Backport PR matplotlib#20761: Fix suplabel autopos

Author: QuLogic

lib/matplotlib/figure.py

@@ -373,7 +373,10 @@ def _suplabels(self, t, info, **kwargs):
 
         x = kwargs.pop('x', None)
         y = kwargs.pop('y', None)
-        autopos = x is None and y is None
+        if info['name'] in ['_supxlabel', '_suptitle']:
+            autopos = y is None
+        elif info['name'] == '_supylabel':
+            autopos = x is None
         if x is None:
             x = info['x0']
         if y is None:

lib/matplotlib/tests/test_constrainedlayout.py

@@ -555,3 +555,26 @@ def test_align_labels():
                                after_align[1].x0, rtol=0, atol=1e-05)
     # ensure labels do not go off the edge
     assert after_align[0].x0 >= 1
+
+
+def test_suplabels():
+    fig, ax = plt.subplots(constrained_layout=True)
+    fig.canvas.draw()
+    pos0 = ax.get_tightbbox(fig.canvas.get_renderer())
+    fig.supxlabel('Boo')
+    fig.supylabel('Booy')
+    fig.canvas.draw()
+    pos = ax.get_tightbbox(fig.canvas.get_renderer())
+    assert pos.y0 > pos0.y0 + 10.0
+    assert pos.x0 > pos0.x0 + 10.0
+
+    fig, ax = plt.subplots(constrained_layout=True)
+    fig.canvas.draw()
+    pos0 = ax.get_tightbbox(fig.canvas.get_renderer())
+    # check that specifying x (y) doesn't ruin the layout
+    fig.supxlabel('Boo', x=0.5)
+    fig.supylabel('Boo', y=0.5)
+    fig.canvas.draw()
+    pos = ax.get_tightbbox(fig.canvas.get_renderer())
+    assert pos.y0 > pos0.y0 + 10.0
+    assert pos.x0 > pos0.x0 + 10.0