dojo_app/js/library/dojox/gfx/canvasext.js

define([
	"./_base",
	"./canvas"],
	function(gfx, canvas){

	/*=====
	 return {
	 	// summary:
	 	//		A module that adds canvas-specific features to the gfx api. You should require this module
	 	//		when your application specifically targets the HTML5 Canvas renderer.
	 }
	 =====*/
	
	var ext = gfx.canvasext = {};
	
	canvas.Surface.extend({
		
		getImageData: function(rect){
			// summary:
			//		Returns the canvas pixel buffer.
			// rect: dojox/gfx.Rectangle
			//		The canvas area.
			
			// flush pending renders queue, if any
			if("pendingRender" in this){
				this._render(true); // force render even if there're pendingImages
			}
			return this.rawNode.getContext("2d").getImageData(rect.x, rect.y, rect.width, rect.height);				
		},
		
		getContext: function(){
			// summary:
			//		Returns the surface CanvasRenderingContext2D.
			return this.rawNode.getContext("2d");
		}
	});		

	return ext;
});