GDモジュールを使ったサンプルコード

use_GD.pl

use strict;
use warnings;
use GD;


my @files= glob("*.JPG");
my $n = @files;
print "handling $n files...\n";


Stopwatch::start();

&resize_all(@files);

my $time = Stopwatch::stop();

print "total ".$time." sec for ".$n." pics\n";
print "for each " .($time/$n) ." sec.\n" unless $n;


sub resize_all {
       my $counter;
       for (@_) {
               &resize("small\\$_", $_ , 0.2 );
               print "$_ ";
               print ++$counter."/".$n." \n";
       }
}

sub resize {

       my ($file_out, $file_in , $rate ) = @_;


       my $in_img = GD::Image->newFromJpeg( $file_in ,1);              # 引数の1は、TrueColorを表す。

       my ( $old_width, $old_height ) = $in_img->getBounds();
       my ( $new_width, $new_height ) = ($old_width * $rate, $old_height * $rate);
       my $out_img = GD::Image->new( $new_width, $new_height, 1 );                             # 1はTrueColorを表す。
       $out_img->copyResampled($in_img, 0, 0, 0, 0, $new_width, $new_height, $old_width, $old_height );

       open( IMG, ">$file_out" );
       binmode IMG;
       print IMG $out_img->jpeg( 100 );
       close( IMG );

}


exit;

#=========  処理時間を計測する  ==================
package Stopwatch;

my $start;
my $end;
my $total_time;

sub start {
       $start = time;
}

sub stop {
       $end = time;
       $total_time = $end - $start;
}

sub print {
       print "total ".$total_time." sec for ".$n." pics\n";
       print "for each " .($total_time/$n) ." sec.\n";
}

1;