Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!ucsd!ucbvax!bloom-beacon!EXPO.LCS.MIT.EDU!keith
From: keith@EXPO.LCS.MIT.EDU (Keith Packard)
Newsgroups: comp.windows.x
Subject: Re: fast, flicker-free animation, how?
Message-ID: <9011021703.AA23452@xenon.lcs.mit.edu>
Date: 2 Nov 90 17:03:07 GMT
References: <16246@hydra.gatech.EDU>
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 34


> > How big is your image?  Unless your X implementation is extremely bad, you
> > should be able to do much better than 4 frames per second this way for
> > "moderate" sized windows (say, 400x400).

> The image is 800x800 and since it's an 8-bit deep visual, XCopyArea has to
> move 640K bytes of data.  I'm not sure if the cg3 framebuffer is natively
> an XYPixmap or a ZPixmap.

It looks to me like you're running OpenWindows 1.0, unless you have a GX.  For
raw data copying, you should get about 8 frame per second with the MIT R4
server.  On the CG3, running OpenWindows 2.0, you should get similar
performance.  OpenWindows 1.0 would only have given you about 3 frames per
second on the cg3, or about 5 frames per second on the GX.

Here is the relavant data from x11perf Copy 500x500 pixmap to window:

		MIT	OW1.0	OW2.0
	CG3	22.3	8.4	17.3	
	GX	18.2	13.5	??

(Except for the OW2.0/CG3 number, all of these were measured by me and are
presented here for purposes of illustration only. i.e. your mileage may vary)

I scaled these numbers by the ratio of the areas between the measurement and
the application (500x500 / 800x800) to get estimates on the performance of
your application.

So, you see that the variety of performance available is very dependent on
both the hardware and software available.

Even still, by careful limitation of the region copied, you can drastically
reduce the time it takes to update your image.  Multiple small copies will run
faster than one large one.