PHP | imagegammacorrect() function

Last Updated : 30 Jan, 2020
The imagegammacorrect() function is an inbuilt function in PHP which is used to apply gamma correction to the given image given an input and an output gamma. Syntax: 
bool imagegammacorrect( resource $image, float $inputgamma, float $outputgamma )
Parameters:This function accepts three parameters as mentioned above and described below:
  • $image: It specifies the image to be worked upon.
  • $inputgamma: It specifies the input gamma.
  • $outputgamma: It specifies the output gamma.
Return Value: This function returns TRUE on success or FALSE on failure. Exceptions: This function throws Exception on error. Below given programs illustrate the imagegammacorrect() function in PHP: Program 1: php 
<?php
// Create an image
$im = imagecreatefrompng('https://media.geeksforgeeks.org/wp-content/uploads/geeksforgeeks-13.png');

// Change the image gamma
imagegammacorrect($im, 3, 1.3);

// Output to browser
header('Content-Type: image/png');
imagepng($im);
imagedestroy($im);
?>
Output: Program 2: php 
<?php
// Create an empty image
$im = imagecreatetruecolor(800, 250);

// Set the background to be light blue
imagefilledrectangle($im, 0, 0, 800, 250, imagecolorallocate($im, 0, 0, 180));

// Add text using a font from local
imagefttext($im, 80, 0, 50, 130, imagecolorallocate($im, 0, 150, 0), './Pacifico.ttf', 'GeeksforGeeks');

// Change the image gamma
imagegammacorrect($im, 3, 1.3);

// Output to browser
header('Content-Type: image/png');
imagepng($im);
imagedestroy($im);
?>
Output: Reference: https://www.php.net/manual/en/function.imagegammacorrect.php
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