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