color.js

// Copyright (c) 2008-2013, Andrew Brehaut, Tim Baumann, Matt Wilson, 
//                          Simon Heimler, Michel Vielmetter 
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
//   this list of conditions and the following disclaimer in the documentation
//   and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.

// color.js - version 1.0.1
//
// HSV <-> RGB code based on code from http://www.cs.rit.edu/~ncs/color/t_convert.html
// object function created by Douglas Crockford.
// Color scheme degrees taken from the colorjack.com colorpicker
//
// HSL support kindly provided by Tim Baumann - http://github.com/timjb

// create namespaces
/*global net */
if ("undefined" == typeof net) {
    var net = {};
}
if (!net.brehaut) {
    net.brehaut = {};
}

// this module function is called with net.brehaut as 'this'
(function() {
    "use strict";
    // Constants

    // css_colors maps color names onto their hex values
    // these names are defined by W3C
    
    var css_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',darkgrey:'#A9A9A9',darkgreen:'#006400',darkkhaki:'#BDB76B',darkmagenta:'#8B008B',darkolivegreen:'#556B2F',darkorange:'#FF8C00',darkorchid:'#9932CC',darkred:'#8B0000',darksalmon:'#E9967A',darkseagreen:'#8FBC8F',darkslateblue:'#483D8B',darkslategray:'#2F4F4F',darkslategrey:'#2F4F4F',darkturquoise:'#00CED1',darkviolet:'#9400D3',deeppink:'#FF1493',deepskyblue:'#00BFFF',dimgray:'#696969',dimgrey:'#696969',dodgerblue:'#1E90FF',firebrick:'#B22222',floralwhite:'#FFFAF0',forestgreen:'#228B22',fuchsia:'#FF00FF',gainsboro:'#DCDCDC',ghostwhite:'#F8F8FF',gold:'#FFD700',goldenrod:'#DAA520',gray:'#808080',grey:'#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',lightgray:'#D3D3D3',lightgrey:'#D3D3D3',lightgreen:'#90EE90',lightpink:'#FFB6C1',lightsalmon:'#FFA07A',lightseagreen:'#20B2AA',lightskyblue:'#87CEFA',lightslategray:'#778899',lightslategrey:'#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',rebeccapurple:'#663399',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',slategrey:'#708090',snow:'#FFFAFA',springgreen:'#00FF7F',steelblue:'#4682B4',tan:'#D2B48C',teal:'#008080',thistle:'#D8BFD8',tomato:'#FF6347',turquoise:'#40E0D0',violet:'#EE82EE',wheat:'#F5DEB3',white:'#FFFFFF',whitesmoke:'#F5F5F5',yellow:'#FFFF00',yellowgreen:'#9ACD32'};


    // CSS value regexes, according to http://www.w3.org/TR/css3-values/
    var css_integer = '(?:\\+|-)?\\d+';
    var css_float = '(?:\\+|-)?\\d*\\.\\d+';
    var css_number = '(?:' + css_integer + ')|(?:' + css_float + ')';
    css_integer = '(' + css_integer + ')';
    css_float = '(' + css_float + ')';
    css_number = '(' + css_number + ')';
    var css_percentage = css_number + '%';
    var css_whitespace = '\\s*?';

    // http://www.w3.org/TR/2003/CR-css3-color-20030514/
    var hsl_hsla_regex = new RegExp([
        '^hsl(a?)\\(', css_number, ',', css_percentage, ',', css_percentage, '(,(', css_number, '))?\\)$'
    ].join(css_whitespace));
    var rgb_rgba_integer_regex = new RegExp([
        '^rgb(a?)\\(', css_integer, ',', css_integer, ',', css_integer, '(,(', css_number, '))?\\)$'
    ].join(css_whitespace));
    var rgb_rgba_percentage_regex = new RegExp([
        '^rgb(a?)\\(', css_percentage, ',', css_percentage, ',', css_percentage, '(,(', css_number, '))?\\)$'
    ].join(css_whitespace));

    // Package wide variables

    // becomes the top level prototype object
    var color;

    /* registered_models contains the template objects for all the
     * models that have been registered for the color class.
     */
    var registered_models = [];


    /* factories contains methods to create new instance of
     * different color models that have been registered.
     */
    var factories = {};

