx, dimensions.height);
        }
        context.stroke();
        context.closePath();
      }
  
      // Horizontal (value) dividers.
      for (var v = 1; v < chartOptions.grid.verticalSections; v++) {
        var gy = Math.round(v * dimensions.height / chartOptions.grid.verticalSections);
        if (chartOptions.grid.sharpLines) {
          gy -= 0.5;
        }
        context.beginPath();
        context.moveTo(0, gy);
        context.lineTo(dimensions.width, gy);
        context.stroke();
        context.closePath();
      }
      // Bounding rectangle.
      if (chartOptions.grid.borderVisible) {
        context.beginPath();
        context.strokeRect(0, 0, dimensions.width, dimensions.height);
        context.closePath();
      }
      context.restore();
  
      // Draw any horizontal lines...
      if (chartOptions.horizontalLines && chartOptions.horizontalLines.length) {
        for (var hl = 0; hl < chartOptions.horizontalLines.length; hl++) {
          var line = chartOptions.horizontalLines[hl],
              hly = Math.round(valueToYPixel(line.value)) - 0.5;
          context.strokeStyle = line.color || '#ffffff';
          context.lineWidth = line.lineWidth || 1;
          context.beginPath();
          context.moveTo(0, hly);
          context.lineTo(dimensions.width, hly);
          context.stroke();
          context.closePath();
        }
      }
  
      // For each data set...
      for (var d = 0; d < this.seriesSet.length; d++) {
        context.save();
        var timeSeries = this.seriesSet[d].timeSeries,
            dataSet = timeSeries.data,
            seriesOptions = this.seriesSet[d].options;
  
        // Delete old data that's moved off the left of the chart.
        timeSeries.dropOldData(oldestValidTime, chartOptions.maxDataSetLength);
  
        // Set style for this dataSet.
        context.lineWidth = seriesOptions.lineWidth;
        context.strokeStyle = seriesOptions.strokeStyle;
        // Draw the line...
        context.beginPath();
        // Retain lastX, lastY for calculating the control points of bezier curves.
        var firstX = 0, lastX = 0, lastY = 0;
        for (var i = 0; i < dataSet.length && dataSet.length !== 1; i++) {
          var x = timeToXPixel(dataSet[i][0]),
              y = valueToYPixel(dataSet[i][1]);
  
          if (i === 0) {
            firstX = x;
            context.moveTo(x, y);
          } else {
            switch (chartOptions.interpolation) {
              case "linear":
              case "line": {
                context.lineTo(x,y);
                break;
              }
              case "bezier":
              default: {
                // Great explanation of Bezier curves: http://en.wikipedia.org/wiki/Bezier_curve#Quadratic_curves
                //
                // Assuming A was the last point in the line plotted and B is the new point,
                // we draw a curve with control points P and Q as below.
                //
                // A---P
                //     |
                //     |
                //     |
                //     Q---B
                //
                // Importantly, A and P are at the same y coordinate, as are B and Q. This is
                // so adjacent curves appear to flow as one.
                //
                context.bezierCurveTo( // startPoint (A) is implicit from last iteration of loop
                  Math.round((lastX + x) / 2), lastY, // controlPoint1 (P)
                  Math.round((lastX + x)) / 2, y, // controlPoint2 (Q)
                  x, y); // endPoint (B)
                break;
              }
              case "step": {
                context.lineTo(x,lastY);
                context.lineTo(x,y);
                break;
              }
            }
          }
  
          lastX = x; lastY = y;
        }
  
        if (dataSet.length > 1) {
          if (seriesOptions.fillStyle) {
            // Close up the fill region.
            context.lineTo(dimensions.width + seriesOptions.lineWidth + 1, lastY);
            context.lineTo(dimensions.width + seriesOptions.lineWidth + 1, dimensions.height + seriesOptions.lineWidth + 1);
            context.lineTo(firstX, dimensions.height + seriesOptions.lineWidth);
            context.fillStyle = seriesOptions.fillStyle;
            context.fill();
          }
  
          if (seriesOptions.strokeStyle && seriesOptions.strokeStyle !== 'none') {
            context.stroke();
          }
          context.closePath();
        }
        context.restore();
      }
  
      // Draw the axis values on the chart.
      if (!chartOptions.labels.disabled && !isNaN(this.valueRange.min) && !isNaN(this.valueRange.max)) {
        var maxValueString = chartOptions.yMaxFormatter(this.valueRange.max, chartOptions.labels.precision),
            minValueString = chartOptions.yMinFormatter(this.valueRange.min, chartOptions.labels.precision),
            labelPos = chartOptions.scrollBackwards ? 0 : dimensions.width - context.measureText(maxValueString).width - 2;
        context.fillStyle = chartOptions.labels.fillStyle;
        context.fillText(maxValueString, labelPos, chartOptions.labels.fontSize);
        context.fillText(minValueString, labelPos, dimensions.height - 2);
      }
  
      // Display timestamps along x-axis at the bottom of the chart.
      if (chartOptions.timestampFormatter && chartOptions.grid.millisPerLine > 0) {
        var textUntilX = chartOptions.scrollBackwards
          ? context.measureText(minValueString).width
          : dimensions.width - context.measureText(minValueString).width + 4;
        for (var t = time - (time % chartOptions.grid.millisPerLine);
             t >= oldestValidTime;
             t -= chartOptions.grid.millisPerLine) {
          var gx = timeToXPixel(t);
          // Only draw the timestamp if it won't overlap with the previously drawn one.
          if ((!chartOptions.scrollBackwards && gx < textUntilX) || (chartOptions.scrollBackwards && gx > textUntilX))  {
            // Formats the timestamp based on user specified formatting function
            // SmoothieChart.timeFormatter function above is one such formatting option
            var tx = new Date(t),
              ts = chartOptions.timestampFormatter(tx),
              tsWidth = context.measureText(ts).width;
  
            textUntilX = chartOptions.scrollBackwards
              ? gx + tsWidth + 2
              : gx - tsWidth - 2;
  
            context.fillStyle = chartOptions.labels.fillStyle;
            if(chartOptions.scrollBackwards) {
              context.fillText(ts, gx, dimensions.height - 2);
            } else {
              context.fillText(ts, gx - tsWidth, dimensions.height - 2);
            }
          }
        }
      }
  
      context.restore(); // See .save() above.
    };
  
    // Sample timestamp formatting function
    SmoothieChart.timeFormatter = function(date) {
      function pad2(number) { return (number < 10 ? '0' : '') + number }
      return pad2(date.getHours()) + ':' + pad2(date.getMinutes()) + ':' + pad2(date.getSeconds());
    };
  
    exports.TimeSeries = TimeSeries;
    exports.SmoothieChart = SmoothieChart;
  
  })(typeof exports === 'undefined' ? this : exports);
  