3.4) The window characteristics.

type win_state_def =
    Created
  | Destroyed
;;
type gr_window =
  { mutable win_id : int
  ; mutable win_top : int
  ; mutable win_left : int
  ; mutable win_width : int
  ; mutable win_height : int
  ; mutable win_state : win_state_def
  }
;;
The type gr_window is used to define a window. The variable to be defined are: its lower left corner, its width and its height in pixels. The win_state variable must be set to Destroyed, because the window is closed. Camlwin manages this variable, and sets it to Created when the window is opened. The win_id variable stores the window's identifier number when the window is opened. The initial state of this variable is unimportant. The module window.ml provides an empty window gr_std_win (coordinates: (0,0), size: (0,0), state: Destroyed)to set some variables when needed.