[edit] Last updated: Fri, 25 May 2012

imagecolorexact

(PHP 4, PHP 5)

imagecolorexact — Get the index of the specified color

Descrierea

int imagecolorexact ( resource $image , int $red , int $green , int $blue )

Returns the index of the specified color in the palette of the image.

Dacă ați creat imaginea din fișier atunci sunt determinate doar culorile utilizate în imagine. Culorile prezente doar în paletă nu sunt determinate.

Parametri

image: O resursă - imagine, întoarsă de una din funcțiile de creare a imaginilor, cum ar fi imagecreatetruecolor().
red: Valoarea componentei roșii.
green: Valoarea componentei verzi.
blue: Valoarea componentei albastre.

Valorile întoarse

Returns the index of the specified color in the palette, or -1 if the color does not exist.

Exemple

Example #1 Get colors from the GD logo


<?php
// Setup an image
$im = imagecreatefrompng('./gdlogo.png');

$colors   = Array();
$colors[] = imagecolorexact($im, 255, 0, 0);
$colors[] = imagecolorexact($im, 0, 0, 0);
$colors[] = imagecolorexact($im, 255, 255, 255);
$colors[] = imagecolorexact($im, 100, 255, 52);

print_r($colors);

// Free from memory
imagedestroy($im);
?>

Exemplul de mai sus va afișa ceva similar cu:

Array
(
    [0] => 16711680
    [1] => 0
    [2] => 16777215
    [3] => 6618932
)

Vedeți de asemenea

imagecolorclosest() - Get the index of the closest color to the specified color

imagecolorexactalpha

imagecolordeallocate

[edit] Last updated: Fri, 25 May 2012

add a note User Contributed Notes imagecolorexact

samtobia at geemail dot com 24-Mar-2011 10:11


A script that changes colors depending on get variable

important to note: I had little success with pngs and getting true red

gifs work much better



<?php

//0 is yellow, 1 is red, 2 is blue

$y = 1 - ceil($_GET["c"]/2);

$r = 1 - floor($_GET["c"]/2);

$b = floor($_GET["c"]/2);



$gd = imagecreatefromgif("example.gif");

imagecolorset($gd, imagecolorexact($gd, 255, 0, 0), $r*255, $y*255, $b*255);

imagecolorset($gd, imagecolorexact($gd, 191, 0, 0), $r*191, $y*191, $b*191);

imagecolorset($gd, imagecolorexact($gd, 128, 0, 0), $r*128, $y*128, $b*128);

imagecolorset($gd, imagecolorexact($gd, 255, 0, 0), $r*64, $y*64, $b*64);



header('Content-Type: image/gif');

imagegif($gd);



?>

jbr at ya-right dot com 18-Feb-2006 12:38


A few notes about this function...



This function will only work on images where the palette is 256 colors or less. You also can not use imagetruecolortopalette() to reduce the palette on a true color PNG image that has greater than 256 colors in it's palette, then call this function. If you try to do this imagecolorexact() will report colors not being in the image when they are in the image!



1. works on png(s) 8bit/256 colors or less.

2. works on all gif(s)

3. does not work on any type of jpg/jpeg image.

info at educar dot pro dot br 16-Nov-2005 11:14


<?php



$src = "../images/pic.gif";



$red = 9;

$green = 9;

$blue = 4;



$pic0026 = imagecreatefromgif ( $src );



$ind = imagecolorexact ( $pic, $red, $green, $blue );



echo '<img src="../images/pic.gif" border="0" alt="pic" title="View pic" /><br /><br />';



echo "RED ( " . $red . " ) GREEN ( " . $green . " ) BLUE ( " . $blue . " )<br />-> Palette Index = " . $ind;



if ( $ind != -1 )

{

echo "<br />[ The color exists! ]";

}

else

{

echo "<br />[ The color does not exist! ]";

}



imagedestroy ( $pic );



?>

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