EPSIAE » eneraptor

// Copyright 2006 Google Inc.

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//   http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

// Known Issues:

//

// * Patterns only support repeat.

// * Radial gradient are not implemented. The VML version of these look very

//   different from the canvas one.

// * Clipping paths are not implemented.

// * Coordsize. The width and height attribute have higher priority than the

//   width and height style values which isn't correct.

// * Painting mode isn't implemented.

// * Canvas width/height should is using content-box by default. IE in

//   Quirks mode will draw the canvas using border-box. Either change your

//   doctype to HTML5

//   (http://www.whatwg.org/specs/web-apps/current-work/#the-doctype)

//   or use Box Sizing Behavior from WebFX

//   (http://webfx.eae.net/dhtml/boxsizing/boxsizing.html)

// * Non uniform scaling does not correctly scale strokes.

// * Filling very large shapes (above 5000 points) is buggy.

// * Optimize. There is always room for speed improvements.

// Only add this code if we do not already have a canvas implementation

if (!document.createElement('canvas').getContext) {

(function() {

  // alias some functions to make (compiled) code shorter

  var m = Math;

  var mr = m.round;

  var ms = m.sin;

  var mc = m.cos;

  var abs = m.abs;

  var sqrt = m.sqrt;

  // this is used for sub pixel precision

  var Z = 10;

  var Z2 = Z / 2;

  /**

   * This funtion is assigned to the <canvas> elements as element.getContext().

   * @this {HTMLElement}

   * @return {CanvasRenderingContext2D_}

   */

  function getContext() {

    return this.context_ ||

        (this.context_ = new CanvasRenderingContext2D_(this));

  }

  var slice = Array.prototype.slice;

  /**

   * Binds a function to an object. The returned function will always use the

   * passed in {@code obj} as {@code this}.

   *

   * Example:

   *

   *   g = bind(f, obj, a, b)

   *   g(c, d) // will do f.call(obj, a, b, c, d)

   *

   * @param {Function} f The function to bind the object to

   * @param {Object} obj The object that should act as this when the function

   *     is called

   * @param {*} var_args Rest arguments that will be used as the initial

   *     arguments when the function is called

   * @return {Function} A new function that has bound this

   */

  function bind(f, obj, var_args) {

    var a = slice.call(arguments, 2);

    return function() {

      return f.apply(obj, a.concat(slice.call(arguments)));

    };

  }

  function encodeHtmlAttribute(s) {

    return String(s).replace(/&/g, '&').replace(/"/g, '"');

  }

  function addNamespacesAndStylesheet(doc) {

    // create xmlns

    if (!doc.namespaces['g_vml_']) {

      doc.namespaces.add('g_vml_', 'urn:schemas-microsoft-com:vml',

                         '#default#VML');

    }

    if (!doc.namespaces['g_o_']) {

      doc.namespaces.add('g_o_', 'urn:schemas-microsoft-com:office:office',

                         '#default#VML');

    }

    // Setup default CSS.  Only add one style sheet per document

    if (!doc.styleSheets['ex_canvas_']) {

      var ss = doc.createStyleSheet();

      ss.owningElement.id = 'ex_canvas_';

      ss.cssText = 'canvas{display:inline-block;overflow:hidden;' +

          // default size is 300x150 in Gecko and Opera

          'text-align:left;width:300px;height:150px}';

    }

  }

  // Add namespaces and stylesheet at startup.

  addNamespacesAndStylesheet(document);

  var G_vmlCanvasManager_ = {

    init: function(opt_doc) {

      if (/MSIE/.test(navigator.userAgent) && !window.opera) {

        var doc = opt_doc || document;

        // Create a dummy element so that IE will allow canvas elements to be

        // recognized.

        doc.createElement('canvas');

        doc.attachEvent('onreadystatechange', bind(this.init_, this, doc));

      }

    },

    init_: function(doc) {

      // find all canvas elements

      var els = doc.getElementsByTagName('canvas');

      for (var i = 0; i < els.length; i++) {

        this.initElement(els[i]);

      }

    },

    /**

     * Public initializes a canvas element so that it can be used as canvas

     * element from now on. This is called automatically before the page is

     * loaded but if you are creating elements using createElement you need to

     * make sure this is called on the element.

     * @param {HTMLElement} el The canvas element to initialize.

     * @return {HTMLElement} the element that was created.

