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<?php |
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/** |
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* |
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* Color values manipulation utilities. Provides methods to convert from and to |
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* Hex, RGB, HSV and HSL color representattions. |
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* |
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* Several color conversion logic are based on pseudo-code from |
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* http://www.easyrgb.com/math.php |
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* |
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* @category Lux |
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* |
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* @package Lux_Color |
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* |
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* @author Rodrigo Moraes <rodrigo.moraes@gmail.com> |
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* |
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* @license http://www.opensource.org/licenses/bsd-license.php BSD License |
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* |
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* @version $Id$ |
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* |
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*/ |
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class Lux_Color |
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{ |
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/** |
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* |
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* Converts hexadecimal colors to RGB. |
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* |
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* @param string $hex Hexadecimal value. Accepts values with 3 or 6 numbers, |
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* with or without #, e.g., CCC, #CCC, CCCCCC or #CCCCCC. |
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* |
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* @return array RGB values: 0 => R, 1 => G, 2 => B |
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* |
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*/ |
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public function hex2rgb($hex) |
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{ |
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// Remove #. |
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if (strpos($hex, '#') === 0) { |
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$hex = substr($hex, 1); |
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} |
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if (strlen($hex) == 3) { |
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$hex .= $hex; |
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} |
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if (strlen($hex) != 6) { |
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return false; |
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} |
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// Convert each tuple to decimal. |
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$r = hexdec(substr($hex, 0, 2)); |
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$g = hexdec(substr($hex, 2, 2)); |
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$b = hexdec(substr($hex, 4, 2)); |
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return array($r, $g, $b); |
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} |
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/** |
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* |
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* Converts hexadecimal colors to HSV. |
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* |
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* @param string $hex Hexadecimal value. Accepts values with 3 or 6 numbers, |
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* with or without #, e.g., CCC, #CCC, CCCCCC or #CCCCCC. |
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* |
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* @return array HSV values: 0 => H, 1 => S, 2 => V |
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* |
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*/ |
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public function hex2hsv($hex) |
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{ |
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return $this->rgb2hsv($this->hex2rgb($hex)); |
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} |
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/** |
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* |
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* Converts hexadecimal colors to HSL. |
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* |
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* @param string $hex Hexadecimal value. Accepts values with 3 or 6 numbers, |
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* with or without #, e.g., CCC, #CCC, CCCCCC or #CCCCCC. |
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* |
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* @return array HSL values: 0 => H, 1 => S, 2 => L |
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* |
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*/ |
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public function hex2hsl($hex) |
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{ |
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return $this->rgb2hsl($this->hex2rgb($hex)); |
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} |
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/** |
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* |
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* Converts RGB colors to hexadecimal. |
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* |
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* @param array $rgb RGB values: 0 => R, 1 => G, 2 => B |
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* |
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* @return string Hexadecimal value with six digits, e.g., CCCCCC. |
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* |
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*/ |
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public function rgb2hex($rgb) |
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{ |
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if(count($rgb) < 3) { |
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return false; |
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} |
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list($r, $g, $b) = $rgb; |
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// From php.net. |
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$r = 0x10000 * max(0, min(255, $r)); |
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$g = 0x100 * max(0, min(255, $g)); |
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$b = max(0, min(255, $b)); |
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return strtoupper(str_pad(dechex($r + $g + $b), 6, 0, STR_PAD_LEFT)); |
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} |
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/** |
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* |
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* Converts RGB to HSV. |
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* |
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* @param array $rgb RGB values: 0 => R, 1 => G, 2 => B |
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* |
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* @return array HSV values: 0 => H, 1 => S, 2 => V |
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* |
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*/ |
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public function rgb2hsv($rgb) |
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{ |
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// RGB values = 0 ÷ 255 |
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$var_R = ($rgb[0] / 255); |
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$var_G = ($rgb[1] / 255); |
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$var_B = ($rgb[2] / 255); |
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// Min. value of RGB |
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$var_Min = min($var_R, $var_G, $var_B); |
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// Max. value of RGB |
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$var_Max = max($var_R, $var_G, $var_B); |
