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From: fiversen on 2 May 2008 10:41
Hallo,

I have a problem with a transparent window.

My message windows are simple CWnd-Windows, whitch are hide.

Only,
if I want to see the window,
I bring them into front with
'bringWindowToTop()'.

Problem:
I want to give the window a transparent border
( later I want to display a transparent bitmap ).

So I have a
- CtrlColor-Func
it returns NULLBRUSH

- OnEraseBkgnd-Func
first I paint the full area with NULLBRUSH
FillRect(..)
then I reduce the Rect
r.left += 20
r.right -= 20
and fill the small area with a color.

- No OnPaint-Func

But the window is grey.

I have already solutions with transparent Buttons and MarqueeText.
But I hope, only to display a window with transparent background is a
little bit easier.

--
Thanks
Frank Iversen


From: David Ching on 2 May 2008 17:25
"fiversen" <fiversen(a)wedding.in-berlin.de> wrote in message
news:5dbfc1ef-7c4c-48b5-b970-7f229b7f270d(a)c65g2000hsa.googlegroups.com...
> Hallo,
>
> I have a problem with a transparent window.
>
> My message windows are simple CWnd-Windows, whitch are hide.
>
> Only,
> if I want to see the window,
> I bring them into front with
> 'bringWindowToTop()'.
>
> Problem:
> I want to give the window a transparent border
> ( later I want to display a transparent bitmap ).
>
> So I have a
> - CtrlColor-Func
> it returns NULLBRUSH
>
> - OnEraseBkgnd-Func
> first I paint the full area with NULLBRUSH
> FillRect(..)
> then I reduce the Rect
> r.left += 20
> r.right -= 20
> and fill the small area with a color.
>
> - No OnPaint-Func
>
> But the window is grey.
>
> I have already solutions with transparent Buttons and MarqueeText.
> But I hope, only to display a window with transparent background is a
> little bit easier.
>

If this is not a child window, then for transparency, I would make it a
WS_EX_LAYERED_WINDOW. Only with layered windows and Windows regions can you
truly achieve transparency.

Painting with a null brush has no effect at all. As for why the window is
gray, are you by chance calling the inherited OnEraseBkgnd()?

-- David


From: fiversen on 5 May 2008 03:53
Hello David,

> > I have a problem with a transparent window.
> >
> > Problem:
> > I want to give the window a transparent border
> > ( later I want to display a transparent bitmap ).


> If this is not a child window, then for transparency, I would make it a
> WS_EX_LAYERED_WINDOW. Only with layered windows and Windows regions can you
> truly achieve transparency.
>
> Painting with a null brush has no effect at all. As for why the window is
> gray, are you by chance calling the inherited OnEraseBkgnd()?

So,
to make a window transparent is a complicate thing to do !

In my
- CStatic, with CtlColor, NULLBRUSH .. I was successfull
- CButton, I need a background-bitmap
- CMarqueeText, I need a background-bitmap

I try
- CWnd, with a background-bitmap

WS_EX_LAYERED I cannot use, because the programms runs also on WinNT
computer.

Thanks.
---
Frank Iversen
From: David Ching on 5 May 2008 10:34
"fiversen" <fiversen(a)wedding.in-berlin.de> wrote in message
news:9dc5535a-3ec2-45c4-8299-5eb287f0b953(a)k13g2000hse.googlegroups.com...
> So,
> to make a window transparent is a complicate thing to do !
>
> In my
> - CStatic, with CtlColor, NULLBRUSH .. I was successfull
> - CButton, I need a background-bitmap
> - CMarqueeText, I need a background-bitmap
>
> I try
> - CWnd, with a background-bitmap
>
> WS_EX_LAYERED I cannot use, because the programms runs also on WinNT
> computer.
>

Oh, these kind of windows are typically WS_CHILD windows, so you don't use
WS_EX_LAYERED with these anyway. With CButton, I would override
WM_ERASEBKGND and draw the bitmap. Same with CMarqueeText.

-- David


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