PHP | Imagick linearStretchImage() Function

The Imagick::linearStretchImage() function is an inbuilt function in PHP which is used to stretch with saturation the image intensity. The calculation of Imagick::linearStretchImage() function is carry by pixels multiples with blackPoint and whitePoint simultaneously.

Syntax:

bool Imagick::linearStretchImage( $blackPoint, $whitePoint )

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

• $blackPoint: This parameter holds the image black point.
• $whitePoint: This parameter holds the image white point.

Return Value: This function returns TRUE on success FALSE on failure.

Below example illustrates the Imagick::linearStretchImage() function in PHP:

Program: This program uses Imagick::linearStretchImage() function to stretch with saturation the image intensity.

<?php

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

// Store the value of variables
$blackThreshold = 23;
$whiteThreshold = 45;

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

// Calculate the pixels of image
$pixels = $imagick->getImageWidth() * $imagick->getImageHeight();

// Use linearStretchImage() function to stretches with
// saturation the image intensity
$imagick->linearStretchImage($blackThreshold * $pixels, $whiteThreshold * $pixels);

header("Content-Type: image/jpeg");

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

?>

Output:

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