Example script to show a bug in pick_event

pick_event_bug.py

"""
Clicking the indicated point on the left-hand side causes the indicated point on the top right to
be highlighted.  Adding 0.1 to the x-value of the left-hand side one seems to alleviate this 
problem -- but not adding 0.01.
"""

import numpy as np
import matplotlib.pyplot as plt

x = np.array([-0.58178965, 
              2.83321334,
              -1.37832619,
              -1.32175584,
              -0.50806319,
              0.40546511,
              0.69314718,
              -1.78294884,
              -0.98390334,
              -0.79728744])
y = np.array([0.10775286,
              0.,
              -0.22789415,
              -0.37623547,
              -0.52806743,
              0.94979714,
              1.25276297, 
              0.10668414,
              -0.03905051, 
              0.5389965 ])

# x[9] += 0.1    # fixes the bug
# x[9] += 0.01   # does not fix the bug

def callback(event):
    print list(event.ind)
    ax = event.artist.axes
    ax.plot(x[event.ind],y[event.ind],'bo')
    plt.draw()

fig = plt.figure()
ax = fig.add_subplot(111)
ax.plot(x,y,marker='o',color='k',alpha=0.2,linestyle='none',picker=5)
ax.text(x[9],y[9],'click this point...', fontsize=10)
ax.text(x[6],y[6],'...and often this one gets highlighted, too', fontsize=10)
fig.canvas.mpl_connect('pick_event', callback)
plt.show()