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]
8 Pixastic.Actions.glow = {
9 process : function(params) {
11 var amount = (parseFloat(params.options.amount)||0);
12 var blurAmount = parseFloat(params.options.radius)||0;
14 amount = Math.min(1,Math.max(0,amount));
15 blurAmount = Math.min(5,Math.max(0,blurAmount));
17 if (Pixastic.Client.hasCanvasImageData()) {
18 var rect = params.options.rect;
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);
27 var smallWidth = Math.round(params.width / scale);
28 var smallHeight = Math.round(params.height / scale);
30 var copy = document.createElement("canvas");
31 copy.width = smallWidth;
32 copy.height = smallHeight;
35 var steps = Math.round(blurAmount * 20);
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));
42 copyCtx.clearRect(0,0,smallWidth,smallHeight);
46 0,0,params.width,params.height,
47 0,0,scaledWidth,scaledHeight
50 blurCtx.clearRect(0,0,params.width,params.height);
54 0,0,scaledWidth,scaledHeight,
55 0,0,params.width,params.height
59 var data = Pixastic.prepareData(params);
60 var blurData = Pixastic.prepareData({canvas:blurCanvas,options:params.options});
66 var offsetY = (y-1)*w4;
69 var offset = offsetY + (x*4-4);
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];
92 checkSupport : function() {
93 return Pixastic.Client.hasCanvasImageData();