29 lines
678 B
JavaScript
29 lines
678 B
JavaScript
import { kCH, kE, sinθ, cosθ, θ, factor } from './constants.js';
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/*
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Convert DIN99o LCh to CIELab D65
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--------------------------------
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*/
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const convertDlchToLab65 = ({ l, c, h, alpha }) => {
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let res = {
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mode: 'lab65',
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l: (Math.exp((l * kE) / factor) - 1) / 0.0039
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};
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if (h === undefined) {
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res.a = res.b = 0;
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} else {
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let G = (Math.exp(0.0435 * c * kCH * kE) - 1) / 0.075;
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let e = G * Math.cos((h / 180) * Math.PI - θ);
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let f = G * Math.sin((h / 180) * Math.PI - θ);
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res.a = e * cosθ - (f / 0.83) * sinθ;
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res.b = e * sinθ + (f / 0.83) * cosθ;
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}
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if (alpha !== undefined) res.alpha = alpha;
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return res;
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};
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export default convertDlchToLab65;
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