python+matplotlib实现鼠标移动三角形高亮及索引显示

import matplotlib.pyplot as pltfrom matplotlib.tri import Triangulationfrom matplotlib.patches import Polygonimport numpy as npdef update_polygon(tri):  if tri == -1:    points = [0, 0, 0]  else:    points = triang.triangles[tri]  xs = triang.x[points]  ys = triang.y[points]  polygon.set_xy(list(zip(xs, ys)))def motion_notify(event):  if event.inaxes is None:    tri = -1  else:    tri = trifinder(event.xdata, event.ydata)  update_polygon(tri)  plt.title('In triangle %i' % tri)  event.canvas.draw()# Create a Triangulation.n_angles = 16n_radii = 5min_radius = 0.25radii = np.linspace(min_radius, 0.95, n_radii)angles = np.linspace(0, 2 * np.pi, n_angles, endpoint=False)angles = np.repeat(angles[..., np.newaxis], n_radii, axis=1)angles[:, 1::2] += np.pi / n_anglesx = (radii*np.cos(angles)).flatten()y = (radii*np.sin(angles)).flatten()triang = Triangulation(x, y)triang.set_mask(np.hypot(x[triang.triangles].mean(axis=1),             y[triang.triangles].mean(axis=1))        < min_radius)# Use the triangulation's default TriFinder object.trifinder = triang.get_trifinder()# Setup plot and callbacks.plt.subplot(111, aspect='equal')plt.triplot(triang, 'bo-')polygon = Polygon([[0, 0], [0, 0]], facecolor='y') # dummy data for xs,ysupdate_polygon(-1)plt.gca().add_patch(polygon)plt.gcf().canvas.mpl_connect('motion_notify_event', motion_notify)plt.show()