PHP Manual: Apply a gamma correction to a GD image

Description

bool imagegammacorrect(GdImage $image, float $input_gamma, float $output_gamma)

Applies gamma correction to the given gd image given an input and an output gamma.

Parameters

image: A GdImage object, returned by one of the image creation functions, such as imagecreatetruecolor.
input_gamma: The input gamma.
output_gamma: The output gamma.

Return Values

Returns true on success or false on failure.

Changelog

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

Examples

Example #1 imagegammacorrect usage

<?php
// Create image instance
$im = imagecreatefromgif('php.gif');

// Correct gamma, out = 1.537
imagegammacorrect($im, 1.0, 1.537);

// Save and free image
imagegif($im, './php_gamma_corrected.gif');
imagedestroy($im);
?>