imagecolorexact

(PHP 4, PHP 5, PHP 7)

Get the index of the specified color

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

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

Parameters:

image

An image resource, returned by one of the image creation functions, such as imagecreatetruecolor().

red

Value of red component.

green

Value of green component.

blue

Value of blue component.

Returns:

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

Examples:

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);
?>

The above example will output something similar to:

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