show-scrollbars in canvas%

Shows or hides scrollbar. The horizontal scrollbar can be shown only if the canvas was created with the 'hscroll style, and the vertical scrollbar can be shown only if the canvas was created with the 'vscroll style. See also init-auto-scrollbars and init-manual-scrollbars.

• (send a-canvas show-scrollbars show-horiz? show-vert?) -> void
     show-horiz? : boolean
     show-vert? : boolean

  Shows or hides the scrollbars as indicated by show-horiz? and show-vert?. If show-horiz? is true and the canvas was not created with the 'hscroll style, an exn:fail:contract exception is raised. Similarly, if show-vert? is true and the canvas was not created with the 'vscroll style, an exn:fail:contract exception is raised.