js2/mwEmbed/libClipEdit/pixastic-lib/actions/desaturate.js

   1 /*
   2  * Pixastic Lib - Desaturation filter - v0.1.0
   3  * Copyright (c) 2008 Jacob Seidelin, jseidelin@nihilogic.dk, http://blog.nihilogic.dk/
   4  * MIT License [http://www.opensource.org/licenses/mit-license.php]
   5  */
   6
   7 Pixastic.Actions.desaturate = {
   8
   9         process : function(params) {
  10                 var useAverage = !!params.options.average;
  11
  12                 if (Pixastic.Client.hasCanvasImageData()) {
  13                         var data = Pixastic.prepareData(params);
  14                         var rect = params.options.rect;
  15                         var w = rect.width;
  16                         var h = rect.height;
  17                         var w4 = w*4;
  18                         var y = h;
  19                         do {
  20                                 var offsetY = (y-1)*w4;
  21                                 var x = w;
  22                                 do {
  23                                         var offset = offsetY + (x-1)*4;
  24                                         var brightness = useAverage ?
  25                                                 (data[offset]+data[offset+1]+data[offset+2])/3
  26                                                 : (data[offset]*0.3 + data[offset+1]*0.59 + data[offset+2]*0.11);
  27                                         data[offset] = data[offset+1] = data[offset+2] = brightness;
  28                                 } while (--x);
  29                         } while (--y);
  30                         return true;
  31                 } else if (Pixastic.Client.isIE()) {
  32                         params.image.style.filter += " gray";
  33                         return true;
  34                 }
  35         },
  36         checkSupport : function() {
  37                 return (Pixastic.Client.hasCanvasImageData() || Pixastic.Client.isIE());
  38         }
  39 }