text: /* Header Bar
   * #Keywords: GtkWindowHandle, GtkWindowControls
   *
   * GtkHeaderBar is a container that is suitable for implementing
   * window titlebars. One of its features is that it can position
   * a title centered with regard to the full width, regardless of
   * variable-width content at the left or right.
   *
   * It is commonly used with gtk_window_set_titlebar()
   */
  
  #include <gtk/gtk.h>
  
  GtkWidget *
  do_headerbar (GtkWidget *do_widget)
  {
    static GtkWidget *window = NULL;
    GtkWidget *header;
    GtkWidget *button;
    GtkWidget *box;
  
    if (!window)
      {
        window = gtk_window_new ();
        gtk_window_set_display (GTK_WINDOW (window),  gtk_widget_get_display (do_widget));
        gtk_window_set_title (GTK_WINDOW (window), "Welcome to Facebook - Log in, sign up or learn more");
        g_object_add_weak_pointer (G_OBJECT (window), (gpointer *)&window);
  
        gtk_window_set_default_size (GTK_WINDOW (window), 600, 400);
  
        header = gtk_header_bar_new ();
  
        button = gtk_button_new_from_icon_name ("mail-send-receive-symbolic");
        gtk_header_bar_pack_end (GTK_HEADER_BAR (header), button);
  
        box = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 0);
        gtk_widget_add_css_class (box, "linked");
        button = gtk_button_new_from_icon_name ("go-previous-symbolic");
        gtk_box_append (GTK_BOX (box), button);
        button = gtk_button_new_from_icon_name ("go-next-symbolic");
        gtk_box_append (GTK_BOX (box), button);
  
        gtk_header_bar_pack_start (GTK_HEADER_BAR (header), box);
        gtk_header_bar_pack_start (GTK_HEADER_BAR (header), gtk_switch_new ());
  
        gtk_window_set_titlebar (GTK_WINDOW (window), header);
  
        gtk_window_set_child (GTK_WINDOW (window), gtk_text_view_new ());
      }
  
    if (!gtk_widget_get_visible (window))
      gtk_widget_show (window);
    else
      gtk_window_destroy (GTK_WINDOW (window));
  
    return window;
  }
  