PHP 8.1.0 RC 4 available for testing

imagecolorclosesthwb

(PHP 4 >= 4.0.1, PHP 5, PHP 7, PHP 8)

imagecolorclosesthwbGet the index of the color which has the hue, white and blackness

Beschreibung

imagecolorclosesthwb(
    GdImage $image,
    int $red,
    int $green,
    int $blue
): int

Get the index of the color which has the hue, white and blackness nearest the given color.

Parameter-Liste

image

Ein GdImage-Objekt, das von einer der Funktionen zur Bilderzeugung, z. B. imagecreatetruecolor(), zurückgegeben wurde.

red

Wert der Rotkomponente.

green

Wert der Grünkomponente.

blue

Wert der Blaukomponente.

Rückgabewerte

Returns an integer with the index of the color which has the hue, white and blackness nearest the given color.

Changelog

Version Beschreibung
8.0.0 image erwartet nun eine GdImage-Instanz; vorher wurde eine Ressource erwartet.

Beispiele

Beispiel #1 Example of using imagecolorclosesthwb()

<?php
$im 
imagecreatefromgif('php.gif');

echo 
'HWB: ' imagecolorclosesthwb($im116115152);

imagedestroy($im);
?>

Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:

HWB: 33

Siehe auch

  • imagecolorclosest() - Ermittelt den Farbwert-Index, der den angegebenen Farben am nächsten liegt
add a note add a note

User Contributed Notes 1 note

up
6
Xong
12 years ago
I have written a function which uses the deltaE-function of the CMC.
It returns much better results than imagecolorclosestHWB() or imageColorClosest().

A test-script is online on http://www.fuhrpark-software.de/spielwiese/color.php?color=ffff00

<?php
/*
* Returns the index of the palette-color which is most similar
* to $givenColor.
*
* $givenColor and the colors in $palette should be either
* formatted as (#)rrggbb
* (e. g. "ff0000", "4da4f3" or "#b5d7f3")
* or arrays with values for red, green and blue
* (e. g. $givenColor = array( 0xff, 0x00, 0x00 ) )
*
* References:
* function rgb2lab
*   - http://www.f4.fhtw-berlin.de/~barthel/ImageJ/ImageJ.htm
*
* function rgb2lab & function deltaE
*   - http://www.brucelindbloom.com
*/
function getNearestColor(
 
$givenColor,
 
$palette = array( 'blue' => '43aafd','red' => 'fe6256','green' => '64b949','yellow' => 'fcf357',
   
'black' => '656565','white' => 'fdfdfd','orange' => 'fea800','purple' => '9773fe')
) {
  if(!
function_exists('rgb2lab')) {
    function
rgb2lab($rgb) {
     
$eps = 216/24389; $k = 24389/27;
     
// reference white D50
     
$xr = 0.964221; $yr = 1.0; $zr = 0.825211;

     
$rgb[0] = $rgb[0]/255; //R 0..1
     
$rgb[1] = $rgb[1]/255; //G 0..1
     
$rgb[2] = $rgb[2]/255; //B 0..1

      // assuming sRGB (D65)
     
$rgb[0] = ($rgb[0] <= 0.04045)?($rgb[0]/12.92):pow(($rgb[0]+0.055)/1.055,2.4);
     
$rgb[1] = ($rgb[1] <= 0.04045)?($rgb[1]/12.92):pow(($rgb[1]+0.055)/1.055,2.4);
     
$rgb[2] = ($rgb[2] <= 0.04045)?($rgb[2]/12.92):pow(($rgb[2]+0.055)/1.055,2.4);

     
// sRGB D50
     
$x 0.4360747*$rgb[0] + 0.3850649*$rgb[1] + 0.1430804 *$rgb[2];
     
$y 0.2225045*$rgb[0] + 0.7168786*$rgb[1] + 0.0606169 *$rgb[2];
     
$z 0.0139322*$rgb[0] + 0.0971045*$rgb[1] + 0.7141733 *$rgb[2];

     
$xr = $x/$xr; $yr = $y/$yr; $zr = $z/$zr;

     
$fx = ($xr > $eps)?pow($xr, 1/3):($fx = ($k * $xr + 16) / 116);
     
$fy = ($yr > $eps)?pow($yr, 1/3):($fy = ($k * $yr + 16) / 116);
     
$fz = ($zr > $eps)?pow($zr, 1/3):($fz = ($k * $zr + 16) / 116);

     
$lab = array();
     
$lab[] = round(( 116 * $fy ) - 16);
     
$lab[] = round(500*($fx-$fy));
     
$lab[] = round(200*($fy-$fz));     
      return
$lab;
    }
  }
 
  if(!
function_exists('deltaE')) {
    function
deltaE($lab1, $lab2) {
     
// CMC 1:1
     
$l = 1; $c = 1;
     
     
$c1 = sqrt($lab1[1]*$lab1[1]+$lab1[2]*$lab1[2]);
     
$c2 = sqrt($lab2[1]*$lab2[1]+$lab2[2]*$lab2[2]);
     
     
$h1 = (((180000000/M_PI) * atan2($lab1[1],$lab1[2]) + 360000000) % 360000000)/1000000;

     
$t = (164 <= $h1 AND $h1 <= 345)?(0.56 + abs(0.2 * cos($h1+168))):(0.36 + abs(0.4 * cos($h1+35)));
     
$f = sqrt(pow($c1,4)/(pow($c1,4) + 1900));
     
     
$sl = ($lab1[0] < 16)?(0.511):((0.040975*$lab1[0])/(1 + 0.01765*$lab1[0]));
     
$sc = (0.0638 * $c1)/(1 + 0.0131 * $c1) + 0.638;
     
$sh = $sc * ($f * $t + 1 -$f);
     
      return
sqrt(
       
pow(($lab1[0]-$lab2[0])/($l * $sl),2) +
       
pow(($c1-$c2)/($c * $sc),2) +
       
pow(sqrt(
              (
$lab1[1]-$lab2[1])*($lab1[1]-$lab2[1]) +
              (
$lab1[2]-$lab2[2])*($lab1[2]-$lab2[2]) +
              (
$c1-$c2)*($c1-$c2)
            )/
$sh,2)
      );
    }
  }
 
  if(!
function_exists('str2rgb')) {
    function
str2rgb($str)
    {
     
$str = preg_replace('~[^0-9a-f]~','',$str);
     
$rgb = str_split($str,2);
      for(
$i=0;$i<3;$i++)
       
$rgb[$i] = intval($rgb[$i],16);

      return
$rgb;
    }
  }
 
 
$givenColorRGB = is_array($givenColor?$givenColor:str2rgb($givenColor);

 
$min = 0xffff;
 
$return = NULL;
 
  foreach(
$palette as $key => $color) {
   
$color = is_array($color)?$color:str2rgb($color);
    if(
$min >= ($deltaE = deltaE(rgb2lab($color),rgb2lab($givenColorRGB))))
    {
     
$min = $deltaE;
     
$return = $key;
    }
  }
 
  return
$return;
}
?>
To Top