File: graphics/js/VMLGraphic.js

            /**
             * <a href="http://www.w3.org/TR/NOTE-VML">VML</a> implementation of the <a href="Graphic.html">`Graphic`</a> class.
             * `VMLGraphic` is not intended to be used directly. Instead, use the <a href="Graphic.html">`Graphic`</a> class.
             * If the browser lacks <a href="http://www.w3.org/TR/SVG/">SVG</a> and <a href="http://www.w3.org/TR/html5/the-canvas-element.html">Canvas</a>
             * capabilities, the <a href="Graphic.html">`Graphic`</a> class will point to the `VMLGraphic` class.
             *
             * @module graphics
             * @class VMLGraphic
             * @constructor
             */
            VMLGraphic = function() {
                VMLGraphic.superclass.constructor.apply(this, arguments);
            };
            
            VMLGraphic.NAME = "vmlGraphic";
            
            VMLGraphic.ATTRS = {
                /**
                 * Whether or not to render the `Graphic` automatically after to a specified parent node after init. This can be a Node
                 * instance or a CSS selector string.
                 *
                 * @config render
                 * @type Node | String
                 */
                render: {},
            
                /**
            	 * Unique id for class instance.
            	 *
            	 * @config id
            	 * @type String
            	 */
            	id: {
            		valueFn: function()
            		{
            			return Y.guid();
            		},
            
            		setter: function(val)
            		{
            			var node = this._node;
            			if(node)
            			{
            				node.setAttribute("id", val);
            			}
            			return val;
            		}
            	},
            
                /**
                 * Key value pairs in which a shape instance is associated with its id.
                 *
                 *  @config shapes
                 *  @type Object
                 *  @readOnly
                 */
                shapes: {
                    readOnly: true,
            
                    getter: function()
                    {
                        return this._shapes;
                    }
                },
            
                /**
                 *  Object containing size and coordinate data for the content of a Graphic in relation to the coordSpace node.
                 *
                 *  @config contentBounds
                 *  @type Object
                 */
                contentBounds: {
                    readOnly: true,
            
                    getter: function()
                    {
                        return this._contentBounds;
                    }
                },
            
                /**
                 *  The html element that represents to coordinate system of the Graphic instance.
                 *
                 *  @config node
                 *  @type HTMLElement
                 */
                node: {
                    readOnly: true,
            
                    getter: function()
                    {
                        return this._node;
                    }
                },
            
            	/**
            	 * Indicates the width of the `Graphic`.
            	 *
            	 * @config width
            	 * @type Number
            	 */
                width: {
                    setter: function(val)
                    {
                        if(this._node)
                        {
                            this._node.style.width = val + "px";
                        }
                        return val;
                    }
                },
            
            	/**
            	 * Indicates the height of the `Graphic`.
            	 *
            	 * @config height
            	 * @type Number
            	 */
                height: {
                    setter: function(val)
                    {
                        if(this._node)
                        {
                            this._node.style.height = val + "px";
                        }
                        return val;
                    }
                },
            
                /**
                 *  Determines the sizing of the Graphic.
                 *
                 *  <dl>
                 *      <dt>sizeContentToGraphic</dt><dd>The Graphic's width and height attributes are, either explicitly set through the
                 *      <code>width</code> and <code>height</code> attributes or are determined by the dimensions of the parent element. The
                 *      content contained in the Graphic will be sized to fit with in the Graphic instance's dimensions. When using this
                 *      setting, the <code>preserveAspectRatio</code> attribute will determine how the contents are sized.</dd>
                 *      <dt>sizeGraphicToContent</dt><dd>(Also accepts a value of true) The Graphic's width and height are determined by the
                 *      size and positioning of the content.</dd>
                 *      <dt>false</dt><dd>The Graphic's width and height attributes are, either explicitly set through the <code>width</code>
                 *      and <code>height</code> attributes or are determined by the dimensions of the parent element. The contents of the
                 *      Graphic instance are not affected by this setting.</dd>
                 *  </dl>
                 *
                 *
                 *  @config autoSize
                 *  @type Boolean | String
                 *  @default false
                 */
                autoSize: {
                    value: false
                },
            
