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

   1 /*
   2  * Pixastic Lib - Glow - 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
   8 Pixastic.Actions.glow = {
   9         process : function(params) {
  10
  11                 var amount = (parseFloat(params.options.amount)||0);
  12                 var blurAmount = parseFloat(params.options.radius)||0;
  13
  14                 amount = Math.min(1,Math.max(0,amount));
  15                 blurAmount = Math.min(5,Math.max(0,blurAmount));
  16
  17                 if (Pixastic.Client.hasCanvasImageData()) {
  18                         var rect = params.options.rect;
  19
  20                         var blurCanvas = document.createElement("canvas");
  21                         blurCanvas.width = params.width;
  22                         blurCanvas.height = params.height;
  23                         var blurCtx = blurCanvas.getContext("2d");
  24                         blurCtx.drawImage(params.canvas,0,0);
  25
  26                         var scale = 2;
  27                         var smallWidth = Math.round(params.width / scale);
  28                         var smallHeight = Math.round(params.height / scale);
  29
  30                         var copy = document.createElement("canvas");
  31                         copy.width = smallWidth;
  32                         copy.height = smallHeight;
  33
  34                         var clear = true;
  35                         var steps = Math.round(blurAmount * 20);
  36
  37                         var copyCtx = copy.getContext("2d");
  38                         for (var i=0;i<steps;i++) {
  39                                 var scaledWidth = Math.max(1,Math.round(smallWidth - i));
  40                                 var scaledHeight = Math.max(1,Math.round(smallHeight - i));
  41
  42                                 copyCtx.clearRect(0,0,smallWidth,smallHeight);
  43
  44                                 copyCtx.drawImage(
  45                                         blurCanvas,
  46                                         0,0,params.width,params.height,
  47                                         0,0,scaledWidth,scaledHeight
  48                                 );
  49
  50                                 blurCtx.clearRect(0,0,params.width,params.height);
  51
  52                                 blurCtx.drawImage(
  53                                         copy,
  54                                         0,0,scaledWidth,scaledHeight,
  55                                         0,0,params.width,params.height
  56                                 );
  57                         }
  58
  59                         var data = Pixastic.prepareData(params);
  60                         var blurData = Pixastic.prepareData({canvas:blurCanvas,options:params.options});
  61                         var w = rect.width;
  62                         var h = rect.height;
  63                         var w4 = w*4;
  64                         var y = h;
  65                         do {
  66                                 var offsetY = (y-1)*w4;
  67                                 var x = w;
  68                                 do {
  69                                         var offset = offsetY + (x*4-4);
  70
  71                                         var r = data[offset] + amount * blurData[offset];
  72                                         var g = data[offset+1] + amount * blurData[offset+1];
  73                                         var b = data[offset+2] + amount * blurData[offset+2];
  74
  75                                         if (r > 255) r = 255;
  76                                         if (g > 255) g = 255;
  77                                         if (b > 255) b = 255;
  78                                         if (r < 0) r = 0;
  79                                         if (g < 0) g = 0;
  80                                         if (b < 0) b = 0;
  81
  82                                         data[offset] = r;
  83                                         data[offset+1] = g;
  84                                         data[offset+2] = b;
  85
  86                                 } while (--x);
  87                         } while (--y);
  88
  89                         return true;
  90                 }
  91         },
  92         checkSupport : function() {
  93                 return Pixastic.Client.hasCanvasImageData();
  94         }
  95 }
  96
  97
  98