/*
 * Pixastic Lib - Desaturation filter - v0.1.1
 * Copyright (c) 2008 Jacob Seidelin, jseidelin@nihilogic.dk, http://blog.nihilogic.dk/
 * MIT License [http://www.opensource.org/licenses/mit-license.php]
 */

Pixastic.Actions.desaturate = {

	process : function(params) {
		var useAverage = !!params.options.average;

		if (Pixastic.Client.hasCanvasImageData()) {
			var data = Pixastic.prepareData(params);
			var rect = params.options.rect;
			var w = rect.width;
			var h = rect.height;

			var p = w*h;
			var pix = p*4, pix1, pix2;

			if (useAverage) {
				while (p--) 
					data[pix-=4] = data[pix1=pix+1] = data[pix2=pix+2] = (data[pix]+data[pix1]+data[pix2])/3
			} else {
				while (p--)
					data[pix-=4] = data[pix1=pix+1] = data[pix2=pix+2] = (data[pix]*0.3 + data[pix1]*0.59 + data[pix2]*0.11);
			}
			return true;
		} else if (Pixastic.Client.isIE()) {
			params.image.style.filter += " gray";
			return true;
		}
	},
	checkSupport : function() {
		return (Pixastic.Client.hasCanvasImageData() || Pixastic.Client.isIE());
	}
}