csscolorparser.js

// (c) Dean McNamee <dean@gmail.com>, 2012.
//
// https://github.com/deanm/css-color-parser-js
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.

// http://www.w3.org/TR/css3-color/
var kCSSColorTable = {
  "transparent": [0,0,0,0], "aliceblue": [240,248,255,1],
  "antiquewhite": [250,235,215,1], "aqua": [0,255,255,1],
  "aquamarine": [127,255,212,1], "azure": [240,255,255,1],
  "beige": [245,245,220,1], "bisque": [255,228,196,1],
  "black": [0,0,0,1], "blanchedalmond": [255,235,205,1],
  "blue": [0,0,255,1], "blueviolet": [138,43,226,1],
  "brown": [165,42,42,1], "burlywood": [222,184,135,1],
  "cadetblue": [95,158,160,1], "chartreuse": [127,255,0,1],
  "chocolate": [210,105,30,1], "coral": [255,127,80,1],
  "cornflowerblue": [100,149,237,1], "cornsilk": [255,248,220,1],
  "crimson": [220,20,60,1], "cyan": [0,255,255,1],
  "darkblue": [0,0,139,1], "darkcyan": [0,139,139,1],
  "darkgoldenrod": [184,134,11,1], "darkgray": [169,169,169,1],
  "darkgreen": [0,100,0,1], "darkgrey": [169,169,169,1],
  "darkkhaki": [189,183,107,1], "darkmagenta": [139,0,139,1],
  "darkolivegreen": [85,107,47,1], "darkorange": [255,140,0,1],
  "darkorchid": [153,50,204,1], "darkred": [139,0,0,1],
  "darksalmon": [233,150,122,1], "darkseagreen": [143,188,143,1],
  "darkslateblue": [72,61,139,1], "darkslategray": [47,79,79,1],
  "darkslategrey": [47,79,79,1], "darkturquoise": [0,206,209,1],
  "darkviolet": [148,0,211,1], "deeppink": [255,20,147,1],
  "deepskyblue": [0,191,255,1], "dimgray": [105,105,105,1],
  "dimgrey": [105,105,105,1], "dodgerblue": [30,144,255,1],
  "firebrick": [178,34,34,1], "floralwhite": [255,250,240,1],
  "forestgreen": [34,139,34,1], "fuchsia": [255,0,255,1],
  "gainsboro": [220,220,220,1], "ghostwhite": [248,248,255,1],
  "gold": [255,215,0,1], "goldenrod": [218,165,32,1],
  "gray": [128,128,128,1], "green": [0,128,0,1],
  "greenyellow": [173,255,47,1], "grey": [128,128,128,1],
  "honeydew": [240,255,240,1], "hotpink": [255,105,180,1],
  "indianred": [205,92,92,1], "indigo": [75,0,130,1],
  "ivory": [255,255,240,1], "khaki": [240,230,140,1],
  "lavender": [230,230,250,1], "lavenderblush": [255,240,245,1],
  "lawngreen": [124,252,0,1], "lemonchiffon": [255,250,205,1],
  "lightblue": [173,216,230,1], "lightcoral": [240,128,128,1],
  "lightcyan": [224,255,255,1], "lightgoldenrodyellow": [250,250,210,1],
  "lightgray": [211,211,211,1], "lightgreen": [144,238,144,1],
  "lightgrey": [211,211,211,1], "lightpink": [255,182,193,1],
  "lightsalmon": [255,160,122,1], "lightseagreen": [32,178,170,1],
  "lightskyblue": [135,206,250,1], "lightslategray": [119,136,153,1],
  "lightslategrey": [119,136,153,1], "lightsteelblue": [176,196,222,1],
  "lightyellow": [255,255,224,1], "lime": [0,255,0,1],
  "limegreen": [50,205,50,1], "linen": [250,240,230,1],
  "magenta": [255,0,255,1], "maroon": [128,0,0,1],
  "mediumaquamarine": [102,205,170,1], "mediumblue": [0,0,205,1],
  "mediumorchid": [186,85,211,1], "mediumpurple": [147,112,219,1],
  "mediumseagreen": [60,179,113,1], "mediumslateblue": [123,104,238,1],
  "mediumspringgreen": [0,250,154,1], "mediumturquoise": [72,209,204,1],
  "mediumvioletred": [199,21,133,1], "midnightblue": [25,25,112,1],
  "mintcream": [245,255,250,1], "mistyrose": [255,228,225,1],
  "moccasin": [255,228,181,1], "navajowhite": [255,222,173,1],
  "navy": [0,0,128,1], "oldlace": [253,245,230,1],
  "olive": [128,128,0,1], "olivedrab": [107,142,35,1],
  "orange": [255,165,0,1], "orangered": [255,69,0,1],
  "orchid": [218,112,214,1], "palegoldenrod": [238,232,170,1],
  "palegreen": [152,251,152,1], "paleturquoise": [175,238,238,1],
  "palevioletred": [219,112,147,1], "papayawhip": [255,239,213,1],
  "peachpuff": [255,218,185,1], "peru": [205,133,63,1],
  "pink": [255,192,203,1], "plum": [221,160,221,1],
  "powderblue": [176,224,230,1], "purple": [128,0,128,1],
  "rebeccapurple": [102,51,153,1],
  "red": [255,0,0,1], "rosybrown": [188,143,143,1],
  "royalblue": [65,105,225,1], "saddlebrown": [139,69,19,1],
  "salmon": [250,128,114,1], "sandybrown": [244,164,96,1],
  "seagreen": [46,139,87,1], "seashell": [255,245,238,1],
  "sienna": [160,82,45,1], "silver": [192,192,192,1],
  "skyblue": [135,206,235,1], "slateblue": [106,90,205,1],
  "slategray": [112,128,144,1], "slategrey": [112,128,144,1],
  "snow": [255,250,250,1], "springgreen": [0,255,127,1],
  "steelblue": [70,130,180,1], "tan": [210,180,140,1],
  "teal": [0,128,128,1], "thistle": [216,191,216,1],
  "tomato": [255,99,71,1], "turquoise": [64,224,208,1],
  "violet": [238,130,238,1], "wheat": [245,222,179,1],
  "white": [255,255,255,1], "whitesmoke": [245,245,245,1],
  "yellow": [255,255,0,1], "yellowgreen": [154,205,50,1]}

