Function rgbToLab

web/js/algorithms.js:16–27

(r, g, b)

}

function rgbToLab(r, g, b) {
    const R = srgbToLinear(r), G = srgbToLinear(g), B = srgbToLinear(b);
    let X = R * 0.4124564 + G * 0.3575761 + B * 0.1804375;
    let Y = R * 0.2126729 + G * 0.7151522 + B * 0.0721750;
    let Z = R * 0.0193339 + G * 0.1191920 + B * 0.9503041;
    X /= 0.95047; Y /= 1.00000; Z /= 1.08883;
    const f = v => v > 0.008856 ? Math.cbrt(v) : (7.787037 * v + 16 / 116);
    const L = 116 * f(Y) - 16;
    const a = 500 * (f(X) - f(Y));
    const bv = 200 * (f(Y) - f(Z));
    return [L, a, bv];
}

function labDistanceSq(lab1, lab2) {
    return (lab1[0] - lab2[0]) ** 2 + (lab1[1] - lab2[1]) ** 2 + (lab1[2] - lab2[2]) ** 2;