sig
val cast : 'a Gobject.obj -> [ `drawable ] Gobject.obj
val get_visual : [> `drawable ] Gobject.obj -> Gdk.visual
val get_depth : [> `drawable ] Gobject.obj -> int
val get_colormap : [> `drawable ] Gobject.obj -> Gdk.colormap
val get_size : [> `drawable ] Gobject.obj -> int * int
end