// Include gtk
#include <gtk/gtk.h>

static void on_activate (GtkApplication *app) {
  // Create a new window
  GtkWidget *window = gtk_application_window_new (app);
  // Create a new button
  GtkWidget *button = gtk_button_new_with_label ("Hello, World!");
  // When the button is clicked, close the window passed as an argument
  g_signal_connect_swapped (button, "clicked", G_CALLBACK (gtk_window_close), window);
  gtk_window_set_child (GTK_WINDOW (window), button);
  gtk_window_present (GTK_WINDOW (window));
}

int main (int argc, char *argv[]) {
  // Create a new application
  GtkApplication *app = gtk_application_new ("com.example.GtkApplication",
                                             G_APPLICATION_DEFAULT_FLAGS);
  g_signal_connect (app, "activate", G_CALLBACK (on_activate), NULL);
  return g_application_run (G_APPLICATION (app), argc, argv);
}

imports.gi.versions['Gtk'] = '4.0';
const Gtk = imports.gi.Gtk;

// Create a new application
let app = new Gtk.Application({ application_id: 'com.example.GtkApplication' });

// When the application is launched…
app.connect('activate', () => {
    // … create a new window …
    let win = new Gtk.ApplicationWindow({ application: app });
    // … with a button in it …
    let btn = new Gtk.Button({ label: 'Hello, World!' });
    // … which closes the window when clicked
    btn.connect('clicked', () => { win.close(); });
    win.set_child(btn);
    win.present();
});

// Run the application
app.run([]);

#!/usr/bin/env perl
use strict; use warnings; use utf8;
use Glib::IO;
use Gtk4;

# Create a new application
my $app =
  Gtk3::Application->new('com.example.Gtk3Application', 'G_APPLICATION_FLAGS_NONE');

# When the application is launched…
$app->signal_connect(
  activate => sub {
    my $app = shift;
    # … create a new window …
    my $win = Gtk3::ApplicationWindow->new($app);
    # … with a button in it …
    my $btn = Gtk3::Button->new('Hello World!');
    # … which closes the window when clicked
    $btn->signal_connect(clicked => sub { $win->close(); });
    $win->set_child($btn);
    $win->present();
  }
);

# Run the application
$app->run(\@ARGV);

# Load Gtk
import gi
gi.require_version('Gtk', '4.0')
from gi.repository import Gtk

# When the application is launched…
def on_activate(app):
    # … create a new window…
    win = Gtk.ApplicationWindow(application=app)
    # … with a button in it…
    btn = Gtk.Button(label='Hello, World!')
    # … which closes the window when clicked
    btn.connect('clicked', lambda x: win.close())
    win.set_child(btn)
    win.present()

# Create a new application
app = Gtk.Application(application_id='com.example.GtkApplication')
app.connect('activate', on_activate)

# Run the application
app.run(None)

use glib::clone;
// glib and other dependencies are re-exported by the gtk crate
use gtk::glib;
use gtk::prelude::*;

// When the application is launched…
fn on_activate(application: &gtk::Application) {
    // … create a new window …
    let window = gtk::ApplicationWindow::new(application);
    // … with a button in it …
    let button = gtk::Button::with_label("Hello World!");
    // … which closes the window when clicked
    button.connect_clicked(clone!(@weak window => move |_| window.close()));
    window.set_child(Some(&button));
    window.present();
}

fn main() {
    // Create a new application with the builder pattern
    let app = gtk::Application::builder()
        .application_id("com.github.gtk-rs.examples.basic")
        .build();
    app.connect_activate(on_activate);
    // Run the application
    app.run();
}

int main (string[] argv) {
    // Create a new application
    var app = new Gtk.Application ("com.example.GtkApplication",
                                   GLib.ApplicationFlags.FLAGS_NONE);

    app.activate.connect (() => {
        // Create a new window
        var window = new Gtk.ApplicationWindow (app);

        // Create a new button
        var button = new Gtk.Button.with_label ("Hello, World!");

        // When the button is clicked, close the window
        button.clicked.connect (() => {
            window.close ();
        });

        window.set_child (button);
        window.present ();
    });

    return app.run (argv);
}

Portability

Projects built using GTK and its dependencies run on well known operating systems.

Stability

GTK delivers the enticing features and superb performance which adds to your applications.

Language Bindings

GTK is written in C but has been designed to support a wide range of languages such as Python, JavaScript, C++, Rust and many more.

Interfaces

GTK has a comprehensive collection of core widgets like Buttons, Windows, Toolbars for use in your application.

Open Source

GTK is a free and open-source project maintained by GNOME and an active community of contributors. GTK is released under the terms of the GNU Lesser General Public License.

API

GTK boasts of an easy to use API which helps in decreasing your development time and help you achieve better results.

Accommodation

GTK caters to many features like Native look and feel, theme support, Object-oriented approach that today’s developers look for in a toolkit.

Foundations

GTK is built on top of GLib. GLib provides the fundamental data types and system integration points to avoid duplicated code in applications.

Develop with GTK

Develop GTK

Looking for Help?

Catch up with GTK development

Get in touch with GTK developers through Matrix. Get updates about GTK and its community from GTK blog or on Mastodon.

Meet the community

As regularly as possible, GTK team meetings take place at conferences and hackfests to discuss the future of GTK and define a roadmap.

Contribute to GTK

If you are a developer and want to contribute to GTK, you are more than welcome to do so.