colour.js

/**
 * A class to parse colour values. Updated by Ben to support colour conversions.
 * @author Stoyan Stefanov <[email protected]>
 * @author Ben Taylor <[email protected]>
 * @link   http://www.phpied.com/rgb-color-parser-in-javascript/
 * @license Use it if you like it
 */
function Colour(colour_string)
{
    this.ok = false;

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

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

    // before getting into regexps, try simple matches
    // and overwrite the input
    var simple_colours = {
        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_colours) {
        if (colour_string == key) {
            colour_string = simple_colours[key];
        }
    }
    // emd of simple type-in colours

    // array of colour definition objects
    var colour_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 < colour_defs.length; i++) {
        var re = colour_defs[i].re;
        var processor = colour_defs[i].process;
        var bits = re.exec(colour_string);
        if (bits) {
            channels = processor(bits);
            this.r = channels[0];
            this.g = channels[1];
            this.b = channels[2];
            this.ok = true;
        }

    }

    // 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);

    // some getters
    this.toRGB = function () {
        return 'rgb(' + this.r + ', ' + this.g + ', ' + this.b + ')';
    }
    
    this.toHex = function () {
        var r = this.r.toString(16);
        var g = this.g.toString(16);
        var b = this.b.toString(16);
        if (r.length == 1) r = '0' + r;
        if (g.length == 1) g = '0' + g;
        if (b.length == 1) b = '0' + b;
        return '#' + r + g + b;
    }
    
    /*
    * Returns an Array of [H,S,L]
    *
    */
    this.toHSL = function(){
        var r = this.r;
        var g = this.g;
        var b = this.b;
        r /= 255, g /= 255, b /= 255;
        var max = Math.max(r, g, b), min = Math.min(r, g, b);
        var h, s, l = (max + min) / 2;

        if(max == min){
            h = s = 0; // achromatic
        }else{
            var d = max - min;
            s = l > 0.5 ? d / (2 - max - min) : d / (max + min);
            switch(max){
                case r: h = (g - b) / d + (g < b ? 6 : 0); break;
                case g: h = (b - r) / d + 2; break;
                case b: h = (r - g) / d + 4; break;
            }
            h /= 6;
        }

        return [h, s, l];
    }
    
    /*
    * Returns an array of [H,S,V]
    */
    this.toHSV = function(){
        var r = this.r;
        var g = this.g;
        var b = this.b;
        r = r/255, g = g/255, b = b/255;
        var max = Math.max(r, g, b), min = Math.min(r, g, b);
        var h, s, v = max;

        var d = max - min;
        s = max == 0 ? 0 : d / max;

        if(max == min){
            h = 0; // achromatic
        }else{
            switch(max){
                case r: h = (g - b) / d + (g < b ? 6 : 0); break;
                case g: h = (b - r) / d + 2; break;
                case b: h = (r - g) / d + 4; break;
            }
            h /= 6;
        }

        return [h, s, v];
    }
    
    /*
    * Returns an array of [X,Y,Z] colour values
    */
    this.toXYZ = function(){
      var R = ( this.r / 255 );        //R from 0 to 255
      var G = ( this.g / 255 )        //G from 0 to 255
      var B = ( this.b / 255 )        //B from 0 to 255

      if ( R > 0.04045 ){
        R = Math.pow(( ( R + 0.055 ) / 1.055 ), 2.4);
      }
      else{
        R = R / 12.92;
      }    
                    
      if ( G > 0.04045 ){
        G = Math.pow((( G + 0.055 ) / 1.055 ), 2.4);
      } 
      else{
        G = G / 12.92;
      }  
                       
      if ( B > 0.04045 ){
        B = Math.pow((( B + 0.055 ) / 1.055 ), 2.4);
      } 
      else{
        B = B / 12.92;
      }

      R = R * 100;
      G = G * 100;
      B = B * 100;

      //Observer. = 2°, Illuminant = D65
      var X = R * 0.4124 + G * 0.3576 + B * 0.1805;
      var Y = R * 0.2126 + G * 0.7152 + B * 0.0722;
      var Z = R * 0.0193 + G * 0.1192 + B * 0.9505;
      return [X,Y,Z];
    }
    
    /*
    * Returns an array of [L,a,b] colour values
    *
    */
    this.toLAB = function(){
      var XYZ = this.toXYZ();
      
      var X = XYZ[0];
      var Y = XYZ[1];
      var Z = XYZ[2];
      
      var L = 10 * Math.sqrt(Y);
      var a = 17.5 * (((1.02 * X) - Y) / Math.sqrt(Y));
      var b = 7 * ((Y - (0.847 * Z)) / Math.sqrt(Y));
      return [L,a,b];
    }
}