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Gnome::Gtk3 cpan:MARTIMM last updated on 2019-12-13

Gnome Gtk3 - Widget toolkit for graphical interfaces

Documentation at this site has the GNU Free Documentation License.

Description

The purpose of this project is to create an interface to the GTK+ version 3 library.

History

There is already a bit of history for this package. It started off building the GTK::Glade package which soon became too big. So a part was separated into GTK::V3. After some working with the library I felt that the class names were a bit too long and that the words gtk and gdk were repeated too many times in the class path. E.g. there was GTK::V3::Gtk::GtkButton and GTK::V3::Gdk::GdkScreen to name a few. So, finally it was split into several other packages named, Gnome::N for the native linkup on behalf of any other Gnome module, Gnome::Glib, Gnome::GObject, Gnome::Gdk3 and Gnome::Gtk3 according to what is shown on the developers page here. The classes in these packages are now renamed into e.g. Gnome::Gtk3::Button, Gnome::Gdk3::Screen, Gnome::GObject::Object and Gnome::Glib::List. As a side effect the package GTK::Glade is also renamed into Gnome::Glade3 to show that it is from Gnome and that it is based on Gtk version 3.

Example

This example does the same as the example from GTK::Simple to show you the differences between the implementations. What immediately is clear is that this example is somewhat longer. To sum up;

Pros

• The defaults of GTK+ are kept. Therefore the buttons are in the proper size compared to what GTK::Simple produces.
• Separation of callbacks from other code. Closures are not needed to get data into the callback code. Data can be provided with named arguments to the register-signal() method.
• The package is designed with the usage of glade interface designer in mind. So to build the interface by hand like below, is not necessary. Use of Gnome::Gtk3::Glade is preferable when building larger user interfaces.
• No fancy stuff like tapping into channels to run signal handlers.
• There is a registration of callback methods to process signals like button clicks as well as events like keyboard input and mouse clicks.. This is not available in GTK::Simple. The provided way to handle a signal there, is fixed into a method. E.g. the button has a 'clicked' method and the container has none while an observer might want to know if an object is inserted into a grid using the 'add' signal.
• The same method, register-signal(), is also used to register other types of signals. There are, for example, events to handle keyboard input and mouse clicks. Not all signal handler types are supported yet but can be installed in time.

Cons

• The code is larger.
• Code is somewhat slower. The setup of the example shown next is about 0.05 sec slower. That isn't much seen in the light that a user interface is mostly set up and drawn once.

A screenshot of the example . The code can be found at examples/01-hello-world.pl6.

use v6;

use Gnome::Gtk3::Main;
use Gnome::Gtk3::Window;
use Gnome::Gtk3::Grid;
use Gnome::Gtk3::Button;

# Instantiate main module for UI control
my Gnome::Gtk3::Main $m .= new;

# Class to handle signals
class AppSignalHandlers {

  # Handle 'Hello World' button click
  method first-button-click ( :widget($b1), :other-button($b2) ) {
    $b1.set-sensitive(False);
    $b2.set-sensitive(True);
  }

  # Handle 'Goodbye' button click
  method second-button-click ( ) {
    $m.gtk-main-quit;
  }

  # Handle window managers 'close app' button
  method exit-program ( ) {
    $m.gtk-main-quit;
  }
}

# Create a top level window and set a title
my Gnome::Gtk3::Window $top-window .= new(:empty);
$top-window.set-title('Hello GTK!');
$top-window.set-border-width(20);

# Create a grid and add it to the window
my Gnome::Gtk3::Grid $grid .= new(:empty);
$top-window.gtk-container-add($grid);

# Create buttons and disable the second one
my Gnome::Gtk3::Button $button .= new(:label('Hello World'));
my Gnome::Gtk3::Button $second .= new(:label('Goodbye'));
$second.set-sensitive(False);

# Add buttons to the grid
$grid.gtk-grid-attach( $button, 0, 0, 1, 1);
$grid.gtk-grid-attach( $second, 0, 1, 1, 1);

# Instantiate the event handler class and register signals
my AppSignalHandlers $ash .= new;
$button.register-signal(
  $ash, 'first-button-click', 'clicked',  :other-button($second)
);
$second.register-signal( $ash, 'second-button-click', 'clicked');

$top-window.register-signal( $ash, 'exit-program', 'destroy');

# Show everything and activate all
$top-window.show-all;

$m.gtk-main;

Documentation

Release notes

• Release notes[release]

Miscellaneous

• Release notes[release]

TODO

Versions of involved software

• Program is tested against the latest version of perl6 on rakudo en moarvm.
• Gtk library used Gtk >= 3.24.

Installation

There are several crossing dependencies from one package to the other because it was one package in the past. To get all packages, just install the Gnome::Gtk3 package and the rest will be installed with it.

zef install Gnome::Gtk3

Issues

There are always some problems! If you find one, please help by filing an issue at my github project.

Attribution

• First of all, I would like to thank the developers of the GTK::Simple project because of the information I got while reading the code. Also because one of the files is copied unaltered for which I did not had to think about to get that right. The examples in that project are also useful to compare code with each other and to see what is or is not possible.
• The inventors of Perl6 of course and the writers of the documentation which help me out every time again and again.
• The builders of the GTK+ library and the documentation.
• Other helpful modules for their insight and use.

Author

Name: Marcel Timmerman Github account name: MARTIMM