PHP | Imagick linearStretchImage() Function

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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.zambiatek.com/wp-content/uploads/zambiatek-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(); 
  
?> 