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(
// 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