Stop/Start/Pause in Python Matplotlib Animation

stop / start / pause in python matplotlib animation

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)
ax.set_ylim(-1, 1)
ax.set_xlim(0, 10)

time_template = 'Time = %.1f s'
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)
fig.show()

How to pause matplotlib animation for some seconds(without using any mouse clicks)?

Answer

You can do it with plt.pause().

I simplified a bit your code in order to use it without the unknown a module (and its get_points() function).

Code

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

fig, ax = plt.subplots(figsize=(12,8))
ax.set(xlim=(0,104), ylim=(0,68))

x_start, y_start = (50, 35)
x_end, y_end = (90, 45)

N = 20
x = np.linspace(x_start, x_end, N)
y = np.linspace(y_start, y_end, N)

sc_1 = ax.scatter([], [], color="green", zorder=4)
line, = ax.plot([], [], color="crimson", zorder=4)
sc_2 = ax.scatter([], [], color="gold", zorder=4)

def animate(i):
    sc_1.set_offsets([x_start, y_start])
    if i == 1:
        plt.pause(2)

    line.set_data(x[:i], y[:i])

    if i == len(x):
        plt.pause(2)
        sc_2.set_offsets([x_end, y_end])

    return sc_1, line, sc_2,

ani = animation.FuncAnimation(fig=fig, func=animate, interval=50, blit=True)

plt.show()

How to pause/resume matplotlib ArtistsAnimation

Although it seems that in this case a FuncAnimation might be better suited than an ArtistAnimation, both can be
stopped / started the same way. See this question stop / start / pause in python matplotlib animation.

The main point is that the 'private' ArtistAnimation._start() function is not doing what you think it does. Therefore it is sensible to use the ArtistAnimation.event_source.stop() and ArtistAnimation.event_source.start() functions.

Below is a minimal, runnable example showing how to start/stop an ArtistAnimation by clicking with the mouse button.

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

class SomeClass():

    def __init__(self):
        self.pause = False

        self.fig, ax = plt.subplots()
        ax.set_aspect("equal")

        self.movie = []
        nt = 10
        X,Y = np.meshgrid(np.arange(16), np.arange(16))

        for t in range(nt):
            data = np.sin((X+t*1)/3.)**2+ 1.5*np.cos((Y+t*1)/3.)**2
            pc = ax.pcolor(data)
            self.movie.append([pc])

        self.ani = animation.ArtistAnimation(self.fig, self.movie, interval=100)    
        self.fig.canvas.mpl_connect('button_press_event', self.onClick)
        plt.show()

    def onClick(self, event):
        if self.pause:
            self.ani.event_source.stop()
        else:
            self.ani.event_source.start()
        self.pause ^= True

a = SomeClass()

Pause matplotlib custom animation loop

You may just replace time.sleep(1) in the else-part with plt.pause, just like you also did it in the if-part.

        ....
        plt.draw()
        plt.pause(0.2)
    else:
        plt.pause(0.2)

The other option is of course to use a matplotlib animation, like FuncAnimation, which has the methods .event_source.stop() and .event_source.start(). (As shown in two of the answers to this question: stop / start / pause in python matplotlib animation)

---

Related Topics