code: def _lower_left_xy(self):
          
          hw = self.width / 2.
          hh = self.height / 2.
          sint = np.sin(self.angle)
          cost = np.cos(self.angle)
          dx = (hh * sint) - (hw * cost)
          dy = -(hh * cost) - (hw * sint)
          x = self.center.x + dx
          y = self.center.y + dy
          return x, y
docs: Compute lower left `xy` position.
  
          This is used for the conversion to matplotlib in ``as_artist``
  
          Taken from http://photutils.readthedocs.io/en/latest/_modules/photutils/aperture/rectangle.html#RectangularAperture.plot