19.1.1.1. The Screenshot.

19.1.1.2. The Code.

The program can be found here: 'gtk2_expander.pl'

 #! /usr/bin/perl -w
 
 use strict;
 use Gtk2 '-init';
 use Glib qw/TRUE FALSE/; 
 
 #standard window creation, placement, and signal connecting
 my $window = Gtk2::Window->new('toplevel');
 $window->signal_connect('delete_event' => sub { Gtk2->main_quit; });
 $window->set_border_width(5);
 $window->set_position('center_always');
 
 #add and show the vbox
 $window->add(&ret_vbox);
 $window->show();
 
 #our main event-loop
 Gtk2->main();
 
 sub ret_vbox {
 
 my $vbox = Gtk2::VBox->new(FALSE,5);
 
 	#create a instance of the Gtk2::Expander class
 	my $expander = Gtk2::Expander->new_with_mnemonic('Expand Me');
 	
 	#create the child that we want to add to it.
 	#----------------------------------------------
 	#NOTE: If we want to resize
 	#the widget containing the Gtk2::Expander Widget 
 	#to the size that it was BEFORE the expansion
 	#we have to "add / remove" the child on each "expanded / closed" cycle
 	#If we just add it, it will be shown and hidden, but we will not be able
 	#to shrink the parent containing the Gtk2::Expander instance when hidden
 	#-------------------------------------------------
 	my $nb = &ret_notebook;
 	$nb->show_all;
 	
 	$expander->signal_connect_after('activate' => sub {
 			
 		if($expander->get_expanded){
 			$expander->set_label('Close Me');
 			$expander->add($nb);
 				
 		}else{ 
 			$expander->set_label('Expand Me');
 			$expander->remove($nb);
 			$window->resize(4,4);	
 		}
 		return FALSE;
 	}); 
 	
 	
 $vbox->pack_start($expander,FALSE,FALSE,0);	
 
 $vbox->show_all();
 return $vbox;
 }
 
 sub ret_notebook {
 
 #this will create a vbox containing a Notebook 
 #and some widgets to manipulate the Notebook's
 #properties.
 
 my $vbox_nb = Gtk2::VBox->new(FALSE,5);
 $vbox_nb->set_size_request (500, 300);
 
 	my $nb = Gtk2::Notebook->new;
 	
 	#pre-set some properties
 	$nb->set_scrollable (TRUE); 
 	$nb->popup_enable;
 		for (0..10) { 
 	
 		my $child = Gtk2::Frame->new("Frame of Tab $_");
 	
 	#________
 		#The tab's label can be a widget, and does not
 		#need to be a label, here we create a hbox containing
 		#a label and close button
 		my $hbox = Gtk2::HBox->new(FALSE,0);
 		$hbox->pack_start(Gtk2::Label->new("Tab $_"),FALSE,FALSE,0);
 	
 			my $btn = Gtk2::Button->new('');
 			$btn->set_image(Gtk2::Image->new_from_stock('gtk-close','menu'));
 			$btn->signal_connect('clicked' => sub {
 			
 				$nb->remove_page ($nb->page_num($child)); 
 			});
 			
 		$hbox->pack_end($btn,FALSE,FALSE,0);
 		$hbox->show_all;
 	#________
 		
 		$nb->append_page ($child,$hbox); 
  
 
 		} 
 	
 $vbox_nb->pack_start($nb,TRUE,TRUE,0);
 $vbox_nb->pack_start(Gtk2::HSeparator->new(),FALSE,FALSE,5);
 
 #call the sub that will create the table containing 
 #controls to manipulate the notebook		
 $vbox_nb->pack_end(&nb_controls($nb),FALSE,FALSE,0);	
 	
 	return $vbox_nb;
 }
 
 
 sub nb_controls {
 
 	my ($nb) = @_;
 	
 	my $table = Gtk2::Table->new(3,2,TRUE);
 	
 	$table->attach_defaults(Gtk2::Label->new('Tab position:'),0,1,0,1);
 	
 		my $cb_position = Gtk2::ComboBox->new_text;
 		
 		foreach my $val (qw/left right top bottom/){
 		
 			$cb_position->append_text($val);
 		}
 		
 		$cb_position->signal_connect("changed" => sub {
 		
 			$nb->set_tab_pos($cb_position->get_active_text);
 		
 		});
 		
 		$cb_position->set_active(2);
 
 	$table->attach_defaults($cb_position,1,2,0,1);
 	
 		my $show_tabs = Gtk2::CheckButton->new("Show Tabs");
 		$show_tabs->set_active(TRUE);
 		$show_tabs->signal_connect('toggled' =>sub {
 		
 			$nb->set_show_tabs($show_tabs->get_active);
 		
 		});
 	$table->attach_defaults($show_tabs,0,1,1,2);
 	
 		my $scrollable = Gtk2::CheckButton->new("Scrollable");
 		$scrollable->set_active(TRUE);
 		$scrollable->signal_connect('toggled' =>sub {
 		
 			$nb->set_scrollable($scrollable->get_active);
 		
 		});
 	$table->attach_defaults($scrollable,1,2,1,2);
 	
 		my $popup = Gtk2::CheckButton->new("Popup Menu (right click on tab)");
 		$popup->set_active(TRUE);
 		$popup->signal_connect('toggled' =>sub {
 		
 			($popup->get_active)&&($nb->popup_enable);
 			($popup->get_active)||($nb->popup_disable);
 		});
 	$table->attach_defaults($popup,0,1,2,3);
 	
 	return $table;
 
 }

19.1.1.3. Points of interest.