[Tex/LaTex] pdfcrop generates larger file

file sizepdfcrop

I use pdfcrop to remove margins from a 10MB PDF, 400pages. Margins are properly removed, but the resulting PDF is 51MB large? Any suggestions?

Best Answer

Here is my version of an improved pdfcrop.

Default operation is to remove white margins from the pdf input, optionally leaving a user defined extra-margin (option -m ...).

Alternative operation is to trim the page edges by user defined amounts (option -t ...).

pdfcrop.sh uses gs (Ghostscript) for page-wise determination of the tightly enclosing bounding box, pdftk for uncompressing/compressing the PDF files and getting the order of pages (which doesn't need to be linear), and perl for replacing original page dimensions by the tight bounding boxes found.

Unlike original pdfcrop the bash script below preserves the original interactive parts of the PDF (links, annotations etc.). The output file size is about the same as before.

Update: Option -two added for two-sided page layout

Usage examples:

#getting help
pdfcrop.sh -help

#default operation
pdfcrop.sh orig.pdf cropped.pdf
pdfcrop.sh -m 10 orig.pdf cropped.pdf
pdfcrop.sh -hires orig.pdf cropped.pdf

#trimming pages
pdfcrop.sh -t "10 20 30 40" orig.pdf trimmed.pdf
#same for two-sided layout
pdfcrop.sh -t "10 20 30 40" -two orig.pdf trimmed.pdf

Content of pdfcrop.sh:

#!/bin/bash

function usage () {
  echo "Usage: `basename $0` [Options] <input.pdf> [<output.pdf>]"
  echo
  echo " * Removes white margins from every page in the file. (Default operation)"
  echo " * Trims page edges by given amounts. (Alternative operation)"
  echo
  echo "If only <input.pdf> is given, it is overwritten with the cropped output."
  echo
  echo "Options:"
  echo
  echo " -m \"<left> [<bottom> [<right> <top>]]\""
  echo "    adds extra margins in default operation mode. Unit is bp. A single number"
  echo "    is used for all margins, two numbers \"<left> <bottom>\" are applied to the"
  echo "    right and top margins alike."
  echo
  echo " -t \"<left> [<bottom> [<right> <top>]]\""
  echo "    trims outer page edges by the given amounts. Unit is bp. A single number"
  echo "    is used for all trims, two numbers \"<left> <bottom>\" are applied to the"
  echo "    right and top trims alike."
  echo
  echo " -two"
  echo "    to be used for documents with two-sided page layout; the meaning of <left>"
  echo "    and <right> changes to <inner> and <outer> for options -m and -t"
  echo
  echo " -hires"
  echo "    %%HiResBoundingBox is used in default operation mode."
  echo
  echo " -help"
  echo "    prints this message."
}

c=0
mar=(0 0 0 0); tri=(0 0 0 0)
bbtype=BoundingBox
two=0

while getopts m:t:h: opt
do
  case $opt
  in
    m)
    eval mar=($OPTARG)
    [[ -z "${mar[1]}" ]] && mar[1]=${mar[0]}
    [[ -z "${mar[2]}" || -z "${mar[3]}" ]] && mar[2]=${mar[0]} && mar[3]=${mar[1]}
    c=0
    ;;
    t)
    if [[ "$OPTARG" == "wo" ]]
    then
      two=1
    else
      eval tri=($OPTARG)
      [[ -z "${tri[1]}" ]] && tri[1]=${tri[0]}
      [[ -z "${tri[2]}" || -z "${tri[3]}" ]] && tri[2]=${tri[0]} && tri[3]=${tri[1]}
      c=1
    fi
    ;;
    h)
    if [[ "$OPTARG" == "ires" ]]
    then
      bbtype=HiResBoundingBox
    else
      usage 1>&2; exit 0
    fi
    ;;
    \?)
    usage 1>&2; exit 1
    ;;
  esac
done
shift $((OPTIND-1))

[[ -z "$1" ]] && echo "`basename $0`: missing filename" 1>&2 && usage 1>&2 && exit 1
input=$1;output=$1;shift;
[[ -n "$1" ]] && output=$1 && shift;

(
    [[ "$c" -eq 0 ]] && gs -dNOPAUSE -q -dBATCH -sDEVICE=bbox "$input" 2>&1 | grep "%%$bbtype"
    pdftk "$input" output - uncompress
) | perl -w -n -s -e '
  BEGIN {@m=split /\s+/, $mar; @t=split /\s+/, $tri; @mb=(); $p=-1;}
  sub fixMB {
    if($c){
      if($two && $p%2) {
        $mb[0]+=$t[2];$mb[1]+=$t[1];$mb[2]-=$t[0];$mb[3]-=$t[3];
      }
      else {
        $mb[0]+=$t[0];$mb[1]+=$t[1];$mb[2]-=$t[2];$mb[3]-=$t[3];
      }
      print "/MediaBox [", join(" ", @mb), "]\n";
    } else {
      @bb=split /\s+/, $bbox[$p];
      if($two && $p%2) {
        $bb[0]+=$mb[0];$bb[1]+=$mb[1];$bb[2]+=$mb[0];$bb[3]+=$mb[1];
        $bb[0]-=$m[2];$bb[1]-=$m[1];$bb[2]+=$m[0];$bb[3]+=$m[3];
      }
      else {
        $bb[0]+=$mb[0];$bb[1]+=$mb[1];$bb[2]+=$mb[0];$bb[3]+=$mb[1];
        $bb[0]-=$m[0];$bb[1]-=$m[1];$bb[2]+=$m[2];$bb[3]+=$m[3];
      }
      print "/MediaBox [", join(" ", @bb), "]\n";
    }
  }
  if (/BoundingBox:\s+([\d\.\s]+\d)/) { push @bbox, $1; next;}
  elsif (/\/MediaBox\s+\[([\d\.\s]+\d)\]/) {
    @mb=split /\s+/, $1; next if($p<0);
    fixMB; @mb=(); $p=-1; next;
  }
  elsif (/pdftk_PageNum\s+(\d+)/) {
    $p=$1-1; next unless(@mb);
    fixMB; @mb=(); $p=-1; next;
  }
  print;
' -- -mar="${mar[*]}" -tri="${tri[*]}" -c=$c -two=$two | pdftk - output "$output" compress
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