当然，您需要将功能添加到中PolygonInteractor。但是不要让它自己绘制任何东西。然后在类中添加新行，self.line2这将是要更新的行。

最后，让全班同学也为您画一条新线。并使用插值函数的结果更新它。

为了方便起见，您可以将“多边形（self.poly）”设置为不可见，也可以从中删除该线，self.line并且仅显示点可能有意义。

import numpy as np
from  scipy.interpolate import interp1d
from matplotlib.lines import Line2D
from matplotlib.artist import Artist
from matplotlib.mlab import dist_point_to_segment


class PolygonInteractor(object):

    """
    A polygon editor.
    https://matplotlib.org/gallery/event_handling/poly_editor.html

    Key-bindings

      't' toggle vertex markers on and off.  When vertex markers are on,
          you can move them, delete them

      'd' delete the vertex under point

      'i' insert a vertex at point.  You must be within epsilon of the
          line connecting two existing vertices

    """

    showverts = True
    epsilon = 5  # max pixel distance to count as a vertex hit

    def __init__(self, ax, poly, visible=False):
        if poly.figure is None:
            raise RuntimeError('You must first add the polygon to a figure '
                               'or canvas before defining the interactor')
        self.ax = ax
        canvas = poly.figure.canvas
        self.poly = poly
        self.poly.set_visible(visible)

        x, y = zip(*self.poly.xy)
        self.line = Line2D(x, y, ls="",
                           marker='o', markerfacecolor='r',
                           animated=True)
        self.ax.add_line(self.line)

        self.cid = self.poly.add_callback(self.poly_changed)
        self._ind = None  # the active vert

        canvas.mpl_connect('draw_event', self.draw_callback)
        canvas.mpl_connect('button_press_event', self.button_press_callback)
        canvas.mpl_connect('key_press_event', self.key_press_callback)
        canvas.mpl_connect('button_release_event', self.button_release_callback)
        canvas.mpl_connect('motion_notify_event', self.motion_notify_callback)
        self.canvas = canvas

        x,y = self.interpolate()
        self.line2 = Line2D(x, y, animated=True)
        self.ax.add_line(self.line2)

    def interpolate(self):
        x, y = self.poly.xy[:].T
        i = np.arange(len(x))

        interp_i = np.linspace(0, i.max(), 100 * i.max())

        xi = interp1d(i, x, kind='cubic')(interp_i)  
        yi = interp1d(i, y, kind='cubic')(interp_i)

        return xi,yi

    def draw_callback(self, event):
        self.background = self.canvas.copy_from_bbox(self.ax.bbox)
        self.ax.draw_artist(self.poly)
        self.ax.draw_artist(self.line)
        self.ax.draw_artist(self.line2)
        # do not need to blit here, this will fire before the screen is
        # updated

    def poly_changed(self, poly):
        'this method is called whenever the polygon object is called'
        # only copy the artist props to the line (except visibility)
        vis = self.line.get_visible()
        Artist.update_from(self.line, poly)
        self.line.set_visible(vis)  # don't use the poly visibility state


    def get_ind_under_point(self, event):
        'get the index of the vertex under point if within epsilon tolerance'

        # display coords
        xy = np.asarray(self.poly.xy)
        xyt = self.poly.get_transform().transform(xy)
        xt, yt = xyt[:, 0], xyt[:, 1]
        d = np.hypot(xt - event.x, yt - event.y)
        indseq, = np.nonzero(d == d.min())
        ind = indseq[0]

        if d[ind] >= self.epsilon:
            ind = None

        return ind

    def button_press_callback(self, event):
        'whenever a mouse button is pressed'
        if not self.showverts:
            return
        if event.inaxes is None:
            return
        if event.button != 1:
            return
        self._ind = self.get_ind_under_point(event)

    def button_release_callback(self, event):
        'whenever a mouse button is released'
        if not self.showverts:
            return
        if event.button != 1:
            return
        self._ind = None

    def key_press_callback(self, event):
        'whenever a key is pressed'
        if not event.inaxes:
            return
        if event.key == 't':
            self.showverts = not self.showverts
            self.line.set_visible(self.showverts)
            if not self.showverts:
                self._ind = None
        elif event.key == 'd':
            ind = self.get_ind_under_point(event)
            if ind is not None:
                self.poly.xy = np.delete(self.poly.xy,
                                         ind, axis=0)
                self.line.set_data(zip(*self.poly.xy))
        elif event.key == 'i':
            xys = self.poly.get_transform().transform(self.poly.xy)
            p = event.x, event.y  # display coords
            for i in range(len(xys) - 1):
                s0 = xys[i]
                s1 = xys[i + 1]
                d = dist_point_to_segment(p, s0, s1)
                if d <= self.epsilon:
                    self.poly.xy = np.insert(
                        self.poly.xy, i+1,
                        [event.xdata, event.ydata],
                        axis=0)
                    self.line.set_data(zip(*self.poly.xy))
                    break
        if self.line.stale:
            self.canvas.draw_idle()

    def motion_notify_callback(self, event):
        'on mouse movement'
        if not self.showverts:
            return
        if self._ind is None:
            return
        if event.inaxes is None:
            return
        if event.button != 1:
            return
        x, y = event.xdata, event.ydata

        self.poly.xy[self._ind] = x, y
        if self._ind == 0:
            self.poly.xy[-1] = x, y
        elif self._ind == len(self.poly.xy) - 1:
            self.poly.xy[0] = x, y
        self.line.set_data(zip(*self.poly.xy))

        x,y = self.interpolate()
        self.line2.set_data(x,y)

        self.canvas.restore_region(self.background)
        self.ax.draw_artist(self.poly)
        self.ax.draw_artist(self.line)
        self.ax.draw_artist(self.line2)
        self.canvas.blit(self.ax.bbox)


if __name__ == '__main__':
    import matplotlib.pyplot as plt
    from matplotlib.patches import Polygon

    #theta = np.arange(0, 2*np.pi, 0.1)
    #r = 1.5

    #xs = r*np.cos(theta)
    #ys = r*np.sin(theta)
    xs = (921, 951, 993, 1035, 1065, 1045, 993, 945)
    ys = (1181, 1230, 1243, 1230, 1181, 1130, 1130, 1130)

    poly = Polygon(list(zip(xs, ys)), animated=True)

    fig, ax = plt.subplots()
    ax.add_patch(poly)
    p = PolygonInteractor(ax, poly, visible=False)

    ax.set_title('Click and drag a point to move it')

    ax.set_xlim((800, 1300))
    ax.set_ylim((1000, 1300))

    plt.show()

请注意，此处创建的曲线不是真正的循环。它有一个起点，曲线并不真正平滑。