[comp.lang.idl-pvwave] Problem with backing store under X windows

rivers@bnlls1.nsls.bnl.gov (Mark Rivers) (03/22/91)

I am having a problem with backing store in PV-WAVE 3.03 under X windows. The
default backing store mechanism is supposed to be that PV-WAVE requests the
server to do the backing store. This is also supposed to be the behavior for
all subsequent windows created after a "DEVICE, RETAIN=1" command. However,
neither of these work for me. I have used two different X windows devices,
both of which I believe are capable of backing store: DECWindows on a
VAXStation 3200 and a Tektronix XN11 terminal (which was set up to have backing
store enabled). DEVICE, RETAIN=2 works, but is quite slow because PV-WAVE itself
makes the backing store.

Has anyone else seen this problem and/or found a fix?
Mark Rivers                              (516) 282-7708 or 5626
Building 815                             rivers@bnlx26.nsls.bnl.gov (Internet) 
Brookhaven National Laboratory           rivers@bnl (Bitnet)                   
Upton, NY 11973                          BNLX26::RIVERS  (Physnet)             

william@kaula.keck.hawaii.edu (William Lupton) (03/22/91)

In article <2676@bnlux0.bnl.gov>, rivers@bnlls1.nsls.bnl.gov (Mark Rivers)
writes...
> 
>I am having a problem with backing store in PV-WAVE 3.03 under X windows. The
>default backing store mechanism is supposed to be that PV-WAVE requests the
>server to do the backing store. This is also supposed to be the behavior for
>all subsequent windows created after a "DEVICE, RETAIN=1" command. However,
>neither of these work for me. I have used two different X windows devices,
>both of which I believe are capable of backing store: DECWindows on a
>VAXStation 3200 and a Tektronix XN11 terminal (which was set up to have backing
>store enabled). DEVICE, RETAIN=2 works, but is quite slow because PV-WAVE
>itself makes the backing store.
> 
>Has anyone else seen this problem and/or found a fix?

Running the same version of PV~WAVE as you on VAXstation 3100's we observe the
same behavior as you (and use RETAIN=2). I just assumed that the server didn't
support backing store.

We have recently borrowed a NCD X-terminal. Its X server can be configured to
provide backing store "on demand". With this setting, RETAIN=1 works and gives
instantaneous re-paint on window move, expose etc. Very nice.

So I suspect that the problem is that your X servers are not in fact configured
to provide backing store on demand.

		William Lupton (wlupton@keck.hawaii.edu)