Apply a gamma correction to a GD image

# imagegammacorrect

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

imagegammacorrect — Apply a gamma correction to a GD image

### Description

imagegammacorrect(GdImage `$image`, float `$input_gamma`, float `$output_gamma`): true

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

Always returns `true`.

### 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
imagegif($im, './php_gamma_corrected.gif');
?>`
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