imagecolorexact

(PHP 4, PHP 5, PHP 7, PHP 8)

imagecolorexact — Devuelve el índice del color especificado

Descripción

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

Devuelve el índice del color especificado en la paleta de la imagen image.

If you created the image from a file, only colors used in the image are resolved. Colors present only in the palette are not resolved.

Parámetros

image: Un objeto GdImage, retornado por una de las funciones de creación de imágenes, como imagecreatetruecolor().
red: Value of red component.
green: Value of green component.
blue: Value of blue component.

Valores devueltos

Devuelve el índice del color especificado en la paleta, o -1 si el color no existe.

Historial de cambios

Versión	Descripción
8.0.0	`image` expects a GdImage instance now; previously, a valid `gd` resource was expected.

Ejemplos

Ejemplo #1 Obtención de los colores que componen el logo GD

<?php
// Define la imagen
$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);
?>

Resultado del ejemplo anterior es similar a :

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

Ver también

imagecolorclosest() - Devuelve el índice de la color más cercana a una color dada

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User Contributed Notes 3 notes

down

jbr at ya-right dot com ¶

19 years ago

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.

down

samtobia at geemail dot com ¶

14 years ago

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);

?>

down

info at educar dot pro dot br ¶

19 years ago

<?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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