    // Utility functions

    /* object is Douglas Crockfords object function for prototypal
     * inheritance.
     */
    if (!this.object) {
        this.object = function(o) {
            function F() {}
            F.prototype = o;
            return new F();
        };
    }
    var object = this.object;

    /* takes a value, converts to string if need be, then pads it
     * to a minimum length.
     */
    function pad(val, len) {
        val = val.toString();
        var padded = [];

        for (var i = 0, j = Math.max(len - val.length, 0); i < j; i++) {
            padded.push('0');
        }

        padded.push(val);
        return padded.join('');
    }


    /* takes a string and returns a new string with the first letter
     * capitalised
     */
    function capitalise(s) {
        return s.slice(0, 1).toUpperCase() + s.slice(1);
    }

    /* removes leading and trailing whitespace
     */
    function trim(str) {
        return str.replace(/^\s+|\s+$/g, '');
    }

    /* used to apply a method to object non-destructively by
     * cloning the object and then apply the method to that
     * new object
     */
    function cloneOnApply(meth) {
        return function() {
            var cloned = this.clone();
            meth.apply(cloned, arguments);
            return cloned;
        };
    }


    /* registerModel is used to add additional representations
     * to the color code, and extend the color API with the new
     * operation that model provides. see before for examples
     */
    function registerModel(name, model) {
        var proto = object(color);
        var fields = []; // used for cloning and generating accessors

        var to_meth = 'to' + capitalise(name);

        function convertAndApply(meth) {
            return function() {
                return meth.apply(this[to_meth](), arguments);
            };
        }

        for (var key in model)
            if (model.hasOwnProperty(key)) {
                proto[key] = model[key];
                var prop = proto[key];

                if (key.slice(0, 1) == '_') {
                    continue;
                }
                if (!(key in color) && "function" == typeof prop) {
                    // the method found on this object is a) public and b) not
                    // currently supported by the color object. Create an impl that
                    // calls the toModel function and passes that new object
                    // onto the correct method with the args.
                    color[key] = convertAndApply(prop);
                } else if ("function" != typeof prop) {
                    // we have found a public property. create accessor methods
                    // and bind them up correctly
                    fields.push(key);
                    var getter = 'get' + capitalise(key);
                    var setter = 'set' + capitalise(key);

                    color[getter] = convertAndApply(
                        proto[getter] = (function(key) {
                            return function() {
                                return this[key];
                            };
                        })(key)
                    );

                    color[setter] = convertAndApply(
                        proto[setter] = (function(key) {
                            return function(val) {
                                var cloned = this.clone();
                                cloned[key] = val;
                                return cloned;
                            };
                        })(key)
                    );
                }
            } // end of for over model

            // a method to create a new object - largely so prototype chains dont
            // get insane. This uses an unrolled 'object' so that F is cached
            // for later use. this is approx a 25% speed improvement

        function F() {}
        F.prototype = proto;

        function factory() {
            return new F();
        }
        factories[name] = factory;

        proto.clone = function() {
            var cloned = factory();
            for (var i = 0, j = fields.length; i < j; i++) {
                var key = fields[i];
                cloned[key] = this[key];
            }
            return cloned;
        };

        color[to_meth] = function() {
            return factory();
        };

        registered_models.push(proto);

        return proto;
    } // end of registerModel

    // Template Objects

    /* color is the root object in the color hierarchy. It starts
     * life as a very simple object, but as color models are
     * registered it has methods programmatically added to manage
     * conversions as needed.
     */
    color = {
        /* fromObject takes an argument and delegates to the internal
         * color models to try to create a new instance.
         */
        fromObject: function(o) {
            if (!o) {
                return object(color);
            }

            for (var i = 0, j = registered_models.length; i < j; i++) {
                var nu = registered_models[i].fromObject(o);
                if (nu) {
                    return nu;
                }
            }

            return object(color);
        },

        toString: function() {
            return this.toCSS();
        }
    };

    var transparent = null; // defined with an RGB later.

