| Re: Expose events [message #17078] |
Tue, 14 September 1999 00:00 |
davidf
Messages: 2866
Registered: September 1996
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Senior Member |
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Phil Aldis (philaldis@geocities.com) writes:
> I've been having some trouble with expose events. I'm writing this
> object/direct graphics window which automatically protects its colours
> when the computer is running in 8 bit mode. So rather than having to
> redraw the objects each time I get an expose event, I thought it would
> be better to employ a pixmap. So I draw into the pixmap and then copy
> to the screen,. Everytime a refresh is required I Device, COPY to teh
> window form the pixmap. However for some reason as soon as the program
> finishes, i.e. after it finishes the first initial drawing, the window
> wipes itself blank for no reason. Then the further device, copies
> whenever there are expose events don't do anything. I have played
> around and it seems that when expose events are on (and so retain is =
> 0) the device copy is a very dubious beast.
Well, this surprises me a bit. And if it were anyone but
you, Phil, I would suspect pilot error. I'll have to give
this a try, but I can't today. Thank God I can write
an IDL program in five minutes and charge for an hour
or I wouldn't ever make any money. :^)
> Also, I find that if someone resizes a window, the I get about 15 secs
> of non-stop resize events which is stupid. Does anyone know why there
> are so many?
You have Show Window Contents While Dragging turned on. Turn it
off by going to Properties->Plus+ on your desktop.
> I'd appreciate any suggestions, as I'd prefer not to have to end up
> just redrawing evrything every time.
Why not? Surely this code is lickitty-split. :-)
Cheers,
David
--
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
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