code: private static int computeE1(int a, int b, int c, int d, int e, int f)
      {
          if (d == b && e != c || b == f && e != a)
          {
              return b;
          }
          return e;
      }
docs: Compute E1 pixel.
  
  @param a The a value.
  @param b The b value.
  @param c The c value.
  @param d The d value.
  @param e The e value.
  @param f The f value.
  @return The computed value.