Mastering Perl/Tk

The Balloon Widget

Using a Balloon widget, you can create help-text-like labels that appear as the mouse hovers over a widget. You can also use it to create help text that appears in a status bar. Let’s look at a very simple example, then go over the relevant options and methods:

use Tk;
use Tk::Balloon;

$mw = MainWindow->new(-title => "Simple Balloon example");
$button = $mw->Button(-text => "Exit", -command => sub { exit })->pack;
$msgarea = $mw->Label(-borderwidth => 2, -relief => 'groove')
  ->pack(-side => 'bottom', fill => 'x');
$balloon = $mw->Balloon(-statusbar => $msgarea);
$balloon->attach($button, -balloonmsg => "Exit the App",  
  -statusmsg => "Press the Button to exit the application");
$balloon->attach($msgarea, -msg => 'Displays the help text for a widget');
MainLoop;

Figure 23-12 illustrates this example.

Figure 23-12.  Using a Balloon as both help text and a status message

Using a status bar is optional. We’ve just included it here to show you how easy it is. Here are the options you can use when creating your Balloon widget:^[1]

-state => 'balloon' | 'status' | ' both ' | 'none'

Determines if the Balloon widget will be displaying only balloons, only status messages, both (the default), or nothing.

-statusbar => widget

Tells the Balloon what widget to use for displaying status messages. The widget specified must have a -text or -textvariable option.

-balloonposition ...