    /* RGB is the red green blue model. This definition is converted
     * to a template object by registerModel.
     */
    registerModel('RGB', {
        red: 0,
        green: 0,
        blue: 0,
        alpha: 0,

        /* getLuminance returns a value between 0 and 1, this is the
         * luminance calcuated according to
         * http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html#RTFToC9
         */
        getLuminance: function() {
            return (this.red * 0.2126) + (this.green * 0.7152) + (this.blue * 0.0722);
        },

        /* does an alpha based blend of color onto this. alpha is the
         * amount of 'color' to use. (0 to 1)
         */
        blend: function(color, alpha) {
            color = color.toRGB();
            alpha = Math.min(Math.max(alpha, 0), 1);
            var rgb = this.clone();

            rgb.red = (rgb.red * (1 - alpha)) + (color.red * alpha);
            rgb.green = (rgb.green * (1 - alpha)) + (color.green * alpha);
            rgb.blue = (rgb.blue * (1 - alpha)) + (color.blue * alpha);
            rgb.alpha = (rgb.alpha * (1 - alpha)) + (color.alpha * alpha);

            return rgb;
        },

        /* fromObject attempts to convert an object o to and RGB
         * instance. This accepts an object with red, green and blue
         * members or a string. If the string is a known CSS color name
         * or a hexdecimal string it will accept it.
         */
        fromObject: function(o) {
            if (o instanceof Array) {
                return this._fromRGBArray(o);
            }
            if ("string" == typeof o) {
                return this._fromCSS(trim(o));
            }
            if (o.hasOwnProperty('red') &&
                o.hasOwnProperty('green') &&
                o.hasOwnProperty('blue')) {
                return this._fromRGB(o);
            }
            // nothing matchs, not an RGB object
        },

        _stringParsers: [
            // CSS RGB(A) literal:
            function(css) {
                css = trim(css);

                var withInteger = match(rgb_rgba_integer_regex, 255);
                if (withInteger) {
                    return withInteger;
                }
                return match(rgb_rgba_percentage_regex, 100);

                function match(regex, max_value) {
                    var colorGroups = css.match(regex);

                    // If there is an "a" after "rgb", there must be a fourth parameter and the other way round
                    if (!colorGroups || (!!colorGroups[1] + !!colorGroups[5] === 1)) {
                        return null;
                    }

                    var rgb = factories.RGB();
                    rgb.red = Math.min(1, Math.max(0, colorGroups[2] / max_value));
                    rgb.green = Math.min(1, Math.max(0, colorGroups[3] / max_value));
                    rgb.blue = Math.min(1, Math.max(0, colorGroups[4] / max_value));
                    rgb.alpha = !!colorGroups[5] ? Math.min(Math.max(parseFloat(colorGroups[6]), 0), 1) : 1;

                    return rgb;
                }
            },

            function(css) {
                var lower = css.toLowerCase();
                if (lower in css_colors) {
                    css = css_colors[lower];
                }

                if (!css.match(/^#([0-9a-fA-F]{3}|[0-9a-fA-F]{6})$/)) {
                    return;
                }

                css = css.replace(/^#/, '');

                var bytes = css.length / 3;

                var max = Math.pow(16, bytes) - 1;

                var rgb = factories.RGB();
                rgb.red = parseInt(css.slice(0, bytes), 16) / max;
                rgb.green = parseInt(css.slice(bytes * 1, bytes * 2), 16) / max;
                rgb.blue = parseInt(css.slice(bytes * 2), 16) / max;
                rgb.alpha = 1;
                return rgb;
            },

            function(css) {
                if (css.toLowerCase() !== 'transparent') return;

                return transparent;
            }
        ],

        _fromCSS: function(css) {
            var color = null;
            for (var i = 0, j = this._stringParsers.length; i < j; i++) {
                color = this._stringParsers[i](css);
                if (color) return color;
            }
        },

        _fromRGB: function(RGB) {
            var newRGB = factories.RGB();

            newRGB.red = RGB.red;
            newRGB.green = RGB.green;
            newRGB.blue = RGB.blue;
            newRGB.alpha = RGB.hasOwnProperty('alpha') ? RGB.alpha : 1;

            return newRGB;
        },

        _fromRGBArray: function(RGB) {
            var newRGB = factories.RGB();

            newRGB.red = Math.max(0, Math.min(1, RGB[0] / 255));
            newRGB.green = Math.max(0, Math.min(1, RGB[1] / 255));
            newRGB.blue = Math.max(0, Math.min(1, RGB[2] / 255));
            newRGB.alpha = RGB[3] !== undefined ? Math.max(0, Math.min(1, RGB[3])) : 1;

