The Imagick::setImageAlphaChannel() function is an inbuilt function in PHP which is used to set the image alpha channel.
Syntax:
bool Imagick::setImageAlphaChannel( int $mode )
Parameters: This function accepts single parameter $mode which holds an integer value corresponding to one of the ALPHACHANNEL constants.
List of ALPHACHANNEL constants are given below:
- imagick::ALPHACHANNEL_ACTIVATE (0)
- imagick::ALPHACHANNEL_DEACTIVATE (1)
- imagick::ALPHACHANNEL_RESET (2)
- imagick::ALPHACHANNEL_SET (3)
- imagick::ALPHACHANNEL_UNDEFINED (4)
- imagick::ALPHACHANNEL_COPY (5)
- imagick::ALPHACHANNEL_EXTRACT (6)
- imagick::ALPHACHANNEL_OPAQUE (7)
- imagick::ALPHACHANNEL_SHAPE (8)
- imagick::ALPHACHANNEL_TRANSPARENT (9)
Return Value: This function returns TRUE on success.
Below programs illustrate the Imagick::setImageAlphaChannel() function in PHP:
Program 1:
<?php   // Create a new imagick object $imagick = new Imagick(   // Set background color $imagick->setImageBackgroundColor('blue');   // Set the ImageAlphaChannel to 9 which corresponds // to imagick::ALPHACHANNEL_TRANSPARENT $imagick->setImageAlphaChannel(9);   // Display the image header("Content-Type: image/png");   echo $imagick->getImageBlob(); ?> |
Output:
Program 2:
<?php   // Create a new imagick object $imagick = new Imagick(   // Set the ImageAlphaChannel to 3 which corresponds to // imagick::ALPHACHANNEL_SET $imagick->setImageAlphaChannel(3);   // Display the image header("Content-Type: image/png");   echo $imagick->getImageBlob(); ?> |
Output:
Reference: https://www.php.net/manual/en/imagick.setimagealphachannel.php
