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Re: expose events and window dragging in object graphics

Richard Tyc (richt@sbrc.umanitoba.ca) writes:

> I have a IDLgrWindow object which generates expose events and the RETAIN is
> set to 0 indicating no backing store as the manuals suggest to improve
> performance and utilize hardware acceleration.
> In the app, I create a modal , top level CW_FORM widget and when I drag this
> widget in front of the Window, it does not update the window until AFTER I
> release the mouse which results in a very unprofessional look during the
> drag since the widget is essentially sweeping across the Draw Widget
> (IDLgrWindow) with no background update.
> Are expose events not produced during the drag ?
> Anyway around this ?

I've read the warning, and in fact I almost always set
RETAIN=0 in my object graphics windows, but I keep noticing
in code written at RSI that RETAIN is always set to 2.
I find this *very* suspicious. :-)



P.S. I don't know any ways around it.

David Fanning, Ph.D.
Fanning Software Consulting
Phone: 970-221-0438 E-Mail: davidf@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155