CODEWITHSUNDEEP
pythonanimationmatplotlibmovie
Caleb
Caleb

Reputation: 4091

Matplotlib movies from complete figures without using setData

I am interested in making movies using matplotlib. Examples I've seen so far, such as this one for moviewriter, seem to have you editing the data in-place for each frame. This is very efficient, avoiding redrawing the parts of the image that stay the same each time. However, it can be clunky for rapid data exploration. I would like a recipe that lets me simply take a fully drawn figure as each frame (clearing the same figure object each time is fine).

The reason for this: I often create moderately complicated figures using custom functions, with a form like plotme(ax, data, **options). Often I develop these functions without animations in mind, and later want to animate the figures by calling the plotting function in a loop. I don't want to have to change the logic of the functions to "setData" of existing artists in the figure for each frame.

Upvotes: 2

Views: 1651

Answers (1)

Suever
Suever

Reputation: 65430

Although the example code you've shown updates existing plot objects, there is no reason that you need to do so. The critical part of the attached code is the writer.grab_frame() which simply gets a screen capture of the current figure.

Here is an example without using existing plot objects

import matplotlib
matplotlib.use("Agg")
import matplotlib.pyplot as plt
import matplotlib.animation as manimation

FFMpegWriter = manimation.writers['ffmpeg']
metadata = dict(title='Movie Test', artist='Matplotlib',
                comment='Movie support!')
writer = FFMpegWriter(fps=15, metadata=metadata)

fig = plt.figure()

with writer.saving(fig, "writer_test.mp4", 100):
    for k in range(10):
        # Create a new plot object
        plt.plot(range(k), range(k), 'o')
        writer.grab_frame()

Upvotes: 3

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