3.8) The scrollbars.

type gr_scrollbar =
  { sb_window : gr_window
  ; mutable sb_left : int
  ; mutable sb_top : int
  ; mutable sb_length : int
  ; mutable sb_pos : int
  ; mutable sb_delta : int
  ; mutable sb_dir : direction
  ; mutable sb_callback : gr_scrollbar -> event -> bool
  }
;;
The vertical and horizontal scrollbars are objects of type gr_scroll. If the user presses the mouse button when the mouse cursor is on the shaft, the shaft follows the mouse motions until the user releases the mouse button. If the user clicks outside the shaft, the shaft moves a variable number of pixels in the direction of the mouse cursor. The scrollbars are define by: The variables and functions linked to scrollbars are:
gr_shaft_width : int
is the width of the shaft in pixels (changes with the look).
gr_shaft_height : int
is the height of the shaft (changes with look).
gr_scroll_width : int
is the width of a scrollbar.
gr_scroll_course : int -> int
gr_scroll_course Scroll.sb_length returns the maximum value that Scroll.sb_pos can take.
gr_draw_scrollbar : gr_scrollbar -> unit
gr_draw_scrollbar Scroll draws the scrollbar Scroll.
gr_scrollbar_managed : gr_scrollbar -> event -> bool
is the function used by Camlwin to manage the scrollbars.