canvas.mpl_connect in jupyter notebook

Question

I have the following code in test.py:

fig = plt.figure()
ax = fig.add_subplot(111)
ax.plot(np.random.rand(10))

def onclick(event):
    print('button=%d, x=%d, y=%d, xdata=%f, ydata=%f' %
          (event.button, event.x, event.y, event.xdata, event.ydata))

cid = fig.canvas.mpl_connect('button_press_event', onclick)

when i run test.py in the command line by "python test.py", 'button=%d, x=%d, y=%d, xdata=%f, ydata=%f' gets printed as i click the plot

however, the results are not printed in jupyter notebook.

how to fix it?

thanks in advance!

Answer 1

It will depend which backend you use in jupyter notebook.

• If you use the inline backend (i.e. %matplotlib inline), interactive features cannot work, because the plots are just png images.

• If you use the notebook backend (i.e. %matplotlib notebook) the interactive features do work, but the question would be where to print the result to. So in order to show the text one may add it to the figure as follows

  %matplotlib notebook
  import numpy as np
  import matplotlib.pyplot as plt
  fig = plt.figure()
  ax = fig.add_subplot(111)
  ax.plot(np.random.rand(10))
  text=ax.text(0,0, "", va="bottom", ha="left")
  
  def onclick(event):
      tx = 'button=%d, x=%d, y=%d, xdata=%f, ydata=%f' % (event.button, event.x, event.y, event.xdata, event.ydata)
      text.set_text(tx)
  
  cid = fig.canvas.mpl_connect('button_press_event', onclick)