PHP | Imagick getImageAlphaChannel() Function

The Imagick::getImageAphaChannel() function is an inbuilt function in PHP which is used to get the image alpha channel. The returned value is one of the ALPHACHANNEL constants.

Syntax:

int Imagick::getImageAlphaChannel( void )

Parameters: This function does not accept any parameters.

Exceptions: This function throws ImagickException on error.

Return Value: This function returns an integer value on success.

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)

Below programs illustrate the Imagick::getImageAlphaChannel() function in PHP:

Program 1:

<?php

// Create a new imagick object with a PNG image
$imagick = new Imagick(
'https://media.geeksforgeeks.org/wp-content/uploads/geeksforgeeks-13.png');

// Get the Alpha Channel
$alphaChannel = $imagick->getImageAlphaChannel();

echo $alphaChannel;
?>

Output:

1 ( which corresponds to imagick::ALPHACHANNEL_DEACTIVATE. )

Program 2:

<?php

// Create a new imagick object with a PNG image
$imagick = new Imagick(
'https://media.geeksforgeeks.org/wp-content/uploads/20191112214917/geeksforgeeks8.jpg');

// Get the Alpha Channel
$alphaChannel = $imagick->getImageAlphaChannel();

echo $alphaChannel . "<br>";

// Set the alpha channel
$alphaChannel = $imagick->setImageAlphaChannel(imagick::ALPHACHANNEL_RESET );
// Get the Alpha Channel
$alphaChannel = $imagick->getImageAlphaChannel();

echo $alphaChannel;
?>

Output:

0
1

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