Re: [PATCH] NSScroller some event handling cleanups.

[Alexander Malmberg]

Benhur Stein wrote:
> >          * Source/NSScroller.m (trackKnob:): stop slogging through mounds of
> >          mouse motion events and use periodic events.
> I think that this kind of code exists in more than one place in
> GNUstep (and probably in some applications, like in mine), because
> there are too many mouse moved events that are generated by X.
> Wouldn't it be a better idea to change the backend to filter out
> some of those events and not have to have this solution
> reimplemented many times in many places?

It (-x11, at least) already does.

However, I'm not sure the backend should be filtering user input events.
Either way, the whole mess with periodic events and such is just silly,
so I've finally took some time to write a proper solution:

do
{
   /* Inner loop that gets and (quickly) handles all events that have
already arrived. */
   while (theEvent && [theEvent type]!=NSLeftMouseUp)
   {
      /* Note the event here. Don't do any expensive handling. */

      theEvent = [app nextEventMatchingMask: eventMask
         untilDate: [NSDate distantPast] /* Only get events that have
already arrived. */
         inMode: NSEventTrackingRunLoopMode
         dequeue: YES];
   }

   if ([theEvent type]==NSLeftMouseUp)
      break;

   /* No more events right now. Do expensive handling, like drawing,
here. */

   /* Get the next event, blocking if necessary. */
   theEvent = [app nextEventMatchingMask: eventMask
      untilDate: nil /* No limit, block until we get an event. */
      inMode: NSEventTrackingRunLoopMode
      dequeue: YES];
} while ([theEvent type] != NSLeftMouseUp);
/* Clean up. */

- Alexander Malmberg