pdfrasterize

#!/bin/sh

if [ $# != 3 ]; then # If too many / too few paraters are given, print help
	echo "Usage: $0 fromfile.pdf tofile.pdf dpi" >&2
	echo 'This makes a rasterized version of fromfile.pdf, optimizes it with ghostscript and outputs into into tofile.pdf' >&2
	exit 1
fi
if [ ! -f "$1" ]; then # Check input file paramter
	echo 'Inputfile does not exist' >&2
	exit 1
fi
if [ -f "$2" ]; then # Check output file paramter
	echo 'Outputfile does already exist' >&2
	exit 1
fi
if ! echo -n "$3" | grep -Pq '^\d+$'; then # Check dpi paramter
	echo 'DPI Paramter is not a number' >&2
	exit 1
fi

# Create temporary file
TMPFILE="$(mktemp --suffix=.pdf)"

# Rasterize image with image magick
echo "Creating raster version... (in $TMPFILE)"
if ! convert -render -density "$3" "$1" "$TMPFILE"; then
	echo 'Imagemagick error' >&2
	exit 1
fi

# Shrink pdf with ghostscript
echo "Optimizing to shrink pdf file..."
if ! gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dNOPAUSE -dQUIET -dBATCH -sOutputFile="$2" "$TMPFILE"; then
	echo 'Ghostscript error' >&2
	exit 1
fi

echo "Deleting $TMPFILE ..."
if ! env rm "$TMPFILE"; then
	echo "Error while removing temporary file $TMPFILE" >&2
	exit 1
fi

echo 'Finished without errors'