Make interactive matplotlib window not pop to front on each update (Windows 7)

Question

Today I upgraded matplotlib to version 2.0.2, after not upgrading for possibly 3 years.

Now I have the problem that in interactive plots the window always comes to t

Answer 1

Changing the backend

The issue seems only present using the Tk backend. Using the Qt backend, the window would stay where it was while updating with plt.pause.

To change the backend use those lines at the beginning of your script.

import matplotlib
matplotlib.use("Qt4agg") # or "Qt5agg" depending on you version of Qt

Modifying plt.pause

If changing the backend is not an option, the following might help. The cause of the window constantly popping up to the front comes from plt.pause calling plt.show() internally. You therefore implement you own pause function, without calling show. This requires to be in interactive mode plt.ion() first and then at least once call plt.show(). Afterwards you may update the plot with the custom mypause function as shown below.

import matplotlib
matplotlib.use("TkAgg")
import matplotlib.pyplot as plt
from time import time
from random import random

plt.ion()
# set up the figure
fig = plt.figure()
plt.xlabel('Time')
plt.ylabel('Value')

plt.show(block=False)

def mypause(interval):
    backend = plt.rcParams['backend']
    if backend in matplotlib.rcsetup.interactive_bk:
        figManager = matplotlib._pylab_helpers.Gcf.get_active()
        if figManager is not None:
            canvas = figManager.canvas
            if canvas.figure.stale:
                canvas.draw()
            canvas.start_event_loop(interval)
            return


t0 = time()
t = []
y = []
while True:
    t.append( time()-t0 )
    y.append( random() )
    plt.gca().clear()
    plt.plot( t , y )
    mypause(1)

Using an animation.

Finally, using a matplotlib.animation class would render all of the above obsolete. An example for matplotlib.animation.FuncAnimation is shown on the matplotlib page.