Color Space Conversions

colorConvert.js

// grok'd from TinyColor.js
// https://bgrins.github.io/TinyColor/docs/tinycolor.html
//



function rgbToHsl(r, g, b) {

    r = bound01(r, 255);
    g = bound01(g, 255);
    b = bound01(b, 255);

    var max = mathMax(r, g, b), min = mathMin(r, g, b);
    var h, s, l = (max + min) / 2;

    if(max == min) {
        h = s = 0; // achromatic
    }
    else {
        var d = max - min;
        s = l > 0.5 ? d / (2 - max - min) : d / (max + min);
        switch(max) {
            case r: h = (g - b) / d + (g < b ? 6 : 0); break;
            case g: h = (b - r) / d + 2; break;
            case b: h = (r - g) / d + 4; break;
        }

        h /= 6;
    }

    return { h: h, s: s, l: l };
}

function hslToRgb(h, s, l) {
    var r, g, b;

    h = bound01(h, 360);
    s = bound01(s, 100);
    l = bound01(l, 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;
    }

    if(s === 0) {
        r = g = b = l; // achromatic
    }
    else {
        var q = l < 0.5 ? l * (1 + s) : l + s - l * s;
        var p = 2 * l - q;
        r = hue2rgb(p, q, h + 1/3);
        g = hue2rgb(p, q, h);
        b = hue2rgb(p, q, h - 1/3);
    }

    return { r: r * 255, g: g * 255, b: b * 255 };
}

function hslToRgb(h, s, l) {
    var r, g, b;

    h = bound01(h, 360);
    s = bound01(s, 100);
    l = bound01(l, 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;
    }

    if(s === 0) {
        r = g = b = l; // achromatic
    }
    else {
        var q = l < 0.5 ? l * (1 + s) : l + s - l * s;
        var p = 2 * l - q;
        r = hue2rgb(p, q, h + 1/3);
        g = hue2rgb(p, q, h);
        b = hue2rgb(p, q, h - 1/3);
    }

    return { r: r * 255, g: g * 255, b: b * 255 };
}