Added Sepia Filter

Add Sepia Filter from Pixastic Library

src/filters/Sepia.js

@@ -0,0 +1,48 @@
+(function() {
+    /**
+     * Sepia Filter
+	 * Based on: Pixastic Lib - Sepia filter - v0.1.0
+	 * Copyright (c) 2008 Jacob Seidelin, jseidelin@nihilogic.dk, http://blog.nihilogic.dk/
+     * @function
+     * @memberof Kinetic.Filters
+     * @param {Object} imageData
+     * @author Jacob Seidelin <jseidelin@nihilogic.dk>
+     * @license MPL v1.1 [http://www.pixastic.com/lib/license.txt]
+     */
+     
+    Kinetic.Filters.Sepia = function(imageData) {
+        var data = imageData.data,
+			w = imageData.width,
+        	y = imageData.height,
+			w4 = w*4,
+			offsetY,
+			x,
+			offset,
+			or,
+			og,
+			ob,
+			r,
+			g,
+			b;
+		
+		do {
+			offsetY = (y-1)*w4;
+			x = w;
+			do {
+				offset = offsetY + (x-1)*4;
+				
+				or = data[offset];
+				og = data[offset+1];
+				ob = data[offset+2];
+
+				r = or * 0.393 + og * 0.769 + ob * 0.189;
+				g = or * 0.349 + og * 0.686 + ob * 0.168;
+				b = or * 0.272 + og * 0.534 + ob * 0.131;
+
+				data[offset] = r > 255 ? 255 : r;
+				data[offset+1] = g > 255 ? 255 : g;
+				data[offset+2] = b > 255 ? 255 : b;
+			} while (--x);
+		} while (--y);
+    };
+})();