PHP | Gmagick setimagedepth() function

<?php 

// require_once('path/vendor/autoload.php');
  
// Create an Gmagick Object
$image = new Gmagick(
'https://media.geeksforgeeks.org/wp-content/uploads/geeksforgeeks-15.png');
  
// Use getImageDepth function to find the depth 
// of image
$res= $image->getImageDepth();
  
// Display the depth of image
echo "Previous Depth: " . $res; 

$image->setimagedepth(16);

$res = $image->getImageDepth();
echo "</br>After Set the Depth: " . $res; 
?>

<?php 
$string = "Computer Science portal for Geeks!"; 
    
// Creating new image of above String 
// and add color and background 
$im = new Gmagick(); 
$draw = new GmagickDraw(); 
   
// Fill the color in image 
$draw->setFillColor(new GmagickPixel('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 GmagickPixel('white')); 
            
// Draw the image          
$im->drawImage($draw); 
   
$im->setImageFormat('jpeg');

$dpth = $im->getImageDepth();
   
// Display the depth of image
print("Previous Depth = " . $dpth);
 
$im->setimagedepth(32);
$dpthnew = $im->getImageDepth();
 
// Display the depth of image
print("</br>Depth After Set  = " . $dpthnew);
?>