Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!rutgers!mcnc!thorin!tigger!bmh
From: bmh@tigger.cs.unc.edu (Brad Hemminger)
Newsgroups: comp.windows.x
Subject: How to display exactly n frames of an image?
Message-ID: <15007@thorin.cs.unc.edu>
Date: 6 Jul 90 14:01:50 GMT
Sender: news@thorin.cs.unc.edu
Lines: 19


  For some vision experiments we would like to do I need to be able to
display a blank screen, then exactly n frames of a image, then blank 
screen, etc, etc.  Question:  is there any way to have this fine a level
of control under X11?  E.g. some machines might allow me to see a
vertical retrace interrupt, but so far under X I don't see anything at
that level (e.g. no X events that indicate vertical retrace, etc).
  If anyone has any answers, or hints on how to do this I would greatly
appreciate it.  The best I have come up with so far is to use gettimeofday
to delay for the amount of time equal to n*(time each frame is displayed);
however, this may in certain cases cause the display of n-1 or n+1 frames
instead of n.


thanks, 
  Brad Hemminger
  Dept of Radiology
  UNC
  bmh@rad.unc.edu