            return newRGB;
        },

        // convert to a CSS string. defaults to two bytes a value
        toCSSHex: function(bytes) {
            bytes = bytes || 2;

            var max = Math.pow(16, bytes) - 1;
            var css = [
                "#",
                pad(Math.round(this.red * max).toString(16).toUpperCase(), bytes),
                pad(Math.round(this.green * max).toString(16).toUpperCase(), bytes),
                pad(Math.round(this.blue * max).toString(16).toUpperCase(), bytes)
            ];

            return css.join('');
        },

        toCSS: function(bytes) {
            if (this.alpha === 1) return this.toCSSHex(bytes);

            var max = 255;

            var components = [
                'rgba(',
                Math.max(0, Math.min(max, Math.round(this.red * max))), ',',
                Math.max(0, Math.min(max, Math.round(this.green * max))), ',',
                Math.max(0, Math.min(max, Math.round(this.blue * max))), ',',
                Math.max(0, Math.min(1, this.alpha)),
                ')'
            ];

            return components.join('');
        },

        toHSV: function() {
            var hsv = factories.HSV();
            var min, max, delta;

            min = Math.min(this.red, this.green, this.blue);
            max = Math.max(this.red, this.green, this.blue);
            hsv.value = max; // v

            delta = max - min;

            if (delta == 0) { // white, grey, black
                hsv.hue = hsv.saturation = 0;
            } else { // chroma
                hsv.saturation = delta / max;

                if (this.red == max) {
                    hsv.hue = (this.green - this.blue) / delta; // between yellow & magenta
                } else if (this.green == max) {
                    hsv.hue = 2 + (this.blue - this.red) / delta; // between cyan & yellow
                } else {
                    hsv.hue = 4 + (this.red - this.green) / delta; // between magenta & cyan
                }

                hsv.hue = ((hsv.hue * 60) + 360) % 360; // degrees
            }

            hsv.alpha = this.alpha;

            return hsv;
        },
        toHSL: function() {
            return this.toHSV().toHSL();
        },

        toRGB: function() {
            return this.clone();
        }
    });

    transparent = color.fromObject({
        red: 0,
        blue: 0,
        green: 0,
        alpha: 0
    });


    /* Like RGB above, this object describes what will become the HSV
     * template object. This model handles hue, saturation and value.
     * hue is the number of degrees around the color wheel, saturation
     * describes how much color their is and value is the brightness.
     */
    registerModel('HSV', {
        hue: 0,
        saturation: 0,
        value: 1,
        alpha: 1,

        shiftHue: cloneOnApply(function(degrees) {
            var hue = (this.hue + degrees) % 360;
            if (hue < 0) {
                hue = (360 + hue) % 360;
            }

            this.hue = hue;
        }),

        devalueByAmount: cloneOnApply(function(val) {
            this.value = Math.min(1, Math.max(this.value - val, 0));
        }),

        devalueByRatio: cloneOnApply(function(val) {
            this.value = Math.min(1, Math.max(this.value * (1 - val), 0));
        }),

        valueByAmount: cloneOnApply(function(val) {
            this.value = Math.min(1, Math.max(this.value + val, 0));
        }),

        valueByRatio: cloneOnApply(function(val) {
            this.value = Math.min(1, Math.max(this.value * (1 + val), 0));
        }),

        desaturateByAmount: cloneOnApply(function(val) {
            this.saturation = Math.min(1, Math.max(this.saturation - val, 0));
        }),

        desaturateByRatio: cloneOnApply(function(val) {
            this.saturation = Math.min(1, Math.max(this.saturation * (1 - val), 0));
        }),

        saturateByAmount: cloneOnApply(function(val) {
            this.saturation = Math.min(1, Math.max(this.saturation + val, 0));
        }),

        saturateByRatio: cloneOnApply(function(val) {
            this.saturation = Math.min(1, Math.max(this.saturation * (1 + val), 0));
        }),

        schemeFromDegrees: function(degrees) {
            var newColors = [];
            for (var i = 0, j = degrees.length; i < j; i++) {
                var col = this.clone();
                col.hue = (this.hue + degrees[i]) % 360;
                newColors.push(col);
            }
            return newColors;
        },

