voluptasquisquam/src/util/color.js

Image processing and manipulation in JavaScript

import {cssColor} from 'color-functions';

export function css2array(string) {
    let color = cssColor(string);
    return [color.r, color.g, color.b, Math.round(color.a * 255 / 100)];
}

function hue2rgb(p, q, t) {
    if (t < 0) {
        t += 1;
    }
    if (t > 1) {
        t -= 1;
    }
    if (t < 1 / 6) {
        return p + (q - p) * 6 * t;
    }
    if (t < 1 / 2) {
        return q;
    }
    if (t < 2 / 3) {
        return p + (q - p) * (2 / 3 - t) * 6;
    }
    return p;
}

function hsl2rgb(h, s, l) {
    let m1, m2, hue, r, g, b;
    s /= 100;
    l /= 100;

    if (s === 0) {
        r = g = b = (l * 255);
    } else {
        if (l <= 0.5) {
            m2 = l * (s + 1);
        } else {
            m2 = l + s - l * s;
        }

        m1 = l * 2 - m2;
        hue = h / 360;
        r = hue2rgb(m1, m2, hue + 1 / 3);
        g = hue2rgb(m1, m2, hue);
        b = hue2rgb(m1, m2, hue - 1 / 3);
    }
    return {r: r, g: g, b: b};
}

export function getDistinctColors(numColors) {
    let colors = new Array(numColors);
    let j = 0;
    for (let i = 0; i < 360; i += 360 / numColors) {
        j++;
        let color = hsl2rgb(i, 100, 30 + j % 4 * 15);
        colors[j - 1] = [Math.round(color.r * 255), Math.round(color.g * 255), Math.round(color.b * 255)];
    }
    return colors;
}

export function getRandomColor() {
    return [(Math.floor(Math.random() * 256)), (Math.floor(Math.random() * 256)), (Math.floor(Math.random() * 256))];
}