Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ncar!ames!vsi1!daver!athsys!jim
From: jim@athsys.uucp (Jim Becker)
Newsgroups: comp.windows.x
Subject: Detecting/Compressing Multiple Exposure Events - how ?
Keywords: XCheck*()
Message-ID: <126@tityus.UUCP>
Date: 30 Aug 88 17:54:08 GMT
Organization: Athena Systems, Inc., Sunnyvale, CA
Lines: 37


	In managing window interactions and refresh there I have a
nagging problem that has recently compunded. I am looking for
enlightenment!

	When managing window events, I currently process exposure
events as full window re-renders. I would like to minimize the
rendering as much as possible, by way of only rendering the *last*
time there is an exposure event for the target window in the current
event queue.  Hence, I would like to skip the re-rendering in the
situation where there are more xexpose events further down the queue.
The "count" field seems to only apply with chained xexpose events on
regions of the window, but is not global in nature to the entire event
stream.

	All the XCheck*() calls are very nice, and would perform the
needed checking logic, but they remove the matched event from the
input queue. I would like to process all the events in order, as I
would think that processing out-of-synch with other events would cause
problems (although I have not tested this theory).

	Is there some method to determine globally if an exposure
event (or any given event/window combination) is the last such event,
with only scanning of the event queue taking place ??

	This would also be helpful for other purposes, such as
building damage lists of graphics redraw regions (that are complete
for the entire queue) before re-rendering from a database or
datastructure resource.

	If this functionality does not exist, maybe it could be
created simply for R3 by passing NULL XEvent pointers to the XCheck*()
routines. They would detect and return status, yet keep the event
queue intact.


-Jim Becker