uses SDL;
procedure SDL_UpdateRect( screen : PSDL_Surface; x, y: SInt32; w, h: UInt32 );
Makes sure the given area is updated on the given screen.
If 'x', 'y ', 'w' and 'h ' are all 0, SDL_UpdateRect will update the entire screen.
This function should not be called while 'screen ' is locked.
SDL_UpdateRects , TSDL_Rect, TSDL_Surface , SDL_LockSurface