#!/usr/bin/perl
use strict;
use String::ShellQuote 'shell_quote';
use Cwd;
use File::Which;
use Getopt::Std::Strict 't:b:l:r:T:nhv';

our $VERSION = sprintf "%d.%02d", q$Revision: 1.4 $ =~ /(\d+)/g;

# are they asking for help or version of command?
$opt_h and ( print STDERR usage() ) and exit;
$opt_v and print $VERSION and exit;




# make sure we have path to ImageMagick mogrify on system..
my $mogrify_bin = File::Which::which('mogrify') 
   or die("Can't find which 'mogrify', is ImageMagick installed on this system?");



# what are the file args
my @files;
@ARGV or die("missing arguments\n");
for (@ARGV){
   my $abs = Cwd::abs_path($_) or die("Can't find abs path to '$_', not on disk?\n");
   -f $abs or die("Not file on disk: $abs\n");
   push @files, $abs;
}

# made sure we did have files as args..
scalar @files or die("missing file arguments\n");


# what's the bare bones command ?
my @cmd = cmd();


# if they want to only see what the command is.. 
# then print as if we are doing it for each file sepparately
if ($opt_n){
   for (@files){
      my $p = shell_quote($_);
      print "@cmd $p\n";
   }
   exit;
}


# in actual production, go ahead and run command for all files together
push @cmd, @files;
system(@cmd) == 0 
   or die("failed command, $? - command was:\n@cmd");

exit;


# this is a subroutine to consolidate what the command would be
# this leaves out the actual file arg we are doing this to..
sub cmd {

   if ( $opt_T ){
      map { $OPT{$_} = $opt_T } qw(t b l r);
   }

   $opt_t + $opt_b + $opt_l + $opt_r or die('missing arguments');
   
   my @cmd = ( $mogrify_bin );

   ( push @cmd, '-gravity', 'north', '-chop', "0x$opt_t" ) if $opt_t;
   ( push @cmd, '-gravity', 'south', '-chop', "0x$opt_b" ) if $opt_b;
   ( push @cmd, '-gravity', 'west',  '-chop', $opt_l."x0" ) if $opt_l;
   ( push @cmd, '-gravity', 'east',  '-chop', $opt_r."x0" ) if $opt_r;

   return @cmd;
}



# this prints usage to screen if user asks for help
sub usage {
   q{imgtrim [OPTION] IMAGE..
Trim sides of IMAGE.

   -t number      top
   -b number      bottom
   -l number      left
   -r number      right
   -T number      overall trim
   -h             help
   -v             version
   -n             don't do it, just print the command to stdout

Try 'man imgtrim' for more info'.
}
}



# everything below is pod documentation, it is called
# when user runs command 'man imgtrim'- only available if 
# this has already been installed
# you can also see "inline" documentation for a script like this
# by running the command 'perldoc ./bin/imgtrim'

__END__

=pod

=head1 NAME

imgtrim - Trim sides of IMAGE.

=head1 USAGE

imgtrim [OPTION] IMAGE..

   -t number      top
   -b number      bottom
   -l number      left
   -r number      right
   -T number      overall trim
   -d             debug
   -h             help
   -v             version

=head1 USAGE EXAMPLES

Trim 100 pixels from top
   imgtrim -t 100 ./img.jpg

Trim 210 pixels from bottom and 50 from top
   imgtrim -b 210 -t 50 ./img.jpg

Trim 50 pixels from all sides
   imgtrim -T 50 ./img.jpg

=head1 DESCRIPTION

I work off and on with scans of images clients send me. Sometimes they need to be
trimmed up on sides, for example. The images are sometimes very large, and I don't want
to have to open 5MB jpeg files in gimp to trim 100 pixels off the top.
So with this command, I can simply say, trim 100 pixels off top of this image.

Wait, but.. you could do this in imagemagick's mogrify and convert! you say. Yes- this
command uses convert in the background.
But the thing is tailored to trim- which has saved me a good deal of time.

=head1 CAVEATS

Uses mogrify, alters original image.

=head1 REQUIREMENTS

You will need a posix environment.
You will need ImageMagick mogrify installed.

=head1 AUTHOR

Leo Charre leocharre at cpan dot org

=head1 COPYRIGHT

Copyright (c) 2010 Leo Charre. All rights reserved.

=head1 LICENSE

This package is free software; you can redistribute it and/or modify it under the same terms as Perl itself, i.e., under the terms of the "Artistic License" or the "GNU General Public License".

=head1 DISCLAIMER

This package is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the "GNU General Public License" for more details.

=cut