how to make window transparent

hi

i want to know how to make windows transparent . and whatever the text scrolling in that window it appear like only text scrolling.window should not appear. i tried with WS_EX_TRANSPARENT,but it is not working the way i want ,is their any other way to do.please help me out to do this.

 

Just having the property will not help and you need to handle the WM_PAINT to do the transparent drawing.

 

You can have the Dialog as OWNER_DRAW and handle the OnDraw.

 

Oops. Just did not read your one.

 

can you please explain what i have to do in WM_PAINT.

 

I will try. You need to paint the Dialog in such a manner that it becomes transparent by using the API's like TransparentBlt

 

Maybe I do not know what you are talking about exactly...
But check out the results of this snippet on Windows NT (or XP)

Code:

int translevel = 100;  /* 0 - 255 */
          SetWindowLong(hwnd,GWL_EXSTYLE,GetWindowLong(h,GWL_EXSTYLE)|WS_EX_LAYERED);
SetLayeredWindowAttributes(hwnd,RGB(0,0,0),translevel, 0x02);

 

thanks for the help,i tried the above code but it is giving error like this:
error C2065: 'SetLayeredWindowAttributes' : undeclared identifier
error C2065: 'WS_EX_LAYERED' : undeclared identifier.
i included both winuser.h and windows.h.
how to come out of this error.

 

ummm.... ummm... let me think....
When I say that it only works in windows NT or later, I mean it -- it won't work in win9x
In the Dev-cpp developing environment, there are certain #define s that you have to put before you #include <windows.h> . For example I would have to put #define _WIN32_WINNT 0x500 before i include. It is definitely supposed to be in the winuser header... hmmm... See, I don't know much about VC so I don't know how it handles those defines like that.
The only thing I can come up with that could possible help is to tell you this.
Open up winuser.h
Search for SetLayeredWindowAttributes
If you find it, find out what #ifdef s are preventing it from being defined
If you don't find it, add it in. The declaration should look like this

WINUSERAPI BOOL WINAPI SetLayeredWindowAttributes(HWND,COLORREF,BYTE,DWORD);

And the same thing for WS_EX_LAYERED\
if you can't find it -- add it in

#define WS_EX_LAYERED 0x80000


Hope this helps

 

Thanks for help.i followed what u said,like i searched for setLayeredWindowAttributes in winuser.h that function was not their.
just i added the code in winuser.h like this
typedef BOOL (CALLBACK* SetLayeredWindowAttributes)(HWND,COLORREF,BYTE,DWORD);
and executed my program.then i got the error like this error C2564: 'int (__stdcall *)(struct HWND__ *,unsigned long,unsigned char,unsigned long)' : function-style conversion to builtin type takes only one argument
Error executing cl.exe.
i think it is the problem with the declaration of the function in winuser.h.
can you please tell me how to come out of this error.

 

Well... I really meant for you to copy the declaration letter for letter.

So at the bottom of winuser.h COPY AND PASTE this

Code:

#define WS_EX_LAYERED 0x80000
BOOL WINAPI SetLayeredWindowAttributes(HWND,COLORREF,BYTE,DWORD);

-------------------------------
I'm pretty sure that this will NOT work, and the error you get is concurrent.
"typedef BOOL (CALLBACK* SetLayeredWindowAttributes)(HWND,COLORREF,BYTE,DWORD);"

Sorry for any misunderstanding