#!/usr/bin/perl
use strict;
use warnings 'all';
use Tk;

# MainWindow erstellen
my $mw = tkinit();

# WaitBox erstellen
my $wb = $mw->Toplevel(-title => "Please wait...");
$wb->Label(-text => "Generating Graph. Please wait.",
       -font => '{Impact} 20 {bold}')->pack;
$wb->withdraw();

# WaitBox aufrufen
$mw->iconify();
$wb->deiconify();
$wb->raise();
$wb->update();

# Graph generieren
# ...
sleep 5;

# WaitBox verstecken
$wb->withdraw();
$mw->deiconify();

MainLoop;