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When removing colorbar, restore the correct parent axes. #31040

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When removing colorbar, restore the correct parent axes. #31040

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37 changes: 22 additions & 15 deletions lib/matplotlib/colorbar.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1026,12 +1026,13 @@ def remove(self):
If the colorbar was created with ``use_gridspec=True`` the previous
gridspec is restored.
"""
if hasattr(self.ax, '_colorbar_info'):
parents = self.ax._colorbar_info['parents']
for a in parents:
if self.ax in a._colorbars:
a._colorbars.remove(self.ax)
parents = (self.ax._colorbar_info["parents"]
if hasattr(self.ax, "_colorbar_info") else [])
for ax in parents:
if self.ax in ax._colorbars:
ax._colorbars.remove(self.ax)

fig = self.ax.figure
self.ax.remove()

self.mappable.callbacks.disconnect(self.mappable.colorbar_cid)
Expand All @@ -1041,17 +1042,23 @@ def remove(self):
self.ax.callbacks.disconnect(self._extend_cid1)
self.ax.callbacks.disconnect(self._extend_cid2)

try:
ax = self.mappable.axes
except AttributeError:
if not fig.get_layout_engine().colorbar_gridspec:
# Don't do anything, the layout engine fully handles repositioning.
return
try:
subplotspec = self.ax.get_subplotspec().get_gridspec()._subplot_spec
except AttributeError: # use_gridspec was False
pos = ax.get_position(original=True)
ax._set_position(pos)
else: # use_gridspec was True
ax.set_subplotspec(subplotspec)
if parents:
# self.ax was created via make_axes or make_axes_gridspec; try to
# restore parents' original positions, i.e. to the state before
# they were resized to make room for the colorbar Axes.
if (self.ax.get_subplotspec() # use_gridspec is True
and len(parents) == 1
and parents[0].get_subplotspec()
and (self.ax.get_subplotspec().get_gridspec()
is parents[0].get_subplotspec().get_gridspec())):
parents[0].set_subplotspec(

@timhoffm timhoffm Jan 27, 2026

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Why do we only reset parents[0]. What happens for the case colorbar(ax=[ax1, ax2])?

@anntzer anntzer Jan 27, 2026

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If borrowing from multiple colorbars we never actually rely on use_gridspec=True (see Figure.colorbar) so self.ax.get_subplotspec() will already be false above; in any case I also check for len(parents) == 1 just above just to be safe.

self.ax.get_subplotspec().get_gridspec()._subplot_spec)
else: # use_gridspec is False
for ax in parents:
ax._set_position(ax.get_position(original=True))

def _process_values(self):
"""
Expand Down
27 changes: 17 additions & 10 deletions lib/matplotlib/tests/test_colorbar.py
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Original file line number Diff line number Diff line change
Expand Up @@ -280,38 +280,45 @@ def test_colorbar_single_scatter():

@pytest.mark.parametrize('use_gridspec', [True, False])
@pytest.mark.parametrize('nested_gridspecs', [True, False])
def test_remove_from_figure(nested_gridspecs, use_gridspec):
@pytest.mark.parametrize('orphan_mappable', [True, False])
def test_remove_from_figure(use_gridspec, nested_gridspecs, orphan_mappable):
"""Test `remove` with the specified ``use_gridspec`` setting."""
fig = plt.figure()
if nested_gridspecs:
gs = fig.add_gridspec(2, 2)[1, 1].subgridspec(2, 2)
ax = fig.add_subplot(gs[1, 1])
else:
ax = fig.add_subplot()
sc = ax.scatter([1, 2], [3, 4])
sc.set_array(np.array([5, 6]))
pre_position = ax.get_position()
cb = fig.colorbar(sc, use_gridspec=use_gridspec)
if orphan_mappable:
cb = fig.colorbar(mpl.cm.ScalarMappable(), ax=ax, use_gridspec=use_gridspec)
else:
sc = ax.scatter([1, 2], [3, 4], c=[5, 6])
cb = fig.colorbar(sc, use_gridspec=use_gridspec)
fig.subplots_adjust()
cb.remove()
fig.subplots_adjust()
post_position = ax.get_position()
assert (pre_position.get_points() == post_position.get_points()).all()


def test_remove_from_figure_cl():
@pytest.mark.parametrize('orphan_mappable', [True, False])
def test_remove_from_figure_cl(orphan_mappable):
"""Test `remove` with constrained_layout."""
fig, ax = plt.subplots(constrained_layout=True)
sc = ax.scatter([1, 2], [3, 4])
sc.set_array(np.array([5, 6]))
fig.draw_without_rendering()
pre_position = ax.get_position()
cb = fig.colorbar(sc)
if orphan_mappable:
cb = fig.colorbar(mpl.cm.ScalarMappable(), ax=ax)
else:
sc = ax.scatter([1, 2], [3, 4], c=[5, 6])
cb = fig.colorbar(sc)
cb.remove()
fig.draw_without_rendering()
post_position = ax.get_position()
np.testing.assert_allclose(pre_position.get_points(),
post_position.get_points())
np.testing.assert_allclose(
pre_position.get_points(), post_position.get_points(),
atol=0.0002 if orphan_mappable else 0)


def test_colorbarbase():
Expand Down
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