#!/usr/bin/perl

use strict;
use warnings;
use Tk;
use Tk::ProgressBar;

my $mw = MainWindow->new(-title => 'ProgressBar example');
my $percent_done = '';

my $progress = $mw->ProgressBar(
    -width => 30,
    -from => 0,
    -to => 100,
    -blocks => 50,
    -colors => [0, 'red', 50, 'white' , 80, 'blue'],
    -variable => \$percent_done
)->pack(-fill => 'x');

$mw->Button(-text => 'Go!', -command=> sub {
    foreach (my $i = 0; $i < 1000; ++$i) { 
        $percent_done = $i/10;
        print "$i\n";
        $mw->update; 
    }
})->pack(-side => 'bottom');

MainLoop;