9 blending modes added as LESS operations

README.md

@@ -1,20 +1,35 @@
-less.js
-=======
+less.js + blending modes
+========================
 
-The **dynamic** stylesheet language.
+The **dynamic** stylesheet language, powered with blending modes.
 
-<http://lesscss.org>
+The full credits for the original project of LESS goes to Alexis Sellier, more information: <http://lesscss.org>.
 
 about
 -----
 
-This is the JavaScript, and now official, stable version of LESS.
+This is the JavaScript stable version of LESS with some blending modes (such those from Photoshop, GIMP or Fireworks).
 
-For more information, visit <http://lesscss.org>.
+These blending methods are implemented as LESS operations.
+
+blending modes
+--------------
+
+**list of implemented blending modes**
+
+ * multiply
+ * screen
+ * overlay
+ * softlight
+ * hardlight
+ * difference
+ * exclusion
+ * average
+ * negation
 
 license
 -------
 
 See `LICENSE` file.
 
-> Copyright (c) 2009-2011 Alexis Sellier
+> Copyright (c) 2012 Rubens Mariuzzo

lib/less/functions.js

@@ -201,6 +201,66 @@ tree.functions = {
     },
     _isa: function (n, Type) {
         return (n instanceof Type) ? tree.True : tree.False;
+    },
+
+    /* Blending modes */
+
+    multiply: function(color1, color2) {
+        var r = color1.rgb[0] * color2.rgb[0] / 255;
+        var g = color1.rgb[1] * color2.rgb[1] / 255;
+        var b = color1.rgb[2] * color2.rgb[2] / 255;
+        return this.rgb(r, g, b);
+    },
+    screen: function(color1, color2) {
+        var r = 255 - (255 - color1.rgb[0]) * (255 - color2.rgb[0]) / 255;
+        var g = 255 - (255 - color1.rgb[1]) * (255 - color2.rgb[1]) / 255;
+        var b = 255 - (255 - color1.rgb[2]) * (255 - color2.rgb[2]) / 255;
+        return this.rgb(r, g, b);
+    },
+    overlay: function(color1, color2) {
+        var r = color1.rgb[0] < 128 ? 2 * color1.rgb[0] * color2.rgb[0] / 255 : 255 - 2 * (255 - color1.rgb[0]) * (255 - color2.rgb[0]) / 255;
+        var g = color1.rgb[1] < 128 ? 2 * color1.rgb[1] * color2.rgb[1] / 255 : 255 - 2 * (255 - color1.rgb[1]) * (255 - color2.rgb[1]) / 255;
+        var b = color1.rgb[2] < 128 ? 2 * color1.rgb[2] * color2.rgb[2] / 255 : 255 - 2 * (255 - color1.rgb[2]) * (255 - color2.rgb[2]) / 255;
+        return this.rgb(r, g, b);
+    },
+    softlight: function(color1, color2) {
+        var t = color2.rgb[0] * color1.rgb[0] / 255;
+        var r = t + color1.rgb[0] * (255 - (255 - color1.rgb[0]) * (255 - color2.rgb[0]) / 255 - t) / 255;
+        t = color2.rgb[1] * color1.rgb[1] / 255;
+        var g = t + color1.rgb[1] * (255 - (255 - color1.rgb[1]) * (255 - color2.rgb[1]) / 255 - t) / 255;
+        t = color2.rgb[2] * color1.rgb[2] / 255;
+        var b = t + color1.rgb[2] * (255 - (255 - color1.rgb[2]) * (255 - color2.rgb[2]) / 255 - t) / 255;
+        return this.rgb(r, g, b);
+    },
+    hardlight: function(color1, color2) {
+        var r = color2.rgb[0] < 128 ? 2 * color2.rgb[0] * color1.rgb[0] / 255 : 255 - 2 * (255 - color2.rgb[0]) * (255 - color1.rgb[0]) / 255;
+        var g = color2.rgb[1] < 128 ? 2 * color2.rgb[1] * color1.rgb[1] / 255 : 255 - 2 * (255 - color2.rgb[1]) * (255 - color1.rgb[1]) / 255;
+        var b = color2.rgb[2] < 128 ? 2 * color2.rgb[2] * color1.rgb[2] / 255 : 255 - 2 * (255 - color2.rgb[2]) * (255 - color1.rgb[2]) / 255;
+        return this.rgb(r, g, b);
+    },
+    difference: function(color1, color2) {
+        var r = Math.abs(color1.rgb[0] - color2.rgb[0]);
+        var g = Math.abs(color1.rgb[1] - color2.rgb[1]);
+        var b = Math.abs(color1.rgb[2] - color2.rgb[2]);
+        return this.rgb(r, g, b);
+    },
+    exclusion: function(color1, color2) {
+        var r = color1.rgb[0] + color2.rgb[0] * (255 - color1.rgb[0] - color1.rgb[0]) / 255;
+        var g = color1.rgb[1] + color2.rgb[1] * (255 - color1.rgb[1] - color1.rgb[1]) / 255;
+        var b = color1.rgb[2] + color2.rgb[2] * (255 - color1.rgb[2] - color1.rgb[2]) / 255;
+        return this.rgb(r, g, b);
+    },
+    average: function(color1, color2) {
+        var r = (color1.rgb[0] + color2.rgb[0]) / 2;
+        var g = (color1.rgb[1] + color2.rgb[1]) / 2;
+        var b = (color1.rgb[2] + color2.rgb[2]) / 2;
+        return this.rgb(r, g, b);
+    },
+    negation: function(color1, color2) {
+        var r = 255 - Math.abs(255 - color2.rgb[0] - color1.rgb[0]);
+        var g = 255 - Math.abs(255 - color2.rgb[1] - color1.rgb[1]);
+        var b = 255 - Math.abs(255 - color2.rgb[2] - color1.rgb[2]);
+        return this.rgb(r, g, b);
     }
 };
 

test/css/functions.css

@@ -41,3 +41,14 @@
 #alpha {
   alpha: rgba(153, 94, 51, 0.6);
 }
+#blendmodes {
+  multiply: #ed0000;
+  screen: #f600f6;
+  overlay: #ed0000;
+  softlight: #ff0000;
+  hardlight: #0000ed;
+  difference: #f600f6;
+  exclusion: #f600f6;
+  average: #7b007b;
+  negation: #d73131;
+}

test/less/functions.less

@@ -47,3 +47,15 @@
 #alpha {
   alpha: darken(hsla(25, 50%, 50%, 0.6), 10%);
 }
+
+#blendmodes {
+  multiply: multiply(#f60000, #f60000);
+  screen: screen(#f60000, #0000f6);
+  overlay: overlay(#f60000, #0000f6);
+  softlight: softlight(#f60000, #ffffff);
+  hardlight: hardlight(#f60000, #0000f6);
+  difference: difference(#f60000, #0000f6);
+  exclusion: exclusion(#f60000, #0000f6);
+  average: average(#f60000, #0000f6);
+  negation: negation(#f60000, #313131);
+}