Merge pull request matplotlib#26926 from cgadal-forks/subfigure-zorder

Closes matplotlib#22011: Changes to SubFigures so it behaves like a regular artist

Author: ksunden

doc/users/next_whats_new/subfigure_zorder.rst

@@ -0,0 +1,22 @@
+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)

lib/matplotlib/figure.py

@@ -152,12 +152,6 @@ def __init__(self, **kwargs):
     def _get_draw_artists(self, renderer):
         """Also runs apply_aspect"""
         artists = self.get_children()
-        for sfig in self.subfigs:
-            artists.remove(sfig)
-            childa = sfig.get_children()
-            for child in childa:
-                if child in artists:
-                    artists.remove(child)
 
         artists.remove(self.patch)
         artists = sorted(
@@ -2310,8 +2304,6 @@ def draw(self, renderer):
             self.patch.draw(renderer)
             mimage._draw_list_compositing_images(
                 renderer, self, artists, self.figure.suppressComposite)
-            for sfig in self.subfigs:
-                sfig.draw(renderer)
             renderer.close_group('subfigure')
 
         finally:
@@ -3117,9 +3109,6 @@ def draw(self, renderer):
                 mimage._draw_list_compositing_images(
                     renderer, self, artists, self.suppressComposite)
 
-                for sfig in self.subfigs:
-                    sfig.draw(renderer)
-
                 renderer.close_group('figure')
             finally:
                 self.stale = False

lib/matplotlib/tests/baseline_images/test_figure/test_subfigure.png

@@ -1286,6 +1286,12 @@ def test_subfigure():
 
     fig.suptitle('Figure suptitle', fontsize='xx-large')
 
+    # 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)
+
 
 def test_subfigure_tightbbox():
     # test that we can get the tightbbox with a subfigure...