SassColour.php in Sassy 7

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phamlp/sass/script/literals/SassColour.php

<?php

/* SVN FILE: $Id$ */

/**
 * SassColour class file.
 * @author			Chris Yates <[e-mail]>
 * @copyright 	Copyright (c) 2010 PBM Web Development
 * @license			http://phamlp.googlecode.com/files/license.txt
 * @package			PHamlP
 * @subpackage	Sass.script.literals
 */
require_once 'SassLiteral.php';

/**
 * SassColour class.
 * A SassScript object representing a CSS colour.
 * 
 * A colour may be represented internally as RGBA, HSLA, or both. It is
 * originally represented as whatever its input is; if it’s created with RGB
 * values, it’s represented as RGBA, and if it’s created with HSL values, it’s
 * represented as HSLA. Once a property is accessed that requires the other
 * representation – for example, SassColour::red for an HSL color – that
 * component is calculated and cached.
 * 
 * The alpha channel of a color is independent of its RGB or HSL representation.
 * It’s always stored, as 1 if nothing else is specified. If only the alpha
 * channel is modified using SassColour::with(), the cached RGB and HSL values
 * are retained.
 * 
 * Colour operations are all piecewise, e.g. when adding two colours each
 * component is added independantly; Rr = R1 + R2, Gr = G1 + G2, Br = B1 + B2.
 * 
 * Colours are returned as a named colour if possible or #rrggbb.
 *
 * @package			PHamlP
 * @subpackage	Sass.script.literals
 */
class SassColour extends SassLiteral {

  /**@#+
   * Regexes for matching and extracting colours
   */
  const MATCH = '/^((#([\\da-f]{6}|[\\da-f]{3}))|transparent|{CSS_COLOURS})/';
  const EXTRACT_3 = '/#([\\da-f])([\\da-f])([\\da-f])/';
  const EXTRACT_6 = '/#([\\da-f]{2})([\\da-f]{2})([\\da-f]{2})/';
  const TRANSPARENT = 'transparent';

  /**@#-*/

  /**@#-*/
  private static $svgColours = array(
    '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',
    'darkgrey' => '#a9a9a9',
    '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',
    'green' => '#008000',
    'greenyellow' => '#adff2f',
    'grey' => '#808080',
    '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',
    'lightgreen' => '#90ee90',
    'lightgrey' => '#d3d3d3',
    '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' => '#9370db',
    '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' => '#db7093',
    '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',
    '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',
  );

  /**
   * @var array reverse array (value => name) of named SVG1.0 colours
   */
  private static $_svgColours;

  /**
   * @var array reverse array (value => name) of named HTML4 colours
   */
  private static $_html4Colours = array(
    '#000000' => 'black',
    '#000080' => 'navy',
    '#0000ff' => 'blue',
    '#008000' => 'green',
    '#008080' => 'teal',
    '#00ff00' => 'lime',
    '#00ffff' => 'aqua',
    '#800000' => 'maroon',
    '#800080' => 'purple',
    '#808000' => 'olive',
    '#808080' => 'gray',
    '#c0c0c0' => 'silver',
    '#ff0000' => 'red',
    '#ff00ff' => 'fuchsia',
    '#ffff00' => 'yellow',
    '#ffffff' => 'white',
  );
  private static $regex;

  /**@#+
   * RGB colour components
   */

  /**
   * @var array RGB colour components. Used to check for RGB attributes.
   */
  private static $rgb = array(
    'red',
    'green',
    'blue',
  );

  /**
   * @var integer red component. 0 - 255
   */
  private $red;

  /**
   * @var integer green component. 0 - 255
   */
  private $green;

  /**
   * @var integer blue component. 0 - 255
   */
  private $blue;

  /**@#-*/

  /**@#+
   * HSL colour components
   */

  /**
   * @var array HSL colour components. Used to check for HSL attributes.
   */
  private static $hsl = array(
    'hue',
    'saturation',
    'lightness',
  );

  /**
   * @var float hue component. 0 - 360
   */
  private $hue;

