Clear CWnd Child with png
in [MFC]
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From: Manuel Hoeger on 1 Mar 2010 14:04 Thanks for helping me but I still have some Problems: > You will have to "erase" the original image by writing the transparent > pixels over it. How can I do this??? > What you have done, apparently, works like this. Let T be the transparent > color and other > letters opaque > > Current picture > TTTabcTTT > > New picture > TTTxTwTTT > > Result of OnPaint after current image is replaced with new image and > repainted: > > TTTxbwTTT > That is exactly what I see. > So in this case, you either draw all-transparent or use OnEraseBkgnd to > erase to the > transparent color. Because the color b was overwritten by a transparent > pixel, it remains > in place, because you did nothing to make it go away. > What do you mean with "draw all-transparent"? Manu
From: Joseph M. Newcomer on 2 Mar 2010 09:35 Well, I don't use CImage for much, so I'm not all that familiar with its features. But without knowing how you create the "transparent" window I'm not sure what to look up to see what I'd do to write a completely transparent set of pixels into it. joe On Mon, 1 Mar 2010 20:04:50 +0100, "Manuel Hoeger" <Manuel.Hoeger(a)physik.stud.uni-erlangen.de> wrote: >Thanks for helping me > >but I still have some Problems: > >> You will have to "erase" the original image by writing the transparent >> pixels over it. > > >How can I do this??? > > > >> What you have done, apparently, works like this. Let T be the transparent >> color and other >> letters opaque >> >> Current picture >> TTTabcTTT >> >> New picture >> TTTxTwTTT >> >> Result of OnPaint after current image is replaced with new image and >> repainted: >> >> TTTxbwTTT >> > >That is exactly what I see. > > > >> So in this case, you either draw all-transparent or use OnEraseBkgnd to >> erase to the >> transparent color. Because the color b was overwritten by a transparent >> pixel, it remains >> in place, because you did nothing to make it go away. >> > >What do you mean with "draw all-transparent"? > >Manu > > Joseph M. Newcomer [MVP] email: newcomer(a)flounder.com Web: http://www.flounder.com MVP Tips: http://www.flounder.com/mvp_tips.htm
From: Manuel Hoeger on 3 Mar 2010 13:39
Yes I have an CWnd as Parent which has a Bitmap on it. and if i do fillrect I see a square in this bitmap |