| Re: Slow exposure events [message #37572] |
Fri, 09 January 2004 08:17 |
Michael Wallace
Messages: 409
Registered: December 2003
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Senior Member |
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> P.S. This is best down in your IDL startup file if you do
> it for all windows, or you can probably set the value in
> a .cshrc file or equivalent. I'd have to look for the
> proper resource (perhaps Idl_retain?).
Yep.
Idl.retain: 2
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| Re: Slow exposure events [message #37574 is a reply to message #37572] |
Fri, 09 January 2004 06:59  |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Nuno Oliveira writes:
> I've seen that IDL doesn't refresh windows. If I have an application and
> simply minimize e get the window again the image on the window is lost. This
> is particularly annoying when you have a window (made by widget draw) that
> has a size greater then the window you have defined and you use a scroll
> bar. When you go down on your image you don't see anything at all. This can
> be avoided by using the keyword EXPOSURE EVENTS on the widget draw. But this
> makes the application slower.
>
> Two questions:
>
> This happens only in the Unix operating system? (I work with both Window and
> Unix and this, as far as I've seen, doesn't happen in Windows) Anyone knows
> why?
>
> Is there any solution that not the keyword EXPOSURE EVENTS?
What you are talking about, repairing window damage, is called
"backing store". By default, IDL asks the window manager to
handle this technical detail. The window manager doesn't have
to, although almost all of them do. (And probably all of them
can be configured to, although I don't know the details.)
In any case, if yours doesn't, you can ask IDL to keep track
of the backing store for you. To do it for *all* graphics
windows, type this:
Device, Retain=2
To do it for a *particular* window, do this:
Window, 3, Retain=2
This will keep you from having to deal with Expose_Events.
Cheers,
David
P.S. This is best down in your IDL startup file if you do
it for all windows, or you can probably set the value in
a .cshrc file or equivalent. I'd have to look for the
proper resource (perhaps Idl_retain?).
--
David W. Fanning, Ph.D.
Fanning Software Consulting, Inc.
Phone: 970-221-0438, E-mail: david@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155
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