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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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&nb |