function clamp_css_byte(i) {  // Clamp to integer 0 .. 255.
  i = Math.round(i);  // Seems to be what Chrome does (vs truncation).
  return i < 0 ? 0 : i > 255 ? 255 : i;
}

function clamp_css_float(f) {  // Clamp to float 0.0 .. 1.0.
  return f < 0 ? 0 : f > 1 ? 1 : f;
}

function parse_css_int(str) {  // int or percentage.
  if (str[str.length - 1] === '%')
    return clamp_css_byte(parseFloat(str) / 100 * 255);
  return clamp_css_byte(parseInt(str));
}

function parse_css_float(str) {  // float or percentage.
  if (str[str.length - 1] === '%')
    return clamp_css_float(parseFloat(str) / 100);
  return clamp_css_float(parseFloat(str));
}

function css_hue_to_rgb(m1, m2, h) {
  if (h < 0) h += 1;
  else if (h > 1) h -= 1;

  if (h * 6 < 1) return m1 + (m2 - m1) * h * 6;
  if (h * 2 < 1) return m2;
  if (h * 3 < 2) return m1 + (m2 - m1) * (2/3 - h) * 6;
  return m1;
}

function parseCSSColor(css_str) {
  // Remove all whitespace, not compliant, but should just be more accepting.
  var str = css_str.replace(/ /g, '').toLowerCase();

  // Color keywords (and transparent) lookup.
  if (str in kCSSColorTable) return kCSSColorTable[str].slice();  // dup.

  // #abc and #abc123 syntax.
  if (str[0] === '#') {
    if (str.length === 4) {
      var iv = parseInt(str.substr(1), 16);  // TODO(deanm): Stricter parsing.
      if (!(iv >= 0 && iv <= 0xfff)) return null;  // Covers NaN.
      return [((iv & 0xf00) >> 4) | ((iv & 0xf00) >> 8),
              (iv & 0xf0) | ((iv & 0xf0) >> 4),
              (iv & 0xf) | ((iv & 0xf) << 4),
              1];
    } else if (str.length === 7) {
      var iv = parseInt(str.substr(1), 16);  // TODO(deanm): Stricter parsing.
      if (!(iv >= 0 && iv <= 0xffffff)) return null;  // Covers NaN.
      return [(iv & 0xff0000) >> 16,
              (iv & 0xff00) >> 8,
              iv & 0xff,
              1];
    }

    return null;
  }

  var op = str.indexOf('('), ep = str.indexOf(')');
  if (op !== -1 && ep + 1 === str.length) {
    var fname = str.substr(0, op);
    var params = str.substr(op+1, ep-(op+1)).split(',');
    var alpha = 1;  // To allow case fallthrough.
    switch (fname) {
      case 'rgba':
        if (params.length !== 4) return null;
        alpha = parse_css_float(params.pop());
        // Fall through.
      case 'rgb':
        if (params.length !== 3) return null;
        return [parse_css_int(params[0]),
                parse_css_int(params[1]),
                parse_css_int(params[2]),
                alpha];
      case 'hsla':
        if (params.length !== 4) return null;
        alpha = parse_css_float(params.pop());
        // Fall through.
      case 'hsl':
        if (params.length !== 3) return null;
        var h = (((parseFloat(params[0]) % 360) + 360) % 360) / 360;  // 0 .. 1
        // NOTE(deanm): According to the CSS spec s/l should only be
        // percentages, but we don't bother and let float or percentage.
        var s = parse_css_float(params[1]);
        var l = parse_css_float(params[2]);
        var m2 = l <= 0.5 ? l * (s + 1) : l + s - l * s;
        var m1 = l * 2 - m2;
        return [clamp_css_byte(css_hue_to_rgb(m1, m2, h+1/3) * 255),
                clamp_css_byte(css_hue_to_rgb(m1, m2, h) * 255),
                clamp_css_byte(css_hue_to_rgb(m1, m2, h-1/3) * 255),
                alpha];
      default:
        return null;
    }
  }

  return null;
}

try { exports.parseCSSColor = parseCSSColor } catch(e) { }