convertHSBtoRGB()

最小色调0 最大色调360（开区间）。

////////////////////////////////////////////////////////////////////////////////
//
//  ADOBE SYSTEMS INCORPORATED
//  Copyright 2008 Adobe Systems Incorporated
//  All Rights Reserved.
//
//  NOTICE: Adobe permits you to use, modify, and distribute this file
//  in accordance with the terms of the license agreement accompanying it.
//
////////////////////////////////////////////////////////////////////////////////

function convertHSBtoRGB(hue, saturation, brightness) {
    // Conversion taken from Foley, van Dam, et al
    var r, g, b;
    if (saturation == 0) {
        r = g = b = 1;
    } else {
        var h = (hue % 360) / 60;
        var i = h | 0;
        var f = h - i;
        var p = 1 - saturation;
        var q = 1 - saturation * f;
        var t = 1 - saturation * (1 - f);
        switch (i) {
            case 0: r = 1; g = t; b = p; break;
            case 1: r = q; g = 1; b = p; break;
            case 2: r = p; g = 1; b = t; break;
            case 3: r = p; g = q; b = 1; break;
            case 4: r = t; g = p; b = 1; break;
            case 5: r = 1; g = p; b = q; break;
        }
    }
    r *= 255 * brightness;
    g *= 255 * brightness;
    b *= 255 * brightness;
    return r << 16 | g << 8 | b;
}

TODO: 补充测试用例