Python interactive window drops fps when creating many plots - SVG rendering is slow

Not sure how hard it is to do anything about this but I noticed that if the Python interactive window contains lots of plots already (above maybe 30), adding new ones brings the frame rate down quite significantly. Above around 60 plots, it’s at less than 1 fps and makes all of VS Code become unresponsive. Once the plots are done, VS Code (including the interactive window) returns to normal.

Here’s some example code to reproduce the issue.

#%%
import matplotlib.pyplot as plt
import numpy as np

for i in range(100):
    plt.plot()
    N = 50
    x = np.random.rand(N)
    y = np.random.rand(N)
    colors = np.random.rand(N)
    area = (30 * np.random.rand(N)) ** 2  # 0 to 15 point radii
    plt.title(f"plot #{i + 1}")
    plt.scatter(x, y, s=area, c=colors, alpha=0.5)
    plt.show()

[rchiodo]

@DonJayamanne yes we want to do that too. Something like this looks promising: https://github.com/twobin/react-lazyload

However, SVG is a lot slower than PNG. We can fix jupyter to generate both.

[rchiodo]

@DavidKutu my fix for microsoft/vscode-jupyter#3233 should fix this too.