#!/bin/bash
#
# Syntax:  pdf_compress_gs [-h] pdf_files
#
# Purpose: Use gs to "compress" a pdf file (by replacing hi-resolution
#          images by lower resolution ones).
#          Output is stored in the file pdf_file_compressed.pdf
#          The -h flag shows the help info for this command.

# Created: Jan 10, 2011       by Bart De Schutter
# Last revised:
#
# See http://www.deschutter.info/util/scripts.html for the latest version of
# this script.

# Status: public
# Category: pdf

# 
# Process options
#
while getopts :h option
do
   case "$option" in
      h) sed '/^$/q;/^#!/d;s/^# //;s/^#//' $0 >&2
         exit 1;;
     \?) echo >&2
         echo >&2 "Unknown option: $OPTARG"
         echo >&2
         sed '/^$/q;/^#!/d;s/^# //;s/^#//' $0 >&2
         exit 1;;
   esac
done
shift $(($OPTIND-1))

if [ $# -eq 0 ];
then
   echo >&2
   echo >&2 "ERROR: ${0##*/} requires at least 1 input argument."
   echo >&2
   sed '/^$/q;/^#!/d;s/^# //;s/^#//' $0 >&2
   exit 1
fi

for fil in "$@"
do
   basename=${fil%.pdf}
   gs -q -sDEVICE=pdfwrite -dNOPAUSE -dBATCH -dSAFER \
      -dCompatibilityLevel=1.4 \
      -dEmbedAllFonts=true -dSubsetFonts=true -dMaxSubsetPct=100 \
      -sOutputFile="${basename}_compressed.pdf" \
      "${basename}.pdf"
   if [ $? -ne 0 ];
   then
      echo >&2
      echo >&2 "ERROR processing ${basename}.pdf"
      echo >&2
      exit 1
   else
      echo "Written ${basename}_compressed.pdf"
   fi
done

# Extra option: -sPAPERSIZE=a4
#               -dPDFSETTINGS=/prepress
###      -dAutoFilterColorImages=false -dAutoFilterGrayImages=false \
###      -dColorImageFilter=/FlateEncode -dGrayImageFilter=/FlateEncode \
###      -dAutoFilterMonoImages=false -dMonoImageFilter=/CCITTFaxEncode \