Error when color value is None #4192
Description
Commit d58a84a changed validate_colors so that value in rcParams is None rather than "None". However, in some cases, it seems that a string is still expected downstream.
For example,
import matplotlib.pyplot as plt
import matplotlib as mpl
mpl.rcParams['patch.edgecolor'] = None
plt.plot(list(range(5)))results in
Traceback (most recent call last):
File "[...]/matplotlib/lib/matplotlib/colors.py", line 322, in to_rgb
'cannot convert argument to rgb sequence')
ValueError: cannot convert argument to rgb sequence
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "[...]/matplotlib/lib/matplotlib/colors.py", line 370, in to_rgba
r, g, b = self.to_rgb(arg)
File "[...]/matplotlib/lib/matplotlib/colors.py", line 328, in to_rgb
'to_rgb: Invalid rgb arg "%s"\n%s' % (str(arg), exc))
ValueError: to_rgb: Invalid rgb arg "None"
cannot convert argument to rgb sequence
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "./scratch.py", line 9, in <module>
plt.plot(list(range(5)))
File "[...]/matplotlib/lib/matplotlib/pyplot.py", line 3092, in plot
ax = gca()
File "[...]/matplotlib/lib/matplotlib/pyplot.py", line 827, in gca
ax = gcf().gca(**kwargs)
File "[...]/matplotlib/lib/matplotlib/figure.py", line 1288, in gca
return self.add_subplot(1, 1, 1, **kwargs)
File "[...]/matplotlib/lib/matplotlib/figure.py", line 973, in add_subplot
a = subplot_class_factory(projection_class)(self, *args, **kwargs)
File "[...]/matplotlib/lib/matplotlib/axes/_subplots.py", line 73, in __init__
self._axes_class.__init__(self, fig, self.figbox, **kwargs)
File "[...]/matplotlib/lib/matplotlib/axes/_base.py", line 422, in __init__
self.spines = self._gen_axes_spines()
File "[...]/matplotlib/lib/matplotlib/axes/_base.py", line 812, in _gen_axes_spines
'left': mspines.Spine.linear_spine(self, 'left'),
File "[...]/matplotlib/lib/matplotlib/spines.py", line 454, in linear_spine
result = cls(axes, spine_type, path, **kwargs)
File "[...]/matplotlib/lib/matplotlib/spines.py", line 54, in __init__
super(Spine, self).__init__(**kwargs)
File "[...]/matplotlib/lib/matplotlib/patches.py", line 111, in __init__
self.set_edgecolor(edgecolor)
File "[...]/matplotlib/lib/matplotlib/patches.py", line 274, in set_edgecolor
self._edgecolor = colors.colorConverter.to_rgba(color, self._alpha)
File "[...]/matplotlib/lib/matplotlib/colors.py", line 376, in to_rgba
'to_rgba: Invalid rgba arg "%s"\n%s' % (str(arg), exc))
ValueError: to_rgba: Invalid rgba arg "None"
to_rgb: Invalid rgb arg "None"
cannot convert argument to rgb sequence
This particular error can be fixed with
diff --git a/lib/matplotlib/colors.py b/lib/matplotlib/colors.py
index 772da0f..810a528 100644
--- a/lib/matplotlib/colors.py
+++ b/lib/matplotlib/colors.py
@@ -342,7 +342,7 @@ def to_rgba(self, arg, alpha=None):
*alpha* will replace the original *A*.
"""
try:
- if arg.lower() == 'none':
+ if arg is None or arg.lower() == 'none':
return (0.0, 0.0, 0.0, 0.0)
except AttributeError:
passA few other places also seem to expect a string.
lib/matplotlib/collections.py:572: if c.lower() == 'none':
lib/matplotlib/collections.py:611: if c.lower() == 'none':
lib/matplotlib/colors.py:393: if nc == 0 or c.lower() == 'none':
lib/matplotlib/lines.py:725: if is_string_like(edgecolor) and edgecolor.lower() == 'none':
lib/matplotlib/lines.py:1155: if is_string_like(facecolor) and facecolor.lower() == 'none':
lib/matplotlib/lines.py:1163: if is_string_like(facecolor) and facecolor.lower() == 'none':
Should these cases be updated to support None? I'd be happy to submit a PR, but I'm not clear on what the intended behavior is.