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From: jensen@winery.DEC.COM.UUCP
Newsgroups: comp.windows.x
Subject: re: Handling ExposeWindow events for nested windows
Message-ID: <8704101917.AA27651@decwrl.dec.com>
Date: Fri, 10-Apr-87 13:46:58 EST
Article-I.D.: decwrl.8704101917.AA27651
Posted: Fri Apr 10 13:46:58 1987
Date-Received: Sat, 11-Apr-87 18:15:39 EST
Sender: daemon@ucbvax.BERKELEY.EDU
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If you are going to do this under X10, the best approach I have seen
is to defer processing Exposure events until you receive an event
which is not an expose event (or you run out of events).  Then you
look at the last exposure event and test to see if it is a resize.
If so, discard all the previous exposure events; otherwise process
them.  Whether this will work for you depends on the nature of
the application; you will have to be careful not to discard an
exposure event you really need to process.

For an example of this, take a look at bitmap.c in the X.V10R4 release,
in particular ProcessEvent, ProcessEventReally, and HandleExposure.
ProcessEvent makes a call to HandleExposure, which in turn recursively
calls itself until the event string terminates.  Then if the last
exposure event is not a resize, HandleExposure returns with a
"PROCESS_IT" status, which will cause the stack to unwind, processing
the deferred events (N.B.: in reverse order).  Otherwise, HandleExposure
returns a "DISCARD_IT" status, causing the deferred events to be
thrown away.  There are some details I have skipped, but these routines
are a good starting point.

Regards,


					/Paul Jensen
					 Western Area Operations
					 Digital Equipment Corp.
					 Santa Clara, CA