// 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.
// * 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;

  var IE_VERSION = +navigator.userAgent.match(/MSIE ([\d.]+)?/)[1];

  /**
   * 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, '&amp;').replace(/"/g, '&quot;');
  }

  addcallcount = 0;
  function addNamespace(doc, prefix, urn) {
	/*
	IE8 (v8.0.7600.16385 Win7/64) sometimes doesn't have the document.namespaces Object initialized by the time we get here.

	Of course we depend on those namespaces being added, but we need to give the browser time and the ability to continue what it
	was doing, so we can only use setTimeout() to wait until it is indeed ready.

	This happens despite the lazy-loading of this javascript code; probably because the lazyloader starts before the
	document has been parsed completely in IE8 (THIS IS A HUNCH; i DO NOT HAVE EVIDENCE FOR THIS JUST YET!)
	*/
	var nst = typeof(doc.namespaces);
	var nso;
	if (nst == 'object')
	{
		nso = typeof(doc.namespaces.item);
		if (nso == 'string')
		{
			nso = doc.namespaces.item; // "[object HTMLNamespaceInfoCollection]"
			var cln = nso.match(/\[object\s*(\w+)\]/);
			if (cln && cln.length == 2)
			{
				nso = cln[1];
			}
		}
	}
	if (nst != 'object' && nso != 'HTMLNamespaceInfoCollection')
	{
		var t = setTimeout(function(){
			if (addcallcount % 50 == 49)
			{
				alert('failed to init namespaces in EXCANVAS: ' + addcallcount);
				return; // fail
			}
			addNamespace(doc, prefix, urn);
			addcallcount++;
		}, 20);
		//alert('ns: ' + typeof(doc.namespaces));
		//alert('nslen: ' + doc.namespaces.length);
		return;
	}
	else
	{
		//alert('final: ' + addcallcount + ', ' + nso);
	}
	/*
    //if (!doc.namespaces[prefix]) {        // IE8 b0rks with 'invalid argument'!   v8.0.7600.16385 Win7/64
    //if (!doc.namespaces.item(prefix)) {   // IE8 b0rks with 'invalid argument'!   v8.0.7600.16385 Win7/64

	official documentation says ( http://msdn.microsoft.com/en-us/library/ms537470%28VS.85%29.aspx ):

	item(): iIndex	Required. Integer that specifies the zero-based index of the item to be returned.

	WE, however, pass in a NAMESPACE (prefix variable), so we'll have to do it another way:
	*/
	var i;
	var found = 0;
	for (i = 0; i < doc.namespaces.length; i++)
	{
		var nsi = doc.namespaces.item(i);
		if (nsi.name == prefix)
		{
			found = 1;
			break;
		}
	}
    if (!found)
	{
      doc.namespaces.add(prefix, urn, '#default#VML');
    }
  }

  function addNamespacesAndStylesheet(doc) {
    addNamespace(doc, 'g_vml_', 'urn:schemas-microsoft-com:vml');
    addNamespace(doc, 'g_o_', 'urn:schemas-microsoft-com:office:office');

    // 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) {
      var doc = opt_doc || document;
      // Create a dummy element so that IE will allow canvas elements to be
      // recognized.
      doc.createElement('canvas');
      /*
       * When lazy loading excanvas.js, the onreadystatechange event is never fired
       * because doc.readyState already reports "complete".
       */
      if(doc.readyState !== "complete"){
        doc.attachEvent('onreadystatechange', bind(this.init_, this, doc));
      } else {
        this.init_(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;
    },

    /*
    Release canvas node to prevent memory leaks (issue #82 - http://code.google.com/p/explorercanvas/issues/detail?id=82).

    This method should be called manually before destroying your reference(s) to the excanvas object.
    */
    uninitElement: function(el) {
      if (el.getContext) {
        var ctx = el.getContext();
        delete ctx.element_;
        delete ctx.canvas;
        el.innerHTML = "";
        el.context_ = null;
        el.getContext = null;
        el.detachEvent("onpropertychange", onPropertyChange);
        el.detachEvent("onresize", onResize);
      }
    }
  };

  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.charAt(3) != 'a') {
      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, s, l;
    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;
  }

  var processStyleCache = {};

  function processStyle(styleString) {
    if (styleString in processStyleCache) {
      return processStyleCache[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 = +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 processStyleCache[styleString] = {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;
  }

  var lineCapMap = {
    'butt': 'flat',
    'round': 'round'
  };

  function processLineCap(lineCap) {
    return lineCapMap[lineCap] || 'square';
  }

  // used by draw timer
  var drawDelay = 1000 / 30;  //30 "renders" a second, on average.