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// Delta RGB value |
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$del_Max = $var_Max - $var_Min; |
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$V = $var_Max; |
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// This is a gray, no chroma... |
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if ( $del_Max == 0 ) { |
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// HSV results = 0 ÷ 1 |
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$H = 0; |
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$S = 0; |
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} else { |
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// Chromatic data... |
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$S = $del_Max / $var_Max; |
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$del_R = ((($var_Max - $var_R) / 6) + ($del_Max / 2)) / $del_Max; |
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$del_G = ((($var_Max - $var_G) / 6) + ($del_Max / 2)) / $del_Max; |
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$del_B = ((($var_Max - $var_B) / 6) + ($del_Max / 2)) / $del_Max; |
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if ($var_R == $var_Max) { |
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$H = $del_B - $del_G; |
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} else if ($var_G == $var_Max) { |
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$H = (1 / 3) + $del_R - $del_B; |
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} else if ($var_B == $var_Max) { |
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$H = (2 / 3) + $del_G - $del_R; |
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} |
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if ($H < 0) { |
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$H += 1; |
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} |
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if ($H > 1) { |
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$H -= 1; |
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} |
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} |
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// Returns agnostic values. |
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// Range will depend on the application: e.g. $H*360, $S*100, $V*100. |
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return array($H, $S, $V); |
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} |
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/** |
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* |
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* Converts RGB to HSL. |
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* |
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* @param array $rgb RGB values: 0 => R, 1 => G, 2 => B |
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* |
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* @return array HSL values: 0 => H, 1 => S, 2 => L |
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* |
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*/ |
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public function rgb2hsl($rgb) |
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{ |
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// Where RGB values = 0 ÷ 255. |
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$var_R = $rgb[0] / 255; |
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$var_G = $rgb[1] / 255; |
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$var_B = $rgb[2] / 255; |
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// Min. value of RGB |
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$var_Min = min($var_R, $var_G, $var_B); |
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// Max. value of RGB |
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$var_Max = max($var_R, $var_G, $var_B); |
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// Delta RGB value |
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$del_Max = $var_Max - $var_Min; |
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$L = ($var_Max + $var_Min) / 2; |
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if ( $del_Max == 0 ) { |
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// This is a gray, no chroma... |
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// HSL results = 0 ÷ 1 |
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$H = 0; |
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$S = 0; |
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} else { |
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// Chromatic data... |
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if ($L < 0.5) { |
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$S = $del_Max / ($var_Max + $var_Min); |
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} else { |
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$S = $del_Max / ( 2 - $var_Max - $var_Min ); |
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} |
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$del_R = ((($var_Max - $var_R) / 6) + ($del_Max / 2)) / $del_Max; |
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$del_G = ((($var_Max - $var_G) / 6) + ($del_Max / 2)) / $del_Max; |
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$del_B = ((($var_Max - $var_B) / 6) + ($del_Max / 2)) / $del_Max; |
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if ($var_R == $var_Max) { |
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$H = $del_B - $del_G; |
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} else if ($var_G == $var_Max) { |
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$H = ( 1 / 3 ) + $del_R - $del_B; |
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} else if ($var_B == $var_Max) { |
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$H = ( 2 / 3 ) + $del_G - $del_R; |
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} |
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if ($H < 0) { |
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$H += 1; |
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} |
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if ($H > 1) { |
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$H -= 1; |
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} |
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} |
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return array($H, $S, $L); |
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} |
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/** |
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* |
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* Converts HSV colors to hexadecimal. |
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* |
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* @param array $hsv HSV values: 0 => H, 1 => S, 2 => V |
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* |
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* @return string Hexadecimal value with six digits, e.g., CCCCCC. |
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* |
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*/ |
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public function hsv2hex($hsv) |
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{ |
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return $this->rgb2hex($this->hsv2rgb($hsv)); |
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} |
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/** |
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* |
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* Converts HSV to RGB. |
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* |
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* @param array $hsv HSV values: 0 => H, 1 => S, 2 => V |
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* |
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* @return array RGB values: 0 => R, 1 => G, 2 => B |
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* |
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*/ |
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public function hsv2rgb($hsv) |
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{ |
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$H = $hsv[0]; |
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$S = $hsv[1]; |
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$V = $hsv[2]; |
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// HSV values = 0 ÷ 1 |
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if ($S == 0) { |
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$R = $V * 255; |
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$G = $V * 255; |
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$B = $V * 255; |