                /**
                 * Determines how content is sized when <code>autoSize</code> is set to <code>sizeContentToGraphic</code>.
                 *
                 *  <dl>
                 *      <dt>none<dt><dd>Do not force uniform scaling. Scale the graphic content of the given element non-uniformly if necessary
                 *      such that the element's bounding box exactly matches the viewport rectangle.</dd>
                 *      <dt>xMinYMin</dt><dd>Force uniform scaling position along the top left of the Graphic's node.</dd>
                 *      <dt>xMidYMin</dt><dd>Force uniform scaling horizontally centered and positioned at the top of the Graphic's node.<dd>
                 *      <dt>xMaxYMin</dt><dd>Force uniform scaling positioned horizontally from the right and vertically from the top.</dd>
                 *      <dt>xMinYMid</dt>Force uniform scaling positioned horizontally from the left and vertically centered.</dd>
                 *      <dt>xMidYMid (the default)</dt><dd>Force uniform scaling with the content centered.</dd>
                 *      <dt>xMaxYMid</dt><dd>Force uniform scaling positioned horizontally from the right and vertically centered.</dd>
                 *      <dt>xMinYMax</dt><dd>Force uniform scaling positioned horizontally from the left and vertically from the bottom.</dd>
                 *      <dt>xMidYMax</dt><dd>Force uniform scaling horizontally centered and position vertically from the bottom.</dd>
                 *      <dt>xMaxYMax</dt><dd>Force uniform scaling positioned horizontally from the right and vertically from the bottom.</dd>
                 *  </dl>
                 *
                 * @config preserveAspectRatio
                 * @type String
                 * @default xMidYMid
                 */
                preserveAspectRatio: {
                    value: "xMidYMid"
                },
            
                /**
                 * The contentBounds will resize to greater values but not values. (for performance)
                 * When resizing the contentBounds down is desirable, set the resizeDown value to true.
                 *
                 * @config resizeDown
                 * @type Boolean
                 */
                resizeDown: {
                    resizeDown: false
                },
            
            	/**
            	 * Indicates the x-coordinate for the instance.
            	 *
            	 * @config x
            	 * @type Number
            	 */
                x: {
                    getter: function()
                    {
                        return this._x;
                    },
            
                    setter: function(val)
                    {
                        this._x = val;
                        if(this._node)
                        {
                            this._node.style.left = val + "px";
                        }
                        return val;
                    }
                },
            
            	/**
            	 * Indicates the y-coordinate for the instance.
            	 *
            	 * @config y
            	 * @type Number
            	 */
                y: {
                    getter: function()
                    {
                        return this._y;
                    },
            
                    setter: function(val)
                    {
                        this._y = val;
                        if(this._node)
                        {
                            this._node.style.top = val + "px";
                        }
                        return val;
                    }
                },
            
                /**
                 * Indicates whether or not the instance will automatically redraw after a change is made to a shape.
                 * This property will get set to false when batching operations.
                 *
                 * @config autoDraw
                 * @type Boolean
                 * @default true
                 * @private
                 */
                autoDraw: {
                    value: true
                },
            
                visible: {
                    value: true,
            
                    setter: function(val)
                    {
                        this._toggleVisible(val);
                        return val;
                    }
                }
            };
            
            Y.extend(VMLGraphic, Y.GraphicBase, {
                /**
                 * Sets the value of an attribute.
                 *
                 * @method set
                 * @param {String|Object} name The name of the attribute. Alternatively, an object of key value pairs can
                 * be passed in to set multiple attributes at once.
                 * @param {Any} value The value to set the attribute to. This value is ignored if an object is received as
                 * the name param.
                 */
            	set: function()
            	{
            		var host = this,
                        attr = arguments[0],
                        redrawAttrs = {
                            autoDraw: true,
                            autoSize: true,
                            preserveAspectRatio: true,
                            resizeDown: true
                        },
                        key,
                        forceRedraw = false;
            		AttributeLite.prototype.set.apply(host, arguments);
                    if(host._state.autoDraw === true && Y.Object.size(this._shapes) > 0)
                    {
                        if(Y_LANG.isString && redrawAttrs[attr])
                        {
                            forceRedraw = true;
                        }
                        else if(Y_LANG.isObject(attr))
                        {
                            for(key in redrawAttrs)
                            {
                                if(redrawAttrs.hasOwnProperty(key) && attr[key])
                                {
                                    forceRedraw = true;
                                    break;
                                }
                            }
                        }
                    }
                    if(forceRedraw)
                    {
                        host._redraw();
                    }
            	},
            
                /**
                 * Storage for `x` attribute.
                 *
                 * @property _x
                 * @type Number
                 * @private
                 */
                _x: 0,
            
