The Imagick::getImageChannelRange() function is an inbuilt function in PHP which is used to gets the range of channel.
Syntax:
array Imagick ::getImageChannelRange( $channel )
Parameters: This function accept single parameter $channel which specifies the channel to find image channel range. The default value of channel is Imagick::CHANNEL_DEFAULT.
Return Value: This function returns an array containing the minima and maxima of the required channel.
Below programs illustrate the Imagick ::getImageChannelRange() function in PHP:
Program 1:
Original Image:
<?php   // Create new Imagick object $im = new Imagick(   // Using getImageChannelRange function // with red channel $res = $im->getImageChannelRange(imagick::CHANNEL_RED);   // Display result print_r($res); ?> |
Output:
Array ( [minima] => 0 [maxima] => 65535 )
Program 2:
Original Image:
<?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 getImageChannelRange function // with red channel $res = $im->getImageChannelRange(imagick::CHANNEL_GREEN);   // Display result print_r($res); ?> |
Output:
Array ( [minima] => 32896 [maxima] => 65535 )
Reference: http://php.net/manual/en/imagick.getimagechannelrange.php

