Creating PDF thumbnails in PHP

pdf-thumbnail-php.md

Creating PDF thumbnails in PHP

Install Ghostscript

Download and install right version of ghostscript. In my case my PHP was x86 architecture, so I download Ghostscript 9.14 for Windows (32 bit).

Enable ImageMagick

Check, is imagick extension available and loaded.

This line should be present in your php.ini:

extension=php_imagick.dll

Also, check php_imagick.dll in PHP's ext directory.

PHP function

<?php
	function genPdfThumbnail($source, $target)
	{
		//$source = realpath($source);
		$target = dirname($source).DIRECTORY_SEPARATOR.$target;
		$im     = new Imagick($source."[0]"); // 0-first page, 1-second page
		$im->setImageColorspace(255); // prevent image colors from inverting
		$im->setimageformat("jpeg");
		$im->thumbnailimage(160, 120); // width and height
		$im->writeimage($target);
		$im->clear();
		$im->destroy();
	}

Call that function:

<?php
genPdfThumbnail('/uploads/my.pdf','my.jpg'); // generates /uploads/my.jpg

Use an PHP's external program execution functions to call pdftoppm which has the ability select pages thereby avoiding the whole "loading everything into memory problem", it's in poppler-utils on Ubuntu

example:

pdftoppm -l 1 -scale-to 150 -jpeg example.pdf > thumb.jpg

which translates to take the last page as 1 (you can specify a first page), scale the largest size to 150 pixels and throw out a jpeg.

https://linux.die.net/man/1/pdftoppm if windows is required then the poppler libraries are listed as containing pdftocairo which use the same arguments and has some windows specific printing options.

2019-04-09 adaptation from https://gist.github.com/umidjons/11037635

added error capture when a source is not a pdf or not a file path, else function outputs the new file path.
added optional size and page number, defaults to 256 pix made from first page in the pdf.
added page orentation and relative resize of height vs width as whatever is smaller than the maximum given size.
added the option of putting the output jpeg into a sub folder, auto creating directory if not already existent.
added correction of black zones on transparency in a pdf.

to call my version of the function implement it for example like this:

$pdf_thumb = genPdfThumbnail('/nfs/vsp/servername/u/username/public_html/any.pdf','thumbs/any.jpg')

to get page 2 as 150 pixel jpeg implement it for example as below.
however if the pdf does not have more than 1 page, be assured errors will occur.

$pdf_thumb = genPdfThumbnail('/nfs/vsp/servername/u/username/public_html/any.pdf','any_p02.pdf.jpeg',150,'02')

to see the result from the function thereafter implement this:

if($pdf_thumb){ echo $pdf_thumb; }else{ echo 'pdf source error'; }

the function itself:

<?
function genPdfThumbnail ( $source, $target, $size=256, $page=1 ){

	if(file_exists($source) && !is_dir($source)): // source path must be available and not be a directory
		if(mime_content_type($source) != 'application/pdf'):
			return FALSE;				// source is not a pdf file returns a failure
		endif;
		
		$sepa	=	'/';				// using '/' as file separation for nfs on linux.
		$target	= 	dirname($source).$sepa.$target;
		$size	= 	intval($size); 			// only use as integer, default is 256
		$page	= 	intval($page); 			// only use as integer, default is 1
		
		$page--;					// default page 1, must be treated as 0 hereafter
		if ($page<0) 	{$page=0;}			// we cannot have negative values

		$img	= 	new Imagick($source."[$page]"); // [0] = first page, [1] = second page
		
		$imH 	= 	$img->getImageHeight();
		$imW 	= 	$img->getImageWidth();
		if ($imH==0) 	{$imH=1;}			// if the pdf page has no height use 1 instead
		if ($imW==0) 	{$imW=1;}			// if the pdf page has no width use 1 instead

		$sizR	=	round($size*(min($imW,$imH)/max($imW,$imH))); // relative pixels of the shorter side 
		
		$img	->	setImageColorspace(255); 		// prevent image colors from inverting
		$img	->	setImageBackgroundColor('white'); 	// set background color and flatten
		$img	= 	$img->flattenImages(); 			// prevents black zones on transparency in pdf
		$img	->	setimageformat('jpeg');
		
		if ($imH == $imW){$img->thumbnailimage($size,$size);}	// square page 
		if ($imH < $imW) {$img->thumbnailimage($size,$sizR);}	// landscape page orientation
		if ($imH > $imW) {$img->thumbnailimage($sizR,$size);}	// portrait page orientation
		
		if(!is_dir(dirname($target))){mkdir(dirname($target),0777,true);} // if not there make target directory 

		$img->	writeimage($target);
		$img->	clear();
		$img->	destroy();
	
		if(file_exists( $target )){ return $target; } // return the path to the new file for further processing
	endif;

	return FALSE; 	// the source file was not available, or Imagick didn't create a file, so returns a failure
}
?>

below two questions to my own concept above:

A. Is it technically possible that a provided PDF contains zero pages, if so: how can we test this?
B. Can the img obtained from the PDF be 0 in width or height? As this would cause a NAN error.

