PHP | Gmagick setimagechanneldepth() Function
Last Updated :
29 Aug, 2019
The Gmagick::setimagechanneldepth() function is an inbuilt function in PHP which is used to set the depth of a particular channel image.
Syntax:
Gmagick Gmagick::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:
- Gmagick::CHANNEL_UNDEFINED
- Gmagick::CHANNEL_RED
- Gmagick::CHANNEL_GRAY
- Gmagick::CHANNEL_CYAN
- Gmagick::CHANNEL_GREEN
- Gmagick::CHANNEL_MAGENTA
- Gmagick::CHANNEL_BLUE
- Gmagick::CHANNEL_YELLOW
- Gmagick::CHANNEL_ALPHA
- Gmagick::CHANNEL_OPACITY
- Gmagick::CHANNEL_MATTE
- Gmagick::CHANNEL_BLACK
- Gmagick::CHANNEL_INDEX
- Gmagick::CHANNEL_ALL
- Gmagick::CHANNEL_DEFAULT
- $depth: This parameter is used to specify the depth to be set for Gmagick object.
Return Value: This function returns the Gmagick object on success.
Below programs illustrate the Gmagick::setimagechanneldepth() function in PHP:
Program 1:
Original Image:
<?php
$im = new Gmagick(
echo "Before Set Channel depth: " . "</br>" ;
echo $im ->getImageChannelDepth(Gmagick::CHANNEL_RED) . "</br>" ;
$im ->setimagechanneldepth(Gmagick::CHANNEL_RED, 4);
echo "After Set Channel depth: " . "</br>" ;
echo $im ->getImageChannelDepth(Gmagick::CHANNEL_RED) . "</br>" ;
?>
|
Output:
Before Set Channel depth:
8
After Set Channel depth:
4
Program 2:
Original Image:
<?php
$string = "Computer Science portal for Geeks!" ;
$im = new Gmagick();
$draw = new GmagickDraw();
$draw ->setFillColor( new GmagickPixel( 'green' ));
$draw ->setFontSize(50);
$metrix = $im ->queryFontMetrics( $draw , $string );
$draw ->annotation(0, 40, $string );
$im ->newImage( $metrix [ 'textWidth' ], $metrix [ 'textHeight' ],
new GmagickPixel( 'white' ));
$im ->drawImage( $draw );
$im ->setImageFormat( 'jpeg' );
echo "Before Set Channel depth: " . "</br>" ;
echo $im ->getImageChannelDepth(Gmagick::CHANNEL_GREEN) . "</br>" ;
$im ->setimagechanneldepth(Gmagick::CHANNEL_GREEN, 8);
echo "After Set Channel depth: " . "</br>" ;
echo $im ->getImageChannelDepth(Gmagick::CHANNEL_GREEN) . "</br>" ;
?>
|
Output:
Before Set Channel depth:
16
After Set Channel depth:
8
Reference: http://php.net/manual/en/gmagick.setimagechanneldepth.php
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