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} else { |
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$var_h = $H * 6; |
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// H must be < 1 |
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if ( $var_h == 6 ) { |
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$var_h = 0; |
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} |
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// Or ... $var_i = floor( $var_h ) |
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$var_i = floor( $var_h ); |
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$var_1 = $V * ( 1 - $S ); |
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$var_2 = $V * ( 1 - $S * ( $var_h - $var_i ) ); |
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$var_3 = $V * ( 1 - $S * ( 1 - ( $var_h - $var_i ) ) ); |
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switch($var_i) { |
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case 0: |
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$var_r = $V; |
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$var_g = $var_3; |
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$var_b = $var_1; |
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break; |
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case 1: |
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$var_r = $var_2; |
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$var_g = $V; |
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$var_b = $var_1; |
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break; |
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case 2: |
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$var_r = $var_1; |
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$var_g = $V; |
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$var_b = $var_3; |
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break; |
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case 3: |
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$var_r = $var_1; |
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$var_g = $var_2; |
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$var_b = $V; |
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break; |
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case 4: |
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$var_r = $var_3; |
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$var_g = $var_1; |
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$var_b = $V; |
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break; |
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default: |
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$var_r = $V; |
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$var_g = $var_1; |
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$var_b = $var_2; |
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} |
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//RGB results = 0 ÷ 255 |
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$R = $var_r * 255; |
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$G = $var_g * 255; |
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$B = $var_b * 255; |
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} |
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return array($R, $G, $B); |
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} |
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/** |
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* |
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* Converts HSV colors to HSL. |
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* |
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* @param array $hsv HSV values: 0 => H, 1 => S, 2 => V |
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* |
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* @return array HSL values: 0 => H, 1 => S, 2 => L |
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* |
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*/ |
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public function hsv2hsl($hsv) |
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{ |
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return $this->rgb2hsl($this->hsv2rgb($hsv)); |
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} |
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/** |
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* |
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* Converts hexadecimal colors to HSL. |
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* |
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* @param array $hsl HSL values: 0 => H, 1 => S, 2 => L |
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* |
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* @return string Hexadecimal value. Accepts values with 3 or 6 numbers, |
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* with or without #, e.g., CCC, #CCC, CCCCCC or #CCCCCC. |
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* |
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*/ |
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public function hsl2hex($hsl) |
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{ |
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return $this->rgb2hex($this->hsl2rgb($hsl)); |
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} |
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/** |
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* |
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* Converts HSL to RGB. |
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* |
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* @param array $hsv HSL values: 0 => H, 1 => S, 2 => L |
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* |
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* @return array RGB values: 0 => R, 1 => G, 2 => B |
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* |
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*/ |
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public function hsl2rgb($hsl) |
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{ |
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list($H, $S, $L) = $hsl; |
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if ($S == 0) { |
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// HSL values = 0 ÷ 1 |
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// RGB results = 0 ÷ 255 |
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$R = $L * 255; |
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$G = $L * 255; |
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$B = $L * 255; |
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} else { |
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if ($L < 0.5) { |
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$var_2 = $L * (1 + $S); |
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} else { |
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$var_2 = ($L + $S) - ($S * $L); |
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} |
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$var_1 = 2 * $L - $var_2; |
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$R = 255 * $this->_hue2rgb($var_1, $var_2, $H + (1 / 3)); |
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$G = 255 * $this->_hue2rgb($var_1, $var_2, $H); |
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$B = 255 * $this->_hue2rgb($var_1, $var_2, $H - (1 / 3)); |
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} |
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return array($R, $G, $B); |
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} |
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/** |
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* |
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* Support method for hsl2rgb(): converts hue ro RGB. |
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* |
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* @param |
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* |
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* @param |
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* |
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* @param |
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* |
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* @return int |
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* |
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*/ |
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protected function _hue2rgb($v1, $v2, $vH) |
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{ |
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if ($vH < 0) { |
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$vH += 1; |
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