     */

    initElement: function(el) {

      if (!el.getContext) {

        el.getContext = getContext;

        // Add namespaces and stylesheet to document of the element.

        addNamespacesAndStylesheet(el.ownerDocument);

        // Remove fallback content. There is no way to hide text nodes so we

        // just remove all childNodes. We could hide all elements and remove

        // text nodes but who really cares about the fallback content.

        el.innerHTML = '';

        // do not use inline function because that will leak memory

        el.attachEvent('onpropertychange', onPropertyChange);

        el.attachEvent('onresize', onResize);

        var attrs = el.attributes;

        if (attrs.width && attrs.width.specified) {

          // TODO: use runtimeStyle and coordsize

          // el.getContext().setWidth_(attrs.width.nodeValue);

          el.style.width = attrs.width.nodeValue + 'px';

        } else {

          el.width = el.clientWidth;

        }

        if (attrs.height && attrs.height.specified) {

          // TODO: use runtimeStyle and coordsize

          // el.getContext().setHeight_(attrs.height.nodeValue);

          el.style.height = attrs.height.nodeValue + 'px';

        } else {

          el.height = el.clientHeight;

        }

        //el.getContext().setCoordsize_()

      }

      return el;

    }

  };

  function onPropertyChange(e) {

    var el = e.srcElement;

    switch (e.propertyName) {

      case 'width':

        el.getContext().clearRect();

        el.style.width = el.attributes.width.nodeValue + 'px';

        // In IE8 this does not trigger onresize.

        el.firstChild.style.width =  el.clientWidth + 'px';

        break;

      case 'height':

        el.getContext().clearRect();

        el.style.height = el.attributes.height.nodeValue + 'px';

        el.firstChild.style.height = el.clientHeight + 'px';

        break;

    }

  }

  function onResize(e) {

    var el = e.srcElement;

    if (el.firstChild) {

      el.firstChild.style.width =  el.clientWidth + 'px';

      el.firstChild.style.height = el.clientHeight + 'px';

    }

  }

  G_vmlCanvasManager_.init();

  // precompute "00" to "FF"

  var decToHex = [];

  for (var i = 0; i < 16; i++) {

    for (var j = 0; j < 16; j++) {

      decToHex[i * 16 + j] = i.toString(16) + j.toString(16);

    }

  }

  function createMatrixIdentity() {

    return [

      [1, 0, 0],

      [0, 1, 0],

      [0, 0, 1]

    ];

  }

  function matrixMultiply(m1, m2) {

    var result = createMatrixIdentity();

    for (var x = 0; x < 3; x++) {

      for (var y = 0; y < 3; y++) {

        var sum = 0;

        for (var z = 0; z < 3; z++) {

          sum += m1[x][z] * m2[z][y];

        }

        result[x][y] = sum;

      }

    }

    return result;

  }

  function copyState(o1, o2) {

    o2.fillStyle     = o1.fillStyle;

    o2.lineCap       = o1.lineCap;

    o2.lineJoin      = o1.lineJoin;

    o2.lineWidth     = o1.lineWidth;

    o2.miterLimit    = o1.miterLimit;

    o2.shadowBlur    = o1.shadowBlur;

    o2.shadowColor   = o1.shadowColor;

    o2.shadowOffsetX = o1.shadowOffsetX;

    o2.shadowOffsetY = o1.shadowOffsetY;

    o2.strokeStyle   = o1.strokeStyle;

    o2.globalAlpha   = o1.globalAlpha;

    o2.font          = o1.font;

    o2.textAlign     = o1.textAlign;

    o2.textBaseline  = o1.textBaseline;

    o2.arcScaleX_    = o1.arcScaleX_;

    o2.arcScaleY_    = o1.arcScaleY_;

    o2.lineScale_    = o1.lineScale_;

