Basic animated line plot

Output generated via matplotlib.animation.Animation.to_jshtml.

import matplotlib.pyplot as plt
import numpy as np

import matplotlib.animation as animation

fig, ax = plt.subplots()

x = np.arange(0, 2*np.pi, 0.01)
line, = ax.plot(x, np.sin(x))


def animate(i):
    line.set_ydata(np.sin(x + i / 50))  # update the data.
    return line,


ani = animation.FuncAnimation(
    fig, animate, interval=20, blit=True, save_count=50)

# To save the animation, use e.g.
#
# ani.save("movie.mp4")
#
# or
#
# writer = animation.FFMpegWriter(
#     fps=15, metadata=dict(artist='Me'), bitrate=1800)
# ani.save("movie.mp4", writer=writer)

plt.show()

Contours are updated the same way, with ContourSet.set_data. Recontouring the existing artist is faster than removing the ContourSet and making a new one, and it keeps the contours in the same place in the draw order, which matters when blitting. The levels are not recomputed, so the colors mean the same thing in every frame.

fig, ax = plt.subplots()

X, Y = np.meshgrid(np.linspace(-3, 3, 100), np.linspace(-3, 3, 100))


def f(t):
    return np.sin(X + t) * np.cos(Y - t)


cs = ax.contour(X, Y, f(0), levels=np.linspace(-0.9, 0.9, 7))


def animate_contour(i):
    cs.set_data(X, Y, f(i / 25))  # update the data.
    return cs,


ani_contour = animation.FuncAnimation(
    fig, animate_contour, interval=20, blit=True, save_count=50)

plt.show()

Tags: component: animation level: beginner