code: private static TransitionType getTransition(TransitionType a, TransitionType b, int ox, int oy)
      {
          final TransitionType type = getTransitionHorizontalVertical(a, b, ox, oy);
          if (type != null)
          {
              return type;
          }
          return getTransitionDiagonals(a, b, ox, oy);
      }
docs: Get the new transition type from two transitions.
  
  @param a The inner transition.
  @param b The outer transition.
  @param ox The horizontal offset to update.
  @param oy The vertical offset to update.
  @return The new transition type, <code>null</code> if none.