  }

  var colorData = {

    aliceblue: '#F0F8FF',

    antiquewhite: '#FAEBD7',

    aquamarine: '#7FFFD4',

    azure: '#F0FFFF',

    beige: '#F5F5DC',

    bisque: '#FFE4C4',

    black: '#000000',

    blanchedalmond: '#FFEBCD',

    blueviolet: '#8A2BE2',

    brown: '#A52A2A',

    burlywood: '#DEB887',

    cadetblue: '#5F9EA0',

    chartreuse: '#7FFF00',

    chocolate: '#D2691E',

    coral: '#FF7F50',

    cornflowerblue: '#6495ED',

    cornsilk: '#FFF8DC',

    crimson: '#DC143C',

    cyan: '#00FFFF',

    darkblue: '#00008B',

    darkcyan: '#008B8B',

    darkgoldenrod: '#B8860B',

    darkgray: '#A9A9A9',

    darkgreen: '#006400',

    darkgrey: '#A9A9A9',

    darkkhaki: '#BDB76B',

    darkmagenta: '#8B008B',

    darkolivegreen: '#556B2F',

    darkorange: '#FF8C00',

    darkorchid: '#9932CC',

    darkred: '#8B0000',

    darksalmon: '#E9967A',

    darkseagreen: '#8FBC8F',

    darkslateblue: '#483D8B',

    darkslategray: '#2F4F4F',

    darkslategrey: '#2F4F4F',

    darkturquoise: '#00CED1',

    darkviolet: '#9400D3',

    deeppink: '#FF1493',

    deepskyblue: '#00BFFF',

    dimgray: '#696969',

    dimgrey: '#696969',

    dodgerblue: '#1E90FF',

    firebrick: '#B22222',

    floralwhite: '#FFFAF0',

    forestgreen: '#228B22',

    gainsboro: '#DCDCDC',

    ghostwhite: '#F8F8FF',

    gold: '#FFD700',

    goldenrod: '#DAA520',

    grey: '#808080',

    greenyellow: '#ADFF2F',

    honeydew: '#F0FFF0',

    hotpink: '#FF69B4',

    indianred: '#CD5C5C',

    indigo: '#4B0082',

    ivory: '#FFFFF0',

    khaki: '#F0E68C',

    lavender: '#E6E6FA',

    lavenderblush: '#FFF0F5',

    lawngreen: '#7CFC00',

    lemonchiffon: '#FFFACD',

    lightblue: '#ADD8E6',

    lightcoral: '#F08080',

    lightcyan: '#E0FFFF',

    lightgoldenrodyellow: '#FAFAD2',

    lightgreen: '#90EE90',

    lightgrey: '#D3D3D3',

    lightpink: '#FFB6C1',

    lightsalmon: '#FFA07A',

    lightseagreen: '#20B2AA',

    lightskyblue: '#87CEFA',

    lightslategray: '#778899',

    lightslategrey: '#778899',

    lightsteelblue: '#B0C4DE',

    lightyellow: '#FFFFE0',

    limegreen: '#32CD32',

    linen: '#FAF0E6',

    magenta: '#FF00FF',

    mediumaquamarine: '#66CDAA',

    mediumblue: '#0000CD',

    mediumorchid: '#BA55D3',

    mediumpurple: '#9370DB',

    mediumseagreen: '#3CB371',

    mediumslateblue: '#7B68EE',

    mediumspringgreen: '#00FA9A',

    mediumturquoise: '#48D1CC',

    mediumvioletred: '#C71585',

    midnightblue: '#191970',

    mintcream: '#F5FFFA',

    mistyrose: '#FFE4E1',

    moccasin: '#FFE4B5',

    navajowhite: '#FFDEAD',

    oldlace: '#FDF5E6',

    olivedrab: '#6B8E23',

    orange: '#FFA500',

    orangered: '#FF4500',

    orchid: '#DA70D6',

    palegoldenrod: '#EEE8AA',

    palegreen: '#98FB98',

    paleturquoise: '#AFEEEE',

    palevioletred: '#DB7093',

    papayawhip: '#FFEFD5',

    peachpuff: '#FFDAB9',

    peru: '#CD853F',

    pink: '#FFC0CB',

    plum: '#DDA0DD',

    powderblue: '#B0E0E6',

    rosybrown: '#BC8F8F',

    royalblue: '#4169E1',

    saddlebrown: '#8B4513',

    salmon: '#FA8072',

    sandybrown: '#F4A460',

    seagreen: '#2E8B57',

    seashell: '#FFF5EE',

    sienna: '#A0522D',

    skyblue: '#87CEEB',

    slateblue: '#6A5ACD',

    slategray: '#708090',

    slategrey: '#708090',

    snow: '#FFFAFA',

    springgreen: '#00FF7F',

    steelblue: '#4682B4',

    tan: '#D2B48C',

    thistle: '#D8BFD8',

    tomato: '#FF6347',

    turquoise: '#40E0D0',

    violet: '#EE82EE',

    wheat: '#F5DEB3',

    whitesmoke: '#F5F5F5',

    yellowgreen: '#9ACD32'

  };

  function getRgbHslContent(styleString) {

    var start = styleString.indexOf('(', 3);

    var end = styleString.indexOf(')', start + 1);

    var parts = styleString.substring(start + 1, end).split(',');

    // add alpha if needed

    if (parts.length == 4 && styleString.substr(3, 1) == 'a') {

      alpha = Number(parts[3]);

    } else {

      parts[3] = 1;

    }

    return parts;

  }

  function percent(s) {

    return parseFloat(s) / 100;

  }

  function clamp(v, min, max) {

    return Math.min(max, Math.max(min, v));

