PHP | Imagick levelImage() Function

The Imagick::levelImage() function is an inbuilt function in PHP that is used to adjust the levels of an image. 

Syntax:

bool Imagick::levelImage( $blackPoint, $gamma, 
                   $whitePoint, $channel = Imagick::CHANNEL_DEFAULT ) 

Parameters: This function accepts four parameters as mentioned above and described below:

• blackPoint: This parameter holds the black point of an image.
• gamma: This parameter holds the value of gamma.
• whitePoint: This parameter holds the white point of an image.
• channel: This parameter holds the channel constant that is valid for channel mode. Use a bit-wise operator to combine more than one channel.

Return Value: This function returns TRUE on success. 

Errors/Exceptions: This function throws ImagickException on error. The below program illustrates the Imagick::levelImage() function in PHP.

Program: 

<?php

// Store the image into variable
$imagick=
"https://media.geeksforgeeks.org/wp-content/uploads/geeksforgeeks-9.png";

// Declare new Imagick object
$imagick = new \Imagick($imagick);

// Use Imagick::newPseudoImage() function to create
// a new image using ImageMagick pseudo-formats
$imagick->newPseudoimage(700, 250, 'radial-gradient:red-blue');

// Function to set image format
$imagick->setFormat('png');

//  Use Imagick::getQuantum() function to
// return the ImageMagick quantum range
$quantum = $imagick->getQuantum();

// Use Imagick::levelImage() function
$imagick->levelImage($blackPoint / 100, $gamma, $quantum * $whitePoint / 100);
 
header("Content-Type: image/png");

// Display the image as output
echo $imagick->getImageBlob();

?>

Output: 

Reference: https://www.php.net/manual/en/imagick.levelimage.php