/*
 * Pixastic Lib - Invert filter - v0.1.0
 * Copyright (c) 2008 Jacob Seidelin, jseidelin@nihilogic.dk, http://blog.nihilogic.dk/
 * MIT License [http://www.opensource.org/licenses/mit-license.php]
 */

Pixastic.Actions.invert = {
	process : function(params) {
		if (Pixastic.Client.hasCanvasImageData()) {
			var data = Pixastic.prepareData(params);

			var invertAlpha = !!params.options.invertAlpha;
			var rect = params.options.rect;
			var w = rect.width;
			var h = rect.height;

			var w4 = w*4;
			var y = h;
			do {
				var offsetY = (y-1)*w4;
				var x = w;
				do {
					var offset = offsetY + (x-1)*4;
					data[offset] = 255 - data[offset];
					data[offset+1] = 255 - data[offset+1];
					data[offset+2] = 255 - data[offset+2];
					if (invertAlpha) data[offset+3] = 255 - data[offset+3];
				} while (--x);
			} while (--y);

			return true;
		} else if (Pixastic.Client.isIE()) {
			params.image.style.filter += " invert";
			return true;
		}
	},
	checkSupport : function() {
		return (Pixastic.Client.hasCanvasImageData() || Pixastic.Client.isIE());
	}
}