public static extern bool ClientToScreen(IntPtr hWnd, ref POINTAPI pt);
public static extern bool ScreenToClient(IntPtr hWnd, ref POINTAPI point);
public static extern bool UpdateLayeredWindow(IntPtr hwnd, IntPtr hdcDst, ref POINTAPI pptDst, ref SIZE psize, IntPtr hdcSrc, ref POINTAPI pprSrc, Int32 crKey, ref BLENDFUNCTION pblend, UpdateLayeredWindowFlags dwFlags);