Animating Plots in 2D

We can use html5 for animation, as suggested in this web page: http://louistiao.me/posts/notebooks/embedding-matplotlib-animations-in-jupyter-notebooks/

This seems to be the modern way to do animation in Python.

First step is to initialize some things in Python. - we need %matplotlib inline to get things to plot right on the notebook

we need numpy for the math
we need matplotlib for plotting
we need animation from matplotlib, and HTML from iPython.display to show the animations

We get all these with the following imports:



In [1]:

    
%matplotlib inline
from numpy import *
from matplotlib.pyplot import *
from matplotlib import animation
from IPython.display import HTML

We now have four steps to get an animated plot

set up the figure frame
define the initializing function
define the function that draws each frame of the animation
call the animator function, which creates all the frames and saves them for you

Then we are ready to call “HTML” to display the animation.



In [2]:

    
# First set up the figure, the axis, and the plot element we want to animate
fig, ax = subplots()

ax.set_xlim(( 0, 2))
ax.set_ylim((-2, 2))

line, = ax.plot([], [], lw=2)
# NOTE: THIS WILL DISPLAY JUST AN EMPTY BOX.



In [3]:

    
# initialization function: plot the background of each frame
def init():
    line.set_data([], [])
    return (line,)



In [4]:

    
# animation function. This is called sequentially
def animate(i):
    x = linspace(0, 2, 1000)
    y = sin(2 * pi * (x - 0.01 * i))
    line.set_data(x, y)
    return (line,)



In [5]:

    
# call the animator. blit=True means only re-draw the parts that have changed.
anim = animation.FuncAnimation(fig, animate, init_func=init,
                               frames=100, interval=20, blit=True)



In [6]:

    
HTML(anim.to_html5_video())









    Out[6]:



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