Method circle

lib/matplotlib/path.py:860–925

Return a `Path` representing a circle of a given radius and center. Parameters ---------- center : (float, float), default: (0, 0) The center of the circle. radius : float, default: 1 The radius of the circle. readonly : bool

(cls, center=(0., 0.), radius=1., readonly=False)

    @classmethod
    def circle(cls, center=(0., 0.), radius=1., readonly=False):
        """
        Return a `Path` representing a circle of a given radius and center.

        Parameters
        ----------
        center : (float, float), default: (0, 0)
            The center of the circle.
        radius : float, default: 1
            The radius of the circle.
        readonly : bool
            Whether the created path should have the "readonly" argument
            set when creating the Path instance.

        Notes
        -----
        The circle is approximated using 8 cubic Bézier curves, as described in

          Lancaster, Don.  `Approximating a Circle or an Ellipse Using Four
          Bezier Cubic Splines <https://www.tinaja.com/glib/ellipse4.pdf>`_.
        """
        MAGIC = 0.2652031
        SQRTHALF = np.sqrt(0.5)
        MAGIC45 = SQRTHALF * MAGIC

        vertices = np.array([[0.0, -1.0],

                             [MAGIC, -1.0],
                             [SQRTHALF-MAGIC45, -SQRTHALF-MAGIC45],
                             [SQRTHALF, -SQRTHALF],

                             [SQRTHALF+MAGIC45, -SQRTHALF+MAGIC45],
                             [1.0, -MAGIC],
                             [1.0, 0.0],

                             [1.0, MAGIC],
                             [SQRTHALF+MAGIC45, SQRTHALF-MAGIC45],
                             [SQRTHALF, SQRTHALF],

                             [SQRTHALF-MAGIC45, SQRTHALF+MAGIC45],
                             [MAGIC, 1.0],
                             [0.0, 1.0],

                             [-MAGIC, 1.0],
                             [-SQRTHALF+MAGIC45, SQRTHALF+MAGIC45],
                             [-SQRTHALF, SQRTHALF],

                             [-SQRTHALF-MAGIC45, SQRTHALF-MAGIC45],
                             [-1.0, MAGIC],
                             [-1.0, 0.0],

                             [-1.0, -MAGIC],
                             [-SQRTHALF-MAGIC45, -SQRTHALF+MAGIC45],
                             [-SQRTHALF, -SQRTHALF],

                             [-SQRTHALF+MAGIC45, -SQRTHALF-MAGIC45],
                             [-MAGIC, -1.0],
                             [0.0, -1.0],