  /**
   * @var float saturation component. 0 - 100
   */
  private $saturation;

  /**
   * @var float lightness component. 0 - 100
   */
  private $lightness;

  /**@#-*/

  /**
   * @var float alpha component. 0 - 1
   */
  private $alpha = 1;

  /**
   * Constructs an RGB or HSL color object, optionally with an alpha channel.
   * RGB values must be between 0 and 255. Saturation and lightness values must
   * be between 0 and 100. The alpha value must be between 0 and 1.
   * The colour can be specified as:
   *  + a string that is an SVG colour or of the form #rgb or #rrggbb
   *  + an array with either 'red', 'green', and 'blue' keys, and optionally
   * an alpha key.
   *  + an array with 'hue', 'saturation', and 'lightness' keys, and optionally
   * an alpha key.
   * + an array of red, green, and blue values, and optionally an alpha value.
   * @param mixed the colour
   * @return SassColour
   */
  public function __construct($colour) {
    if (is_string($colour)) {
      $colour = strtolower($colour);
      if ($colour === self::TRANSPARENT) {
        $this->red = 0;
        $this->green = 0;
        $this->blue = 0;
        $this->alpha = 0;
      }
      else {
        if (array_key_exists($colour, self::$svgColours)) {
          $colour = self::$svgColours[$colour];
        }
        if (strlen($colour) == 4) {
          preg_match(self::EXTRACT_3, $colour, $matches);
          for ($i = 1; $i < 4; $i++) {
            $matches[$i] = str_repeat($matches[$i], 2);
          }
        }
        else {
          preg_match(self::EXTRACT_6, $colour, $matches);
        }
        if (empty($matches)) {
          throw new SassColourException('Invalid {what}', array(
            '{what}' => 'SassColour string',
          ), SassScriptParser::$context->node);
        }
        $this->red = intval($matches[1], 16);
        $this->green = intval($matches[2], 16);
        $this->blue = intval($matches[3], 16);
        $this->alpha = 1;
      }
    }
    elseif (is_array($colour)) {
      $scheme = $this
        ->assertValid($colour);
      if ($scheme == 'rgb') {
        $this->red = $colour['red'];
        $this->green = $colour['green'];
        $this->blue = $colour['blue'];
        $this->alpha = isset($colour['alpha']) ? $colour['alpha'] : 1;
      }
      elseif ($scheme == 'hsl') {
        $this->hue = $colour['hue'];
        $this->saturation = $colour['saturation'];
        $this->lightness = $colour['lightness'];
        $this->alpha = isset($colour['alpha']) ? $colour['alpha'] : 1;
      }
      else {
        $this->red = $colour[0];
        $this->green = $colour[1];
        $this->blue = $colour[2];
        $this->alpha = isset($colour[3]) ? $colour[3] : 1;
      }
    }
    else {
      throw new SassColourException('{what} must be a {type}', array(
        '{what}' => 'Colour',
        '{type}' => 'array',
      ), SassScriptParser::$context->node);
    }
  }

  /**
   * Colour addition
   * @param mixed SassColour|SassNumber value to add
   * @return sassColour the colour result
   */
  public function op_plus($other) {
    if ($other instanceof SassNumber) {
      if (!$other
        ->isUnitless()) {
        throw new SassColourException('{what} must be a {type}', array(
          '{what}' => Phamlp::t('sass', 'Number'),
          '{type}' => Phamlp::t('sass', 'unitless number'),
        ), SassScriptParser::$context->node);
      }
      $this->red = $this
        ->getRed() + $other->value;
      $this->green = $this
        ->getGreen() + $other->value;
      $this->blue = $this
        ->getBlue() + $other->value;
    }
    elseif (!$other instanceof SassColour) {
      throw new SassColourException('{what} must be a {type}', array(
        '{what}' => 'Argument',
        '{type}' => 'SassColour or SassNumber',
      ), SassScriptParser::$context->node);
    }
    else {
      $this->red = $this
        ->getRed() + $other
        ->getRed();
      $this->green = $this
        ->getGreen() + $other
        ->getGreen();
      $this->blue = $this
        ->getBlue() + $other
        ->getBlue();
    }
    return $this;
  }

