How to convert a PDF to PNG with ImageMagick "convert" or Ghostscript?

I'm trying to convert a PDF to a PNG image (at least the cover of one). I'm successfully extracting the first page of the PDF with pdftk. I'm using imagemagick to do the conversion:

convert cover.pdf cover.png

This works, but unfortunately the cover.png comes through incorrectly rendered (some of the alpha object in the PDF aren't rendered properly). I know ImageMagick uses GhostScript to do the conversion and if I do it directly with gs I can get the desired results, but I'd rather use the convert library as it has other tools I'd like to leverage.

This command in GhostScript accomplishes the desired image:

gs -sDEVICE=pngalpha -sOutputFile=cover.png -r144 cover.pdf

I'm wondering is there any way to pass arguments through convert to GhostScript or am I stuck with calling GhostScript directly?

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1 Answer

Out of all the available alternatives I found Inkscape to produce the most accurate results when converting PDFs to PNG. Especially when the source file had transparent layers, Inkscape succeeded where Imagemagick and other tools failed.

This is the command I use:

inkscape "$pdf" -z --export-dpi=600 --export-area-drawing --export-png="$pngfile"

And here it is implemented in a script:

#!/bin/bash

while [ $# -gt 0 ]; do

pdf=$1
echo "Converting "$pdf" ..."
pngfile=`echo "$pdf" | sed 's/\.\w*$/.png/'`
inkscape "$pdf" -z --export-dpi=600 --export-area-drawing --export-png="$pngfile"
echo "Converted to "$pngfile""
shift

done

echo "All jobs done. Exiting."

answered 2013-03-18T18:59:30.967

How to convert a PDF to PNG with ImageMagick "convert" or Ghostscript?

1 Answer

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