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

   1 /*
   2  * Pixastic Lib - Brightness/Contrast 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.brightness = {
   8
   9         process : function(params) {
  10
  11                 var brightness = parseInt(params.options.brightness,10) || 0;
  12                 var contrast = parseFloat(params.options.contrast)||0;
  13                 var legacy = !!(params.options.legacy);
  14
  15                 if (legacy) {
  16                         brightness = Math.min(150,Math.max(-150,brightness));
  17                 } else {
  18                         var brightMul = 1 + Math.min(150,Math.max(-150,brightness)) / 150;
  19                 }
  20                 contrast = Math.max(0,contrast+1);
  21
  22                 if (Pixastic.Client.hasCanvasImageData()) {
  23                         var data = Pixastic.prepareData(params);
  24                         var rect = params.options.rect;
  25                         var w = rect.width;
  26                         var h = rect.height;
  27                         var w4 = w*4;
  28                         var y = h;
  29                         do {
  30                                 var offsetY = (y-1)*w4;
  31                                 var x = w;
  32                                 do {
  33                                         var offset = offsetY + (x-1)*4;
  34
  35                                         if (legacy) {
  36                                                 var r = data[offset] + brightness;
  37                                                 var g = data[offset+1] + brightness;
  38                                                 var b = data[offset+2] + brightness;
  39                                         } else {
  40                                                 var r = data[offset] * brightMul;
  41                                                 var g = data[offset+1] * brightMul;
  42                                                 var b = data[offset+2] * brightMul;
  43                                         }
  44
  45                                         if (contrast != 1) {
  46                                                 r = (r - 128) * contrast + 128;
  47                                                 g = (g - 128) * contrast + 128;
  48                                                 b = (b - 128) * contrast + 128;
  49                                         }
  50
  51                                         if (r < 0 ) r = 0;
  52                                         if (g < 0 ) g = 0;
  53                                         if (b < 0 ) b = 0;
  54                                         if (r > 255 ) r = 255;
  55                                         if (g > 255 ) g = 255;
  56                                         if (b > 255 ) b = 255;
  57
  58                                         data[offset] = r;
  59                                         data[offset+1] = g;
  60                                         data[offset+2] = b;
  61
  62                                 } while (--x);
  63                         } while (--y);
  64                         return true;
  65                 }
  66         },
  67         checkSupport : function() {
  68                 return Pixastic.Client.hasCanvasImageData();
  69         }
  70 }
  71