python+matplotlib实现鼠标移动三角形高亮及索引显示

import matplotlib.pyplot as plt
from matplotlib.tri import Triangulation
from matplotlib.patches import Polygon
import numpy as np


def update_polygon(tri):
  if tri == -1:
    points = [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 = 16
n_radii = 5
min_radius = 0.25
radii = 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_angles
x = (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,ys
update_polygon(-1)
plt.gca().add_patch(polygon)
plt.gcf().canvas.mpl_connect('motion_notify_event',motion_notify)
plt.show()