Sdl.Frect
val create : x:float -> y:float -> w:float -> h:float -> frect
val x : frect -> float
val y : frect -> float
val w : frect -> float
val h : frect -> float
val set_x : frect -> float -> unit
val set_y : frect -> float -> unit
val set_w : frect -> float -> unit
val set_h : frect -> float -> unit