text: // MIT License:
  //
  // Copyright (c) 2010-2011, Joe Walnes
  //
  // 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) 2010-2012, Joe Walnes
   *
   * 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.iterpolation = '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
   */
  
  function TimeSeries(options) {
    options = options || {};
    options.resetBoundsInterval = options.resetBoundsInterval || 3000; // Reset the max/min bounds after this many milliseconds
    options.resetBounds = options.resetBounds || false; // Enable or disable the resetBounds timer
    this.options = options;
    this.data = [];
  
    this.maxValue = Number.NaN; // The maximum value ever seen in this time series.
    this.minValue = Number.NaN; // The minimum value ever seen in this time series.
  
    // Start a resetBounds Interval timer desired
    if (options.resetBounds) {
      this.boundsTimer = setInterval(function(thisObj) { thisObj.resetBounds(); }, options.resetBoundsInterval, this);
    }
  }
  
  // Reset the min and max for this timeseries so the graph rescales itself
  TimeSeries.prototype.resetBounds = function() {
    this.maxValue = Number.NaN;
    this.minValue = Number.NaN;
    for (var i = 0; i < this.data.length; i++) {
      this.maxValue = !isNaN(this.maxValue) ? Math.max(this.maxValue, this.data[i][1]) : this.data[i][1];
      this.minValue = !isNaN(this.minValue) ? Math.min(this.minValue, this.data[i][1]) : this.data[i][1];
    }
  };
  
  TimeSeries.prototype.append = function(timestamp, value) {
    this.data.push([timestamp, value]);
    this.maxValue = !isNaN(this.maxValue) ? Math.max(this.maxValue, value) : value;
    this.minValue = !isNaN(this.minValue) ? Math.min(this.minValue, value) : value;
  };
  
  function SmoothieChart(options) {
    // Defaults
    options = options || {};
    options.grid = options.grid || { fillStyle:'#000000', strokeStyle: '#777777', lineWidth: 1, millisPerLine: 1000, verticalSections: 2 };
    options.millisPerPixel = options.millisPerPixel || 20;
    options.fps = options.fps || 50;
    options.maxValueScale = options.maxValueScale || 1;
    options.minValue = options.minValue;
    options.maxValue = options.maxValue;
    options.labels = options.labels || { fillStyle:'#ffffff' };
    options.interpolation = options.interpolation || "bezier";
    options.scaleSmoothing = options.scaleSmoothing || 0.125;
    this.options = options;
    this.seriesSet = [];
    this.currentValueRange = 1;
    this.currentVisMinValue = 0;
  }
  
  SmoothieChart.prototype.addTimeSeries = function(timeSeries, options) {
    this.seriesSet.push({timeSeries: timeSeries, options: options || {}});
  };
  
  SmoothieChart.prototype.removeTimeSeries = function(timeSeries) {
    this.seriesSet.splice(this.seriesSet.indexOf(timeSeries), 1);
  };
  
  SmoothieChart.prototype.streamTo = function(canvas, delay) {
    var self = this;
    this.render_on_tick = function() {
      self.render(canvas, new Date().getTime() - (delay || 0));
    };
  
    this.start();
  };
  
  SmoothieChart.prototype.start = function() {
    if (!this.timer)
      this.timer = setInterval(this.render_on_tick, 1000/this.options.fps);
  };
  
  SmoothieChart.prototype.stop = function() {
    if (this.timer) {
      clearInterval(this.timer);
      this.timer = undefined;
    }
  };
  
  SmoothieChart.prototype.render = function(canvas, time) {
    var canvasContext = canvas.getContext("2d");
    var options = this.options;
    var dimensions = {top: 0, left: 0, width: canvas.clientWidth, height: canvas.clientHeight};
  
    // 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.
    canvasContext.save();
  
    // Round time down to pixel granularity, so motion appears smoother.
    time = time - time % options.millisPerPixel;
  
    // Move the origin.
    canvasContext.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 neeed no explanation).
    canvasContext.beginPath();
    canvasContext.rect(0, 0, dimensions.width, dimensions.height);
    canvasContext.clip();
  
    // Clear the working area.
    canvasContext.save();
    canvasContext.fillStyle = options.grid.fillStyle;
    canvasContext.clearRect(0, 0, dimensions.width, dimensions.height);
    canvasContext.fillRect(0, 0, dimensions.width, dimensions.height);
    canvasContext.restore();
  
    // Grid lines....
    canvasContext.save();
    canvasContext.lineWidth = options.grid.lineWidth || 1;
    canvasContext.strokeStyle = options.grid.strokeStyle || '#ffffff';
    // Vertical (time) dividers.
    if (options.grid.millisPerLine > 0) {
      for (var t = time - (time % options.grid.millisPerLine); t >= time - (dimensions.width * options.millisPerPixel); t -= options.grid.millisPerLine) {
        canvasContext.beginPath();
        var gx = Math.round(dimensions.width - ((time - t) / options.millisPerPixel));
        canvasContext.moveTo(gx, 0);
        canvasContext.lineTo(gx, dimensions.height);
        canvasContext.stroke();
        canvasContext.closePath();
      }
    }
  
