#193 Animation using python

# create an animation
import numpy as np
import matplotlib.pyplot as plt
import matplotlib. Animation as manimation

n = 1000
x = np.linspace(0, 6*np.pi, n)
y = np.sin(x)
# Define the meta data for the movie
FFMpegWriter = manimation.writers["ffmpeg"]
metadata = dict(title="Movie Test", artist="Matplotlib",
                comment="a red circle following a blue sine wave")
writer = FFMpegWriter(fps=25, metadata=metadata)
# Initialize the movie
fig = plt.figure()
# plot the sine wave line
sine_line, = plt.plot(x, y, "b")
red_circle, = plt.plot([], [], "ro", markersize = 10)
plt.xlabel("x")
plt.ylabel("sin(x)")
# Update the frames for the movie
with writer.saving(fig, "writer_test.mp4", 200):
    for i in range(n):
        x0 = x[i]
        y0 = y[i]
        red_circle.set_data(x0, y0)
        writer.grab_frame()