basic enhancements api implemented

lib/pixastic/actions/brightness.js

@@ -0,0 +1,79 @@
+/*
+ * Pixastic Lib - Brightness/Contrast filter - v0.1.1
+ * Copyright (c) 2008 Jacob Seidelin, jseidelin@nihilogic.dk, http://blog.nihilogic.dk/
+ * License: [http://www.pixastic.com/lib/license.txt]
+ */
+
+Pixastic.Actions.brightness = {
+
+	process : function(params) {
+
+		var brightness = parseInt(params.options.brightness,10) || 0;
+		var contrast = parseFloat(params.options.contrast)||0;
+		var legacy = !!(params.options.legacy && params.options.legacy != "false");
+
+		if (legacy) {
+			brightness = Math.min(150,Math.max(-150,brightness));
+		} else {
+			var brightMul = 1 + Math.min(150,Math.max(-150,brightness)) / 150;
+		}
+		contrast = Math.max(0,contrast+1);
+
+		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;
+
+			var mul, add;
+			if (contrast != 1) {
+				if (legacy) {
+					mul = contrast;
+					add = (brightness - 128) * contrast + 128;
+				} else {
+					mul = brightMul * contrast;
+					add = - contrast * 128 + 128;
+				}
+			} else {  // this if-then is not necessary anymore, is it?
+				if (legacy) {
+					mul = 1;
+					add = brightness;
+				} else {
+					mul = brightMul;
+					add = 0;
+				}
+			}
+			var r, g, b;
+			while (p--) {
+				if ((r = data[pix-=4] * mul + add) > 255 )
+					data[pix] = 255;
+				else if (r < 0)
+					data[pix] = 0;
+				else
+ 					data[pix] = r;
+
+				if ((g = data[pix1=pix+1] * mul + add) > 255 ) 
+					data[pix1] = 255;
+				else if (g < 0)
+					data[pix1] = 0;
+				else
+					data[pix1] = g;
+
+				if ((b = data[pix2=pix+2] * mul + add) > 255 ) 
+					data[pix2] = 255;
+				else if (b < 0)
+					data[pix2] = 0;
+				else
+					data[pix2] = b;
+			}
+			return true;
+		}
+	},
+	checkSupport : function() {
+		return Pixastic.Client.hasCanvasImageData();
+	}
+}
+