  /**
   * Colour subraction
   * @param mixed value (SassColour or SassNumber) to subtract
   * @return sassColour the colour result
   */
  public function op_minus($other) {
    if ($other instanceof SassNumber) {
      if (!$other
        ->isUnitless()) {
        throw new SassColourException('{what} must be a {type}', array(
          '{what}' => Phamlp::t('sass', 'Number'),
          '{type}' => Phamlp::t('sass', 'unitless number'),
        ), SassScriptParser::$context->node);
      }
      $this->red = $this
        ->getRed() - $other->value;
      $this->green = $this
        ->getGreen() - $other->value;
      $this->blue = $this
        ->getBlue() - $other->value;
    }
    elseif (!$other instanceof SassColour) {
      throw new SassColourException('{what} must be a {type}', array(
        '{what}' => 'Argument',
        '{type}' => 'SassColour or SassNumber',
      ), SassScriptParser::$context->node);
    }
    else {
      $this->red = $this
        ->getRed() - $other
        ->getRed();
      $this->green = $this
        ->getGreen() - $other
        ->getGreen();
      $this->blue = $this
        ->getBlue() - $other
        ->getBlue();
    }
    return $this;
  }

  /**
   * Colour multiplication
   * @param mixed SassColour|SassNumber value to multiply by
   * @return sassColour the colour result
   */
  public function op_times($other) {
    if ($other instanceof SassNumber) {
      if (!$other
        ->isUnitless()) {
        throw new SassColourException('{what} must be a {type}', array(
          '{what}' => Phamlp::t('sass', 'Number'),
          '{type}' => Phamlp::t('sass', 'unitless number'),
        ), SassScriptParser::$context->node);
      }
      $this->red = $this
        ->getRed() * $other->value;
      $this->green = $this
        ->getGreen() * $other->value;
      $this->blue = $this
        ->getBlue() * $other->value;
    }
    elseif (!$other instanceof SassColour) {
      throw new SassColourException('{what} must be a {type}', array(
        '{what}' => 'Argument',
        '{type}' => 'SassColour or SassNumber',
      ), SassScriptParser::$context->node);
    }
    else {
      $this->red = $this
        ->getRed() * $other
        ->getRed();
      $this->green = $this
        ->getGreen() * $other
        ->getGreen();
      $this->blue = $this
        ->getBlue() * $other
        ->getBlue();
    }
    return $this;
  }

  /**
   * Colour division
   * @param mixed value (SassColour or SassNumber) to divide by
   * @return sassColour the colour result
   */
  public function op_div($other) {
    if ($other instanceof SassNumber) {
      if (!$other
        ->isUnitless()) {
        throw new SassColourException('{what} must be a {type}', array(
          '{what}' => Phamlp::t('sass', 'Number'),
          '{type}' => Phamlp::t('sass', 'unitless number'),
        ), SassScriptParser::$context->node);
      }
      $this->red = $this
        ->getRed() / $other->value;
      $this->green = $this
        ->getGreen() / $other->value;
      $this->blue = $this
        ->getBlue() / $other->value;
    }
    elseif (!$other instanceof SassColour) {
      throw new SassColourException('{what} must be a {type}', array(
        '{what}' => 'Argument',
        '{type}' => 'SassColour or SassNumber',
      ), SassScriptParser::$context->node);
    }
    else {
      $this->red = $this
        ->getRed() / $other
        ->getRed();
      $this->green = $this
        ->getGreen() / $other
        ->getGreen();
      $this->blue = $this
        ->getBlue() / $other
        ->getBlue();
    }
    return $this;
  }