  /**
   * Add a block of VML to the scene. This VML will be added at some point in the future,but after this call completes.
   * @param ctx CanvasRenderingContext2D_ object.
   * @param vmlStr VML to add.
   */
  function insertVML(ctx, vmlStr) {
    ctx.vmlList_.push(vmlStr);
    startDrawTimer(ctx);
  }

  //Called exclusively by insertVML.
  function startDrawTimer(ctx) {
    if (!ctx.drawScheduled_) {
      ctx.drawScheduled_ = true;
      var timer = function () {
        drawTimerFired(ctx);
      };
      var now = new Date().getTime();
      var delay = clamp(drawDelay - (now - ctx.lastDrawn_), 1, drawDelay);
      setTimeout(timer, delay);
    }
  }

  //Called exclusively by the Draw timer.
  function drawTimerFired(ctx) {
    ctx.lastDrawn_ = new Date().getTime();
    var vml = '';
    if (ctx.vmlList_.length > 0) {
      vml = ctx.vmlList_.join('\n');
    }
    if (ctx.textMeasureEl_) {
      ctx.textMeasureEl_.removeNode(true);
      ctx.textMeasureEl_ = null;
    }
    ctx.element_.innerHTML = vml;
    ctx.drawScheduled_ = false;
  }

  /**
   * This class implements CanvasRenderingContext2D interface as described by
   * the WHATWG.
   * @param {HTMLElement} canvasElement The element that the 2D context should
   * be associated with
   */
  function CanvasRenderingContext2D_(canvasElement) {
    this.m_ = createMatrixIdentity();

    this.mStack_ = [];
    this.aStack_ = [];
    this.currentPath_ = [];

    //Draw timer properties
    this.drawScheduled_ = false;
    this.lastDrawn_ = 0;
    this.vmlList_ = [];

    // 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 = canvasElement;

    var cssText = 'width:' + canvasElement.clientWidth + 'px;height:' +
        canvasElement.clientHeight + 'px;overflow:hidden;position:absolute';
    var el = canvasElement.ownerDocument.createElement('div');
    el.style.cssText = cssText;
    canvasElement.appendChild(el);

    var overlayEl = el.cloneNode(false);
    // Use a non transparent background.
	// [i_a] removed the next few lines so the ugly red background for the MochaUI windows is GONE in IE8
    //overlayEl.style.backgroundColor = 'red';
    //overlayEl.style.filter = 'alpha(opacity=0)';
	//alert('element = ' + canvasElement.id + ', ' + canvasElement.className + ', ' + canvasElement.style);
    canvasElement.appendChild(overlayEl);

    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.vmlList_ = [];
    this.mStack_ = [];
    this.aStack_ = [];
    this.currentPath_ = [];

    startDrawTimer(this);
  };

  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 = getCoords(this, 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 = getCoords(this, 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 = getCoords(this, aX, aY);
    var cp1 = getCoords(this, aCP1x, aCP1y);
    var cp2 = getCoords(this, 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 = getCoords(this, aCPx, aCPy);
    var p = getCoords(this, 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 = getCoords(this, aX, aY);
    var pStart = getCoords(this, xStart, yStart);
    var pEnd = getCoords(this, 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 = getCoords(this, 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 = getCoords(this, dx + dw, dy);
      var c3 = getCoords(this, dx, dy + dh);
      var c4 = getCoords(this, 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>');

    insertVML(this, vmlStr.join(''));
  };

  contextPrototype.stroke = function(aFill) {
    var lineStr = [];
    var lineOpen = false;

    var W = 10;
    var H = 10;

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

    for (var i = 0; i < this.currentPath_.length; i++) {
      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>');

    insertVML(this, 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 = getCoords(ctx, x0, y0);
        var p1 = getCoords(ctx, 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 = getCoords(ctx, 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'});
  };

  function getCoords(ctx, aX, aY) {
    var m = ctx.m_;
    return {
      x: Z * (aX * m[0][0] + aY * m[1][0] + m[2][0]) - Z2,
      y: Z * (aX * m[0][1] + aY * m[1][1] + m[2][1]) - Z2
    };
  };

  contextPrototype.save = function() {
    var o = {};
    copyState(this, o);
    this.aStack_.push(o);
    this.mStack_.push(this.m_);
    this.m_ = matrixMultiply(createMatrixIdentity(), this.m_);
  };

  contextPrototype.restore = function() {
    if (this.aStack_.length) {
      copyState(this.aStack_.pop(), this);
      this.m_ = this.mStack_.pop();
    }
  };

