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From: etaylor@wilkins.iaims.bcm.tmc.edu (Eric Taylor)
Newsgroups: comp.windows.x
Subject: Re: Too many expose events
Message-ID: <3010@gazette.bcm.tmc.edu>
Date: 3 Dec 90 16:04:47 GMT
References: <1990Dec01.065919.16258@iecc.cambridge.ma.us>
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Reply-To: etaylor@wilkins.iaims.bcm.tmc.edu (Eric Taylor)
Organization: Baylor College of Medicine, Houston, Tx
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In article <1990Dec01.065919.16258@iecc.cambridge.ma.us>, johnl@iecc.cambridge.ma.us (John R. Levine) writes:
|> I am writing what I think is a straightforward X application, which mostly
|> writes fixed pitch text of various colors into a rectangular widget, and
|> reads keystrokes and passes them back to the application.  (Think of it as
|> a special purpose xterm wired to its application.)
|> 
|> About half the time when I type a keystroke, the X server clears the
|> window and sends an expose event that forces me to redraw the whole thing.
|> There isn't much of a discernable pattern, but it's fairly repeatable,
|> e.g. if I set up the window with certain contents and press cursor down, I
|> get the cleared window and expose every time I do it.  This makes the
|> performance look dreadful, since I sometimes have to redraw the whole window
|> on every keystroke.  I'm not using XtMainLoop, since this code is glued
|> into an existing application -- there's an event loop of XtNextEvent and
|> XtDispatchEvent inside the "get keystroke or mouse button" routine, but I
|> can't see how that should affect the server.
|> 
|> The server is Interactive's X11R3 VGA server 1.1 running on a Paradise
|> super VGA.  My widget is written with the basic Xt toolkit, though I am
|> running the Motif window manager.  The widget uses 10 colors, but it gets
|> its pixels at the start of the session and changes its GC as it draws text
|> in different colors.  Other than setting the icon at startup, there's no
|> window manager interactions beyond what Xt does automatically.
|> 
|> Is this a server bug, or is there some arcane server interaction that I
|> am fouling up?  I'm baffled.
|> 
|> -- 
|> John R. Levine, IECC, POB 349, Cambridge MA 02238, +1 617 864 9650
|> johnl@iecc.cambridge.ma.us, {ima|spdcc|world}!iecc!johnl
|> "Typically supercomputers use a single microprocessor." -Boston Globe

This does not seem like a server bug at all.  You need to supply
more information, though.

	Which widget are you using?  Is it a widget that you authored?
	Is it a widget that already existed?  If so, which widget
	is it?

	It you wrote your own widget, it sounds like there is a bug
	in your widget.

	Are you using SetValues on your widget when a keystroke is
	pressed?  If so, then the behavior you describe is not a bug.
--
					Eric Taylor
					Baylor College of Medicine
					etaylor@wilkins.bcm.tmc.edu
					(713) 798-3776