Click above to get retro games delivered to your door ever month!

void pascal WinScreenRectToClient(HWND hWnd, LPRECT lpRect)

  This function transforms a set of rectangular coordinates expressed
in screen coordinates into a corresponding rectangle expressed in
client coordinates. The client coordinates are relative to the
upper-left corner of a window's client area, and the screen
coordinates are relative to the upper-left corner of the screen.

Parameters
  hWnd is the handle of the window whose client rectangle we should use.
  lpRect contains the screen coordinates. After this function is done,
   it will contain the client coordinates.

Returns
  Nothing.