Transparent Main Panel?

[d.]

Hi,

Does anyone know if this is possible?  I'd ike to make an application that is transparent and runs on top of a 3rd party application.  I would plot data in my application over top of the other app.

Do-able or not?  I've looked around and don't see a way of doing it.

Thanks,

Dave

[Johannes_T]

Hello Dave!

Unfortunately there isn't a direct way of making a LabWindows/CVI panel trasparent, by using a predefined panel attribute.

However, here is a workaround to make your panel transparent, using Win32 API:

1. #include <windows.h> in your source code.
2. Get the window handle (HWND) of the panel, using the ATTR_SYSTEM_WINDOW_HANDLE panel attribute:
   HWND hwnd;
   GetPanelAttribute (panelHandle, ATTR_SYSTEM_WINDOW_HANDLE, &hwnd);
3. Configure windows layering: 
   SetWindowLong ((HWND)hwnd, GWL_EXSTYLE, GetWindowLong((HWND)hwnd, GWL_EXSTYLE) | WS_EX_LAYERED);
4. Enable window transparency (see MSDN😞
   // Set the alpha for transparency: 0 is transparent and 255 is opaque.
   double transparency = 50; // Set transparency to 50%.
   double alpha = transparency * (255.0 / 100);
   SetLayeredWindowAttributes ((HWND)hwnd, 0, alpha, LWA_ALPHA);

Hope this helps!

- Johannes

[d.]

Hi Johannes,

That was exactly what I was looking for.  THANKS!

Just had to change HWND hwnd; to int HWND; in order to get the right variable type for GetPanelAttribute(), which works OK since it's cast to HWND below that.

Thanks again!

Dave