code: public static final boolean areAligned(double ox, double oy, double x1, double y1, double x2, double y2)
      {
          return areAligned(x1-ox, y1-oy, x2-ox, y2-oy);
      }
docs: Returns true if vectors (x1, y1) and (x2, y2) are aligned (ox, oy) centered
  coordinate.
  @param ox
  @param oy
  @param x1
  @param y1
  @param x2
  @param y2
  @return