optimize-pdf with fallback to dockerized gs

optimize-pdf

#!/bin/bash

# Optimizes and compresses the specified PDF using Ghostscript (gs).
# If gs is not found on path, will attempt with dockerized gs
#
# [NOTE]
# You need at least Ghostscript 9.10 in order for page labels defined in the
# PDF to be preserved (e.g., front matter pages numbered using roman numerals).

if [ -z $1 ]; then
   echo "Please supply a PDF file to optimize"
   exit 1
fi

FILE=$1
FILE_DIR="$(dirname $FILE)"
FILE_BARE="$(basename $FILE)"

if [[ $(gs --version 2>/dev/null) =~ (9\.[1-9][0-9]|1[0-9]) ]] ; then
  GS=gs
elif [[ $(docker run holmes/ghostscript:9.15 2>/dev/null) == "9.15" ]] ; then
  GS="docker run -v $FILE_DIR:/solr holmes/ghostscript:9.15"
  FILE_DIR=/solr
else
  echo "Could not find Ghostscript or Docker, PDF not optimized"
  exit 1
fi

FILE_BASENAME=${FILE_BARE%.pdf}
FILE="$FILE_DIR/${FILE_BARE}"
FILE_OPTIMIZED="$FILE_DIR/${FILE_BASENAME}-optimized.pdf"
FILE_PDFMARK=
if [ -f "$FILE_BASENAME.pdfmark" ]; then
  FILE_PDFMARK="$FILE_DIR/${FILE_BASENAME}.pdfmark"
fi
DOWNSAMPLE_IMAGES=true
if [ -z $IMAGE_DPI ]; then
  IMAGE_DPI=300
fi

echo "Reducing file size of $FILE using $GS, producing $FILE_OPTIMIZED"
$GS -q -dNOPAUSE -dBATCH -dSAFER -dNOOUTERSAVE \
  -sDEVICE=pdfwrite \
  -dPDFSETTINGS=/prepress \
  -dCannotEmbedFontPolicy=/Warning \
  -dDownsampleColorImages=$DOWNSAMPLE_IMAGES \
  -dColorImageResolution=$IMAGE_DPI \
  -dDownsampleGrayImages=$DOWNSAMPLE_IMAGES \
  -dGrayImageResolution=$IMAGE_DPI \
  -dDownsampleMonoImages=$DOWNSAMPLE_IMAGES \
  -dMonoImageResolution=$IMAGE_DPI \
  -sOutputFile="$FILE_OPTIMIZED" \
  "$FILE" $FILE_PDFMARK

exit 0