https://matplotlib.org/3.3.0/tutorials/advanced/blitting.html#sphx-glr-tutorials-advanced-blitting-py is probably of use here.

The issue is that when using bliting, we mark the artists as "animated" via obj.set_animated(True) which means they are excluded from the normal draw process (so that you can get a "clean" background). In FuncAnimation we enable this (just to be on the safe side) to prevent artifacts where a previous data is "stuck" in the animation. When you pause the animation you do not un-set this state so when the figure redraws it skips rendering the plots (because it is the problem of what ever is managing the animation to do the render + blit).

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation
from matplotlib.widgets import Button


class PlotAnimation:
    def __init__(self):
        self.fig, self.ax = plt.subplots()
        self.x = np.linspace(-10, 10, 1000)
        self.N = 200
        self.interv = 50
        self.n0 = (
            1.0
            / (4 * np.pi * 2e-4 * 0.1) ** 0.5
            * np.exp(-self.x ** 2 / (4 * 2e-4 * 0.1))
        )
        (self.p,) = self.ax.plot(self.x, self.n0)
        self.anim_running = True
        self.Myanimation = animation.FuncAnimation(
            self.fig, self.update, frames=self.N, interval=self.interv, blit=True
        )

    def update(self, i):
        self.n0 += i / 100 % 5
        self.p.set_ydata(self.n0 % 20)
        return (self.p,)

    def animate(self):
        pause_ax = self.fig.add_axes((0.7, 0.025, 0.1, 0.04))
        pause_button = Button(pause_ax, "pause", hovercolor="0.975")
        pause_button.on_clicked(self._pause)
        plt.show()

    def _pause(self, event):
        if self.anim_running:
            self.Myanimation.event_source.stop()
            self.p.set_animated(False)
            self.anim_running = False
            self.fig.canvas.draw_idle()
        else:
            self.p.set_animated(True)
            self.Myanimation.event_source.start()
            self.anim_running = True


animated_plot = PlotAnimation()
animated_plot.animate()

works as expected.

I really like this example! This is probably something that should be generalized and added to the Animation classes.

Thank you a lot for your solution, this is great help ! I had never found this page during my research, maybe you should attach a link on the doc page https://matplotlib.org/3.2.1/api/_as_gen/matplotlib.animation.FuncAnimation.html .

Glad to read, feel free to use it !

Also I have posted a logarithmic slider solution on stackoverflow (2nd answer to the question) : https://stackoverflow.com/questions/39960791/logarithmic-slider-with-matplotlib/62326375#62326375
I think it would be great to have logarithmic sliders in matplotlib (as well as integer sliders, it's easy to make one but it often leads to rounding errors), I've used as much linear as log_10 sliders to be honest. I have feedback that my solution has a problem with the argument "orientation" that is not well recognized, maybe because I have not used an init function, I am not sure.
Well again feel free to use it the way you want and to generalize to more log base if you like my recommendation.

Thanks again.

@Luluser Can you open a PR with the text in the FuncAnimation docs that would have saved you and a PR adding the SliderLog?

and that link went live last night (that text was merged as part of the 3.3.0 release of which we just tagged RC1), it was just very good timing ;)

I'm going to close this as resolved.