创建透明窗口

hWnd：窗口句柄；nDegree：透明程度

void TranslateWnd(HWND hWnd, int nDegree)
{
	::SetWindowPos(hWnd, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOSIZE | SWP_NOMOVE);	// TopMost

	DWORD dwStyle = GetWindowLong(hWnd, GWL_EXSTYLE);
	::SetWindowLong(hWnd, GWL_EXSTYLE, dwStyle^WS_EX_LAYERED);

	HINSTANCE hInst = LoadLibrary(_T("User32.DLL"));
	if (hInst)
	{           
		typedef BOOL (WINAPI *MYFUNC)(HWND, COLORREF, BYTE, DWORD);         
		MYFUNC pFun = NULL;
		// 取得SetLayeredWindowAttributes函数指针    
		pFun = (MYFUNC)GetProcAddress(hInst, "SetLayeredWindowAttributes");
		if (pFun) // 128为透明值 
		{
			pFun(hWnd, 0, nDegree, LWA_ALPHA);   
		}
		FreeLibrary(hInst);
	}
}