  /**
   * Colour modulus
   * @param mixed value (SassColour or SassNumber) to divide by
   * @return sassColour the colour result
   */
  public function op_modulo($other) {
    if ($other instanceof SassNumber) {
      if (!$other
        ->isUnitless()) {
        throw new SassColourException('{what} must be a {type}', array(
          '{what}' => Phamlp::t('sass', 'Number'),
          '{type}' => Phamlp::t('sass', 'unitless number'),
        ), SassScriptParser::$context->node);
      }
      $this->red = fmod($this
        ->getRed(), $other->value);
      $this->green = fmod($this
        ->getGreen(), $other->value);
      $this->blue = fmod($this
        ->getBlue(), $other->value);
    }
    elseif (!$other instanceof SassColour) {
      throw new SassColourException('{what} must be a {type}', array(
        '{what}' => 'Argument',
        '{type}' => 'SassColour or SassNumber',
      ), SassScriptParser::$context->node);
    }
    else {
      $this->red = fmod($this
        ->getRed(), $other
        ->getRed());
      $this->green = fmod($this
        ->getGreen(), $other
        ->getGreen());
      $this->blue = fmod($this
        ->getBlue(), $other
        ->getBlue());
    }
    return $this;
  }

  /**
   * Colour bitwise AND
   * @param mixed value (SassColour or SassNumber) to bitwise AND with
   * @return sassColour the colour result
   */
  public function op_bw_and($other) {
    if ($other instanceof SassNumber) {
      if (!$other
        ->isUnitless()) {
        throw new SassColourException('{what} must be a {type}', array(
          '{what}' => Phamlp::t('sass', 'Number'),
          '{type}' => Phamlp::t('sass', 'unitless number'),
        ), SassScriptParser::$context->node);
      }
      $this->red = $this
        ->getRed() & $other->value;
      $this->green = $this
        ->getGreen() & $other->value;
      $this->blue = $this
        ->getBlue() & $other->value;
    }
    elseif (!$other instanceof SassColour) {
      throw new SassColourException('{what} must be a {type}', array(
        '{what}' => 'Argument',
        '{type}' => 'SassColour or SassNumber',
      ), SassScriptParser::$context->node);
    }
    else {
      $this->red = $this
        ->getRed() & $other
        ->getRed();
      $this->green = $this
        ->getGreen() & $other
        ->getGreen();
      $this->blue = $this
        ->getBlue() & $other
        ->getBlue();
    }
    return $this;
  }

  /**
   * Colour bitwise OR
   * @param mixed value (SassColour or SassNumber) to bitwise OR with
   * @return sassColour the colour result
   */
  public function op_bw_or($other) {
    if ($other instanceof SassNumber) {
      if (!$other
        ->isUnitless()) {
        throw new SassColourException('{what} must be a {type}', array(
          '{what}' => Phamlp::t('sass', 'Number'),
          '{type}' => Phamlp::t('sass', 'unitless number'),
        ), SassScriptParser::$context->node);
      }
      $this->red = $this
        ->getRed() | $other->value;
      $this->green = $this
        ->getGreen() | $other->value;
      $this->blue = $this
        ->getBlue() | $other->value;
    }
    elseif (!$other instanceof SassColour) {
      throw new SassColourException('{what} must be a {type}', array(
        '{what}' => 'Argument',
        '{type}' => 'SassColour or SassNumber',
      ), SassScriptParser::$context->node);
    }
    else {
      $this->red = $this
        ->getRed() | $other
        ->getRed();
      $this->green = $this
        ->getGreen() | $other
        ->getGreen();
      $this->blue = $this
        ->getBlue() | $other
        ->getBlue();
    }
    return $this;
  }

  /**
   * Colour bitwise XOR
   * @param mixed value (SassColour or SassNumber) to bitwise XOR with
   * @return sassColour the colour result
   */
  public function op_bw_xor($other) {
    if ($other instanceof SassNumber) {
      if (!$other
        ->isUnitless()) {
        throw new SassColourException('{what} must be a {type}', array(
          '{what}' => Phamlp::t('sass', 'Number'),
          '{type}' => Phamlp::t('sass', 'unitless number'),
        ), SassScriptParser::$context->node);
      }
      $this->red = $this
        ->getRed() ^ $other->value;
      $this->green = $this
        ->getGreen() ^ $other->value;
      $this->blue = $this
        ->getBlue() ^ $other->value;
    }
    elseif (!$other instanceof SassColour) {
      throw new SassColourException('{what} must be a {type}', array(
        '{what}' => 'Argument',
        '{type}' => 'SassColour or SassNumber',
      ), SassScriptParser::$context->node);
    }
    else {
      $this->red = $this
        ->getRed() ^ $other
        ->getRed();
      $this->green = $this
        ->getGreen() ^ $other
        ->getGreen();
      $this->blue = $this
        ->getBlue() ^ $other
        ->getBlue();
    }
    return $this;
  }

