#!perl

use strict;
use warnings;

use Tk;
use Tk::Button;
use Tk::ProgressBar;

my $mw = MainWindow->new();

my $progress;
my $toggle = 0;
my @colours = (
    [ 0 => q{#ff0000}, 30 => q{#00ff00}, 60 => q{#0000ff} ],
    [ 0 => q{#ffff00}, 30 => q{#00ffff}, 60 => q{#ff00ff} ],
);

my $pb = $mw->ProgressBar(
    -width => 20,
    -length => 200,
    -colors => $colours[$toggle],
    -variable => \$progress,
)->pack();

$mw->Button(-text => q{Jump WITH Change},
    -command => sub {
        $progress ||= 0;
        $progress = ($progress + 10) % 110;
        $toggle ^= 1;
        $pb->configure(-colors => $colours[$toggle]);
        Tk::ProgressBar::_layoutRequest($pb, 1);
    }
)->pack();

$mw->Button(-text => q{Jump NO Change},
    -command => sub {
        $progress ||= 0;
        $progress = ($progress + 10) % 110;
        $toggle ^= 1;
        $pb->configure(-colors => $colours[$toggle]);
    }
)->pack();

$mw->Button(-text => q{Exit}, -command => sub { exit })->pack();

MainLoop;