matplotlib绘制动画

　　matplotlib从1.1.0版本以后就开始支持绘制动画，具体使用可以参考官方帮助文档。下面是一个很基本的例子：

"""

A simple example of an animated plot

"""

import numpy as np

from matplotlib import pyplot as plt

from matplotlib import animation

# First set up the figure, the axis, and the plot element we want to animate

fig = plt.figure()

# create our line object which will be modified in the animation

ax = plt.axes(xlim=(0, 2), ylim=(-2, 2))

# we simply plot an empty line: we’ll add data to the line later

line, = ax.plot([], [], lw=2) 

# initialization function: plot the background of each frame

def init():

    line.set_data([], [])

    return line,

# animation function.  This is called sequentially

# It takes a single parameter, the frame number i

def animate(i):

    x = np.linspace(0, 2, 1000)

    y = np.sin(2 * np.pi * (x - 0.01 * i))  # update the data

    line.set_data(x, y)

    return line,

# Makes an animation by repeatedly calling a function func

# frames can be a generator, an iterable, or a number of frames.

# interval draws a new frame every interval milliseconds.

# blit=True means only re-draw the parts that have changed.

# 在这里设置一个200帧的动画，每帧之间间隔20毫秒

anim = animation.FuncAnimation(fig, animate, init_func=init,

                               frames=200, interval=20, blit=True)

# save the animation as an mp4.  This requires ffmpeg or mencoder to be

# installed.  The extra_args ensure that the x264 codec is used, so that

# the video can be embedded in html5.  You may need to adjust this for

# your system: for more information, see

# http://matplotlib.sourceforge.net/api/animation_api.html

anim.save('basic_animation.mp4', fps=30, extra_args=['-vcodec', 'libx264'])

plt.show()  # plt.show() 会一直循环播放动画