        complementaryScheme: function() {
            return this.schemeFromDegrees([0, 180]);
        },

        splitComplementaryScheme: function() {
            return this.schemeFromDegrees([0, 150, 320]);
        },

        splitComplementaryCWScheme: function() {
            return this.schemeFromDegrees([0, 150, 300]);
        },

        splitComplementaryCCWScheme: function() {
            return this.schemeFromDegrees([0, 60, 210]);
        },

        triadicScheme: function() {
            return this.schemeFromDegrees([0, 120, 240]);
        },

        clashScheme: function() {
            return this.schemeFromDegrees([0, 90, 270]);
        },

        tetradicScheme: function() {
            return this.schemeFromDegrees([0, 90, 180, 270]);
        },

        fourToneCWScheme: function() {
            return this.schemeFromDegrees([0, 60, 180, 240]);
        },

        fourToneCCWScheme: function() {
            return this.schemeFromDegrees([0, 120, 180, 300]);
        },

        fiveToneAScheme: function() {
            return this.schemeFromDegrees([0, 115, 155, 205, 245]);
        },

        fiveToneBScheme: function() {
            return this.schemeFromDegrees([0, 40, 90, 130, 245]);
        },

        fiveToneCScheme: function() {
            return this.schemeFromDegrees([0, 50, 90, 205, 320]);
        },

        fiveToneDScheme: function() {
            return this.schemeFromDegrees([0, 40, 155, 270, 310]);
        },

        fiveToneEScheme: function() {
            return this.schemeFromDegrees([0, 115, 230, 270, 320]);
        },

        sixToneCWScheme: function() {
            return this.schemeFromDegrees([0, 30, 120, 150, 240, 270]);
        },

        sixToneCCWScheme: function() {
            return this.schemeFromDegrees([0, 90, 120, 210, 240, 330]);
        },

        neutralScheme: function() {
            return this.schemeFromDegrees([0, 15, 30, 45, 60, 75]);
        },

        analogousScheme: function() {
            return this.schemeFromDegrees([0, 30, 60, 90, 120, 150]);
        },

        fromObject: function(o) {
            if (o.hasOwnProperty('hue') &&
                o.hasOwnProperty('saturation') &&
                o.hasOwnProperty('value')) {
                var hsv = factories.HSV();

                hsv.hue = o.hue;
                hsv.saturation = o.saturation;
                hsv.value = o.value;
                hsv.alpha = o.hasOwnProperty('alpha') ? o.alpha : 1;

                return hsv;
            }
            // nothing matches, not an HSV object
            return null;
        },

        _normalise: function() {
            this.hue %= 360;
            this.saturation = Math.min(Math.max(0, this.saturation), 1);
            this.value = Math.min(Math.max(0, this.value));
            this.alpha = Math.min(1, Math.max(0, this.alpha));
        },

        toRGB: function() {
            this._normalise();

            var rgb = factories.RGB();
            var i;
            var f, p, q, t;

            if (this.saturation === 0) {
                // achromatic (grey)
                rgb.red = this.value;
                rgb.green = this.value;
                rgb.blue = this.value;
                rgb.alpha = this.alpha;
                return rgb;
            }

            var h = this.hue / 60; // sector 0 to 5
            i = Math.floor(h);
            f = h - i; // factorial part of h
            p = this.value * (1 - this.saturation);
            q = this.value * (1 - this.saturation * f);
            t = this.value * (1 - this.saturation * (1 - f));

            switch (i) {
                case 0:
                    rgb.red = this.value;
                    rgb.green = t;
                    rgb.blue = p;
                    break;
                case 1:
                    rgb.red = q;
                    rgb.green = this.value;
                    rgb.blue = p;
                    break;
                case 2:
                    rgb.red = p;
                    rgb.green = this.value;
                    rgb.blue = t;
                    break;
                case 3:
                    rgb.red = p;
                    rgb.green = q;
                    rgb.blue = this.value;
                    break;
                case 4:
                    rgb.red = t;
                    rgb.green = p;
                    rgb.blue = this.value;
                    break;
                default: // case 5:
                    rgb.red = this.value;
                    rgb.green = p;
                    rgb.blue = q;
                    break;
            }