  function matrixIsFinite(m) {
    return isFinite(m[0][0]) && isFinite(m[0][1]) &&
        isFinite(m[1][0]) && isFinite(m[1][1]) &&
        isFinite(m[2][0]) && isFinite(m[2][1]);
  }

  function setM(ctx, m, updateLineScale) {
    if (!matrixIsFinite(m)) {
      return;
    }
    ctx.m_ = m;

    if (updateLineScale) {
      // Get the line scale.
      // Determinant of this.m_ means how much the area is enlarged by the
      // transformation. So its square root can be used as a scale factor
      // for width.
      var det = m[0][0] * m[1][1] - m[0][1] * m[1][0];
      ctx.lineScale_ = sqrt(abs(det));
    }
  }

  contextPrototype.translate = function(aX, aY) {
    var m1 = [
      [1,  0,  0],
      [0,  1,  0],
      [aX, aY, 1]
    ];

    setM(this, matrixMultiply(m1, this.m_), false);
  };

  contextPrototype.rotate = function(aRot) {
    var c = mc(aRot);
    var s = ms(aRot);

    var m1 = [
      [c,  s, 0],
      [-s, c, 0],
      [0,  0, 1]
    ];

    setM(this, matrixMultiply(m1, this.m_), false);
  };

  contextPrototype.scale = function(aX, aY) {
    this.arcScaleX_ *= aX;
    this.arcScaleY_ *= aY;
    var m1 = [
      [aX, 0,  0],
      [0,  aY, 0],
      [0,  0,  1]
    ];

    setM(this, matrixMultiply(m1, this.m_), true);
  };

  contextPrototype.transform = function(m11, m12, m21, m22, dx, dy) {
    var m1 = [
      [m11, m12, 0],
      [m21, m22, 0],
      [dx,  dy,  1]
    ];

    setM(this, matrixMultiply(m1, this.m_), true);
  };

  contextPrototype.setTransform = function(m11, m12, m21, m22, dx, dy) {
    var m = [
      [m11, m12, 0],
      [m21, m22, 0],
      [dx,  dy,  1]
    ];

    setM(this, m, true);
  };

  /**
   * The text drawing function.
   * The maxWidth argument isn't taken in account, since no browser supports
   * it yet.
   */
  contextPrototype.drawText_ = function(text, x, y, maxWidth, stroke) {
    var m = this.m_,
        delta = 1000,
        left = 0,
        right = delta,
        offset = {x: 0, y: 0},
        lineStr = [];

    var fontStyle = getComputedStyle(processFontStyle(this.font),
                                     this.element_);

    var fontStyleString = buildStyle(fontStyle);

    var elementStyle = this.element_.currentStyle;
    var textAlign = this.textAlign.toLowerCase();
    switch (textAlign) {
      case 'left':
      case 'center':
      case 'right':
        break;
      case 'end':
        textAlign = elementStyle.direction == 'ltr' ? 'right' : 'left';
        break;
      case 'start':
        textAlign = elementStyle.direction == 'rtl' ? 'right' : 'left';
        break;
      default:
        textAlign = 'left';
    }

    // 1.75 is an arbitrary number, as there is no info about the text baseline
    switch (this.textBaseline) {
      case 'hanging':
      case 'top':
        offset.y = fontStyle.size / 1.75;
        break;
      case 'middle':
        break;
      default:
      case null:
      case 'alphabetic':
      case 'ideographic':
      case 'bottom':
        offset.y = -fontStyle.size / 2.25;
        break;
    }

    switch(textAlign) {
      case 'right':
        left = delta;
        right = 0.05;
        break;
      case 'center':
        left = right = delta / 2;
        break;
    }

    var d = getCoords(this, x + offset.x, y + offset.y);

    lineStr.push('<g_vml_:line from="', -left ,' 0" to="', right ,' 0.05" ',
                 ' coordsize="100 100" coordorigin="0 0"',
                 ' filled="', !stroke, '" stroked="', !!stroke,
                 '" style="position:absolute;width:1px;height:1px;">');

    if (stroke) {
      appendStroke(this, lineStr);
    } else {
      // TODO: Fix the min and max params.
      appendFill(this, lineStr, {x: -left, y: 0},
                 {x: right, y: fontStyle.size});
    }

    var skewM = m[0][0].toFixed(3) + ',' + m[1][0].toFixed(3) + ',' +
                m[0][1].toFixed(3) + ',' + m[1][1].toFixed(3) + ',0,0';

    var skewOffset = mr(d.x / Z) + ',' + mr(d.y / Z);