    // Horizontal (value) dividers.
    for (var v = 1; v < options.grid.verticalSections; v++) {
      var gy = Math.round(v * dimensions.height / options.grid.verticalSections);
      canvasContext.beginPath();
      canvasContext.moveTo(0, gy);
      canvasContext.lineTo(dimensions.width, gy);
      canvasContext.stroke();
      canvasContext.closePath();
    }
    // Bounding rectangle.
    canvasContext.beginPath();
    canvasContext.strokeRect(0, 0, dimensions.width, dimensions.height);
    canvasContext.closePath();
    canvasContext.restore();
  
    // Calculate the current scale of the chart, from all time series.
    var maxValue = Number.NaN;
    var minValue = 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)) {
          maxValue = !isNaN(maxValue) ? Math.max(maxValue, timeSeries.maxValue) : timeSeries.maxValue;
      }
  
      if (!isNaN(timeSeries.minValue)) {
          minValue = !isNaN(minValue) ? Math.min(minValue, timeSeries.minValue) : timeSeries.minValue;
      }
    }
  
    if (isNaN(maxValue) && isNaN(minValue)) {
        return;
    }
  
    // Scale the maxValue to add padding at the top if required
    if (options.maxValue != null)
      maxValue = options.maxValue;
    else
      maxValue = maxValue * options.maxValueScale;
    // Set the minimum if we've specified one
    if (options.minValue != null)
      minValue = options.minValue;
    var targetValueRange = maxValue - minValue;
    this.currentValueRange += options.scaleSmoothing*(targetValueRange - this.currentValueRange);
    this.currentVisMinValue += options.scaleSmoothing*(minValue - this.currentVisMinValue);
    var valueRange = this.currentValueRange;
    var visMinValue = this.currentVisMinValue;
  
    // For each data set...
    for (var d = 0; d < this.seriesSet.length; d++) {
      canvasContext.save();
      var timeSeries = this.seriesSet[d].timeSeries;
      var dataSet = timeSeries.data;
      var seriesOptions = this.seriesSet[d].options;
  
      // Delete old data that's moved off the left of the chart.
      // We must always keep the last expired data point as we need this to draw the
      // line that comes into the chart, but any points prior to that can be removed.
      while (dataSet.length >= 2 && dataSet[1][0] < time - (dimensions.width * options.millisPerPixel)) {
        dataSet.splice(0, 1);
      }
  
      // Set style for this dataSet.
      canvasContext.lineWidth = seriesOptions.lineWidth || 1;
      canvasContext.fillStyle = seriesOptions.fillStyle;
      canvasContext.strokeStyle = seriesOptions.strokeStyle || '#ffffff';
      // Draw the line...
      canvasContext.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; i++) {
        // TODO: Deal with dataSet.length < 2.
        var x = Math.round(dimensions.width - ((time - dataSet[i][0]) / options.millisPerPixel));
        var value = dataSet[i][1];
        var offset = value - visMinValue;
        var scaledValue = dimensions.height - (valueRange ? Math.round((offset / valueRange) * dimensions.height) : 0);
        var y = Math.max(Math.min(scaledValue, dimensions.height - 1), 1); // Ensure line is always on chart.
  
        if (i == 0) {
          firstX = x;
          canvasContext.moveTo(x, y);
        }
        // Great explanation of Bezier curves: http://en.wikipedia.org/wiki/Bï¿½zier_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.
        //
        else {
          switch (options.interpolation) {
          case "line":
            canvasContext.lineTo(x,y);
            break;
          case "bezier":
          default:
            canvasContext.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;
          }
        }
  
        lastX = x, lastY = y;
      }
      if (dataSet.length > 0 && seriesOptions.fillStyle) {
        // Close up the fill region.
        canvasContext.lineTo(dimensions.width + seriesOptions.lineWidth + 1, lastY);
        canvasContext.lineTo(dimensions.width + seriesOptions.lineWidth + 1, dimensions.height + seriesOptions.lineWidth + 1);
        canvasContext.lineTo(firstX, dimensions.height + seriesOptions.lineWidth);
        canvasContext.fill();
      }
      canvasContext.stroke();
      canvasContext.closePath();
      canvasContext.restore();
    }
  
    // Draw the axis values on the chart.
    if (!options.labels.disabled) {
      canvasContext.fillStyle = options.labels.fillStyle;
      var maxValueString = parseFloat(maxValue).toFixed(2);
      var minValueString = parseFloat(minValue).toFixed(2);
      canvasContext.fillText(maxValueString, dimensions.width - canvasContext.measureText(maxValueString).width - 2, 10);
      canvasContext.fillText(minValueString, dimensions.width - canvasContext.measureText(minValueString).width - 2, dimensions.height - 2);
    }
  
    canvasContext.restore(); // See .save() above.
  }
  