                /**
                 * Storage for `y` attribute.
                 *
                 * @property _y
                 * @type Number
                 * @private
                 */
                _y: 0,
            
                /**
                 * Gets the current position of the graphic instance in page coordinates.
                 *
                 * @method getXY
                 * @return Array The XY position of the shape.
                 */
                getXY: function()
                {
                    var node = this.parentNode,
                        x = this.get("x"),
                        y = this.get("y"),
                        xy;
                    if(node)
                    {
                        xy = Y.DOM.getXY(node);
                        xy[0] += x;
                        xy[1] += y;
                    }
                    else
                    {
                        xy = Y.DOM._getOffset(this._node);
                    }
                    return xy;
                },
            
                /**
                 * Initializes the class.
                 *
                 * @method initializer
                 * @private
                 */
                initializer: function() {
                    var render = this.get("render"),
                        visibility = this.get("visible") ? "visible" : "hidden";
                    this._shapes = {};
            		this._contentBounds = {
                        left: 0,
                        top: 0,
                        right: 0,
                        bottom: 0
                    };
                    this._node = this._createGraphic();
                    this._node.style.left = this.get("x") + "px";
                    this._node.style.top = this.get("y") + "px";
                    this._node.style.visibility = visibility;
                    this._node.setAttribute("id", this.get("id"));
                    if(render)
                    {
                        this.render(render);
                    }
                },
            
                /**
                 * Adds the graphics node to the dom.
                 *
                 * @method render
                 * @param {HTMLElement} parentNode node in which to render the graphics node into.
                 */
                render: function(render) {
                    var parentNode = render || DOCUMENT.body,
                        node = this._node,
                        w,
                        h;
                    if(render instanceof Y.Node)
                    {
                        parentNode = render._node;
                    }
                    else if(Y.Lang.isString(render))
                    {
                        parentNode = Y.Selector.query(render, DOCUMENT.body, true);
                    }
                    w = this.get("width") || parseInt(Y.DOM.getComputedStyle(parentNode, "width"), 10);
                    h = this.get("height") || parseInt(Y.DOM.getComputedStyle(parentNode, "height"), 10);
                    parentNode.appendChild(node);
                    this.parentNode = parentNode;
                    this.set("width", w);
                    this.set("height", h);
                    return this;
                },
            
                /**
                 * Removes all nodes.
                 *
                 * @method destroy
                 */
                destroy: function()
                {
                    this.removeAllShapes();
                    if(this._node)
                    {
                        this._removeChildren(this._node);
                        if(this._node.parentNode)
                        {
                            this._node.parentNode.removeChild(this._node);
                        }
                        this._node = null;
                    }
                },
            
                /**
                 * Generates a shape instance by type.
                 *
                 * @method addShape
                 * @param {Object} cfg attributes for the shape
                 * @return Shape
                 */
                addShape: function(cfg)
                {
                    cfg.graphic = this;
                    if(!this.get("visible"))
                    {
                        cfg.visible = false;
                    }
                    var ShapeClass = this._getShapeClass(cfg.type),
                        shape = new ShapeClass(cfg);
                    this._appendShape(shape);
                    shape._appendStrokeAndFill();
                    return shape;
                },
            
                /**
                 * Adds a shape instance to the graphic instance.
                 *
                 * @method _appendShape
                 * @param {Shape} shape The shape instance to be added to the graphic.
                 * @private
                 */
                _appendShape: function(shape)
                {
                    var node = shape.node,
                        parentNode = this._frag || this._node;
                    if(this.get("autoDraw") || this.get("autoSize") === "sizeContentToGraphic")
                    {
                        parentNode.appendChild(node);
                    }
                    else
                    {
                        this._getDocFrag().appendChild(node);
                    }
                },
            
                /**
                 * Removes a shape instance from from the graphic instance.
                 *
                 * @method removeShape
                 * @param {Shape|String} shape The instance or id of the shape to be removed.
                 */
                removeShape: function(shape)
                {
                    if(!(shape instanceof VMLShape))
                    {
                        if(Y_LANG.isString(shape))
                        {
                            shape = this._shapes[shape];
                        }
                    }
                    if(shape && (shape instanceof VMLShape))
                    {
                        shape._destroy();
                        this._shapes[shape.get("id")] = null;
                        delete this._shapes[shape.get("id")];
                    }
                    if(this.get("autoDraw"))
                    {
                        this._redraw();
                    }
                },
            