  }

  function hslToRgb(parts){

    var r, g, b;

    h = parseFloat(parts[0]) / 360 % 360;

    if (h < 0)

      h++;

    s = clamp(percent(parts[1]), 0, 1);

    l = clamp(percent(parts[2]), 0, 1);

    if (s == 0) {

      r = g = b = l; // achromatic

    } else {

      var q = l < 0.5 ? l * (1 + s) : l + s - l * s;

      var p = 2 * l - q;

      r = hueToRgb(p, q, h + 1 / 3);

      g = hueToRgb(p, q, h);

      b = hueToRgb(p, q, h - 1 / 3);

    }

    return '#' + decToHex[Math.floor(r * 255)] +

        decToHex[Math.floor(g * 255)] +

        decToHex[Math.floor(b * 255)];

  }

  function hueToRgb(m1, m2, h) {

    if (h < 0)

      h++;

    if (h > 1)

      h--;

    if (6 * h < 1)

      return m1 + (m2 - m1) * 6 * h;

    else if (2 * h < 1)

      return m2;

    else if (3 * h < 2)

      return m1 + (m2 - m1) * (2 / 3 - h) * 6;

    else

      return m1;

  }

  function processStyle(styleString) {

    var str, alpha = 1;

    styleString = String(styleString);

    if (styleString.charAt(0) == '#') {

      str = styleString;

    } else if (/^rgb/.test(styleString)) {

      var parts = getRgbHslContent(styleString);

      var str = '#', n;

      for (var i = 0; i < 3; i++) {

        if (parts[i].indexOf('%') != -1) {

          n = Math.floor(percent(parts[i]) * 255);

        } else {

          n = Number(parts[i]);

        }

        str += decToHex[clamp(n, 0, 255)];

      }

      alpha = parts[3];

    } else if (/^hsl/.test(styleString)) {

      var parts = getRgbHslContent(styleString);

      str = hslToRgb(parts);

      alpha = parts[3];

    } else {

      str = colorData[styleString] || styleString;

    }

    return {color: str, alpha: alpha};

  }

  var DEFAULT_STYLE = {

    style: 'normal',

    variant: 'normal',

    weight: 'normal',

    size: 10,

    family: 'sans-serif'

  };

  // Internal text style cache

  var fontStyleCache = {};

  function processFontStyle(styleString) {

    if (fontStyleCache[styleString]) {

      return fontStyleCache[styleString];

    }

    var el = document.createElement('div');

    var style = el.style;

    try {

      style.font = styleString;

    } catch (ex) {

      // Ignore failures to set to invalid font.

    }

    return fontStyleCache[styleString] = {

      style: style.fontStyle || DEFAULT_STYLE.style,

      variant: style.fontVariant || DEFAULT_STYLE.variant,

      weight: style.fontWeight || DEFAULT_STYLE.weight,

      size: style.fontSize || DEFAULT_STYLE.size,

      family: style.fontFamily || DEFAULT_STYLE.family

    };

  }

  function getComputedStyle(style, element) {

    var computedStyle = {};

    for (var p in style) {

      computedStyle[p] = style[p];

    }

    // Compute the size

    var canvasFontSize = parseFloat(element.currentStyle.fontSize),

        fontSize = parseFloat(style.size);

    if (typeof style.size == 'number') {

      computedStyle.size = style.size;

    } else if (style.size.indexOf('px') != -1) {

      computedStyle.size = fontSize;

    } else if (style.size.indexOf('em') != -1) {

      computedStyle.size = canvasFontSize * fontSize;

    } else if(style.size.indexOf('%') != -1) {

      computedStyle.size = (canvasFontSize / 100) * fontSize;

    } else if (style.size.indexOf('pt') != -1) {

      computedStyle.size = fontSize / .75;

    } else {

      computedStyle.size = canvasFontSize;

    }

    // Different scaling between normal text and VML text. This was found using

    // trial and error to get the same size as non VML text.

    computedStyle.size *= 0.981;

    return computedStyle;

  }

  function buildStyle(style) {

    return style.style + ' ' + style.variant + ' ' + style.weight + ' ' +

        style.size + 'px ' + style.family;

  }

  function processLineCap(lineCap) {

    switch (lineCap) {

      case 'butt':

        return 'flat';

      case 'round':

        return 'round';

      case 'square':

      default:

        return 'square';

    }

  }

  /**

   * This class implements CanvasRenderingContext2D interface as described by

   * the WHATWG.

