🚀 go-pugleaf

In article <724545535snz@chrism.demon.co.uk>, chris@chrism.demon.co.uk (Chris Marriott) writes:
|> Are you selecting the old clip region before deleting the one you created?
|> Remember, Windows won't let you delete an object that's currently selected
|> in a DC.

Unlike the other GDI objects, a copy of the region is placed in the DC so
you won't get an error if you delete the region.


|> What you should be doing is:
|> 
|>     ClipRegion = CreateRegion( ..... );
|>     OldRegion = SelectObject( hDC, ClipRegion );
|>     .....
|>     SelectObject( hDC, OldRegion );
|>     DeleteObject( ClipRegion );
|> 
|> That should work OK.

Nope -- in a fit of perversity someone at Microsoft decided that for
regions, and regions only, the return value from SelectObject() should
_not_ be the old region, but should be a value indicating what type
of region is being installed.

You must (as far as I know) use SaveDC/RestoreDC around your own
clipping code in order to ensure that the old region is restored, unless
you know (by virtue of initializing a default DC) what region to put
back in the DC.


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Tom Brown               |  "She turned me into a newt...
PE Nelson Systems       |                                  ... I got better"
twbrown@pe-nelson.com   |                    Monty Python and the Holy Grail
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