                /**
                 * Removes all shape instances from the dom.
                 *
                 * @method removeAllShapes
                 */
                removeAllShapes: function()
                {
                    var shapes = this._shapes,
                        i;
                    for(i in shapes)
                    {
                        if(shapes.hasOwnProperty(i))
                        {
                            shapes[i].destroy();
                        }
                    }
                    this._shapes = {};
                },
            
                /**
                 * Removes all child nodes.
                 *
                 * @method _removeChildren
                 * @param node
                 * @private
                 */
                _removeChildren: function(node)
                {
                    if(node.hasChildNodes())
                    {
                        var child;
                        while(node.firstChild)
                        {
                            child = node.firstChild;
                            this._removeChildren(child);
                            node.removeChild(child);
                        }
                    }
                },
            
                /**
                 * Clears the graphics object.
                 *
                 * @method clear
                 */
                clear: function() {
                    this.removeAllShapes();
                    this._removeChildren(this._node);
                },
            
                /**
                 * Toggles visibility
                 *
                 * @method _toggleVisible
                 * @param {Boolean} val indicates visibilitye
                 * @private
                 */
                _toggleVisible: function(val)
                {
                    var i,
                        shapes = this._shapes,
                        visibility = val ? "visible" : "hidden";
                    if(shapes)
                    {
                        for(i in shapes)
                        {
                            if(shapes.hasOwnProperty(i))
                            {
                                shapes[i].set("visible", val);
                            }
                        }
                    }
                    if(this._node)
                    {
                        this._node.style.visibility = visibility;
                    }
                    if(this._node)
                    {
                        this._node.style.visibility = visibility;
                    }
                },
            
                /**
                 * Sets the size of the graphics object.
                 *
                 * @method setSize
                 * @param w {Number} width to set for the instance.
                 * @param h {Number} height to set for the instance.
                 */
                setSize: function(w, h) {
                    w = Math.round(w);
                    h = Math.round(h);
                    this._node.style.width = w + 'px';
                    this._node.style.height = h + 'px';
                },
            
                /**
                 * Sets the positon of the graphics object.
                 *
                 * @method setPosition
                 * @param {Number} x x-coordinate for the object.
                 * @param {Number} y y-coordinate for the object.
                 */
                setPosition: function(x, y)
                {
                    x = Math.round(x);
                    y = Math.round(y);
                    this._node.style.left = x + "px";
                    this._node.style.top = y + "px";
                },
            
                /**
                 * Creates a group element
                 *
                 * @method _createGraphic
                 * @private
                 */
                _createGraphic: function() {
                    var group = DOCUMENT.createElement(
                        '<group xmlns="urn:schemas-microsft.com:vml"' +
                        ' style="behavior:url(#default#VML);padding:0px 0px 0px 0px;display:block;position:absolute;top:0px;left:0px;zoom:1;"' +
                        '/>'
                    );
                    return group;
                },
            
                /**
                 * Creates a graphic node
                 *
                 * @method _createGraphicNode
                 * @param {String} type node type to create
                 * @param {String} pe specified pointer-events value
                 * @return HTMLElement
                 * @private
                 */
                _createGraphicNode: function(type)
                {
                    return DOCUMENT.createElement(
                        '<' +
                        type +
                        ' xmlns="urn:schemas-microsft.com:vml"' +
                        ' style="behavior:url(#default#VML);display:inline-block;zoom:1;"' +
                        '/>'
                    );
            
                },
            
                /**
                 * Returns a shape based on the id of its dom node.
                 *
                 * @method getShapeById
                 * @param {String} id Dom id of the shape's node attribute.
                 * @return Shape
                 */
                getShapeById: function(id)
                {
                    return this._shapes[id];
                },
            
                /**
                 * Returns a shape class. Used by `addShape`.
                 *
                 * @method _getShapeClass
                 * @param {Shape | String} val Indicates which shape class.
                 * @return Function
                 * @private
                 */
                _getShapeClass: function(val)
                {
                    var shape = this._shapeClass[val];
                    if(shape)
                    {
                        return shape;
                    }
                    return val;
                },
            
                /**
                 * Look up for shape classes. Used by `addShape` to retrieve a class for instantiation.
                 *
                 * @property _shapeClass
                 * @type Object
                 * @private
                 */
                _shapeClass: {
                    circle: Y.VMLCircle,
                    rect: Y.VMLRect,
                    path: Y.VMLPath,
                    ellipse: Y.VMLEllipse,
                    pieslice: Y.VMLPieSlice
                },
            