            rgb.alpha = this.alpha;

            return rgb;
        },
        toHSL: function() {
            this._normalise();

            var hsl = factories.HSL();

            hsl.hue = this.hue;
            var l = (2 - this.saturation) * this.value,
                s = this.saturation * this.value;
            if (l && 2 - l) {
                s /= (l <= 1) ? l : 2 - l;
            }
            l /= 2;
            hsl.saturation = s;
            hsl.lightness = l;
            hsl.alpha = this.alpha;

            return hsl;
        },

        toHSV: function() {
            return this.clone();
        }
    });

    registerModel('HSL', {
        hue: 0,
        saturation: 0,
        lightness: 0,
        alpha: 1,

        darkenByAmount: cloneOnApply(function(val) {
            this.lightness = Math.min(1, Math.max(this.lightness - val, 0));
        }),

        darkenByRatio: cloneOnApply(function(val) {
            this.lightness = Math.min(1, Math.max(this.lightness * (1 - val), 0));
        }),

        lightenByAmount: cloneOnApply(function(val) {
            this.lightness = Math.min(1, Math.max(this.lightness + val, 0));
        }),

        lightenByRatio: cloneOnApply(function(val) {
            this.lightness = Math.min(1, Math.max(this.lightness * (1 + val), 0));
        }),

        fromObject: function(o) {
            if ("string" == typeof o) {
                return this._fromCSS(o);
            }
            if (o.hasOwnProperty('hue') &&
                o.hasOwnProperty('saturation') &&
                o.hasOwnProperty('lightness')) {
                return this._fromHSL(o);
            }
            // nothing matchs, not an RGB object
        },

        _fromCSS: function(css) {
            var colorGroups = trim(css).match(hsl_hsla_regex);

            // if there is an "a" after "hsl", there must be a fourth parameter and the other way round
            if (!colorGroups || (!!colorGroups[1] + !!colorGroups[5] === 1)) {
                return null;
            }

            var hsl = factories.HSL();
            hsl.hue = (colorGroups[2] % 360 + 360) % 360;
            hsl.saturation = Math.max(0, Math.min(parseInt(colorGroups[3], 10) / 100, 1));
            hsl.lightness = Math.max(0, Math.min(parseInt(colorGroups[4], 10) / 100, 1));
            hsl.alpha = !!colorGroups[5] ? Math.max(0, Math.min(1, parseFloat(colorGroups[6]))) : 1;

            return hsl;
        },

        _fromHSL: function(HSL) {
            var newHSL = factories.HSL();

            newHSL.hue = HSL.hue;
            newHSL.saturation = HSL.saturation;
            newHSL.lightness = HSL.lightness;

            newHSL.alpha = HSL.hasOwnProperty('alpha') ? HSL.alpha : 1;

            return newHSL;
        },

        _normalise: function() {
            this.hue = (this.hue % 360 + 360) % 360;
            this.saturation = Math.min(Math.max(0, this.saturation), 1);
            this.lightness = Math.min(Math.max(0, this.lightness));
            this.alpha = Math.min(1, Math.max(0, this.alpha));
        },

        toHSL: function() {
            return this.clone();
        },
        toHSV: function() {
            this._normalise();

            var hsv = factories.HSV();

            // http://ariya.blogspot.com/2008/07/converting-between-hsl-and-hsv.html
            hsv.hue = this.hue; // H
            var l = 2 * this.lightness,
                s = this.saturation * ((l <= 1) ? l : 2 - l);
            hsv.value = (l + s) / 2; // V
            hsv.saturation = ((2 * s) / (l + s)) || 0; // S
            hsv.alpha = this.alpha;

            return hsv;
        },
        toRGB: function() {
            return this.toHSV().toRGB();
        }
    });

    // Package specific exports

    /* the Color function is a factory for new color objects.
     */
    function Color(o) {
        return color.fromObject(o);
    }
    Color.isValid = function(str) {
        var key, c = Color(str);

        var length = 0;
        for (key in c) {
            if (c.hasOwnProperty(key)) {
                length++;
            }
        }

        return length > 0;
    };
    net.brehaut.Color = Color;
}).call(net.brehaut);

/* Export to CommonJS
 */
if (typeof module !== 'undefined') {
    module.exports = net.brehaut.Color;
}