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Fixed a bug with drawing an empty Collection #32228

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Fixed a bug with drawing an empty Collection #32228

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2f04f46
Skip drawing a Collection if offsets is an empty list
ayshih Aug 18, 2026
07cd7fc
Still open/close the group (for SVG) for an empty Collection
ayshih Aug 20, 2026
886fc82
Update lib/matplotlib/collections.py
ayshih Aug 20, 2026
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6 changes: 6 additions & 0 deletions lib/matplotlib/collections.py
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Original file line number Diff line number Diff line change
Expand Up @@ -363,6 +363,12 @@ def draw(self, renderer):
return
renderer.open_group(self.__class__.__name__, self.get_gid())

# Bail if the collection does not have any offsets (e.g., an empty scatter plot)
if len(self.get_offsets()) == 0:
renderer.close_group(self.__class__.__name__)
self.stale = False
return
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self.update_scalarmappable()

transform, offset_trf, offsets, paths = self._prepare_points()
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18 changes: 18 additions & 0 deletions lib/matplotlib/tests/test_axes.py
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Expand Up @@ -3217,6 +3217,24 @@ def test_scatter_singular_plural_arguments(self):
facecolors=["#ffffff", "#000000", "#f0f0f0"],
facecolor="#ffffff")

@pytest.mark.parametrize('edgecolor, facecolor, linestyle',
[('red', 'blue', 'solid'),
('red', 'blue', 'dashed'),
('red', 'none', 'solid'),
('none', 'blue', 'solid')])
@check_figures_equal()
def test_empty_scatter(self, fig_test, fig_ref, edgecolor, facecolor, linestyle):
# Verify that a spurious marker is not plotted in the bottom-left corner
# https://github.com/matplotlib/matplotlib/issues/32219
ax_test = fig_test.subplots()
ax_test.scatter([], [], ec=edgecolor, fc=facecolor, ls=linestyle, clip_on=False)
ax_test.set_xlim(0, 1)
ax_test.set_ylim(0, 1)

ax_ref = fig_ref.subplots()
ax_ref.set_xlim(0, 1)
ax_ref.set_ylim(0, 1)


def _params(c=None, xsize=2, *, edgecolors=None, **kwargs):
return (c, edgecolors, kwargs, xsize)
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