Simple color utils for JavaScript

color.js

/**
 * A class to parse color values
 * @author Stoyan Stefanov <sstoo@gmail.com>
 * @link   http://www.phpied.com/rgb-color-parser-in-javascript/
 * @license Use it if you like it
 */
/*
I've modded this class a bit. It's not perfect but does many cool things already! Feel free to hack as you like.

Note that I have wrapped the class and one utility func in RequireJS module format.
*/
define(function() {
    function Color(colorString) {
        this.init(colorString);
    }
    Color.prototype = {
        init: function(colorString) {
            if ( colorString == undefined ) {
                colorString = 'black';
            }

            // strip any leading #
            if (colorString.charAt(0) == '#') { // remove # if any
                colorString = colorString.substr(1,6);
            }

            colorString = colorString.replace(/ /g,'');
            colorString = colorString.toLowerCase();

            // before getting into regexps, try simple matches
            // and overwrite the input
            var simple_colors = {
                aliceblue: 'f0f8ff',
                antiquewhite: 'faebd7',
                aqua: '00ffff',
                aquamarine: '7fffd4',
                azure: 'f0ffff',
                beige: 'f5f5dc',
                bisque: 'ffe4c4',
                black: '000000',
                blanchedalmond: 'ffebcd',
                blue: '0000ff',
                blueviolet: '8a2be2',
                brown: 'a52a2a',
                burlywood: 'deb887',
                cadetblue: '5f9ea0',
                chartreuse: '7fff00',
                chocolate: 'd2691e',
                coral: 'ff7f50',
                cornflowerblue: '6495ed',
                cornsilk: 'fff8dc',
                crimson: 'dc143c',
                cyan: '00ffff',
                darkblue: '00008b',
                darkcyan: '008b8b',
                darkgoldenrod: 'b8860b',
                darkgray: 'a9a9a9',
                darkgreen: '006400',
                darkkhaki: 'bdb76b',
                darkmagenta: '8b008b',
                darkolivegreen: '556b2f',
                darkorange: 'ff8c00',
                darkorchid: '9932cc',
                darkred: '8b0000',
                darksalmon: 'e9967a',
                darkseagreen: '8fbc8f',
                darkslateblue: '483d8b',
                darkslategray: '2f4f4f',
                darkturquoise: '00ced1',
                darkviolet: '9400d3',
                deeppink: 'ff1493',
                deepskyblue: '00bfff',
                dimgray: '696969',
                dodgerblue: '1e90ff',
                feldspar: 'd19275',
                firebrick: 'b22222',
                floralwhite: 'fffaf0',
                forestgreen: '228b22',
                fuchsia: 'ff00ff',
                gainsboro: 'dcdcdc',
                ghostwhite: 'f8f8ff',
                gold: 'ffd700',
                goldenrod: 'daa520',
                gray: '808080',
                green: '008000',
                greenyellow: 'adff2f',
                honeydew: 'f0fff0',
                hotpink: 'ff69b4',
                indianred : 'cd5c5c',
                indigo : '4b0082',
                ivory: 'fffff0',
                khaki: 'f0e68c',
                lavender: 'e6e6fa',
                lavenderblush: 'fff0f5',
                lawngreen: '7cfc00',
                lemonchiffon: 'fffacd',
                lightblue: 'add8e6',
                lightcoral: 'f08080',
                lightcyan: 'e0ffff',
                lightgoldenrodyellow: 'fafad2',
                lightgrey: 'd3d3d3',
                lightgreen: '90ee90',
                lightpink: 'ffb6c1',
                lightsalmon: 'ffa07a',
                lightseagreen: '20b2aa',
                lightskyblue: '87cefa',
                lightslateblue: '8470ff',
                lightslategray: '778899',
                lightsteelblue: 'b0c4de',
                lightyellow: 'ffffe0',
                lime: '00ff00',
                limegreen: '32cd32',
                linen: 'faf0e6',
                magenta: 'ff00ff',
                maroon: '800000',
                mediumaquamarine: '66cdaa',
                mediumblue: '0000cd',
                mediumorchid: 'ba55d3',
                mediumpurple: '9370d8',
                mediumseagreen: '3cb371',
                mediumslateblue: '7b68ee',
                mediumspringgreen: '00fa9a',
                mediumturquoise: '48d1cc',
                mediumvioletred: 'c71585',
                midnightblue: '191970',
                mintcream: 'f5fffa',
                mistyrose: 'ffe4e1',
                moccasin: 'ffe4b5',
                navajowhite: 'ffdead',
                navy: '000080',
                oldlace: 'fdf5e6',
                olive: '808000',
                olivedrab: '6b8e23',
                orange: 'ffa500',
                orangered: 'ff4500',
                orchid: 'da70d6',
                palegoldenrod: 'eee8aa',
                palegreen: '98fb98',
                paleturquoise: 'afeeee',
                palevioletred: 'd87093',
                papayawhip: 'ffefd5',
                peachpuff: 'ffdab9',
                peru: 'cd853f',
                pink: 'ffc0cb',
                plum: 'dda0dd',
                powderblue: 'b0e0e6',
                purple: '800080',
                red: 'ff0000',
                rosybrown: 'bc8f8f',
                royalblue: '4169e1',
                saddlebrown: '8b4513',
                salmon: 'fa8072',
                sandybrown: 'f4a460',
                seagreen: '2e8b57',
                seashell: 'fff5ee',
                sienna: 'a0522d',
                silver: 'c0c0c0',
                skyblue: '87ceeb',
                slateblue: '6a5acd',
                slategray: '708090',
                snow: 'fffafa',
                springgreen: '00ff7f',
                steelblue: '4682b4',
                tan: 'd2b48c',
                teal: '008080',
                thistle: 'd8bfd8',
                tomato: 'ff6347',
                turquoise: '40e0d0',
                violet: 'ee82ee',
                violetred: 'd02090',
                wheat: 'f5deb3',
                white: 'ffffff',
                whitesmoke: 'f5f5f5',
                yellow: 'ffff00',
                yellowgreen: '9acd32'
            };
            for (var key in simple_colors) {
                if (colorString == key) {
                    colorString = simple_colors[key];
                }
            }
            // emd of simple type-in colors

