FIX: correctly handle ax.legend(..., legendcolor='none')

Previously this would result in the label color being ignored because
colors.to_rgba_array('none') results in a 0 length array which in turn has
a 0 length cycle, which results in the zip over texts and colors terminating
before we have touched any of the texts, ignoring the color.

This makes::

     ax.legend(..., legendcolor='none')
     ax.legend(..., legendcolor=['none'])

behave the same

Author: tacaswell

lib/matplotlib/legend.py

@@ -550,6 +550,9 @@ def __init__(self, parent, handles, labels,
                         break
                     except AttributeError:
                         pass
+        elif isinstance(labelcolor, str) and labelcolor == 'none':
+            for text in self.texts:
+                text.set_color(labelcolor)
         elif np.iterable(labelcolor):
             for text, color in zip(self.texts,
                                    itertools.cycle(

lib/matplotlib/tests/test_legend.py

@@ -583,16 +583,17 @@ def test_legend_title_fontprop_fontsize():
     assert leg5.get_title().get_fontsize() == 20
 
 
-def test_legend_labelcolor_single():
+@pytest.mark.parametrize('color', ('red', 'none', (.5, .5, .5)))
+def test_legend_labelcolor_single(color):
     # test labelcolor for a single color
     fig, ax = plt.subplots()
     ax.plot(np.arange(10), np.arange(10)*1, label='#1')
     ax.plot(np.arange(10), np.arange(10)*2, label='#2')
     ax.plot(np.arange(10), np.arange(10)*3, label='#3')
 
-    leg = ax.legend(labelcolor='red')
+    leg = ax.legend(labelcolor=color)
     for text in leg.get_texts():
-        assert mpl.colors.same_color(text.get_color(), 'red')
+        assert mpl.colors.same_color(text.get_color(), color)
 
 
 def test_legend_labelcolor_list():