> # To subscribers of the xforms list from "Andrew V. Messier" <amess@WPI.EDU> :
> My problem is this: In my GUI I have a topographical map which is
> created by reading data from a 10 meg USGS elevation file, and
> simply painting the appropriate pixel color on the screen. The
> problem is that now when I move something like an image of an
> aircraft over the map, the pixels of the map are obviously erased.
> Also, the scope of the map is slighlty larger than the area of
> the map that is viewable in my GUI. I think If I read the data
> into a pixmap first, and then show the pixmap I can keep track
> of the pixels that the plane is over and redraw them, and also
> have a scrollable view area. However, I'm not sure how to do it.
> Any help in pointing me in the right direction to learn about
> creating a pixmap on the fly, and doing things like scrollbars
> would be greatly appricieted.
How about using Xor drawing mode - draw the a/c twice to make it disappear.
Dick
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Dick Middleton
Phone: +44 131-331 7530
Fax: +44 131-331 7443 ( )
email: dick@sqf.hp.com ( )
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- I'd rather be soaring
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