I found this question/answer with the following code How do I get a fill_between shape in Funcanimation?
import numpy as np
from matplotlib import pyplot as plt
from matplotlib import animation
X = np.linspace(0,3.428, num=250)
Y = np.sin(X*3)
fig = plt.figure(figsize=(13,5), dpi=80)
ax = plt.axes(xlim=(0, 3.428), ylim=(-1,1))
line, = ax.plot([], [], lw=5)
def init():
line.set_data([], [])
return line,
def animate(i):
x = X[0:(i-1)]
y = Y[0:(i-1)]
line.set_data(x,y)
p = plt.fill_between(x, y, 0, facecolor = 'C0', alpha = 0.2)
return line, p,
anim = animation.FuncAnimation(fig,animate, init_func=init,
frames = 250, interval=20, blit=True)
plt.show()
when I run this in spyder it works fine. however as soon as I save it (ffmpeg)
anim.save('test_fill.mp4', fps=30)
the fill appears from frame 0 and is refilled on top as I want.
the following images are done with a different step function but represents the same problem as with the sin(X*3) function from the example
play after running with spyder
play after being saved as mp4
How can I avoid the first fill?
I tried defining p = ax.fill_between([], [], 0, facecolor = 'C0', alpha = 0.0) in Init() but this didnt make any difference
and I also saw in a post some proposed the use .remove() or clear(). But I got either local variable error or a complete white animation respectively.
