57 lines
1.3 KiB
JavaScript
Executable file
57 lines
1.3 KiB
JavaScript
Executable file
/*
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* Pixastic Lib - Posterize effect - v0.1.0
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* Copyright (c) 2008 Jacob Seidelin, jseidelin@nihilogic.dk, http://blog.nihilogic.dk/
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* MIT License [http://www.opensource.org/licenses/mit-license.php]
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*/
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Pixastic.Actions.posterize = {
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process : function(params) {
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var numLevels = 256;
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if (typeof params.options.levels != "undefined")
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numLevels = parseInt(params.options.levels,10)||1;
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if (Pixastic.Client.hasCanvasImageData()) {
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var data = Pixastic.prepareData(params);
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numLevels = Math.max(2,Math.min(256,numLevels));
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var numAreas = 256 / numLevels;
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var numValues = 256 / (numLevels-1);
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var rect = params.options.rect;
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var w = rect.width;
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var h = rect.height;
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var w4 = w*4;
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var y = h;
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do {
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var offsetY = (y-1)*w4;
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var x = w;
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do {
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var offset = offsetY + (x-1)*4;
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var r = numValues * ((data[offset] / numAreas)>>0);
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var g = numValues * ((data[offset+1] / numAreas)>>0);
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var b = numValues * ((data[offset+2] / numAreas)>>0);
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if (r > 255) r = 255;
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if (g > 255) g = 255;
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if (b > 255) b = 255;
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data[offset] = r;
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data[offset+1] = g;
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data[offset+2] = b;
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} while (--x);
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} while (--y);
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return true;
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}
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},
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checkSupport : function() {
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return Pixastic.Client.hasCanvasImageData();
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}
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}
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