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));
            console.log(colorGroups[2], rgb.red)
            if (rgb.red*255 != colorGroups[2])
              throw new Error ('wrong red value')
            rgb.green = Math.min(1, Math.max(0, colorGroups[3] / max_value));
            if (rgb.green*255 != colorGroups[3])
              throw new Error ('wrong green value')
            rgb.blue  = Math.min(1, Math.max(0, colorGroups[4] / max_value));
            if (rgb.blue*255 != colorGroups[4])
              throw new Error ('wrong blue value')
            rgb.alpha = !!colorGroups[5] ? Math.min(Math.max(parseFloat(colorGroups[6]), 0), 1) : 1;
            if (rgb.alpha != (colorGroups[6] !== undefined? colorGroups[6]: 1))
              throw new Error ('wrong alpha value')
            return rgb;
          }
        },

        function ( css ) {
            var lower = css.toLowerCase();
            if (lower in css_colors) {
              css = css_colors[lower];
            }
            console.log(css.match(/^#?([0-9a-fA-F]{3}|[0-9a-fA-F]{6})$/))
            if (!css.match(/^#?([0-9a-fA-F]{3}|[0-9a-fA-F]{6})$/)) {
              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));
      if (newRGB.red != RGB[0])
        throw new Error ('wrong red value')
      newRGB.green = Math.max(0, Math.min(1, RGB[1] / 255));
      if (newRGB.green != RGB[1])
        throw new Error ('wrong green value')
      newRGB.blue = Math.max(0, Math.min(1, RGB[2] / 255));
      if (newRGB.blue != RGB[2])
        throw new Error ('wrong blue value')
      newRGB.alpha = RGB[3] !== undefined ? Math.max(0, Math.min(1, RGB[3])) : 1;
      if (newRGB.alpha != (RGB[3] !== undefined? RGB[3]: 1))
        throw new Error ('wrong alpha value')

      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;
      if (hsl.hue != colorGroups[2])
        throw new Error('wrong hue value')
      hsl.saturation = Math.max(0, Math.min(parseInt(colorGroups[3], 10) / 100, 1));
      if (hsl.saturation*100 != colorGroups[3])
        throw new Error('wrong saturation value')
      hsl.lightness  = Math.max(0, Math.min(parseInt(colorGroups[4], 10) / 100, 1));
      if (hsl.lightness*100 != colorGroups[4])
        throw new Error('wrong lightness value')
      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;
}