Convert PDF to CBZ archives via GhostScript; run with --help for some help

pdf2cbz_gs.sh

#!/bin/bash
# take care of spaces in filenames
SAVEIFS="$IFS"
IFS=$(echo -en "\n\b")

# requires ghostscript, ionice, zip, jhead & imagemagick/graphicsmagick

# do not delete temp directory with temp files
DELETE=false
# do not up/down-scale images
UPDOWNSCALE=false
CONVERTSCALE="100"
# default resolution is 150 dpi (*2 because we create JPGs at 50%)
PDF_RES=150
PDF_RES_ORI=$PDF_RES
# default JPEG qulity is 80%
JPEGQ=80


for param in "$@"
do
  if [ "$param" = "--delete" ] || [ "$param" = "-d" ]; then
    echo "config: will delete temporary files"
    DELETE=true
  elif [ "$param" = "--updownscale" ]; then
    echo "config: will render to twice the size and rescale when creating final images"
    UPDOWNSCALE=true
  elif [ "$param" = "--scale" ]; then
    # TODO get percentage (pop next?)
    CONVERTSCALE="100"
  elif [ "$param" = "--50dpi" ]; then
    echo "config: render PDF to 50 dpi"
    PDF_RES=50
    PDF_RES_ORI=$PDF_RES
  elif [ "$param" = "--96dpi" ]; then
    echo "config: render PDF to 96 dpi"
    PDF_RES=96
    PDF_RES_ORI=$PDF_RES
  elif [ "$param" = "--200dpi" ]; then
    echo "config: render PDF to 200 dpi"
    PDF_RES=200
    PDF_RES_ORI=$PDF_RES
  elif [ "$param" = "--300dpi" ]; then
    echo "config: render PDF to 300 dpi"
    PDF_RES=300
    PDF_RES_ORI=$PDF_RES
  elif [ "$param" = "--help" ]; then
    echo "options [--delete] [--96dpi|--200dpi|--300dpi] [--scale X]"
    echo ""
    echo "  --delete"
    echo "    delete temporary directory after CBZ creation"
    echo "  --50dpi|--96dpi|--200dpi|--300dpi"
    echo "    render PDF to 50/96/200/300 dpi images, if not set defaults to 150 dpi"
    echo "  --updownscale"
    echo "    render to twice the default dpi and scale down when converting to JPGs"
    echo "  --scale <PERCENT>"
    echo "    scale PDF rendered PNGs to PERCENT % when converting to JPGs; not compatible with --updownscale"
    exit 0
  fi
done

# are we doing up/down-scaling ?
if [ "$UPDOWNSCALE" = "true" ]; then
  PDF_RES=$(echo "$PDF_RES * 2" | bc)
  CONVERTSCALE=$(echo "$CONVERTSCALE / 2" | bc)
fi

# for all PDFs
#for PDF in $(ls -1 *.pdf);
for PDF in "$@"
do
  if [ ${PDF: -4} == ".pdf" ]
  then
    echo "Working on [$PDF]"
    # get filename without extension
    FILEP=${PDF%.*}
    # clean filename without spaces
    FILEPC=`echo $FILEP | sed 's| |\.|g'`
    mkdir $FILEPC
    # -dGraphicsAlphaBits=1
    echo " - [1/3] Extracting pages from [$PDF]"
    gs -q -dNOPAUSE -dBATCH \
       -sDEVICE=png16m \
       -r$PDF_RES \
       -dTextAlphaBits=4 \
       -dUseCropBox \
       -sOutputFile=$FILEPC/%03d.png $PDF

    echo " - [2/3] Converting pages to JPG, quality is $JPEGQ %"
    for I in $(ls -1 $FILEPC/*.png)
    do
      convert $I -scale $CONVERTSCALE% -quality $JPEGQ ${I%%.png}.jpg && rm $I
    done
    jhead -purejpg -q $FILEPC/*.jpg

    CBZ=$FILEP.$PDF_RES_ORI\dpi.cbz
    echo " - [3/3] Packing to CBZ file [$CBZ]"
    ionice -c 3 find "$FILEPC/" -type f | sort | zip -j -T -9 "$CBZ" -@ > /dev/null
    if [ "$DELETE" = "true" ]; then
      rm -rf $FILEPC
    fi
    echo ""
  fi
done

IFS="$SAVEIFS"