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Description
Bug summary
The legend kwarg labelcolor='linecolor' does not play nicely with histtype='step' histograms or with fc='None' scatter plots, resulting in an invisible legend label for the histogram, and in an IndexError for the scatter plot.
Code for reproduction
import numpy as np
import matplotlib.pyplot as plt
plt.rcParams['figure.figsize'] = (5, 5)
plt.rcParams['legend.loc'] = 1
plt.rcParams['legend.framealpha'] = 1
x, y = np.random.randn(2, 1000)
fig, axes = plt.subplots(2, 2, sharex=True, sharey='row')
axes[0, 0].hist(x, histtype='bar', label="spam")
axes[0, 1].hist(x, histtype='step', label="spam")
axes[1, 0].scatter(x, y, label="spam")
axes[1, 1].scatter(x, y, ec='C0', fc='None', label="spam")
for ax in axes.ravel():
ax.legend(labelcolor='linecolor')Actual outcome
Note:
- correctly coloured legend labels in both left panels
- invisible legend label in the top right panel
- no legend for the bottom right panel, instead the following error message:
---------------------------------------------------------------------------
IndexError Traceback (most recent call last)
Cell In[1], line 15
13 axes[1, 1].scatter(x, y, ec='C0', fc='None', label="spam")
14 for ax in axes.ravel():
---> 15 ax.legend(labelcolor='linecolor')
File [~/.virtualenv/py3121env/lib/python3.12/site-packages/matplotlib/axes/_axes.py:337](http://localhost:8888/home/lukas/.virtualenv/py3121env/lib/python3.12/site-packages/matplotlib/axes/_axes.py#line=336), in Axes.legend(self, *args, **kwargs)
220 """
221 Place a legend on the Axes.
222
(...) 334 .. plot:: gallery[/text_labels_and_annotations/legend.py](http://localhost:8888/text_labels_and_annotations/legend.py)
335 """
336 handles, labels, kwargs = mlegend._parse_legend_args([self], *args, **kwargs)
--> 337 self.legend_ = mlegend.Legend(self, handles, labels, **kwargs)
338 self.legend_._remove_method = self._remove_legend
339 return self.legend_
File [~/.virtualenv/py3121env/lib/python3.12/site-packages/matplotlib/legend.py:601](http://localhost:8888/home/lukas/.virtualenv/py3121env/lib/python3.12/site-packages/matplotlib/legend.py#line=600), in Legend.__init__(self, parent, handles, labels, loc, numpoints, markerscale, markerfirst, reverse, scatterpoints, scatteryoffsets, prop, fontsize, labelcolor, borderpad, labelspacing, handlelength, handleheight, handletextpad, borderaxespad, columnspacing, ncols, mode, fancybox, shadow, title, title_fontsize, framealpha, edgecolor, facecolor, bbox_to_anchor, bbox_transform, frameon, handler_map, title_fontproperties, alignment, ncol, draggable)
597 color = getattr(handle, getter_name)()
598 if isinstance(color, np.ndarray):
599 if (
600 color.shape[0] == 1
--> 601 or np.isclose(color, color[0]).all()
602 ):
603 text.set_color(color[0])
604 else:
IndexError: index 0 is out of bounds for axis 0 with size 0
Expected outcome
The example plot should look like this:
(I managed to create this figure by changing labelcolor='linecolor' to labelcolor='C0' in the provided example.)
In words:
- The legend label for the
histtype='step'histogram (top right) should be the same as the one for thehisttype='bar'histogram (top left). - The scatter plot with empty markers (bottom right) should provide the same legend as the one with filled markers (bottom left), except that the legend handles should be obviously empty for the first and filled for the latter.
- There should be no error.
Additional information
Might be related to #3670, #28153.
Operating system
Manjaro Linux
Matplotlib Version
3.10.3
Matplotlib Backend
module://matplotlib_inline.backend_inline
Python version
3.12.1
Jupyter version
4.4.2
Installation
pip
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