   * @param {HTMLElement} surfaceElement The element that the 2D context should

   * be associated with

   */

  function CanvasRenderingContext2D_(surfaceElement) {

    this.m_ = createMatrixIdentity();

    this.mStack_ = [];

    this.aStack_ = [];

    this.currentPath_ = [];

    // Canvas context properties

    this.strokeStyle = '#000';

    this.fillStyle = '#000';

    this.lineWidth = 1;

    this.lineJoin = 'miter';

    this.lineCap = 'butt';

    this.miterLimit = Z * 1;

    this.globalAlpha = 1;

    this.font = '10px sans-serif';

    this.textAlign = 'left';

    this.textBaseline = 'alphabetic';

    this.canvas = surfaceElement;

    var el = surfaceElement.ownerDocument.createElement('div');

    el.style.width =  surfaceElement.clientWidth + 'px';

    el.style.height = surfaceElement.clientHeight + 'px';

    el.style.overflow = 'hidden';

    el.style.position = 'absolute';

    surfaceElement.appendChild(el);

    this.element_ = el;

    this.arcScaleX_ = 1;

    this.arcScaleY_ = 1;

    this.lineScale_ = 1;

  }

  var contextPrototype = CanvasRenderingContext2D_.prototype;

  contextPrototype.clearRect = function() {

    if (this.textMeasureEl_) {

      this.textMeasureEl_.removeNode(true);

      this.textMeasureEl_ = null;

    }

    this.element_.innerHTML = '';

  };

  contextPrototype.beginPath = function() {

    // TODO: Branch current matrix so that save/restore has no effect

    //       as per safari docs.

    this.currentPath_ = [];

  };

  contextPrototype.moveTo = function(aX, aY) {

    var p = this.getCoords_(aX, aY);

    this.currentPath_.push({type: 'moveTo', x: p.x, y: p.y});

    this.currentX_ = p.x;

    this.currentY_ = p.y;

  };

  contextPrototype.lineTo = function(aX, aY) {

    var p = this.getCoords_(aX, aY);

    this.currentPath_.push({type: 'lineTo', x: p.x, y: p.y});

    this.currentX_ = p.x;

    this.currentY_ = p.y;

  };

  contextPrototype.bezierCurveTo = function(aCP1x, aCP1y,

                                            aCP2x, aCP2y,

                                            aX, aY) {

    var p = this.getCoords_(aX, aY);

    var cp1 = this.getCoords_(aCP1x, aCP1y);

    var cp2 = this.getCoords_(aCP2x, aCP2y);

    bezierCurveTo(this, cp1, cp2, p);

  };

  // Helper function that takes the already fixed cordinates.

  function bezierCurveTo(self, cp1, cp2, p) {

    self.currentPath_.push({

      type: 'bezierCurveTo',

      cp1x: cp1.x,

      cp1y: cp1.y,

      cp2x: cp2.x,

      cp2y: cp2.y,

      x: p.x,

      y: p.y

    });

    self.currentX_ = p.x;

    self.currentY_ = p.y;

  }

  contextPrototype.quadraticCurveTo = function(aCPx, aCPy, aX, aY) {

    // the following is lifted almost directly from

    // http://developer.mozilla.org/en/docs/Canvas_tutorial:Drawing_shapes

    var cp = this.getCoords_(aCPx, aCPy);

    var p = this.getCoords_(aX, aY);

    var cp1 = {

      x: this.currentX_ + 2.0 / 3.0 * (cp.x - this.currentX_),

      y: this.currentY_ + 2.0 / 3.0 * (cp.y - this.currentY_)

    };

    var cp2 = {

      x: cp1.x + (p.x - this.currentX_) / 3.0,

      y: cp1.y + (p.y - this.currentY_) / 3.0

    };

    bezierCurveTo(this, cp1, cp2, p);

  };

  contextPrototype.arc = function(aX, aY, aRadius,

                                  aStartAngle, aEndAngle, aClockwise) {

    aRadius *= Z;

    var arcType = aClockwise ? 'at' : 'wa';

    var xStart = aX + mc(aStartAngle) * aRadius - Z2;

    var yStart = aY + ms(aStartAngle) * aRadius - Z2;

    var xEnd = aX + mc(aEndAngle) * aRadius - Z2;

    var yEnd = aY + ms(aEndAngle) * aRadius - Z2;

    // IE won't render arches drawn counter clockwise if xStart == xEnd.

    if (xStart == xEnd && !aClockwise) {

      xStart += 0.125; // Offset xStart by 1/80 of a pixel. Use something

                       // that can be represented in binary

    }

    var p = this.getCoords_(aX, aY);

    var pStart = this.getCoords_(xStart, yStart);

    var pEnd = this.getCoords_(xEnd, yEnd);

    this.currentPath_.push({type: arcType,

                           x: p.x,

                           y: p.y,

                           radius: aRadius,

                           xStart: pStart.x,

                           yStart: pStart.y,

                           xEnd: pEnd.x,

                           yEnd: pEnd.y});

