FIX constrained_layout w/ hidden axes (matplotlib#14919)

FIX constrained_layout w/ hidden axes

Author: anntzer

lib/matplotlib/_constrained_layout.py

@@ -272,7 +272,11 @@ def _make_layout_margins(ax, renderer, h_pad, w_pad):
     invTransFig = fig.transFigure.inverted().transform_bbox
     pos = ax.get_position(original=True)
     tightbbox = ax.get_tightbbox(renderer=renderer)
-    bbox = invTransFig(tightbbox)
+    if tightbbox is None:
+        bbox = pos
+    else:
+        bbox = invTransFig(tightbbox)
+
     # this can go wrong:
     if not (np.isfinite(bbox.width) and np.isfinite(bbox.height)):
         # just abort, this is likely a bad set of co-ordinates that

lib/matplotlib/tests/test_constrainedlayout.py

@@ -387,3 +387,16 @@ def test_colorbar_location():
     fig.colorbar(pcm, ax=axs[-2, 3:], shrink=0.5, location='top')
     fig.colorbar(pcm, ax=axs[0, 0], shrink=0.5, location='left')
     fig.colorbar(pcm, ax=axs[1:3, 2], shrink=0.5, location='right')
+
+
+def test_hidden_axes():
+    # test that if we make an axes not visible that constrained_layout
+    # still works.  Note the axes still takes space in the layout
+    # (as does a gridspec slot that is empty)
+    fig, axs = plt.subplots(2, 2, constrained_layout=True)
+    axs[0, 1].set_visible(False)
+    fig.canvas.draw()
+    extents1 = np.copy(axs[0, 0].get_position().extents)
+
+    np.testing.assert_allclose(extents1,
+        [0.045552, 0.548288, 0.47319, 0.982638], rtol=1e-5)