47 lines
889 B
JavaScript
47 lines
889 B
JavaScript
/**
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* Hunter-lab space.
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*
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* @module color-space/labh
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*/
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import xyz from './xyz.js';
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var labh = {
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name: 'labh',
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//mins/maxes are taken from colormine
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//FIXME: check whether mins/maxes correct
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min: [0, -128, -128],
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max: [100, 128, 128],
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channel: ['lightness', 'a', 'b'],
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alias: ['LABh', 'hunter-lab', 'hlab'],
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//maths are taken from EasyRGB
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xyz: function (lab) {
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var l = lab[0], a = lab[1], b = lab[2];
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var _y = l / 10;
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var _x = a / 17.5 * l / 10;
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var _z = b / 7 * l / 10;
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var y = _y * _y;
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var x = (_x + y) / 1.02;
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var z = -(_z - y) / 0.847;
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return [x, y, z];
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}
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};
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export default (labh);
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//extend xyz
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xyz.labh = function (xyz) {
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var x = xyz[0], y = xyz[1], z = xyz[2];
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var _y12 = Math.sqrt(y);
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var l = 10 * _y12;
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var a = y === 0 ? 0 : 17.5 * (((1.02 * x) - y) / _y12);
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var b = y === 0 ? 0 : 7 * ((y - (0.847 * z)) / _y12);
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return [l, a, b];
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};
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