  };

  contextPrototype.rect = function(aX, aY, aWidth, aHeight) {

    this.moveTo(aX, aY);

    this.lineTo(aX + aWidth, aY);

    this.lineTo(aX + aWidth, aY + aHeight);

    this.lineTo(aX, aY + aHeight);

    this.closePath();

  };

  contextPrototype.strokeRect = function(aX, aY, aWidth, aHeight) {

    var oldPath = this.currentPath_;

    this.beginPath();

    this.moveTo(aX, aY);

    this.lineTo(aX + aWidth, aY);

    this.lineTo(aX + aWidth, aY + aHeight);

    this.lineTo(aX, aY + aHeight);

    this.closePath();

    this.stroke();

    this.currentPath_ = oldPath;

  };

  contextPrototype.fillRect = function(aX, aY, aWidth, aHeight) {

    var oldPath = this.currentPath_;

    this.beginPath();

    this.moveTo(aX, aY);

    this.lineTo(aX + aWidth, aY);

    this.lineTo(aX + aWidth, aY + aHeight);

    this.lineTo(aX, aY + aHeight);

    this.closePath();

    this.fill();

    this.currentPath_ = oldPath;

  };

  contextPrototype.createLinearGradient = function(aX0, aY0, aX1, aY1) {

    var gradient = new CanvasGradient_('gradient');

    gradient.x0_ = aX0;

    gradient.y0_ = aY0;

    gradient.x1_ = aX1;

    gradient.y1_ = aY1;

    return gradient;

  };

  contextPrototype.createRadialGradient = function(aX0, aY0, aR0,

                                                   aX1, aY1, aR1) {

    var gradient = new CanvasGradient_('gradientradial');

    gradient.x0_ = aX0;

    gradient.y0_ = aY0;

    gradient.r0_ = aR0;

    gradient.x1_ = aX1;

    gradient.y1_ = aY1;

    gradient.r1_ = aR1;

    return gradient;

  };

  contextPrototype.drawImage = function(image, var_args) {

    var dx, dy, dw, dh, sx, sy, sw, sh;

    // to find the original width we overide the width and height

    var oldRuntimeWidth = image.runtimeStyle.width;

    var oldRuntimeHeight = image.runtimeStyle.height;

    image.runtimeStyle.width = 'auto';

    image.runtimeStyle.height = 'auto';

    // get the original size

    var w = image.width;

    var h = image.height;

    // and remove overides

    image.runtimeStyle.width = oldRuntimeWidth;

    image.runtimeStyle.height = oldRuntimeHeight;

    if (arguments.length == 3) {

      dx = arguments[1];

      dy = arguments[2];

      sx = sy = 0;

      sw = dw = w;

      sh = dh = h;

    } else if (arguments.length == 5) {

      dx = arguments[1];

      dy = arguments[2];

      dw = arguments[3];

      dh = arguments[4];

      sx = sy = 0;

      sw = w;

      sh = h;

    } else if (arguments.length == 9) {

      sx = arguments[1];

      sy = arguments[2];

      sw = arguments[3];

      sh = arguments[4];

      dx = arguments[5];

      dy = arguments[6];

      dw = arguments[7];

      dh = arguments[8];

    } else {

      throw Error('Invalid number of arguments');

    }

    var d = this.getCoords_(dx, dy);

    var w2 = sw / 2;

    var h2 = sh / 2;

    var vmlStr = [];

    var W = 10;

    var H = 10;

    // For some reason that I've now forgotten, using divs didn't work

    vmlStr.push(' <g_vml_:group',

                ' coordsize="', Z * W, ',', Z * H, '"',

                ' coordorigin="0,0"' ,

                ' style="width:', W, 'px;height:', H, 'px;position:absolute;');

    // If filters are necessary (rotation exists), create them

    // filters are bog-slow, so only create them if abbsolutely necessary

    // The following check doesn't account for skews (which don't exist

    // in the canvas spec (yet) anyway.

    if (this.m_[0][0] != 1 || this.m_[0][1] ||

        this.m_[1][1] != 1 || this.m_[1][0]) {

      var filter = [];

      // Note the 12/21 reversal

      filter.push('M11=', this.m_[0][0], ',',

                  'M12=', this.m_[1][0], ',',

                  'M21=', this.m_[0][1], ',',

                  'M22=', this.m_[1][1], ',',

                  'Dx=', mr(d.x / Z), ',',

                  'Dy=', mr(d.y / Z), '');

      // Bounding box calculation (need to minimize displayed area so that

      // filters don't waste time on unused pixels.

