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

static gboolean iconify_window(GtkWindow* w) {
    g_print("%s\n", __FUNCTION__);
    gtk_window_iconify(w);
    return FALSE;
}

static gboolean on_expose(GtkWidget *widget, GdkEvent *event, gpointer user_data) {
    g_print("%s\n", __FUNCTION__);

    GdkWindow* gdk_window = gtk_widget_get_window(widget);

    GdkRectangle rect = {50, 50, 100, 100};
    GdkRegion* region = gdk_region_rectangle(&rect);

    gdk_window_input_shape_combine_region(gdk_window, region, 0,0);

    gdk_region_destroy(region);
    return FALSE;
}

int main(int argc, char *argv[]) {
    gtk_init(&argc, &argv);

    GtkWidget *window = gtk_window_new(GTK_WINDOW_TOPLEVEL);

    g_signal_connect(G_OBJECT(window), "expose-event",
            G_CALLBACK(on_expose), NULL);
    g_signal_connect(window, "destroy",
            G_CALLBACK(gtk_main_quit), NULL);

    gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
    gtk_window_set_default_size(GTK_WINDOW(window), 300, 300);
    gtk_window_set_title(GTK_WINDOW(window), "Input transparent window");
    gtk_window_set_decorated(GTK_WINDOW(window), FALSE);

    gtk_widget_realize(window);
    gtk_widget_show_all(window);
    gdk_threads_add_timeout(3000, (GSourceFunc) iconify_window, window);

    gtk_main();

    return 0;
}