GD and Image Functions
PHP Manual

imagecolorexact

Get the index of the specified color

Description

int imagecolorexact(
    GdImage $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

A GdImage object, 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.

Return Values

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

Changelog

Version Description
8.0.0 image expects a GdImage instance now; previously, a valid gd resource was expected.

Examples

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);
?>

The above example will output something similar to:

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

See Also

  • imagecolorclosest