seethru client area   

hi,

I want to create a window where you can "see-thru" it,i.e the contents
of the window below it should be visible.
How can I do this?

Regards
Chimanrao

date: Sun, 30 Mar 2008 20:40:06 -0700 (PDT)   author:   Chimanrao

Re: seethru client area   

On Mar 30, 8:40 pm, Chimanrao  wrote:
> hi,
>
> I want to create a window where you can "see-thru" it,i.e the contents
> of the window below it should be visible.
> How can I do this?
>
> Regards
> Chimanrao


Hi,

Well... you can achieve certain kinds of transparency by using
alpha blending, which is part of GDI and GDI. So, you can use
the following APIs to accomplish that:

	CreateWindowEx()		WS_EX_TRANSPARENT

	UpdateLayeredWindow()

	SetLayeredWindowAttributes()

	SetWindowRgn()

	SetBkMode()		TRANSPARENT

	AlphaBlend()

	TransparentBlt()

http://msdn2.microsoft.com/en-us/library/ms632680.aspx

http://msdn2.microsoft.com/en-us/library/ms633556.aspx

http://msdn2.microsoft.com/en-us/library/ms633540.aspx

http://msdn2.microsoft.com/en-us/library/ms534845.aspx

http://msdn2.microsoft.com/en-us/library/ms534862.aspx

http://msdn2.microsoft.com/en-us/library/ms532324.aspx

http://msdn2.microsoft.com/en-us/library/ms532303.aspx

Kellie.

date: Mon, 31 Mar 2008 08:04:29 -0700 (PDT)   author:   Kellie Fitton

Re: seethru client area   

"Chimanrao"  wrote in message 
news:270e398a-a73b-4c7f-9b26-fae3886e2630@i29g2000prf.googlegroups.com...
> hi,
>
> I want to create a window where you can "see-thru" it,i.e the contents
> of the window below it should be visible.
> How can I do this?


If your window class responds to the WM_ERASEBKGND message and does nothing
in response except return a non-zero value, then the window's client area
will be "transparent".

Mark

-- 
Mark Salsbery
Microsoft MVP - Visual C++




>
> Regards
> Chimanrao

date: Mon, 31 Mar 2008 13:42:30 -0700   author:   Mark Salsbery [MVP] MarkSalsbery[MVP]@newsgroup.nospam

Re: seethru client area   

"Chimanrao"  wrote in message 
news:270e398a-a73b-4c7f-9b26-fae3886e2630@i29g2000prf.googlegroups.com...
> hi,
>
> I want to create a window where you can "see-thru" it,i.e the contents
> of the window below it should be visible.
> How can I do this?


If your window class responds to the WM_ERASEBKGND message and does nothing 
in response except return a non-zero value, then the window's client area 
will be "transparent".

Mark

-- 
Mark Salsbery
Microsoft MVP - Visual C++


>
> Regards
> Chimanrao

date: Mon, 31 Mar 2008 11:48:20 -0700   author:   Mark Salsbery [MVP] MarkSalsbery[MVP]@newsgroup.nospam

Re: seethru client area   

On Mar 31, 8:04 pm, Kellie Fitton  wrote:
> On Mar 30, 8:40 pm, Chimanrao  wrote:
>
> > hi,
>
> > I want to create a window where you can "see-thru" it,i.e the contents
> > of the window below it should be visible.
> > How can I do this?
>
> > Regards
> > Chimanrao
>
> Hi,
>
> Well... you can achieve certain kinds of transparency by using
> alpha blending, which is part of GDI and GDI. So, you can use
> the following APIs to accomplish that:
>
>         CreateWindowEx()                WS_EX_TRANSPARENT
>
>         UpdateLayeredWindow()
>
>         SetLayeredWindowAttributes()
>
>         SetWindowRgn()
>
>         SetBkMode()             TRANSPARENT
>
>         AlphaBlend()
>
>         TransparentBlt()
>
> http://msdn2.microsoft.com/en-us/library/ms632680.aspx
>
> http://msdn2.microsoft.com/en-us/library/ms633556.aspx
>
> http://msdn2.microsoft.com/en-us/library/ms633540.aspx
>
> http://msdn2.microsoft.com/en-us/library/ms534845.aspx
>
> http://msdn2.microsoft.com/en-us/library/ms534862.aspx
>
> http://msdn2.microsoft.com/en-us/library/ms532324.aspx
>
> http://msdn2.microsoft.com/en-us/library/ms532303.aspx
>
> Kellie.

I did use WS_EX_TRANSPARENT style, with this the window see-thru, i.e
I can see the contents of the window below it.
But I dont get paint messages till the window below my window updates.
MSDN says that this style should nto be used for top level windows.
With Layered Windows the entire window blends into the background, I
want to make the lower window visisble thru the client area.

Chimanrao

date: Mon, 31 Mar 2008 20:01:11 -0700 (PDT)   author:   Chimanrao