PHP | Imagick setImageChannelDepth() Function

Last Updated : 26 Aug, 2019

The Imagick::setImageChannelDepth() function is an inbuilt function in PHP which is used to set the depth of a particular channel image.

Syntax:

bool Imagick::setImageChannelDepth( $channel, $depth )

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

$channel: This parameter is used to specify the channel constant. Below is the list of constant channel:
CHANNEL constants:
- imagick::CHANNEL_UNDEFINED
- imagick::CHANNEL_RED
- imagick::CHANNEL_GRAY
- imagick::CHANNEL_CYAN
- imagick::CHANNEL_GREEN
- imagick::CHANNEL_MAGENTA
- imagick::CHANNEL_BLUE
- imagick::CHANNEL_YELLOW
- imagick::CHANNEL_ALPHA
- imagick::CHANNEL_OPACITY
- imagick::CHANNEL_MATTE
- imagick::CHANNEL_BLACK
- imagick::CHANNEL_INDEX
- imagick::CHANNEL_ALL
- imagick::CHANNEL_DEFAULT
$depth: This parameter is used to specify the depth to be set for Imagick object.

Return Value: This function returns True on success.

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

Original Image:

Program 1:

<?php 
  
// Create new Imagick object 
$im = new Imagick( 
'https://media.geeksforgeeks.org/wp-content/uploads/geeksforgeeks-15.png'); 
  
// Using getImageChannelDepth function 
// with red channel 
echo "Before Set Channel depth: " . "</br>"; 
echo $im->getImageChannelDepth(imagick::CHANNEL_RED) . "</br>"; 
  
// Set channel Depth of CYAN and GREEN Channel 
$im->setImageChannelDepth(imagick::CHANNEL_RED, 4); 
  
echo "After Set Channel depth: " . "</br>"; 
echo $im->getImageChannelDepth(imagick::CHANNEL_RED) . "</br>"; 
?> 

Output:

Before Set Channel depth:
8
After Set Channel depth:
4

Original Image:

Program 2:

<?php  
  
$string = "Computer Science portal for Geeks!";  
  
// Creating new image of above String  
// and add color 
$im = new Imagick();  
$draw = new ImagickDraw();  
  
// Fill the color in image  
$draw->setFillColor(new ImagickPixel('green'));  
  
// Set the text font size  
$draw->setFontSize(50);  
  
$metrix = $im->queryFontMetrics($draw, $string);  
$draw->annotation(0, 40, $string);  
$im->newImage($metrix['textWidth'], $metrix['textHeight'],  
        new ImagickPixel('white'));  
  
// Draw the image          
$im->drawImage($draw);  
$im->setImageFormat('jpeg');  
  
// Using getImageChannelDepth function 
// with red channel 
echo "Before Set Channel depth: " . "</br>"; 
echo $im->getImageChannelDepth(imagick::CHANNEL_GREEN) . "</br>"; 
  
// Set channel Depth of Green Channel 
$im->setImageChannelDepth(imagick::CHANNEL_GREEN, 8); 
  
echo "After Set Channel depth: " . "</br>"; 
echo $im->getImageChannelDepth(imagick::CHANNEL_GREEN) . "</br>"; 
?> 

Output:

Before Set Channel depth:
16
After Set Channel depth:
8

Reference: http://php.net/manual/en/imagick.setimagechanneldepth.php

PHP | Imagick setImageAlphaChannel() Function

R_Raj

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PHP | Imagick setImageChannelDepth() Function

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