ghostscript reduce pdf filesize
#!/bin/sh
# http://www.alfredklomp.com/programming/shrinkpdf
# Licensed under the 3-clause BSD license:
#
# Copyright (c) 2014-2019, Alfred Klomp
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
# 1. Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
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# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
#
# Modified by Vivek Gite to suit my needs
#
shrink ()
{
gs \
-q -dNOPAUSE -dBATCH -dSAFER \
-sDEVICE=pdfwrite \
-dCompatibilityLevel=1.3 \
-dPDFSETTINGS=/screen \
-dEmbedAllFonts=true \
-dSubsetFonts=true \
-dAutoRotatePages=/None \
-dColorImageDownsampleType=/Bicubic \
-dColorImageResolution=$3 \
-dGrayImageDownsampleType=/Bicubic \
-dGrayImageResolution=$3 \
-dMonoImageDownsampleType=/Subsample \
-dMonoImageResolution=$3 \
-sOutputFile="$2" \
"$1"
}
check_smaller ()
{
# If $1 and $2 are regular files, we can compare file sizes to
# see if we succeeded in shrinking. If not, we copy $1 over $2:
if [ ! -f "$1" -o ! -f "$2" ]; then
return 0;
fi
ISIZE="$(echo $(wc -c "$1") | cut -f1 -d\ )"
OSIZE="$(echo $(wc -c "$2") | cut -f1 -d\ )"
if [ "$ISIZE" -lt "$OSIZE" ]; then
echo "Input smaller than output, doing straight copy" >&2
cp "$1" "$2"
fi
}
usage ()
{
echo "Reduces PDF filesize by lossy recompressing with Ghostscript."
echo "Not guaranteed to succeed, but usually works."
echo " Usage: $1 infile [outfile] [resolution_in_dpi]"
}
IFILE="$1"
# Need an input file:
if [ -z "$IFILE" ]; then
usage "$0"
exit 1
fi
# Output filename defaults to "-" (stdout) unless given:
if [ ! -z "$2" ]; then
OFILE="$2"
else
OFILE="-"
fi
# Output resolution defaults to 72 unless given:
if [ ! -z "$3" ]; then
res="$3"
else
res="90"
fi
shrink "$IFILE" "$OFILE" "$res" || exit $?
check_smaller "$IFILE" "$OFILE"