71 lines
1.8 KiB
JavaScript
Executable file
71 lines
1.8 KiB
JavaScript
Executable file
/*
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* Pixastic Lib - Brightness/Contrast filter - 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.brightness = {
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process : function(params) {
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var brightness = parseInt(params.options.brightness,10) || 0;
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var contrast = parseFloat(params.options.contrast)||0;
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var legacy = !!(params.options.legacy);
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if (legacy) {
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brightness = Math.min(150,Math.max(-150,brightness));
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} else {
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var brightMul = 1 + Math.min(150,Math.max(-150,brightness)) / 150;
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}
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contrast = Math.max(0,contrast+1);
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if (Pixastic.Client.hasCanvasImageData()) {
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var data = Pixastic.prepareData(params);
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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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if (legacy) {
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var r = data[offset] + brightness;
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var g = data[offset+1] + brightness;
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var b = data[offset+2] + brightness;
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} else {
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var r = data[offset] * brightMul;
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var g = data[offset+1] * brightMul;
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var b = data[offset+2] * brightMul;
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}
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if (contrast != 1) {
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r = (r - 128) * contrast + 128;
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g = (g - 128) * contrast + 128;
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b = (b - 128) * contrast + 128;
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}
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if (r < 0 ) r = 0;
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if (g < 0 ) g = 0;
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if (b < 0 ) b = 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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