  /**
   * Colour bitwise NOT
   * @return sassColour the colour result
   */
  public function op_not() {
    $this->red = ~$this
      ->getRed();
    $this->green = ~$this
      ->getGreen();
    $this->blue = ~$this
      ->getBlue();
    return $this;
  }

  /**
   * Colour bitwise Shift Left
   * @param sassNumber amount to shift left by
   * @return sassColour the colour result
   */
  public function op_shiftl($other) {
    if (!$other instanceof SassNumber || !$other
      ->isUnitless()) {
      throw new SassColourException('{what} must be a {type}', array(
        '{what}' => Phamlp::t('sass', 'Number'),
        '{type}' => Phamlp::t('sass', 'unitless number'),
      ), SassScriptParser::$context->node);
    }
    $this->red = $this
      ->getRed() << $other->value;
    $this->green = $this
      ->getGreen() << $other->value;
    $this->blue = $this
      ->getBlue() << $other->value;
    return $this;
  }

  /**
   * Colour bitwise Shift Right
   * @param sassNumber amount to shift right by
   * @return sassColour the colour result
   */
  public function op_shiftr($other) {
    if (!$other instanceof SassNumber || !$other
      ->isUnitless()) {
      throw new SassColourException('{what} must be a {type}', array(
        '{what}' => Phamlp::t('sass', 'Number'),
        '{type}' => Phamlp::t('sass', 'unitless number'),
      ), SassScriptParser::$context->node);
    }
    $this->red = $this
      ->getRed() >> $other->value;
    $this->green = $this
      ->getGreen() >> $other->value;
    $this->blue = $this
      ->getBlue() >> $other->value;
    return $this;
  }

  /**
   * Returns a copy of this colour with one or more channels changed.
   * RGB or HSL attributes may be changed, but not both at once.
   * @param array attributes to change
   */
  public function with($attributes) {
    if ($this
      ->assertValid($attributes, false) === 'hsl') {
      $colour = array_merge(array(
        'hue' => $this
          ->getHue(),
        'saturation' => $this
          ->getSaturation(),
        'lightness' => $this
          ->getLightness(),
        'alpha' => $this->alpha,
      ), $attributes);
    }
    else {
      $colour = array_merge(array(
        'red' => $this
          ->getRed(),
        'green' => $this
          ->getGreen(),
        'blue' => $this
          ->getBlue(),
        'alpha' => $this->alpha,
      ), $attributes);
    }
    return new SassColour($colour);
  }

  /**
   * Returns the alpha component (opacity) of this colour.
   * @return float the alpha component (opacity) of this colour.
   */
  public function getAlpha() {
    return $this->alpha;
  }

  /**
   * Returns the hue of this colour.
   * @return float the hue of this colour.
   */
  public function getHue() {
    if (is_null($this->hue)) {
      $this
        ->rgb2hsl();
    }
    return $this->hue;
  }

  /**
   * Returns the saturation of this colour.
   * @return float the saturation of this colour.
   */
  public function getSaturation() {
    if (is_null($this->saturation)) {
      $this
        ->rgb2hsl();
    }
    return $this->saturation;
  }

  /**
   * Returns the lightness of this colour.
   * @return float the lightness of this colour.
   */
  public function getLightness() {
    if (is_null($this->lightness)) {
      $this
        ->rgb2hsl();
    }
    return $this->lightness;
  }