            // array of color definition objects
            var color_defs = [
                {
                    re: /^rgb\((\d{1,3}),\s*(\d{1,3}),\s*(\d{1,3})\)$/,
                    example: ['rgb(123, 234, 45)', 'rgb(255,234,245)'],
                    process: function (bits){
                        return [
                            parseInt(bits[1]),
                            parseInt(bits[2]),
                            parseInt(bits[3])
                        ];
                    }
                },
                {
                    re: /^(\w{2})(\w{2})(\w{2})$/,
                    example: ['#00ff00', '336699'],
                    process: function (bits){
                        return [
                            parseInt(bits[1], 16),
                            parseInt(bits[2], 16),
                            parseInt(bits[3], 16)
                        ];
                    }
                },
                {
                    re: /^(\w{1})(\w{1})(\w{1})$/,
                    example: ['#fb0', 'f0f'],
                    process: function (bits){
                        return [
                            parseInt(bits[1] + bits[1], 16),
                            parseInt(bits[2] + bits[2], 16),
                            parseInt(bits[3] + bits[3], 16)
                        ];
                    }
                }
            ];

            // search through the definitions to find a match
            for (var i = 0; i < color_defs.length; i++) {
                var re = color_defs[i].re;
                var processor = color_defs[i].process;
                var bits = re.exec(colorString);
                if (bits) {
                    var channels = processor(bits);
                    this.r = channels[0];
                    this.g = channels[1];
                    this.b = channels[2];
                }

            }

            // validate/cleanup values
            this.r = (this.r < 0 || isNaN(this.r)) ? 0 : ((this.r > 255) ? 255 : this.r);
            this.g = (this.g < 0 || isNaN(this.g)) ? 0 : ((this.g > 255) ? 255 : this.g);
            this.b = (this.b < 0 || isNaN(this.b)) ? 0 : ((this.b > 255) ? 255 : this.b);

            // set up initial hsv
            this.setRGB(this.r, this.g, this.b);
        },
        setRGB: function(r, g, b) { // null = don't change
            var hsv = this.RGB_HSV(
                r==null ? this.r : (this.r = r),
                g==null ? this.g : (this.g = g),
                b==null ? this.b : (this.b = b)
            );

            if (hsv[0] != null) {
                this.h = hsv[0];
            }

            if (hsv[2] != 0) {
                this.s = hsv[1];
            }

            this.v = hsv[2];
        },
        setHSV: function(h, s, v) { // null = don't change
            var rgb = this.HSV_RGB(
                h==null ? this.h : (this.h=h),
                s==null ? this.s : (this.s=s),
                v==null ? this.v : (this.v=v)
            );

            this.r = rgb[0];
            this.g = rgb[1];
            this.b = rgb[2];
        },
        RGB_HSV: function(r, g, b) {
            var n = Math.min(Math.min(r, g), b);
            var v = Math.max(Math.max(r, g), b);
            var m = v - n;

            if(m == 0) {
                return [ null, 0, v ];
            }

            var h = r==n ? 3 + (b - g) / m : (g == n ? 5 + (r - b) / m : 1 + (g - r) / m);

            return [ h == 6? 0: h, m / v, v ];
        },
        HSV_RGB: function(h, s, v) {
            if (h == null) {
                return [ v, v, v ];
            }

            var i = Math.floor(h);
            var f = i % 2 ? h - i : 1 - (h - i);
            var m = v * (1 - s);
            var n = v * (1 - s * f);

            switch(i) {
                case 6:
                case 0:
                    return [ v, n, m ];
                case 1:
                    return [ n, v, m ];
                case 2:
                    return [ m, v, n ];
                case 3:
                    return [ m, n, v ];
                case 4:
                    return [ n, m, v ];
                case 5:
                    return [ v, m, n ];
            }
        },
        toString: function() {
            var r = Math.round(this.r).toString(16);
            var g = Math.round(this.g).toString(16);
            var b = Math.round(this.b).toString(16);

            return (
                (r.length == 1 ? '0' + r : r) +
                (g.length == 1 ? '0' + g : g) +
                (b.length == 1 ? '0' + b : b)
                ).toUpperCase();
        },
        toRGBArray: function() {
            return [this.r, this.g, this.b];
        },
        toHSVArray: function() {
            return [this.h, this.s, this.v];
        }
    }

    return {Color: Color,
        getRGBA: function(color, alpha) {
            return 'rgba(' + color.r + ',' + color.g + ',' + color.b + ',' + alpha + ')';
        }
    };
});