I have this one problem I just can't solve. I'm trying to make a window from my application that is transparent (using flags WS_EX_TRANSPARENT | WS_EX_LAYERED) a child to another window, which is not transparent.

When I don't use the call SetParent( my_window, target_parent_window ) with my_window having the WS_EX_LAYERED flag, the new child window won't be visible.

I found out that a manifest entry could help me, since having a child window with flag WS_EX_LAYERED is supported since Windows 8. I tried it without any success.

::SetWindowLongW( process_window, GWL_STYLE, WS_CLIPSIBLINGS | WS_POPUP | WS_VISIBLE );
::SetWindowLongW( process_window, GWL_EXSTYLE, WS_EX_TRANSPARENT | WS_EX_LAYERED | WS_EX_NOACTIVATE | WS_EX_TOOLWINDOW );

::SetWindowPos( process_window, HWND_TOP, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE );
::ShowWindow( process_window, SW_SHOW );

::SetParent( process_window, new_parent_window); // if i skip this call the window will render perfectly

CodePudding user response：

https://docs.microsoft.com/en-us/windows/win32/winmsg/window-features

To create a layered window, specify the WS_EX_LAYERED extended window style when calling the CreateWindowEx function, or call the SetWindowLong function to set WS_EX_LAYERED after the window has been created. After the CreateWindowEx call, the layered window will not become visible until the SetLayeredWindowAttributes or UpdateLayeredWindow function has been called for this window.