crop.pl

gistfile1.txt

use strict;
use warnings;
 
my @offset = (20, 20, -20, -20);
 
while(<*.pdf>)
{
    next if /-cropped/;
     
    open my $in, $_ or die;
    s/(.*)(\.pdf)$/$1-cropped$2/;
    open my $out, '>', $_ or die;
 
    binmode $in;
    binmode $out;
	 
    while(<$in>)
    {
        s/(\/CropBox\s*\[\s*([^\[]+)\])/crop($1, $2)/eg;
        print $out $_;
    }
}
						     
sub crop
{
    my @offset = @offset;
    my @pos = map{int $_ + shift @offset} split /\s+/, $_[1];
     
    my $crop = sprintf '/CropBox[%d %d %d %d]', @pos;

    my $blank = length($_[0]) - length $crop;
    warn $_[0] and return $_[0] if $blank < 0;
	 
    return $crop.(' ' x $blank);
}