[Matplotlib-users] problem with patches in animation

[Mark B. <ma...@gm...>]

Hello list,

I am trying to animate a patch. The animation should show a circle orbiting
around a point. I took the code from
http://nickcharlton.net/posts/drawing-animating-shapes-matplotlib.html

Problem is that when I run the code, the animation doesn't remove the
initial position of the circle (blit is True) while it works correctly on
the website referenced above.

Does anybody else see this behavior? Here's the code:

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

fig = plt.figure()
fig.set_dpi(100)
fig.set_size_inches(7, 6.5)

ax = plt.axes(xlim=(0, 10), ylim=(0, 10))
patch = plt.Circle((5, -5), 0.75, fc='y')

def init():
    patch.center = (5, 5)
    ax.add_patch(patch)
    return patch,

def animate(i):
    x, y = patch.center
    x = 5 + 3 * np.sin(np.radians(i))
    y = 5 + 3 * np.cos(np.radians(i))
    patch.center = (x, y)
    return patch,

anim = animation.FuncAnimation(fig, animate,
                               init_func=init,
                               frames=360,
                               interval=20,
                               blit=True)

plt.show()

Thanks, Mark