Fix legend labelcolor=‘linecolor’ to handle various corner cases, e.g. step histograms and transparent markers
#30328
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…o `linecolor`, e.g. ensuring that histograms with `step` histtype do not end up with an empty label
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…m `c, fc` to `mfc, fc, mec, ec, c`; check if `color` is empty, `none` or transparent and loop on if so
…ne` for both `c` and `ec` to ensure invisibility, in classic black edges are default
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Nice work @lukashergt ! The tests are really helpful and good. Glad it was fixed by u :) U deserve the credit. |
| pass | ||
| continue | ||
| else: | ||
| text.set_color('none') |
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If I understand correctly this is executed as a fallback if color could not be detected. Then, it feels wrong to set full transparency, because it makes the text invisible. I think we should rather leave the default as we did before.
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Yes, this is a fallback for the case that fc, ec, and c all have continue-ed through, i.e. they are either of the following:
- an empty array,
'none'or'None',- colour with zero alpha value,
AttributeErrorraised on the getter function.
Otherwise they would have broken (note the break statement) out of the loop beforehand, in which case the else case of the for ... else ... construction won't get invoked.
Final example case from the test_legend_labelcolor_linecolor_plot test:
import numpy as np
import matplotlib.pyplot as plt
x = np.arange(5)
fig, ax = plt.subplots()
p = ax.plot(x, 'o', c='none', mec='none', label="invisible circles with invisible label")
leg = ax.legend(labelcolor='linecolor')
So yes, the label entry is invisible because the markers and the legend handle are also invisible. In this stand-alone example this seems nonsensical, but something of this sort might come in handy when trying to insert a dummy legend entry in-between other legend entries for spacing.
Using helper for `'none'` string equality and using the fact that `to_rgba` always returns a 4-element tuple to simplify the code. Co-authored-by: Tim Hoffmann <[email protected]>
PR summary
This PR addresses issue #30298, which pointed out some corner cases, where
labelcolor='linecolor'did not work as expected, e.g.:histtype='step'or scatter plots withfc='none'had an empty legend label.mecandmfcbut notcwould end up with non-matching handle and label colours.The failing checks in this test from commit dabaf62 highlight the issue.
Changes:
'linecolor'ordering of checks fromc, fctomfc, fc, mec, ec, c.coloris empty, equal tononeor with a zero alpha value, e.g. whenfcis'none'continue the loop to check whether there is some color inec.Thanks to @nrnavaneet, who worked on this in #30299, and which this PR is based on.
Closes #30298
PR checklist
Plotting related features are demonstrated in an exampleNew Features and API Changes are noted with a directive and release noteDocumentation complies with general and docstring guidelines