Jaco Vermaak Jaco Vermaak - 2 months ago 50
Python Question

stop / start / pause in python matplotlib animation

I'm using FuncAnimation in matplotlib's animation module for some basic animation. This function perpetually loops through the animation. Is there a way by which I can pause and restart the animation by, say, mouse clicks?

Answer

Here is a FuncAnimation example which I modified to pause on mouse clicks. Since the animation is driven by a generator function, simData, when the global variable pause is True, yielding the same data makes the animation appear paused.

The value of paused is toggled by setting up an event callback:

def onClick(event):
    global pause
    pause ^= True
fig.canvas.mpl_connect('button_press_event', onClick)

import matplotlib.pyplot as plt
import numpy as np
import matplotlib.animation as animation

pause = False
def simData():
    t_max = 10.0
    dt = 0.05
    x = 0.0
    t = 0.0
    while t < t_max:
        if not pause:
            x = np.sin(np.pi*t)
            t = t + dt
        yield x, t

def onClick(event):
    global pause
    pause ^= True

def simPoints(simData):
    x, t = simData[0], simData[1]
    time_text.set_text(time_template%(t))
    line.set_data(t, x)
    return line, time_text

fig = plt.figure()
ax = fig.add_subplot(111)
line, = ax.plot([], [], 'bo', ms=10) # I'm still not clear on this stucture...
ax.set_ylim(-1, 1)
ax.set_xlim(0, 10)

time_template = 'Time = %.1f s'    # prints running simulation time
time_text = ax.text(0.05, 0.9, '', transform=ax.transAxes)
fig.canvas.mpl_connect('button_press_event', onClick)
ani = animation.FuncAnimation(fig, simPoints, simData, blit=False, interval=10,
    repeat=True)
plt.show()
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