/*
 * Pixastic Lib - Sepia 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.sepia = {

	process : function(params) {
		var mode = (parseInt(params.options.mode,10)||0);
		if (mode < 0) mode = 0;
		if (mode > 1) mode = 1;

		if (Pixastic.Client.hasCanvasImageData()) {
			var data = Pixastic.prepareData(params);
			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;

					if (mode) {
						// a bit faster, but not as good
						var d = data[offset] * 0.299 + data[offset+1] * 0.587 + data[offset+2] * 0.114;
						var r = (d + 39);
						var g = (d + 14);
						var b = (d - 36);
					} else {
						// Microsoft
						var or = data[offset];
						var og = data[offset+1];
						var ob = data[offset+2];
	
						var r = (or * 0.393 + og * 0.769 + ob * 0.189);
						var g = (or * 0.349 + og * 0.686 + ob * 0.168);
						var b = (or * 0.272 + og * 0.534 + ob * 0.131);
					}

					if (r < 0) r = 0; if (r > 255) r = 255;
					if (g < 0) g = 0; if (g > 255) g = 255;
					if (b < 0) b = 0; if (b > 255) b = 255;

					data[offset] = r;
					data[offset+1] = g;
					data[offset+2] = b;

				} while (--x);
			} while (--y);
			return true;
		}
	},
	checkSupport : function() {
		return Pixastic.Client.hasCanvasImageData();
	}
}