color.js

function hsvToRgb(h, s, v) {

    var s = s / 100,
        v = v / 100;

    var hi = Math.floor((h / 60) % 6);
    var f = (h / 60) - hi;
    var p = v * (1 - s);
    var q = v * (1 - f * s);
    var t = v * (1 - (1 - f) * s);

    var rgb = [];

    switch (hi) {
        case 0:
            rgb = [v, t, p];
            break;
        case 1:
            rgb = [q, v, p];
            break;
        case 2:
            rgb = [p, v, t];
            break;
        case 3:
            rgb = [p, q, v];
            break;
        case 4:
            rgb = [t, p, v];
            break;
        case 5:
            rgb = [v, p, q];
            break;
    }

    var r = Math.min(255, Math.round(rgb[0] * 256)),
        g = Math.min(255, Math.round(rgb[1] * 256)),
        b = Math.min(255, Math.round(rgb[2] * 256));

    return [r, g, b];

}

function rgbToHsv(r, g, b) {
    var min = Math.min(r, g, b),
        max = Math.max(r, g, b),
        delta = max - min,
        h, s, v = max;

    v = Math.floor(max / 255 * 100);
    if (max != 0) {
        s = Math.floor(delta / max * 100);
    } else {
        // black
        return [0, 0, 0];
    }

    if (r == max) {
        h = (g - b) / delta; // between yellow & magenta
    } else if (g == max) {
        h = 2 + (b - r) / delta; // between cyan & yellow
    } else {
        h = 4 + (r - g) / delta; // between magenta & cyan
    }

    h = Math.floor(h * 60); // degrees
    if (h < 0) {
        h += 360;
    }

    return [h, s, v];
}