js2/mwEmbed/libClipEdit/pixastic-lib/actions/edges2.js

   1 /*
   2  * Pixastic Lib - Edge detection 2 - 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  * Contribution by Oliver Hunt (http://nerget.com/, http://nerget.com/canvas/edgeDetection.js). Thanks Oliver!
   7  *
   8  */
   9
  10 Pixastic.Actions.edges2 = {
  11         process : function(params) {
  12
  13                 if (Pixastic.Client.hasCanvasImageData()) {
  14                         var data = Pixastic.prepareData(params);
  15                         var dataCopy = Pixastic.prepareData(params, true)
  16
  17                         var rect = params.options.rect;
  18                         var w = rect.width;
  19                         var h = rect.height;
  20
  21                         var w4 = w * 4;
  22                         var pixel = w4 + 4; // Start at (1,1)
  23                         var hm1 = h - 1;
  24                         var wm1 = w - 1;
  25                         for (var y = 1; y < hm1; ++y) {
  26                                 // Prepare initial cached values for current row
  27                                 var centerRow = pixel - 4;
  28                                 var priorRow = centerRow - w4;
  29                                 var nextRow = centerRow + w4;
  30
  31                                 var r1 = - dataCopy[priorRow]   - dataCopy[centerRow]   - dataCopy[nextRow];
  32                                 var g1 = - dataCopy[++priorRow] - dataCopy[++centerRow] - dataCopy[++nextRow];
  33                                 var b1 = - dataCopy[++priorRow] - dataCopy[++centerRow] - dataCopy[++nextRow];
  34
  35                                 var rp = dataCopy[priorRow += 2];
  36                                 var gp = dataCopy[++priorRow];
  37                                 var bp = dataCopy[++priorRow];
  38
  39                                 var rc = dataCopy[centerRow += 2];
  40                                 var gc = dataCopy[++centerRow];
  41                                 var bc = dataCopy[++centerRow];
  42
  43                                 var rn = dataCopy[nextRow += 2];
  44                                 var gn = dataCopy[++nextRow];
  45                                 var bn = dataCopy[++nextRow];
  46
  47                                 var r2 = - rp - rc - rn;
  48                                 var g2 = - gp - gc - gn;
  49                                 var b2 = - bp - bc - bn;
  50
  51                                 // Main convolution loop
  52                                 for (var x = 1; x < wm1; ++x) {
  53                                         centerRow = pixel + 4;
  54                                         priorRow = centerRow - w4;
  55                                         nextRow = centerRow + w4;
  56
  57                                         var r = 127 + r1 - rp - (rc * -8) - rn;
  58                                         var g = 127 + g1 - gp - (gc * -8) - gn;
  59                                         var b = 127 + b1 - bp - (bc * -8) - bn;
  60
  61                                         r1 = r2;
  62                                         g1 = g2;
  63                                         b1 = b2;
  64
  65                                         rp = dataCopy[  priorRow];
  66                                         gp = dataCopy[++priorRow];
  67                                         bp = dataCopy[++priorRow];
  68
  69                                         rc = dataCopy[  centerRow];
  70                                         gc = dataCopy[++centerRow];
  71                                         bc = dataCopy[++centerRow];
  72
  73                                         rn = dataCopy[  nextRow];
  74                                         gn = dataCopy[++nextRow];
  75                                         bn = dataCopy[++nextRow];
  76
  77                                         r += (r2 = - rp - rc - rn);
  78                                         g += (g2 = - gp - gc - gn);
  79                                         b += (b2 = - bp - bc - bn);
  80
  81                                         if (r > 255) r = 255;
  82                                         if (g > 255) g = 255;
  83                                         if (b > 255) b = 255;
  84                                         if (r < 0) r = 0;
  85                                         if (g < 0) g = 0;
  86                                         if (b < 0) b = 0;
  87
  88                                         data[pixel] = r;
  89                                         data[++pixel] = g;
  90                                         data[++pixel] = b;
  91                                         //data[++pixel] = 255; // alpha
  92
  93                                         pixel+=2;
  94                                 }
  95                                 pixel += 8;
  96                         }
  97                         return true;
  98                 }
  99         },
 100         checkSupport : function() {
 101                 return Pixastic.Client.hasCanvasImageData();
 102         }
 103 }