            	/**
            	 * Allows for creating multiple shapes in order to batch appending and redraw operations.
            	 *
            	 * @method batch
            	 * @param {Function} method Method to execute.
            	 */
                batch: function(method)
                {
                    var autoDraw = this.get("autoDraw");
                    this.set("autoDraw", false);
                    method.apply();
                    this.set("autoDraw", autoDraw);
                },
            
                /**
                 * Returns a document fragment to for attaching shapes.
                 *
                 * @method _getDocFrag
                 * @return DocumentFragment
                 * @private
                 */
                _getDocFrag: function()
                {
                    if(!this._frag)
                    {
                        this._frag = DOCUMENT.createDocumentFragment();
                    }
                    return this._frag;
                },
            
                /**
                 * Adds a shape to the redraw queue and calculates the contentBounds.
                 *
                 * @method addToRedrawQueue
                 * @param shape {VMLShape}
                 * @protected
                 */
                addToRedrawQueue: function(shape)
                {
                    var shapeBox,
                        box;
                    this._shapes[shape.get("id")] = shape;
                    if(!this.get("resizeDown"))
                    {
                        shapeBox = shape.getBounds();
                        box = this._contentBounds;
                        box.left = box.left < shapeBox.left ? box.left : shapeBox.left;
                        box.top = box.top < shapeBox.top ? box.top : shapeBox.top;
                        box.right = box.right > shapeBox.right ? box.right : shapeBox.right;
                        box.bottom = box.bottom > shapeBox.bottom ? box.bottom : shapeBox.bottom;
                        box.width = box.right - box.left;
                        box.height = box.bottom - box.top;
                        this._contentBounds = box;
                    }
                    if(this.get("autoDraw"))
                    {
                        this._redraw();
                    }
                },
            
                /**
                 * Redraws all shapes.
                 *
                 * @method _redraw
                 * @private
                 */
                _redraw: function()
                {
                    var autoSize = this.get("autoSize"),
                        preserveAspectRatio,
                        node = this.parentNode,
                        nodeWidth = parseFloat(Y.DOM.getComputedStyle(node, "width")),
                        nodeHeight = parseFloat(Y.DOM.getComputedStyle(node, "height")),
                        xCoordOrigin = 0,
                        yCoordOrigin = 0,
                        box = this.get("resizeDown") ? this._getUpdatedContentBounds() : this._contentBounds,
                        left = box.left,
                        right = box.right,
                        top = box.top,
                        bottom = box.bottom,
                        contentWidth = right - left,
                        contentHeight = bottom - top,
                        aspectRatio,
                        xCoordSize,
                        yCoordSize,
                        scaledWidth,
                        scaledHeight,
                        visible = this.get("visible");
                    this._node.style.visibility = "hidden";
                    if(autoSize)
                    {
                        if(autoSize === "sizeContentToGraphic")
                        {
                            preserveAspectRatio = this.get("preserveAspectRatio");
                            if(preserveAspectRatio === "none" || contentWidth/contentHeight === nodeWidth/nodeHeight)
                            {
                                xCoordOrigin = left;
                                yCoordOrigin = top;
                                xCoordSize = contentWidth;
                                yCoordSize = contentHeight;
                            }
                            else
                            {
                                if(contentWidth * nodeHeight/contentHeight > nodeWidth)
                                {
                                    aspectRatio = nodeHeight/nodeWidth;
                                    xCoordSize = contentWidth;
                                    yCoordSize = contentWidth * aspectRatio;
                                    scaledHeight = (nodeWidth * (contentHeight/contentWidth)) * (yCoordSize/nodeHeight);
                                    yCoordOrigin = this._calculateCoordOrigin(preserveAspectRatio.slice(5).toLowerCase(), scaledHeight, yCoordSize);
                                    yCoordOrigin = top + yCoordOrigin;
                                    xCoordOrigin = left;
                                }
                                else
                                {
                                    aspectRatio = nodeWidth/nodeHeight;
                                    xCoordSize = contentHeight * aspectRatio;
                                    yCoordSize = contentHeight;
                                    scaledWidth = (nodeHeight * (contentWidth/contentHeight)) * (xCoordSize/nodeWidth);
                                    xCoordOrigin = this._calculateCoordOrigin(preserveAspectRatio.slice(1, 4).toLowerCase(), scaledWidth, xCoordSize);
                                    xCoordOrigin = xCoordOrigin + left;
                                    yCoordOrigin = top;
                                }
                            }
                            this._node.style.width = nodeWidth + "px";
                            this._node.style.height = nodeHeight + "px";
                            this._node.coordOrigin = xCoordOrigin + ", " + yCoordOrigin;
                        }
                        else
                        {
                            xCoordSize = contentWidth;
                            yCoordSize = contentHeight;
                            this._node.style.width = contentWidth + "px";
                            this._node.style.height = contentHeight + "px";
                            this._state.width = contentWidth;
                            this._state.height =  contentHeight;
            
