Perl in a Nutshell, 2nd Edition

The Scrollbar widget

For more flexibility with a scrollbar, you can use the Scrollbar widget. To do so, you need to create the target widget to scroll. Set the -xscrollcommand or -yscrollcommand option as appropriate, configure the scrollbar to talk to the widget, and position the scrollbar and target widget next to one another. For example:

$scrollbar = $mainwindow->Scrollbar(-orient => 'vertical');
$listbox = $mainwindow->Entry(-yscrollcommand => ['set' => $scrollbar]);
$scrollbar->configure(-command => ['yview' => $listbox]);
$scrollbar->pack(-side => 'right', -fill => 'y');
$listbox->pack(-side => 'left', -fill => 'both');

First, we create the scrollbar with vertical orientation (which is actually the default). Next, we create the Listbox widget with the -yscrollcommand option to define a callback when the widget is scrolled vertically. The scrollbar is then configured with a callback that says to inform the Listbox widget when it is clicked vertically. Finally, the Scrollbar and Listbox widgets are packed side-by-side. See further discussion of the Scrollbar widget later in this chapter for more information.