convertLab65ToDlch.js•672 B
import { kCH, kE, sinθ, cosθ, θ, factor } from './constants.js';
import normalizeHue from '../util/normalizeHue.js';
/*
Convert CIELab D65 to DIN99o LCh
================================
*/
const convertLab65ToDlch = ({ l, a, b, alpha }) => {
let e = a * cosθ + b * sinθ;
let f = 0.83 * (b * cosθ - a * sinθ);
let G = Math.sqrt(e * e + f * f);
let res = {
mode: 'dlch',
l: (factor / kE) * Math.log(1 + 0.0039 * l),
c: Math.log(1 + 0.075 * G) / (0.0435 * kCH * kE)
};
if (res.c) {
res.h = normalizeHue(((Math.atan2(f, e) + θ) / Math.PI) * 180);
}
if (alpha !== undefined) res.alpha = alpha;
return res;
};
export default convertLab65ToDlch;