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PHP | Imagick setImageChannelDepth() Function

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:

Program 1:
Original Image:
https://tutorialspoint.dev/image/geeks-21.png

<?php
  
// Create new Imagick object
$im = new Imagick(
  
// 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

Program 2:
Original Image:
https://tutorialspoint.dev/image/Screenshot-from-2018-10-16-23-23-54.png

<?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



This article is attributed to GeeksforGeeks.org

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