kmaestro/php-ffi-gtk3

require __DIR__ . '/vendor/autoload.php';

use Gtk3\Gtk;
use Gtk3\Gtk\Window;
use Gtk3\Enum\WindowEnum;

$gtk = Gtk::getInstance();

$gtk->init();

$window = new Window(WindowEnum::topLevel);
$window->widget()->show();

$gtk->main();

return 0;