Speed up CanvasProvider.

src/util/CanvasProvider.js

@@ -1,17 +1,32 @@
+// TODO: it might be better to make a ContextProvider class, since you
+// can always find the canvas through context.canvas. This saves code and 
+// speed by not having to do canvas.getContext('2d')
+// TODO: Run through the canvas array to find a canvas with the requested
+// width / height, so we don't need to resize it?
 CanvasProvider = {
 	canvases: [],
 	getCanvas: function(size) {
-		var canvas = this.canvases.length
-			? this.canvases.pop()
-			: document.createElement('canvas');
-		canvas.width = size.width;
-		canvas.height = size.height;
-		return canvas;
+		if(this.canvases.length) {
+			var canvas = this.canvases.pop();
+			// If they are not the same size, we don't need to clear them
+			// using clearRect and visa versa.
+			if((canvas.width != size.width) ||  (canvas.height != size.height)) {
+				canvas.width = size.width;
+				canvas.height = size.height;
+			} else {
+				var context = canvas.getContext('2d');
+				context.clearRect(0, 0, size.width + 1, size.height + 1);
+			}
+			return canvas;
+		} else {
+			var canvas = document.createElement('canvas');
+			canvas.width = size.width;
+			canvas.height = size.height;
+			return canvas;
+		}
 	},
 
 	returnCanvas: function(canvas) {
-		// reset canvas:
-		canvas.width = canvas.width;
 		this.canvases.push(canvas);
 	}
-};
+};