The #GtkOrientable interface is implemented by all widgets that can be oriented horizontally or vertically. Historically, such widgets have been realized as subclasses of a common base class (e.g #GtkBox/#GtkHBox/#GtkVBox or #GtkScale/#GtkHScale/#GtkVScale). #GtkOrientable is more flexible in that it allows the orientation to be changed at runtime, allowing the widgets to “flip”.