                        }
                        this._node.coordSize = xCoordSize + ", " + yCoordSize;
                    }
                    else
                    {
                        this._node.style.width = nodeWidth + "px";
                        this._node.style.height = nodeHeight + "px";
                        this._node.coordSize = nodeWidth + ", " + nodeHeight;
                    }
                    if(this._frag)
                    {
                        this._node.appendChild(this._frag);
                        this._frag = null;
                    }
                    if(visible)
                    {
                        this._node.style.visibility = "visible";
                    }
                },
            
                /**
                 * Determines the value for either an x or y coordinate to be used for the <code>coordOrigin</code> of the Graphic.
                 *
                 * @method _calculateCoordOrigin
                 * @param {String} position The position for placement. Possible values are min, mid and max.
                 * @param {Number} size The total scaled size of the content.
                 * @param {Number} coordsSize The coordsSize for the Graphic.
                 * @return Number
                 * @private
                 */
                _calculateCoordOrigin: function(position, size, coordsSize)
                {
                    var coord;
                    switch(position)
                    {
                        case "min" :
                            coord = 0;
                        break;
                        case "mid" :
                            coord = (size - coordsSize)/2;
                        break;
                        case "max" :
                            coord = (size - coordsSize);
                        break;
                    }
                    return coord;
                },
            
                /**
                 * Recalculates and returns the `contentBounds` for the `Graphic` instance.
                 *
                 * @method _getUpdatedContentBounds
                 * @return {Object}
                 * @private
                 */
                _getUpdatedContentBounds: function()
                {
                    var bounds,
                        i,
                        shape,
                        queue = this._shapes,
                        box = {};
                    for(i in queue)
                    {
                        if(queue.hasOwnProperty(i))
                        {
                            shape = queue[i];
                            bounds = shape.getBounds();
                            box.left = Y_LANG.isNumber(box.left) ? Math.min(box.left, bounds.left) : bounds.left;
                            box.top = Y_LANG.isNumber(box.top) ? Math.min(box.top, bounds.top) : bounds.top;
                            box.right = Y_LANG.isNumber(box.right) ? Math.max(box.right, bounds.right) : bounds.right;
                            box.bottom = Y_LANG.isNumber(box.bottom) ? Math.max(box.bottom, bounds.bottom) : bounds.bottom;
                        }
                    }
                    box.left = Y_LANG.isNumber(box.left) ? box.left : 0;
                    box.top = Y_LANG.isNumber(box.top) ? box.top : 0;
                    box.right = Y_LANG.isNumber(box.right) ? box.right : 0;
                    box.bottom = Y_LANG.isNumber(box.bottom) ? box.bottom : 0;
                    this._contentBounds = box;
                    return box;
                },
            
                /**
                 * Inserts shape on the top of the tree.
                 *
                 * @method _toFront
                 * @param {VMLShape} Shape to add.
                 * @private
                 */
                _toFront: function(shape)
                {
                    var contentNode = this._node;
                    if(shape instanceof Y.VMLShape)
                    {
                        shape = shape.get("node");
                    }
                    if(contentNode && shape)
                    {
                        contentNode.appendChild(shape);
                    }
                },
            
                /**
                 * Inserts shape as the first child of the content node.
                 *
                 * @method _toBack
                 * @param {VMLShape} Shape to add.
                 * @private
                 */
                _toBack: function(shape)
                {
                    var contentNode = this._node,
                        targetNode;
                    if(shape instanceof Y.VMLShape)
                    {
                        shape = shape.get("node");
                    }
                    if(contentNode && shape)
                    {
                        targetNode = contentNode.firstChild;
                        if(targetNode)
                        {
                            contentNode.insertBefore(shape, targetNode);
                        }
                        else
                        {
                            contentNode.appendChild(shape);
                        }
                    }
                }
            });
            Y.VMLGraphic = VMLGraphic;