Trying to clone an uncloneable object of class Imagic

Using a program circulated online to implement pdf screenshots as png, you need to use Imagic extensions. After installing under Windows, prompts:
Fatal error: Trying to clone an uncloneable object of class Imagick in C:\www\hx\pdf_to_png.php on line 17

This will be a prompt when using IIS and Apache. After multiple tests, two solutions were found:

; Enable compatibility mode with Zend Engine 1 (PHP)
zend.ze1_compatibility_mode = Off

The default is On, and it can be solved after changing to Off.

2. Use imagick::... to call this method.
That is, $im->setResolution(120, 120); can be rewritten as:
imagick::setResolution(120, 120);

If other extensions experience such errors, these two methods can generally be used to solve them.

Attached with a program code snippet from pdf to png:

Copy the codeThe code is as follows:

 
function pdf2png($pdf, $filename, $page=0) { 
if (!extension_loaded('imagick')) { 
exit('no imagick'); 
return false; 
} 
if (!file_exists($pdf)) { 
return false; 
} 
$im = new Imagick(); 
$im->setResolution(120, 120); 
$im->setCompressionQuality(100); 
$im->readImage($pdf . "[" . $page . "]"); 
$im->setImageFormat('png'); 
$im->writeImage($filename); 
$im->readImage($filename); 
$im->resizeImage(120, 150, Imagick::FILTER_LANCZOS, 1); 
$im->writeImage($filename); 
return $filename; 
} 