Allegro 5 API: Displays as event sources

[ This document only describes displays acting as event sources,
  cf. Bob's gfx API. ]



- Type: AL_DISPLAY

   [Could be merged with AL_BITMAP in future.]
   Display objects are also event sources.



- Event: AL_EVENT_DISPLAY_EXPOSE

   This event type is generated when an area of a display becomes
   obscured, then later unobscured, so that the area needs to be
   redrawn.  Some graphics drivers will attempt to handle the
   redrawing automatically (and in those cases, expose events won't be
   generated).  However, when that is not possible, you will need to
   redraw the obscured region yourself.

   Fields specific to this event type:

      (int) e.display.x
      (int) e.display.y

         The top-left corner of the exposed region.

      (int) e.display.width
      (int) e.display.height

         The dimensions of the exposed region.  Note that displays may
         be resized by the user, etc.