I never used GD before today, so I made a little program to compare the output given by GD and Image::Magick. Here is the code:

#!/usr/bin/perl

use strict;
use warnings;

use GD;
use Image::Magick;

use vars qw( $default_orientation $default_width $default_height $file
+name );

$default_orientation = 'vertical';
$default_width = 150;
$default_height = 100;
$filename = 'image.jpg';

thumb_with_imagemagick($filename, 'im.jpg');
thumb_with_gd($filename, 'gd.jpg');

exit;

sub thumb_with_imagemagick {
        my ($infile, $outfile, $image, $error, $x, $y,
            $size, $format, $width, $height);

        ($infile, $outfile) = @_;

        $image = Image::Magick->new;
        $error = $image->Read($infile);

        if (!$error)
        {
                ($x, $y, $size, $format) = $image->Ping("$infile");
                ($width, $height) = thumbnail_dimensions($x, $y);
                $image->Scale(width=>$width, height=>$height);
                $error = $image->Write($outfile);
        }

        return $error;
}

sub thumb_with_gd {
        my ($infile, $outfile, $image, $error, $x, $y,
            $width, $height, $thumb);

        ($infile, $outfile) = @_;

        $image = GD::Image->new($infile);
        ($x, $y) = $image->getBounds();
        ($width, $height) = thumbnail_dimensions($x, $y);
        $thumb = new GD::Image($width, $height);
        $thumb->copyResized($image, 0,0 , 0,0 , $width,$height , $x,$y
+);

        open(IMAGE, '>', $outfile);
        print IMAGE $thumb->jpeg;
        close(IMAGE);
}


sub thumbnail_dimensions {
        my ($x, $y, $ratio, $height, $width);

        ($x, $y) = @_;

        $ratio = $x / $y;

        if ($default_orientation eq 'height') {
                $height = $default_height;
                $width = int($height * $ratio);
        }
        else
        {
                $width = $default_width;
                $height = int($width / $ratio);
        }

        return $width, $height;
}
[download]

I made some tests over few images and I still prefer the thumbnails produced by ImageMagick.

Ciao, Valerio

Still being new to perl I am not clear where the values of these variables in both of these subs are coming from?

sub thumb_with_gd
my ($infile, $outfile, $image, $error, $x, $y,
            $width, $height, $thumb);

sub thumbnail_dimensions
my ($x, $y, $ratio, $height, $width);
[download]

Thanks agian Cal

As far as I can see... They get their values later on in the sub, $infile and $outfile from the values passed to the sub, $image becomes the new image created from $infile, $x and $y it's dimensions, $width and $height the new dimensions, and $thumb the new image. Guess $error is a leftover from the ImageMagick version?

As for thumbnail_dimensions... $x and $y are passed to the sub, $ratio is their quotient, and $width and $height are the new dimensions. The mys just give them an undef value.

Hope this helps. Sorry if I misunderstood you.

This is a great comparison script. I whish that I could use it but I cannot use Image::Magik on my server. Howver The GD.pm portion will be extremely helpful] Thanks so much for your help Cal

use Carp;
use Image::Magick;
...
# makethumbnail( jpeg-data )
# creates a thumbnail with maximum size 120x120
sub makethumbnail {
    my $data = shift;
    my $image=Image::Magick->new(magick=>'JPEG');
    my $res;
    $res = $image->BlobToImage($data);
    if ($res) {
    carp("makethumbnail: Error reading image - $res\n");
    return undef;
    }
    $res = $image->Transform(geometry=>'120x120');
    if ($res) {
    $res = $image->Resize(geometry=>'120x120');

    if ($res) {
        carp("makethumbnail: Error while resizing: $res\n");
        return undef;
    }
    }
    my @blob = $image->ImageToBlob();
    if ($#blob!=0) {
    carp("makethumbnail: Error while converting to blob\n");
    return undef;
    }
    return $blob[0];
}
[download]

I seem to recall that the double command for resizing depends on the interface changing at some point.

Maybe I'm misinterpretting, but why would you want to make thumbnails on your server? Why not make them using Perl & Image::Magick on your local machine and upload them from there?

If this doesn't help, please explain your situation in greater detail so your fellow Monks can help you.

John J Reiser
newrisedesigns.com

Thanks, I guess the problem is not being able to get the Image::Magik module loaded on my remote server. The web hosting company feels the module is a security threat.