matplotlib tutorial (13) nitta@tsuda.ac.jp

Chapter 13: Animation (compatible with Google Colab)

JSAnimation

Official document: https://matplotlib.org/api/animation_api.html

JSAnimation has been incorporated into matplotlib since matplotlib 2.1.

JSAnimation realizes animanation by continuously displaying images drawn by matplotlib.pyplot.

Use the magic '% matplotlib notebook'. Note that it is not '% matplotlib inline'.

ArtistAnimation() passes an array of generated images and displays them all together. FuncAnimation() displays every time an image is generated.

ArtistAnimation : Pass an array of images

One coordinate system (Axes)

%matplotlib notebook

import numpy as np
import matplotlib.pyplot as plt
from matplotlib import animation
from IPython import display

is_colab = 'google.colab' in str(get_ipython())   # for Google Colab

x = np.linspace(0, 2 * np.pi, 100)

fig, ax = plt.subplots(1, 1, figsize=(6,4))

images=[]
for i in range(20): 
    y = np.sin(x + 2 * np.pi * (i/20))
    img = ax.plot(x, y, color='b')
    images.append(img)

ax.set_xlabel(r"$x$")
ax.set_ylabel(r"$y$")
ax.set_xlim(0, 2*np.pi)
ax.set_ylim(-1.2, 1.2) 

anim = animation.ArtistAnimation(fig, images, repeat=False, blit=True)

if is_colab:    # for Google Colab
    display.display(display.HTML(anim.to_jshtml()))
    plt.close()
else:
    plt.show()

Once Loop Reflect

anim.save('./anim13a.mp4')

Multiple coordinate systems (Axes)

%matplotlib notebook

import numpy as np
import matplotlib.pyplot as plt
from matplotlib import animation
from IPython import display

is_colab = 'google.colab' in str(get_ipython())   # for Google Colab

x = np.linspace(0, 2 * np.pi, 100)
x2 = np.arange(100)

fig, ax = plt.subplots(1, 2, figsize=(6*2,4))

images=[]
for i in range(20): 
    y = np.sin(x + 2 * np.pi * (i/20))
    y2 = np.random.rand(len(x2))
    img = ax[0].plot(x, y, color='b')
    img2 = ax[1].plot(x2, y2, color='g')
    images.append(img+img2)

ax[0].set_xlabel(r"$x$")
ax[0].set_ylabel(r"$y$")
ax[0].set_xlim(0, 2*np.pi)
ax[0].set_ylim(-1.2, 1.2) 

ax[1].set_xlabel(r"$x$")
ax[1].set_ylabel(r"$y$")
ax[1].set_xlim(0, 100)
ax[1].set_ylim(0, 1)

anim = animation.ArtistAnimation(fig, images, repeat=False, blit=True)

if is_colab:    # for Google Colab
    display.display(display.HTML(anim.to_jshtml()))
    plt.close()
else:
    plt.show()

Once Loop Reflect

anim.save('./anim13b.mp4')

FuncAnimation : Pass the function generating images

One coordinate system (Axes)

%matplotlib notebook

import numpy as np
import matplotlib.pyplot as plt
from matplotlib import animation
from IPython import display

is_colab = 'google.colab' in str(get_ipython())   # for Google Colab

x = np.linspace(0, 2 * np.pi, 100)

fig, ax = plt.subplots(1, 1, figsize=(6,4))

def animate(i):
    ax.clear()
    y = np.sin(x + 2 * np.pi * (i/20))
    img = ax.plot(x, y, color='b', label=r"$y=\sin x$")
    ax.set_xlabel(r"$x$")
    ax.set_ylabel(r"$y$")
    ax.set_xlim(0, 2*np.pi)
    ax.set_ylim(-1.2, 1.2) 
    return img

anim = animation.FuncAnimation(fig, animate, frames=20, repeat=False, blit=True)

if is_colab:    # for Google Colab
    display.display(display.HTML(anim.to_jshtml()))
    plt.close()
else:
    plt.show()

Once Loop Reflect

anim.save('anim13c.mp4')

Multiple coordinate systems (Axes)

%matplotlib notebook

import numpy as np
import matplotlib.pyplot as plt
from matplotlib import animation, rc
from IPython import display

is_colab = 'google.colab' in str(get_ipython())   # for Google Colab

x = np.linspace(0, 2 * np.pi, 100)
x2 = np.arange(100)

fig, ax = plt.subplots(1, 2, figsize=(6*2,4))

def animate(i):
    ax[0].clear()
    y = np.sin(x + 2 * np.pi * (i/20))
    img = ax[0].plot(x, y, color='b')
    ax[0].set_xlabel(r"$x$")
    ax[0].set_ylabel(r"$y$")
    ax[0].set_xlim(0, 2*np.pi)
    ax[0].set_ylim(-1.2, 1.2)

    ax[1].clear()
    y2 = np.random.rand(len(x2))
    img2 =ax[1].plot(x2, y2, color='g')
    ax[1].set_xlabel(r"$x$")
    ax[1].set_ylabel(r"$y$")
    ax[1].set_xlim(0, 100)
    ax[1].set_ylim(0, 1)

    return img + img2

anim = animation.FuncAnimation(fig, animate, frames=20, repeat=False, blit=True)

if is_colab:    # for Google Colab
    display.display(display.HTML(anim.to_jshtml()))
    plt.close()
else:
    plt.show()

Once Loop Reflect

anim.save('anim13d.mp4')