topical media & game development
mobile-query-three-plugins-assets-vendor-pixastic-actions-glow.js / js
/*
* Pixastic Lib - Glow - v0.1.0
* Copyright (c) 2008 Jacob Seidelin, jseidelin@nihilogic.dk, http://blog.nihilogic.dk/
* License: [http://www.pixastic.com/lib/license.txt]
*/
Pixastic.Actions.glow = {
process : function(params) {
var amount = (parseFloat(params.options.amount)||0);
var blurAmount = parseFloat(params.options.radius)||0;
amount = Math.min(1,Math.max(0,amount));
blurAmount = Math.min(5,Math.max(0,blurAmount));
if (Pixastic.Client.hasCanvasImageData()) {
var rect = params.options.rect;
var blurCanvas = document.createElement("canvas");
blurCanvas.width = params.width;
blurCanvas.height = params.height;
var blurCtx = blurCanvas.getContext("2d");
blurCtx.drawImage(params.canvas,0,0);
var scale = 2;
var smallWidth = Math.round(params.width / scale);
var smallHeight = Math.round(params.height / scale);
var copy = document.createElement("canvas");
copy.width = smallWidth;
copy.height = smallHeight;
var clear = true;
var steps = Math.round(blurAmount * 20);
var copyCtx = copy.getContext("2d");
for (var i=0;i<steps;i++) {
var scaledWidth = Math.max(1,Math.round(smallWidth - i));
var scaledHeight = Math.max(1,Math.round(smallHeight - i));
copyCtx.clearRect(0,0,smallWidth,smallHeight);
copyCtx.drawImage(
blurCanvas,
0,0,params.width,params.height,
0,0,scaledWidth,scaledHeight
);
blurCtx.clearRect(0,0,params.width,params.height);
blurCtx.drawImage(
copy,
0,0,scaledWidth,scaledHeight,
0,0,params.width,params.height
);
}
var data = Pixastic.prepareData(params);
var blurData = Pixastic.prepareData({canvas:blurCanvas,options:params.options});
var p = rect.width * rect.height;
var pix = p*4, pix1 = pix + 1, pix2 = pix + 2, pix3 = pix + 3;
while (p--) {
if ((data[pix-=4] += amount * blurData[pix]) > 255) data[pix] = 255;
if ((data[pix1-=4] += amount * blurData[pix1]) > 255) data[pix1] = 255;
if ((data[pix2-=4] += amount * blurData[pix2]) > 255) data[pix2] = 255;
}
return true;
}
},
checkSupport : function() {
return Pixastic.Client.hasCanvasImageData();
}
}
(C) Æliens
04/09/2009
You may not copy or print any of this material without explicit permission of the author or the publisher.
In case of other copyright issues, contact the author.