`sig
val get_system_colormap : unit -> Gdk.colormap
val get_colormap : ?privat:bool -> Gdk.visual -> Gdk.colormap
val get_visual : Gdk.colormap -> Gdk.visual
type spec = [ `BLACK | `NAME of string | `RGB of int * int * int | `WHITE ]
val alloc : colormap:Gdk.colormap -> Gdk.Color.spec -> Gdk.color
val red : Gdk.color -> int
val blue : Gdk.color -> int
val green : Gdk.color -> int
val pixel : Gdk.color -> int
end`