    /**
     * @class Ext.draw.Component
     * @extends Ext.Component
     *
     * The Draw Component is a surface in which sprites can be rendered. The Draw Component
     * manages and holds a `Surface` instance: an interface that has
     * an SVG or VML implementation depending on the browser capabilities and where
     * Sprites can be appended.
     * {@img Ext.draw.Component/Ext.draw.Component.png Ext.draw.Component component}
     * One way to create a draw component is:
     *
     *     var drawComponent = Ext.create('Ext.draw.Component', {
     *         viewBox: false,
     *         items: [{
     *             type: 'circle',
     *             fill: '#79BB3F',
     *             radius: 100,
     *             x: 100,
     *             y: 100
     *         }]
     *     });
     *
     *     Ext.create('Ext.Window', {
     *         width: 215,
     *         height: 235,
     *         layout: 'fit',
     *         items: [drawComponent]
     *     }).show();
     *
     * In this case we created a draw component and added a sprite to it.
     * The *type* of the sprite is *circle* so if you run this code you'll see a yellow-ish
     * circle in a Window. When setting `viewBox` to `false` we are responsible for setting the object's position and
     * dimensions accordingly.
     *
     * You can also add sprites by using the surface's add method:
     *
     *     drawComponent.surface.add({
     *         type: 'circle',
     *         fill: '#79BB3F',
     *         radius: 100,
     *         x: 100,
     *         y: 100
     *     });
     *
     * For more information on Sprites, the core elements added to a draw component's surface,
     * refer to the Ext.draw.Sprite documentation.
     */
    Ext.define('Ext.draw.Component', {

        /* Begin Definitions */

        alias: 'widget.draw',

        extend: 'Ext.Component',

        requires: [
            'Ext.draw.Surface',
            'Ext.layout.component.Draw'
        ],

        /* End Definitions */

        /**
         * @cfg {Array} enginePriority
         * Defines the priority order for which Surface implementation to use. The first
         * one supported by the current environment will be used.
         */
        enginePriority: ['Svg', 'Vml'],

        baseCls: Ext.baseCSSPrefix + 'surface',

        componentLayout: 'draw',

        /**
         * @cfg {Boolean} viewBox
         * Turn on view box support which will scale and position items in the draw component to fit to the component while
         * maintaining aspect ratio. Note that this scaling can override other sizing settings on yor items. Defaults to true.
         */
        viewBox: true,

        /**
         * @cfg {Boolean} autoSize
         * Turn on autoSize support which will set the bounding div's size to the natural size of the contents. Defaults to false.
         */
        autoSize: false,

        /**
         * @cfg {Array} gradients (optional) Define a set of gradients that can be used as `fill` property in sprites.
         * The gradients array is an array of objects with the following properties:
         *
         * <ul>
         * <li><strong>id</strong> - string - The unique name of the gradient.</li>
         * <li><strong>angle</strong> - number, optional - The angle of the gradient in degrees.</li>
         * <li><strong>stops</strong> - object - An object with numbers as keys (from 0 to 100) and style objects
         * as values</li>
         * </ul>
         *

         For example:

         <pre><code>
            gradients: [{
                id: 'gradientId',
                angle: 45,
                stops: {
                    0: {
                        color: '#555'
                    },
                    100: {
                        color: '#ddd'
                    }
                }
            },  {
                id: 'gradientId2',
                angle: 0,
                stops: {
                    0: {
                        color: '#590'
                    },
                    20: {
                        color: '#599'
                    },
                    100: {
                        color: '#ddd'
                    }
                }
            }]
         </code></pre>

         Then the sprites can use `gradientId` and `gradientId2` by setting the fill attributes to those ids, for example:

         <pre><code>
            sprite.setAttributes({
                fill: 'url(#gradientId)'
            }, true);
         </code></pre>

         */

        initComponent: function() {
            this.callParent(arguments);

            this.addEvents(
                'mousedown',
                'mouseup',
                'mousemove',
                'mouseenter',
                'mouseleave',
                'click'
            );
        },

        /**
         * @private
         *
         * Create the Surface on initial render
         */
        onRender: function() {
            var me = this,
                viewBox = me.viewBox,
                autoSize = me.autoSize,
                bbox, items, width, height, x, y;
            me.callParent(arguments);

            me.createSurface();

            items = me.surface.items;

            if (viewBox || autoSize) {
                bbox = items.getBBox();
                width = bbox.width;
                height = bbox.height;
                x = bbox.x;
                y = bbox.y;
                if (me.viewBox) {
                    me.surface.setViewBox(x, y, width, height);
                }
                else {
                    // AutoSized
                    me.autoSizeSurface();
                }
            }
        },

        //@private
        autoSizeSurface: function() {
            var me = this,
                items = me.surface.items,
                bbox = items.getBBox(),
                width = bbox.width,
                height = bbox.height;
            items.setAttributes({
                translate: {
                    x: -bbox.x,
                    //Opera has a slight offset in the y axis.
                    y: -bbox.y + (+Ext.isOpera)
                }
            }, true);
            if (me.rendered) {
                me.setSize(width, height);
            }
            else {
                me.surface.setSize(width, height);
            }
            me.el.setSize(width, height);
        },

        /**
         * Create the Surface instance. Resolves the correct Surface implementation to
         * instantiate based on the 'enginePriority' config. Once the Surface instance is
         * created you can use the handle to that instance to add sprites. For example:
         *
         <pre><code>
            drawComponent.surface.add(sprite);
         </code></pre>
         */
        createSurface: function() {
            var surface = Ext.draw.Surface.create(Ext.apply({}, {
                    width: this.width,
                    height: this.height,
                    renderTo: this.el
                }, this.initialConfig));
            this.surface = surface;

            function refire(eventName) {
                return function(e) {
                    this.fireEvent(eventName, e);
                };
            }

            surface.on({
                scope: this,
                mouseup: refire('mouseup'),
                mousedown: refire('mousedown'),
                mousemove: refire('mousemove'),
                mouseenter: refire('mouseenter'),
                mouseleave: refire('mouseleave'),
                click: refire('click')
            });
        },

        /**
         * @private
         *
         * Clean up the Surface instance on component destruction
         */
        onDestroy: function() {
            var surface = this.surface;
            if (surface) {
                surface.destroy();
            }
            this.callParent(arguments);
        }

    });