#!/usr/bin/perl

use strict;
use Tk;

my $mw = MainWindow->new;
my $btnframe = $mw->Frame()->pack(-side => 'top');
my $lstframe = $mw->Frame()->pack(-side => 'top');

my $listbox = $lstframe->Listbox(-height => 16,
                                 -width => 16)->pack;
my @listdata = <DATA>;
chomp @listdata;
$listbox->insert( 'end', @listdata );

for (qw/5x8 10x10 16x20/) {
    $btnframe->Button(-text => $_,
                      -command => [ \&resize, $listbox, $_ ],
                      )->pack(-side => 'left');
}

MainLoop;

sub resize
{
    my ( $lbox, $size ) = @_;
    my ( $newh, $neww ) = split( /x/, $size );
    $lbox->packForget;
    $lbox->configure(-height => $newh, -width => $neww );
    $lbox->pack;
}

__DATA__
1234567890123456
ABCDEFGHIJK
1234567890
abcdefghi
12345
stuv
foo
bar
baz
junk
extra lines
last line with no blank following