Subfigures have now controllable zorders

Previously, setting the zorder of a subfigure had no effect, and those were plotted on top of any figure-level artists (i.e for example on top of fig-level legends). Now, subfigures behave like any other artists, and their zorder can be controlled, with default a zorder of 0.

.. plot::

:include-source: true

:alt: Example on controlling the zorder of a subfigure

import matplotlib.pyplot as plt

import numpy as np

x = np.linspace(1, 10, 10)

y1, y2 = x, -x

fig = plt.figure(constrained_layout=True)

subfigs = fig.subfigures(nrows=1, ncols=2)

for subfig in subfigs:

axarr = subfig.subplots(2, 1)

for ax in axarr.flatten():

(l1,) = ax.plot(x, y1, label="line1")

(l2,) = ax.plot(x, y2, label="line2")

subfigs[0].set_zorder(6)

l = fig.legend(handles=[l1, l2], loc="upper center", ncol=2)

# below tests for the draw zorder of subfigures.

leg = fig.legend(handles=[plt.Line2D([0], [0], label='Line{}'.format(i))

for i in range(5)], loc='center')

sub[0].set_zorder(leg.get_zorder() - 1)

sub[1].set_zorder(leg.get_zorder() + 1)