# Animation in Python

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

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

fig = plt.figure()
ax = plt.axes(xlim=(0,2), ylim=(-2,2))
line, = ax.plot([],[],lw=2)

# Initialization function : plot the background of each frame

def init():
    line.set_data([],[])
    return line,

# Animation function

def animate(i):
    x = np.linspace(0,2,1000)
    y = np.sin(2*np.pi*(x-0.01*i))
    line.set_data(x,y)
    return line,

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

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.

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

plt.show()
