include/colors.php

   1 <?php
   2 ### RGB >> HSL
   3 function _color_rgb2hsl($rgb) {
   4   $r = $rgb[0]; $g = $rgb[1]; $b = $rgb[2];
   5   $min = min($r, min($g, $b)); $max = max($r, max($g, $b));
   6   $delta = $max - $min; $l = ($min + $max) / 2; $s = 0;
   7   if ($l > 0 && $l < 1) {
   8     $s = $delta / ($l < 0.5 ? (2 * $l) : (2 - 2 * $l));
   9   }
  10   $h = 0;
  11   if ($delta > 0) {
  12     if ($max == $r && $max != $g) $h += ($g - $b) / $delta;
  13     if ($max == $g && $max != $b) $h += (2 + ($b - $r) / $delta);
  14     if ($max == $b && $max != $r) $h += (4 + ($r - $g) / $delta);
  15     $h /= 6;
  16   } return array($h, $s, $l);
  17 }
  18
  19 ### HSL >> RGB
  20 function _color_hsl2rgb($hsl) {
  21   $h = $hsl[0]; $s = $hsl[1]; $l = $hsl[2];
  22   $m2 = ($l <= 0.5) ? $l * ($s + 1) : $l + $s - $l*$s;
  23   $m1 = $l * 2 - $m2;
  24   return array(_color_hue2rgb($m1, $m2, $h + 0.33333),
  25                _color_hue2rgb($m1, $m2, $h),
  26                _color_hue2rgb($m1, $m2, $h - 0.33333));
  27 }
  28
  29 ### Helper function for _color_hsl2rgb().
  30 function _color_hue2rgb($m1, $m2, $h) {
  31   $h = ($h < 0) ? $h + 1 : (($h > 1) ? $h - 1 : $h);
  32   if ($h * 6 < 1) return $m1 + ($m2 - $m1) * $h * 6;
  33   if ($h * 2 < 1) return $m2;
  34   if ($h * 3 < 2) return $m1 + ($m2 - $m1) * (0.66666 - $h) * 6;
  35   return $m1;
  36 }
  37
  38 ### Convert a hex color into an RGB triplet.
  39 function _color_unpack($hex, $normalize = false) {
  40   if (strlen($hex) == 4) {
  41     $hex = $hex[1] . $hex[1] . $hex[2] . $hex[2] . $hex[3] . $hex[3];
  42   } $c = hexdec($hex);
  43   for ($i = 16; $i >= 0; $i -= 8) {
  44     $out[] = (($c >> $i) & 0xFF) / ($normalize ? 255 : 1);
  45   } return $out;
  46 }
  47
  48 ### Convert an RGB triplet to a hex color.
  49 function _color_pack($rgb, $normalize = false) {
  50   foreach ($rgb as $k => $v) {
  51     $out |= (($v * ($normalize ? 255 : 1)) << (16 - $k * 8));
  52   }return '#'. str_pad(dechex($out), 6, 0, STR_PAD_LEFT);
  53 }
  54
  55 function rgb2hsl($arr) {
  56         $r = $arr[0];
  57         $g = $arr[1];
  58         $b = $arr[2];
  59
  60    $var_R = ($r / 255);
  61    $var_G = ($g / 255);
  62    $var_B = ($b / 255);
  63
  64    $var_Min = min($var_R, $var_G, $var_B);
  65    $var_Max = max($var_R, $var_G, $var_B);
  66    $del_Max = $var_Max - $var_Min;
  67
  68    $v = $var_Max;
  69
  70    if ($del_Max == 0) {
  71       $h = 0;
  72       $s = 0;
  73    } else {
  74       $s = $del_Max / $var_Max;
  75
  76       $del_R = ( ( ( $max - $var_R ) / 6 ) + ( $del_Max / 2 ) ) / $del_Max;
  77       $del_G = ( ( ( $max - $var_G ) / 6 ) + ( $del_Max / 2 ) ) / $del_Max;
  78       $del_B = ( ( ( $max - $var_B ) / 6 ) + ( $del_Max / 2 ) ) / $del_Max;
  79
  80       if      ($var_R == $var_Max) $h = $del_B - $del_G;
  81       else if ($var_G == $var_Max) $h = ( 1 / 3 ) + $del_R - $del_B;
  82       else if ($var_B == $var_Max) $h = ( 2 / 3 ) + $del_G - $del_R;
  83
  84       if ($H < 0) $h++;
  85       if ($H > 1) $h--;
  86    }
  87
  88    return array($h, $s, $v);
  89 }
  90
  91 function hsl2rgb($arr) {
  92         $h = $arr[0];
  93         $s = $arr[1];
  94         $v = $arr[2];
  95
  96     if($s == 0) {
  97         $r = $g = $B = $v * 255;
  98     } else {
  99         $var_H = $h * 6;
 100         $var_i = floor( $var_H );
 101         $var_1 = $v * ( 1 - $s );
 102         $var_2 = $v * ( 1 - $s * ( $var_H - $var_i ) );
 103         $var_3 = $v * ( 1 - $s * (1 - ( $var_H - $var_i ) ) );
 104
 105         if       ($var_i == 0) { $var_R = $v     ; $var_G = $var_3  ; $var_B = $var_1 ; }
 106         else if  ($var_i == 1) { $var_R = $var_2 ; $var_G = $v      ; $var_B = $var_1 ; }
 107         else if  ($var_i == 2) { $var_R = $var_1 ; $var_G = $v      ; $var_B = $var_3 ; }
 108         else if  ($var_i == 3) { $var_R = $var_1 ; $var_G = $var_2  ; $var_B = $v     ; }
 109         else if  ($var_i == 4) { $var_R = $var_3 ; $var_G = $var_1  ; $var_B = $v     ; }
 110         else                   { $var_R = $v     ; $var_G = $var_1  ; $var_B = $var_2 ; }
 111
 112         $r = $var_R * 255;
 113         $g = $var_G * 255;
 114         $B = $var_B * 255;
 115     }
 116     return array($r, $g, $B);
 117 }
 118
 119 ?>