canvas-based-HTML5-Comic-Bo.../lib/Effects/desaturate.js
2010-07-13 17:21:54 +01:00

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1 KiB
JavaScript

/*
* Pixastic Lib - Desaturation filter - v0.1.1
* Copyright (c) 2008 Jacob Seidelin, jseidelin@nihilogic.dk, http://blog.nihilogic.dk/
* License: [http://www.pixastic.com/lib/license.txt]
*/
Pixastic.Actions.desaturate = {
process : function(params) {
var useAverage = !!(params.options.average && params.options.average != "false");
if (Pixastic.Client.hasCanvasImageData()) {
var data = Pixastic.prepareData(params);
var rect = params.options.rect;
var w = rect.width;
var h = rect.height;
var p = w*h;
var pix = p*4, pix1, pix2;
if (useAverage) {
while (p--)
data[pix-=4] = data[pix1=pix+1] = data[pix2=pix+2] = (data[pix]+data[pix1]+data[pix2])/3
} else {
while (p--)
data[pix-=4] = data[pix1=pix+1] = data[pix2=pix+2] = (data[pix]*0.3 + data[pix1]*0.59 + data[pix2]*0.11);
}
return true;
} else if (Pixastic.Client.isIE()) {
params.image.style.filter += " gray";
return true;
}
},
checkSupport : function() {
return (Pixastic.Client.hasCanvasImageData() || Pixastic.Client.isIE());
}
}