FIX: logic of title repositioning

jklymak · jklymak · commit b0d9f30a7aad · 2021-10-20T22:29:41.000+02:00
diff --git a/lib/matplotlib/axes/_base.py b/lib/matplotlib/axes/_base.py
@@ -2981,13 +2981,13 @@ def _update_title_position(self, renderer):
                     axs = axs + [ax]
             top = -np.Inf
             for ax in axs:
+                bb = None
                 if (ax.xaxis.get_ticks_position() in ['top', 'unknown']
                         or ax.xaxis.get_label_position() == 'top'):
                     bb = ax.xaxis.get_tightbbox(renderer)
-                else:
+                if bb is None:
                     bb = ax.get_window_extent(renderer)
-                if bb is not None:
-                    top = max(top, bb.ymax)
+                top = max(top, bb.ymax)
             if top < 0:
                 # the top of Axes is not even on the figure, so don't try and
                 # automatically place it.
diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -5627,6 +5627,17 @@ def test_title_location_roundtrip():
         ax.set_title('fail', loc='foo')
 
 
+@pytest.mark.parametrize('sharex', [True, False])
+def test_title_location_shared(sharex):
+    fig, axs = plt.subplots(2, 1, sharex=sharex)
+    axs[0].set_title('A', pad=-40)
+    axs[1].set_title('B', pad=-40)
+    fig.draw_without_rendering()
+    x, y1 = axs[0].title.get_position()
+    x, y2 = axs[1].title.get_position()
+    assert y1 == y2 == 1.0
+
+
 @image_comparison(["loglog.png"], remove_text=True, tol=0.02)
 def test_loglog():
     fig, ax = plt.subplots()