    lineStr.push('<g_vml_:skew on="t" matrix="', skewM ,'" ',
                 ' offset="', skewOffset, '" origin="', left ,' 0" />',
                 '<g_vml_:path textpathok="true" />',
                 '<g_vml_:textpath on="true" string="',
                 encodeHtmlAttribute(text),
                 '" style="v-text-align:', textAlign,
                 ';font:', encodeHtmlAttribute(fontStyleString),
                 '" /></g_vml_:line>');

    insertVML(this, lineStr.join(''));
  };

  contextPrototype.fillText = function(text, x, y, maxWidth) {
    this.drawText_(text, x, y, maxWidth, false);
  };

  contextPrototype.strokeText = function(text, x, y, maxWidth) {
    this.drawText_(text, x, y, maxWidth, true);
  };

  contextPrototype.measureText = function(text) {
    if (!this.textMeasureEl_) {
      var s = '<span style="position:absolute;' +
          'top:-20000px;left:0;padding:0;margin:0;border:none;' +
          'white-space:pre;"></span>';
      this.element_.insertAdjacentHTML('beforeEnd', s);
      this.textMeasureEl_ = this.element_.lastChild;
    }
    var doc = this.element_.ownerDocument;
    this.textMeasureEl_.innerHTML = '';
    this.textMeasureEl_.style.font = this.font;
    // Don't use innerHTML or innerText because they allow markup/whitespace.
    this.textMeasureEl_.appendChild(doc.createTextNode(text));
    return {width: this.textMeasureEl_.offsetWidth};
  };

  /******** STUBS ********/
  contextPrototype.clip = function() {
    // TODO: Implement
  };

  contextPrototype.arcTo = function() {
    // TODO: Implement
  };

  contextPrototype.createPattern = function(image, repetition) {
    return new CanvasPattern_(image, repetition);
  };

  // Gradient / Pattern Stubs
  function CanvasGradient_(aType) {
    this.type_ = aType;
    this.x0_ = 0;
    this.y0_ = 0;
    this.r0_ = 0;
    this.x1_ = 0;
    this.y1_ = 0;
    this.r1_ = 0;
    this.colors_ = [];
  }

  CanvasGradient_.prototype.addColorStop = function(aOffset, aColor) {
    aColor = processStyle(aColor);
    this.colors_.push({offset: aOffset,
                       color: aColor.color,
                       alpha: aColor.alpha});
  };

  function CanvasPattern_(image, repetition) {
    assertImageIsValid(image);
    switch (repetition) {
      case 'repeat':
      case null:
      case '':
        this.repetition_ = 'repeat';
        break
      case 'repeat-x':
      case 'repeat-y':
      case 'no-repeat':
        this.repetition_ = repetition;
        break;
      default:
        throwException('SYNTAX_ERR');
    }

    this.src_ = image.src;
    this.width_ = image.width;
    this.height_ = image.height;
  }

  function throwException(s) {
    throw new DOMException_(s);
  }

  function assertImageIsValid(img) {
    if (!img || img.nodeType != 1 || img.tagName != 'IMG') {
      throwException('TYPE_MISMATCH_ERR');
    }
    if (img.readyState != 'complete') {
      throwException('INVALID_STATE_ERR');
    }
  }

  function DOMException_(s) {
    this.code = this[s];
    this.message = s +': DOM Exception ' + this.code;
  }
  var p = DOMException_.prototype = new Error;
  p.INDEX_SIZE_ERR = 1;
  p.DOMSTRING_SIZE_ERR = 2;
  p.HIERARCHY_REQUEST_ERR = 3;
  p.WRONG_DOCUMENT_ERR = 4;
  p.INVALID_CHARACTER_ERR = 5;
  p.NO_DATA_ALLOWED_ERR = 6;
  p.NO_MODIFICATION_ALLOWED_ERR = 7;
  p.NOT_FOUND_ERR = 8;
  p.NOT_SUPPORTED_ERR = 9;
  p.INUSE_ATTRIBUTE_ERR = 10;
  p.INVALID_STATE_ERR = 11;
  p.SYNTAX_ERR = 12;
  p.INVALID_MODIFICATION_ERR = 13;
  p.NAMESPACE_ERR = 14;
  p.INVALID_ACCESS_ERR = 15;
  p.VALIDATION_ERR = 16;
  p.TYPE_MISMATCH_ERR = 17;

  // set up externs
  G_vmlCanvasManager = G_vmlCanvasManager_;
  CanvasRenderingContext2D = CanvasRenderingContext2D_;
  CanvasGradient = CanvasGradient_;
  CanvasPattern = CanvasPattern_;
  DOMException = DOMException_;
})();

} // if
