58 lines
878 B
JavaScript
58 lines
878 B
JavaScript
/**
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* Cylindrical LAB
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*
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* @module color-space/lchab
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*/
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import xyz from './xyz.js';
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import lab from './lab.js';
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//cylindrical lab
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var lchab = {
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name: 'lchab',
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min: [0, 0, 0],
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max: [100, 100, 360],
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channel: ['lightness', 'chroma', 'hue'],
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alias: ['LCHab', 'cielch', 'LCH', 'HLC', 'LSH'],
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xyz: function (arg) {
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return lab.xyz(lchab.lab(arg));
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},
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lab: function (lch) {
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var l = lch[0],
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c = lch[1],
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h = lch[2],
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a, b, hr;
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hr = h / 360 * 2 * Math.PI;
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a = c * Math.cos(hr);
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b = c * Math.sin(hr);
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return [l, a, b];
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}
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};
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//extend lab
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lab.lchab = function (lab) {
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var l = lab[0],
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a = lab[1],
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b = lab[2],
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hr, h, c;
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hr = Math.atan2(b, a);
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h = hr * 360 / 2 / Math.PI;
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if (h < 0) {
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h += 360;
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}
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c = Math.sqrt(a * a + b * b);
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return [l, c, h];
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};
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xyz.lchab = function (arg) {
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return lab.lchab(xyz.lab(arg));
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};
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export default (lchab);
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