after use('Agg'), the animate does not work well

[zhangciwu]

matplotlib.animation.FuncAnimation(fig, func, frames=None, init_func=None, fargs=None, save_count=None, **kwargs)

after use('Agg')
the function above will trigger "func" function only once, and never all it twice.

scene: using animate to display lines one by one, and then save the picture.(works well without use Agg on windows.)
version:1.3.1

[zhangciwu]

a small sample:

import matplotlib
#matplotlib.use('Agg')
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation

def update_line(num, data, line):
    fig1.savefig('lines.png',format='png')
    line.set_data(data[...,:num])
    print 'run once'

    return line,

fig1 = plt.figure()

data = np.random.rand(2, 25)
l, = plt.plot([], [], 'r-')
plt.xlim(0, 1)
plt.ylim(0, 1)
plt.xlabel('x')
plt.title('test')
line_ani = animation.FuncAnimation(fig1, update_line, 25, fargs=(data, l),
    interval=50, blit=False)

plt.show()

this works well, but when uncomment the second line, it doesn't work

[WeatherGod]

The "Agg" backend is not a GUI backend. When you do a "plt.show()" for such
a backend, nothing will happen, regardless if it was an animation or not.
You can only save the animation.

[zhangciwu]

Thanks.
I think I need to change the method to reach what I want.