  /**
   * Returns the blue component of this colour.
   * @return integer the blue component of this colour.
   */
  public function getBlue() {
    if (is_null($this->blue)) {
      $this
        ->hsl2rgb();
    }
    return max(0, min(255, round($this->blue)));
  }

  /**
   * Returns the green component of this colour.
   * @return integer the green component of this colour.
   */
  public function getGreen() {
    if (is_null($this->green)) {
      $this
        ->hsl2rgb();
    }
    return max(0, min(255, round($this->green)));
  }

  /**
   * Returns the red component of this colour.
   * @return integer the red component of this colour.
   */
  public function getRed() {
    if (is_null($this->red)) {
      $this
        ->hsl2rgb();
    }
    return max(0, min(255, round($this->red)));
  }

  /**
   * Returns an array with the RGB components of this colour.
   * @return array the RGB components of this colour
   */
  public function getRgb() {
    return array(
      $this->red,
      $this->green,
      $this->blue,
    );
  }

  /**
   * Returns an array with the RGB and alpha components of this colour.
   * @return array the RGB and alpha components of this colour
   */
  public function getRgba() {
    return array(
      $this
        ->getRed(),
      $this
        ->getGreen(),
      $this
        ->getBlue(),
      $this->alpha,
    );
  }

  /**
   * Returns an array with the HSL components of this colour.
   * @return array the HSL components of this colour
   */
  public function getHsl() {
    return array(
      $this
        ->getHue(),
      $this
        ->getSaturation(),
      $this
        ->getLightness(),
    );
  }

  /**
   * Returns an array with the HSL and alpha components of this colour.
   * @return array the HSL and alpha components of this colour
   */
  public function getHsla() {
    return array(
      $this
        ->getHue(),
      $this
        ->getSaturation(),
      $this
        ->getLightness(),
      $this->alpha,
    );
  }

  /**
   * Returns the value of this colour.
   * @return array the colour
   * @deprecated
   */
  public function getValue() {
    return $this->rgb;
  }

  /**
   * Returns whether this colour object is translucent; that is, whether the alpha channel is non-1.
   * @return boolean true if this colour is translucent, false if not
   */
  public function isTranslucent() {
    return $this->alpha < 1;
  }

  /**
   * Converts the colour to a string.
   * @param boolean whether to use CSS3 SVG1.0 colour names
   * @return string the colour as a named colour, rgba(r,g,g,a) or #rrggbb
   */
  public function toString($css3 = false) {
    $rgba = $this->rgba;
    if ($rgba[3] == 0) {
      return 'transparent';
    }
    elseif ($rgba[3] < 1) {
      return sprintf('rgba(%d,%d,%d,%1.2f)', $rgba[0], $rgba[1], $rgba[2], $rgba[3]);
    }
    else {
      $colour = sprintf('#%02x%02x%02x', $rgba[0], $rgba[1], $rgba[2]);
    }
    if ($css3) {
      if (empty(self::$_svgColours)) {
        self::$_svgColours = array_flip(self::$svgColours);
      }
      return array_key_exists($colour, self::$svgColours) ? self::$_svgColours[$colour] : $colour;
    }
    else {
      return array_key_exists($colour, self::$_html4Colours) ? self::$_html4Colours[$colour] : $colour;
    }
  }

  /**
   * Converts from HSL to RGB colourspace
   * Algorithm from the CSS3 spec: {@link http://www.w3.org/TR/css3-color/#hsl-color}
   * @uses hue2rgb()
   */
  private function hsl2rgb() {
    $h = $this->hue / 360;
    $s = $this->saturation / 100;
    $l = $this->lightness / 100;
    $m1 = $l <= 0.5 ? $l * ($s + 1) : $l + $s - $l * $s;
    $m2 = $l * 2 - $m1;
    $this->red = $this
      ->hue2rgb($m1, $m2, $h + 1 / 3);
    $this->green = $this
      ->hue2rgb($m1, $m2, $h);
    $this->blue = $this
      ->hue2rgb($m1, $m2, $h - 1 / 3);
  }