      var max = d;

      var c2 = this.getCoords_(dx + dw, dy);

      var c3 = this.getCoords_(dx, dy + dh);

      var c4 = this.getCoords_(dx + dw, dy + dh);

      max.x = m.max(max.x, c2.x, c3.x, c4.x);

      max.y = m.max(max.y, c2.y, c3.y, c4.y);

      vmlStr.push('padding:0 ', mr(max.x / Z), 'px ', mr(max.y / Z),

                  'px 0;filter:progid:DXImageTransform.Microsoft.Matrix(',

                  filter.join(''), ", sizingmethod='clip');");

    } else {

      vmlStr.push('top:', mr(d.y / Z), 'px;left:', mr(d.x / Z), 'px;');

    }

    vmlStr.push(' ">' ,

                '<g_vml_:image src="', image.src, '"',

                ' style="width:', Z * dw, 'px;',

                ' height:', Z * dh, 'px"',

                ' cropleft="', sx / w, '"',

                ' croptop="', sy / h, '"',

                ' cropright="', (w - sx - sw) / w, '"',

                ' cropbottom="', (h - sy - sh) / h, '"',

                ' />',

                '</g_vml_:group>');

    this.element_.insertAdjacentHTML('BeforeEnd', vmlStr.join(''));

  };

  contextPrototype.stroke = function(aFill) {

    var W = 10;

    var H = 10;

    // Divide the shape into chunks if it's too long because IE has a limit

    // somewhere for how long a VML shape can be. This simple division does

    // not work with fills, only strokes, unfortunately.

    var chunkSize = 5000;

    var min = {x: null, y: null};

    var max = {x: null, y: null};

    for (var j = 0; j < this.currentPath_.length; j += chunkSize) {

      var lineStr = [];

      var lineOpen = false;

      lineStr.push('<g_vml_:shape',

                   ' filled="', !!aFill, '"',

                   ' style="position:absolute;width:', W, 'px;height:', H, 'px;"',

                   ' coordorigin="0,0"',

                   ' coordsize="', Z * W, ',', Z * H, '"',

                   ' stroked="', !aFill, '"',

                   ' path="');

      var newSeq = false;

      for (var i = j; i < Math.min(j + chunkSize, this.currentPath_.length); i++) {

        if (i % chunkSize == 0 && i > 0) { // move into position for next chunk

          lineStr.push(' m ', mr(this.currentPath_[i-1].x), ',', mr(this.currentPath_[i-1].y));

        }

        var p = this.currentPath_[i];

        var c;

        switch (p.type) {

          case 'moveTo':

            c = p;

            lineStr.push(' m ', mr(p.x), ',', mr(p.y));

            break;

          case 'lineTo':

            lineStr.push(' l ', mr(p.x), ',', mr(p.y));

            break;

          case 'close':

            lineStr.push(' x ');

            p = null;

            break;

          case 'bezierCurveTo':

            lineStr.push(' c ',

                         mr(p.cp1x), ',', mr(p.cp1y), ',',

                         mr(p.cp2x), ',', mr(p.cp2y), ',',

                         mr(p.x), ',', mr(p.y));

            break;

          case 'at':

          case 'wa':

            lineStr.push(' ', p.type, ' ',

                         mr(p.x - this.arcScaleX_ * p.radius), ',',

                         mr(p.y - this.arcScaleY_ * p.radius), ' ',

                         mr(p.x + this.arcScaleX_ * p.radius), ',',

                         mr(p.y + this.arcScaleY_ * p.radius), ' ',

                         mr(p.xStart), ',', mr(p.yStart), ' ',

                         mr(p.xEnd), ',', mr(p.yEnd));

            break;

        }

        // TODO: Following is broken for curves due to

        //       move to proper paths.

        // Figure out dimensions so we can do gradient fills

        // properly

        if (p) {

          if (min.x == null || p.x < min.x) {

            min.x = p.x;

          }

          if (max.x == null || p.x > max.x) {

            max.x = p.x;

          }

          if (min.y == null || p.y < min.y) {

            min.y = p.y;

          }

          if (max.y == null || p.y > max.y) {

            max.y = p.y;

          }

        }

      }

      lineStr.push(' ">');

      if (!aFill) {

        appendStroke(this, lineStr);

      } else {

        appendFill(this, lineStr, min, max);

      }

      lineStr.push('</g_vml_:shape>');

      this.element_.insertAdjacentHTML('beforeEnd', lineStr.join(''));

    }

  };

  function appendStroke(ctx, lineStr) {

    var a = processStyle(ctx.strokeStyle);

    var color = a.color;

    var opacity = a.alpha * ctx.globalAlpha;

    var lineWidth = ctx.lineScale_ * ctx.lineWidth;

    // VML cannot correctly render a line if the width is less than 1px.

