....................
:                  :
:   ------------   :
:   | viewable |   :
:   | portion  |   :
:   ------------   :
:                  :
....................

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;
use Gtk2 '-init';
use Gtk2::Helper;

my @landscape = qw(800 600);
my @portrait  = qw(600 800);

# Copyright (C) 2004  Carey Tilden <revdiablo@wd39.com>

# This code is dual licensed. You may choose from one of the following:
#  - http://creativecommons.org/licenses/by/1.0/
#  - http://d.revinc.org/pages/license

my ($mw, $sw) = create_widgets();
my $vp;
Gtk2::Helper->add_watch(fileno(STDIN), 'in', \&load_image);
Gtk2->main;

sub load_image {
    exit if eof STDIN;

    my $file = <STDIN>;
    chomp $file;

    $sw->remove($vp) if defined $vp;

    my $img = Gtk2::Image->new_from_file($file);

    my $pb = $img->get_pixbuf;
    my ($x, $y) = ($pb->get_width, $pb->get_height);

    $vp = Gtk2::Viewport->new(undef, undef);
    $vp->add($img);

    $sw->add($vp);

    if ($x > $y) {
        $mw->resize($x > $landscape[0] ? $landscape[0] : $x + 2,
                    $y > $landscape[1] ? $landscape[1] : $y + 2);
    } else {
        $mw->resize($x > $portrait[0] ? $portrait[0] : $x + 2,
                    $y > $portrait[1] ? $portrait[1] : $y + 2);
    }

    # all these values are the same as default, except the first. these
    # values are just for testing. the eventual plan is to adjust them
    # so the viewport is centered, but even with static values it
    # doesn't work.
    my $ha = Gtk2::Adjustment->new(50, 0, 1, 0.1, 0.9, 1);
    my $va = Gtk2::Adjustment->new(50, 0, 1, 0.1, 0.9, 1);

    $sw->set_hadjustment($ha);
    $sw->set_vadjustment($va);

    $mw->set_title("$file ${x}x${y}");
    $mw->show_all();

    return 1;
}

sub create_widgets {
    my $sw = Gtk2::ScrolledWindow->new(undef, undef);
    $sw->set_policy('automatic','automatic');

    my $mw = Gtk2::Window->new;
    $mw->add($sw);

    return ($mw, $sw);
}