Re: How to draw Shapes with solid color, which is transparent?

From:
"David Ching" <dc@remove-this.dcsoft.com>
Newsgroups:
microsoft.public.vc.mfc
Date:
Thu, 29 Mar 2007 14:45:12 GMT
Message-ID:
<YhQOh.3834$u03.715@newssvr21.news.prodigy.net>
"Soney" <Soney@discussions.microsoft.com> wrote in message
news:8E160441-C400-4CDE-AD66-770F1CFDBC69@microsoft.com...

How can i make the shape( Rectangle, Circle, Elipse...) backround as
transparent.
I am using the VC++6, MFC, GDI

Sample code:-

CBrush *pShadingBrush = new CBrush;
pShadingBrush->CreateSolidBrush( RGB( 255, 0, 0 ) );
pDC->SelectObject( pShadingBrush );
pDC->SetBkMode(TRANSPARENT);
pDC->FillRect( &Rect, pShadingBrush );

Using the above code, I am not able to see the bitmap area which is
occupied
by the shape, because the shape is filled with the solid red color but it
is
not transparent. Please advise using windows GDI is it possible or not?


The SetBkMode(TRANSPARENT) does not affect FillRect. You could try not
calling FillRect() which will leave the inside of your shape untouched and
whatever it is drawn on will shine through. But make sure every pixel of
your window is painted with SOMETHING, or else Windows will leave the
contents of the previous window in the unpainted spot when you uncover your
window.

-- David

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