2019-04-09 adaptation from https://gist.github.com/umidjons/11037635

added error capture when a source is not a pdf or not a file path, else function outputs the new file path.
added optional size and page number, defaults to 256 pix made from first page in the pdf.
added page orentation and relative resize of height vs width as whatever is smaller than the maximum given size.
added the option of putting the output jpeg into a sub folder, auto creating directory if not already existent.
added correction of black zones on transparency in a pdf.

to call my version of the function implement it for example like this:

$pdf_thumb = genPdfThumbnail('/nfs/vsp/servername/u/username/public_html/any.pdf','thumbs/any.jpg')

to get page 2 as 150 pixel jpeg implement it for example as below.
however if the pdf does not have more than 1 page, be assured errors will occur.

$pdf_thumb = genPdfThumbnail('/nfs/vsp/servername/u/username/public_html/any.pdf','any_p02.pdf.jpeg',150,'02')

to see the result from the function thereafter implement this:

if($pdf_thumb){ echo $pdf_thumb; }else{ echo 'pdf source error'; }

the function itself:

<?
function genPdfThumbnail ( $source, $target, $size=256, $page=1 ){

	if(file_exists($source) && !is_dir($source)): // source path must be available and not be a directory
		if(mime_content_type($source) != 'application/pdf'):
			return FALSE;				// source is not a pdf file returns a failure
		endif;
		
		$sepa	=	'/';				// using '/' as file separation for nfs on linux.
		$target	= 	dirname($source).$sepa.$target;
		$size	= 	intval($size); 			// only use as integer, default is 256
		$page	= 	intval($page); 			// only use as integer, default is 1
		
		$page--;					// default page 1, must be treated as 0 hereafter
		if ($page<0) 	{$page=0;}			// we cannot have negative values

		$img	= 	new Imagick($source."[$page]"); // [0] = first page, [1] = second page
		
		$imH 	= 	$img->getImageHeight();
		$imW 	= 	$img->getImageWidth();
		if ($imH==0) 	{$imH=1;}			// if the pdf page has no height use 1 instead
		if ($imW==0) 	{$imW=1;}			// if the pdf page has no width use 1 instead

		$sizR	=	round($size*(min($imW,$imH)/max($imW,$imH))); // relative pixels of the shorter side 
		
		$img	->	setImageColorspace(255); 		// prevent image colors from inverting
		$img	->	setImageBackgroundColor('white'); 	// set background color and flatten
		$img	= 	$img->flattenImages(); 			// prevents black zones on transparency in pdf
		$img	->	setimageformat('jpeg');
		
		if ($imH == $imW){$img->thumbnailimage($size,$size);}	// square page 
		if ($imH < $imW) {$img->thumbnailimage($size,$sizR);}	// landscape page orientation
		if ($imH > $imW) {$img->thumbnailimage($sizR,$size);}	// portrait page orientation
		
		if(!is_dir(dirname($target))){mkdir(dirname($target),0777,true);} // if not there make target directory 

		$img->	writeimage($target);
		$img->	clear();
		$img->	destroy();
	
		if(file_exists( $target )){ return $target; } // return the path to the new file for further processing
	endif;

	return FALSE; 	// the source file was not available, or Imagick didn't create a file, so returns a failure
}
?>

You're the best! Exactly what I need! I had a tough situation when I could only use a SharedHosting. Can't express how much thankful I am!

Thanks for this - proved very useful.

NOTES:

GHOSTSCRIPT use to extract image from PDF

https://stackoverflow.com/questions/52998331/imagemagick-security-policy-pdf-blocking-conversion

$ gs --version

If yes, just remove this whole following section from

$ sudo vim /etc/ImageMagick-6/policy.xml

<--- REMOVE THIS LINES --->
<policy domain="coder" rights="none" pattern="PS" />
<policy domain="coder" rights="none" pattern="PS2" />
<policy domain="coder" rights="none" pattern="PS3" />
<policy domain="coder" rights="none" pattern="EPS" />
<policy domain="coder" rights="none" pattern="PDF" />
<policy domain="coder" rights="none" pattern="XPS" />


$ sudo reboot 

Why not accomplish that directly with ImageMagic?

<?php

$im = new imagick('file.pdf[0]');

$im->setImageFormat('jpg');

header('Content-Type: image/jpeg');

echo $im;

?>

@MostafaAttia let's give it a try...

Last famous words... :)