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

i = 1
w = 1

N = 200
alpha = 0.1

xx = []
yy = []
steps = 30
for step in range(steps):
    anoms = np.random.binomial(N, alpha)
    x = np.random.uniform(i, i+w, size=(N-anoms,2))
    y = np.random.uniform(4, 5, size=(anoms,2))
    if step < 10:
        i += 0.5
        w += 0.5
    else:
        i -= 0.25
        w -= 0.25
    xx.append(x)
    yy.append(y)

x_lower, x_higher = 0, 15
y_lower, y_higher = 0, 15

fig, ax = plt.subplots(figsize=(8,8))

ax = plt.axis([x_lower, x_higher, y_lower, y_higher])

anomalies, = plt.plot([0], [np.sin(0)], 'r.')
typicals, = plt.plot([0], [np.sin(0)], 'b.')


def animate(i):
    anomalies.set_data(yy[i][:,0], yy[i][:,1])
    typicals.set_data(xx[i][:,0], xx[i][:,1])
    return anomalies,

# create animation using the animate() function
myAnimation = animation.FuncAnimation(fig, animate, frames=range(steps), interval=10, blit=True, repeat=True)

plt.show()

# Set up formatting for the movie files
Writer = animation.writers['ffmpeg']
writer = Writer(fps=5, metadata=dict(artist='Me'), bitrate=1800)
myAnimation.save('im.mp4', writer=writer)