    // In that case, we dilute the color to make the line look thinner.

    if (lineWidth < 1) {

      opacity *= lineWidth;

    }

    lineStr.push(

      '<g_vml_:stroke',

      ' opacity="', opacity, '"',

      ' joinstyle="', ctx.lineJoin, '"',

      ' miterlimit="', ctx.miterLimit, '"',

      ' endcap="', processLineCap(ctx.lineCap), '"',

      ' weight="', lineWidth, 'px"',

      ' color="', color, '" />'

    );

  }

  function appendFill(ctx, lineStr, min, max) {

    var fillStyle = ctx.fillStyle;

    var arcScaleX = ctx.arcScaleX_;

    var arcScaleY = ctx.arcScaleY_;

    var width = max.x - min.x;

    var height = max.y - min.y;

    if (fillStyle instanceof CanvasGradient_) {

      // TODO: Gradients transformed with the transformation matrix.

      var angle = 0;

      var focus = {x: 0, y: 0};

      // additional offset

      var shift = 0;

      // scale factor for offset

      var expansion = 1;

      if (fillStyle.type_ == 'gradient') {

        var x0 = fillStyle.x0_ / arcScaleX;

        var y0 = fillStyle.y0_ / arcScaleY;

        var x1 = fillStyle.x1_ / arcScaleX;

        var y1 = fillStyle.y1_ / arcScaleY;

        var p0 = ctx.getCoords_(x0, y0);

        var p1 = ctx.getCoords_(x1, y1);

        var dx = p1.x - p0.x;

        var dy = p1.y - p0.y;

        angle = Math.atan2(dx, dy) * 180 / Math.PI;

        // The angle should be a non-negative number.

        if (angle < 0) {

          angle += 360;

        }

        // Very small angles produce an unexpected result because they are

        // converted to a scientific notation string.

        if (angle < 1e-6) {

          angle = 0;

        }

      } else {

        var p0 = ctx.getCoords_(fillStyle.x0_, fillStyle.y0_);

        focus = {

          x: (p0.x - min.x) / width,

          y: (p0.y - min.y) / height

        };

        width  /= arcScaleX * Z;

        height /= arcScaleY * Z;

        var dimension = m.max(width, height);

        shift = 2 * fillStyle.r0_ / dimension;

        expansion = 2 * fillStyle.r1_ / dimension - shift;

      }

      // We need to sort the color stops in ascending order by offset,

      // otherwise IE won't interpret it correctly.

      var stops = fillStyle.colors_;

      stops.sort(function(cs1, cs2) {

        return cs1.offset - cs2.offset;

      });

      var length = stops.length;

      var color1 = stops[0].color;

      var color2 = stops[length - 1].color;

      var opacity1 = stops[0].alpha * ctx.globalAlpha;

      var opacity2 = stops[length - 1].alpha * ctx.globalAlpha;

      var colors = [];

      for (var i = 0; i < length; i++) {

        var stop = stops[i];

        colors.push(stop.offset * expansion + shift + ' ' + stop.color);

      }

      // When colors attribute is used, the meanings of opacity and o:opacity2

      // are reversed.

      lineStr.push('<g_vml_:fill type="', fillStyle.type_, '"',

                   ' method="none" focus="100%"',

                   ' color="', color1, '"',

                   ' color2="', color2, '"',

                   ' colors="', colors.join(','), '"',

                   ' opacity="', opacity2, '"',

                   ' g_o_:opacity2="', opacity1, '"',

                   ' angle="', angle, '"',

                   ' focusposition="', focus.x, ',', focus.y, '" />');

    } else if (fillStyle instanceof CanvasPattern_) {

      if (width && height) {

        var deltaLeft = -min.x;

        var deltaTop = -min.y;

        lineStr.push('<g_vml_:fill',

                     ' position="',

                     deltaLeft / width * arcScaleX * arcScaleX, ',',

                     deltaTop / height * arcScaleY * arcScaleY, '"',

                     ' type="tile"',

                     // TODO: Figure out the correct size to fit the scale.

                     //' size="', w, 'px ', h, 'px"',

                     ' src="', fillStyle.src_, '" />');

       }

    } else {

      var a = processStyle(ctx.fillStyle);

      var color = a.color;

      var opacity = a.alpha * ctx.globalAlpha;

      lineStr.push('<g_vml_:fill color="', color, '" opacity="', opacity,

                   '" />');

    }

  }

  contextPrototype.fill = function() {

    this.stroke(true);

  };

  contextPrototype.closePath = function() {

    this.currentPath_.push({type: 'close'});