When you move a Win32 application window over a DirectX application in Visual C++ .NET, the images in the window flash (899290)



The information in this article applies to:

  • Microsoft Visual C++ .NET (2003)
  • Microsoft Visual C++ .NET (2002)

SYMPTOMS

When you move a Win32 application window over a Microsoft DirectX application in Microsoft Visual C++ .NET, the images in the window flash.

CAUSE

This behavior may occur when all the following conditions are true:
  • You create the window by using the CreateWindowEx function, and the dwExStyle parameter is set to WS_EX_LAYERED.
  • The Win32 application calls the SetLayeredWindowAttributes function to set the opacity and transparency color key of the window.

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

MORE INFORMATION

Steps to reproduce the behavior

  1. Create a Visual C++ Win32 project in Microsoft Visual Studio .NET.
  2. Create a main window by using the CreateWindowEx function. Set the dwExStyle parameter to WS_EX_LAYERED.
  3. Call the SetLayeredWindowAttributes function. The code is similar to the following.
    BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
    {
    	HWND hWnd;
    	hInst = hInstance; // Store instance handle in our global variable
    	hWnd = CreateWindowEx(
    				WS_EX_LAYERED, // extended window style
    				szWindowClass, // registered class name
    				szTitle, // window name
    				WS_OVERLAPPEDWINDOW, // window style
    				CW_USEDEFAULT, // horizontal position of window
    				0, // vertical position of window
    				CW_USEDEFAULT, // window width
    				0, // window height
    				NULL, // handle to parent or owner window
    				NULL, // menu handle or child identifier
    				hInstance, // handle to application instance
    				NULL // window-creation data
    			);
    	if (!hWnd)
    	{
    	return FALSE;
    	}
    	SetLayeredWindowAttributes(hWnd,0,128,LWA_ALPHA);
    	ShowWindow(hWnd, nCmdShow);
    	UpdateWindow(hWnd);
    	return TRUE;
    }
    
  4. On a computer that is running Microsoft Windows 2000 or Microsoft Windows XP, run the application that you created, and then run a DirectX application.
  5. Move the window that you created in step 2 over the DirectX application. The images in the window flash.

    Note This behavior does not occur when you run Graphics Device Interface (GDI) applications that repeatedly paint images in procedures.

Modification Type:MajorLast Reviewed:9/23/2005
Keywords:kbprb kbcode kbtshoot KB899290 kbAudDeveloper