public PlaPointFloat middle_point(PlaPointFloat p_to_point){
  if (p_to_point == this)   return this;
  double middle_x=0.5 * (v_x + p_to_point.v_x);
  double middle_y=0.5 * (v_y + p_to_point.v_y);
  return new PlaPointFloat(middle_x,middle_y);
}

public PlaPointFloat middle_point ( PlaPointFloat p_to_point ) { if ( p_to_point == this ) return this ; double middle_x = 0.5 * ( v_x + p_to_point . v_x ) ; double middle_y = 0.5 * ( v_y + p_to_point . v_y ) ; return new PlaPointFloat ( middle_x , middle_y ) ; }
returns the middle point between this point and p_to_point .
