加快PHP Imagick库PDF - > PNG转换（20秒！）

Question

I am using Imagick to convert the first page of a PDF to a PNG image. It is working, but it is very slow.

A conversion takes between 8 and 20 seconds for a ~100kb PDF.

Is there a way to speed up the conversion?

My code :

$im = new Imagick($url);
$im->setIteratorIndex(0);
$im->setCompression(Imagick::COMPRESSION_LZW);
$im->setCompressionQuality(90);
$im->setImageFormat("png");
$im->writeImage('C:/Shared/test.png');

Answer 1

Is there a way to speed up the convertion?

Sure, upgrade the machine with more processing power, more memory and a faster disk.

Also it looks like you're using a Windows operating system. I suggest you switch to a Linux system and compile the libraries optimized to the computer's architecture its running on.

Answer 2

In fact , I don't need Imagick library to generate a simple JPG preview of the first page of a PDF, I just need GhostScript.

Command line conversion with GhostScript is always faster than Imagick (command line or through PHP)

Example with a 12 pages and 650kb :

• Command line GhostScript => 0.6 second
• Command line Imagick => 0.8 second
• PHP extension Imagick => 2.22 seconds

With some documents, Imagick takes 20 seconds against 1.5 second with direct GS command line.

Here is my test script

   <?php

    $pathToPdf = realpath("in.pdf");

    $pathToJpg = "./out.jpg";
    $pathToPng = "./out.png";

    try
        {

        $time_start = microtime(true);      
        $gsCall = "\"C:\Program Files (x86)\gs\gs9.06\bin\gswin32.exe\" -q -dBATCH -dMaxBitmap=300000000 -dNOPAUSE -dSAFER -sDEVICE=jpeg -dTextAlphaBits=4 -dGraphicsAlphaBits=4 -dFirstPage=1 -dLastPage=1 -sOutputFile=\"{0}\" \"{1}\" -c quit";
        $gsCall = str_replace(array('{0}', '{1}'), array($pathToJpg, $pathToPdf), $gsCall); // or use sprintf
        $str = exec($gsCall, $output=array(), $returnValue);
        echo $gsCall.'<br><br>';
        $time_end = microtime(true);
        $time = $time_end - $time_start;        
        if($returnValue == 0)              
            print "<br><br>Conversion OK ".$time;
        else 
            print "<br><br>Conversion failed.<br />".var_dump($output);     

        $time_start = microtime(true);          
        exec('convert "'.$pathToPdf.'[0]" "'.$pathToPng.'"', $output, $returnValue);                        
        $time_end = microtime(true);
        $time = $time_end - $time_start;
        if($returnValue == 0)              
            print "<br><br>Conversion OK ".$time;
        else 
            print "<br><br>Conversion failed.<br />".var_dump($output);

        $time_start = microtime(true);
        $im = new Imagick($pathToPdf);
        $im->setIteratorIndex(0);
        $im->setCompression(Imagick::COMPRESSION_LZW);
        $im->setCompressionQuality(90);
        $im->setImageFormat("png");
        $im->writeImage('\\\\DELL-PC\Shared\test.png');
        //$im->thumbnailImage(200, 0);
        //echo $im;
        $time_end = microtime(true);
        $time = $time_end - $time_start;
        print "<br><br>Conversion OK ".$time;
    }
catch(Exception $e)
{
    echo $e->getMessage();
}
?>