1, InvaliDateRectthe InvaliDateRect Function Adds a Rectangle To The Specified WINDOW'S Update Region. The Update Region REPRESENTS The Portion of The Window's Client Area That Must Be RedRawn.
Bool InvalidateRect (HWND HWND, // Handle of Window with Changed Update Region Const);
2, InvalidateRgnThe InvalidateRgn function invalidates the client area within the specified region by adding it to the current update region of a window. The invalidated region, along with all other areas in the update region, is marked for painting when the next WM_PAINT message occurs.
Bool Invalidatergn (HWnd Hwnd, // Handle of Window with Changed Update Region HRGN HRGN, // Handle of Region To Add Bool BoRase // Erase-Background Flag)
