每个操作系统MPDF不同的文件大小

Question

I am using mPDF and Ghostscript as a part of a larger application, where the is workflow is as this:

1. A PDF is uploaded by a 3rd party software
2. The file is detected and converted to PDF 1.4 (via a GhostScript wrapper: https://github.com/xthiago/pdf-version-converter )
3. Based on the converted file a new PDF file is generated

In local env (MacOS), because the files uploaded are version 1.6, the converted file has more or less half the size of the original and the same goes for the new created one, but in production server (Ubuntu), even if the converted one has the same size as its local equivalent, the new one has 10x times more size: (eg 48MB vs 480MB)

What might be the case for such difference?

The code used is as this:

$mPdf = new \Mpdf\Mpdf(array(
'dpi' => 300
));

$mPdf -> SetImportUse();
$pageCount = $mPdf -> SetSourceFile($productFileToCopy);

for ($i = 1; $i <= $pageCount; $i++) {
   $importPage = $mPdf -> ImportPage($i);
   $wh = $mPdf -> getTemplateSize($importPage);
   $orientation = $wh['w'] > $wh['h'] ? 'L' : 'P';
   $mPdf -> AddPageByArray(array(
     'orientation' => $orientation,
     'sheet-size' => array(
       $orientation === 'L' ? $wh['h'] : $wh['w'],
       $orientation === 'L' ? $wh['w'] : $wh['h'],
      ),
      'margin-left' => 0,
      'margin-right' => 0,
      'margin-top' => 0,
      'margin-bottom' => 0,
      'margin-header' => 0,
      'margin-footer' => 0,
    ));

    $mPdf -> UseTemplate($importPage);
 }

 $mPdf -> Output($productFileFinal);

Answer 1

Finally it's not mPDF, but Ghostscript.

Slightly different version (9.22 vs 9.23) produces 10x bigger files under this command

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen -dNOPAUSE  -dBATCH -dColorConversionStrategy=/LeaveColorUnchanged -dEncodeColorImages=false -dEncodeGrayImages=false -dEncodeMonoImages=false -dDownsampleMonoImages=false -dDownsampleGrayImages=false -dDownsampleColorImages=false -dAutoFilterColorImages=false -dAutoFilterGrayImages=false -dColorImageFilter=/FlateEncode -dGrayImageFilter=/FlateEncode