  /**
   * Converts from hue to RGB colourspace
   */
  private function hue2rgb($m1, $m2, $h) {
    $h += $h < 0 ? 1 : ($h > 1 ? -1 : 0);
    if ($h * 6 < 1) {
      $c = $m2 + ($m1 - $m2) * $h * 6;
    }
    elseif ($h * 2 < 1) {
      $c = $m1;
    }
    elseif ($h * 3 < 2) {
      $c = $m2 + ($m1 - $m2) * (2 / 3 - $h) * 6;
    }
    else {
      $c = $m2;
    }
    return $c * 255;
  }

  /**
   * Converts from RGB to HSL colourspace
   * Algorithm adapted from {@link http://en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV}
   */
  private function rgb2hsl() {
    $rgb = array(
      $this->red / 255,
      $this->green / 255,
      $this->blue / 255,
    );
    $max = max($rgb);
    $min = min($rgb);
    $c = $max - $min;

    // Lightness
    $l = ($max + $min) / 2;
    $this->lightness = $l * 100;

    // Saturation
    $this->saturation = ($c ? $l <= 0.5 ? $c / (2 * $l) : $c / (2 - 2 * $l) : 0) * 100;

    // Hue
    switch ($max) {
      case $min:
        $h = 0;
        break;
      case $rgb[0]:
        $h = 60 * ($rgb[1] - $rgb[2]) / $c;
        break;
      case $rgb[1]:
        $h = 60 * ($rgb[2] - $rgb[0]) / $c + 120;
        break;
      case $rgb[2]:
        $h = 60 * ($rgb[0] - $rgb[1]) / $c + 240;
        break;
    }
    $this->hue = fmod($h, 360);
  }

  /**
   * Asserts that the colour space is valid.
   * Returns the name of the colour space: 'rgb' if red, green, or blue keys given;
   * 'hsl' if hue, saturation or lightness keys given; null if a non-associative array
   * @param array the colour to test
   * @param boolean whether all colour space keys must be given
   * @return string name of the colour space
   * @throws SassColourException if mixed colour space keys given or not all
   * keys for a colour space are required but not given (contructor)
   */
  private function assertValid($colour, $all = true) {
    if (array_key_exists('red', $colour) || array_key_exists('green', $colour) || array_key_exists('blue', $colour)) {
      if (array_key_exists('hue', $colour) || array_key_exists('saturation', $colour) || array_key_exists('lightness', $colour)) {
        throw new SassColourException('SassColour can not have HSL and RGB keys specified', array(), SassScriptParser::$context->node);
      }
      if ($all && (!array_key_exists('red', $colour) || !array_key_exists('green', $colour) || !array_key_exists('blue', $colour))) {
        throw new SassColourException('SassColour must have all {colourSpace} keys specified', array(
          '{colourSpace}' => 'RGB',
        ), SassScriptParser::$context->node);
      }
      return 'rgb';
    }
    elseif (array_key_exists('hue', $colour) || array_key_exists('saturation', $colour) || array_key_exists('lightness', $colour)) {
      if ($all && (!array_key_exists('hue', $colour) || !array_key_exists('saturation', $colour) || !array_key_exists('lightness', $colour))) {
        throw new SassColourException('SassColour must have all {colourSpace} keys specified', array(
          '{colourSpace}' => 'HSL',
        ), SassScriptParser::$context->node);
      }
      return 'hsl';
    }
    elseif ($all && sizeof($colour) < 3) {
      throw new SassColourException('SassColour array must have at least 3 elements', array(), SassScriptParser::$context->node);
    }
  }

  /**
   * Returns a value indicating if a token of this type can be matched at
   * the start of the subject string.
   * @param string the subject string
   * @return mixed match at the start of the string or false if no match
   */
  public static function isa($subject) {
    if (empty(self::$regex)) {
      self::$regex = str_replace('{CSS_COLOURS}', join('|', array_reverse(array_keys(self::$svgColours))), self::MATCH);
    }
    return preg_match(self::$regex, strtolower($subject), $matches) ? $matches[0] : false;
  }

}

Classes

Name	Description
SassColour	SassColour class. A SassScript object representing a CSS colour.