The Gmagick::separateimagechannel() function is an inbuilt function in PHP which is used to separate a channel from the image and returns a grayscale image. A channel is a particular color component of each pixel in the image.
Syntax:
Gmagick Gmagick::separateimagechannel( int $channel )
Parameters: This function accepts a single parameter $channel which holds the integer value corresponding to one of the CHANNEL constants.
Return Value: This function returns Gmagick object on success.
Exceptions: This function throws GmagickException on error.
Below given programs illustrate the Gmagick::separateimagechannel() function in PHP:
Used Image:
Program 1 (Separating the RED channel):
<?php   // Create a new Gmagick object $gmagick = new Gmagick('neveropen.png');   // Separate the Gmagick::CHANNEL_RED $gmagick->separateimagechannel(Gmagick::CHANNEL_RED);   // Display the image header("Content-Type: image/png"); echo $gmagick; ?> |
Output:
Program 2 (Separating the Green channel):
<?php   // Create a new Gmagick object $gmagick = new Gmagick('neveropen.png');   // Separate the Gmagick::CHANNEL_GREEN $gmagick->separateimagechannel(Gmagick::CHANNEL_GREEN);   // Display the image header("Content-Type: image/png"); echo $gmagick; ?> |
Output:
Program 3 (For a drawing):
<?php   // Create a new Gmagick object $gmagick = new Gmagick('neveropen.png');   // Create a GmagickDraw object $draw = new GmagickDraw();   // Set the color $draw->setFillColor('white');   // Function to draw rectangle $draw->rectangle(0, 0, 800, 400);   // Set the fill color $draw->setFillColor('yellow');   // Set the font size $draw->setfontsize(50);   // Annotate a text $draw->annotate(30, 100, 'neveropen');   // Use of drawimage function $gmagick->drawImage($draw);   // Separate the Gmagick::CHANNEL_BLUE $gmagick->separateimagechannel(Gmagick::CHANNEL_BLUE);   // Display the output image header("Content-Type: image/png"); echo $gmagick->getImageBlob(); ?> |
Output:
Reference: https://www.php.net/manual/en/gmagick.separateimagechannel.php
