Add legend.labelcolor in rcParams

Carloscerq · Carloscerq · commit 64661dbf1cb9 · 2021-04-26T20:15:00.000-03:00
diff --git a/doc/users/next_whats_new/rcparams_legend.rst b/doc/users/next_whats_new/rcparams_legend.rst
@@ -0,0 +1,26 @@
+New rcParams for ledend: set legend labelcolor globaly
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The new :rc:`legend.labelcolor` allows toggling valid color string(for example, 'black'),
+versus choosing to match the color of the line of marker using 'linecolor',
+'markerfacecolor'(or 'mfc'), or 'markeredgecolor' (or 'mec').
+
+.. plot::
+
+    import numpy as np
+    import matplotlib.pyplot as plt
+    
+    # Make some fake data.
+    a = np.arange(0, 3, .02)
+    c = np.exp(a)
+    d = c[::-1]
+    plt.rcParams['legend.labelcolor'] = 'linecolor'
+
+
+    fig, ax = plt.subplots()
+    ax.plot(a, c, 'g--', label='Model length')
+    ax.plot(a, d, 'r:', label='Data length')
+
+    legend = ax.legend()
+
+    plt.show()
diff --git a/lib/matplotlib/legend.py b/lib/matplotlib/legend.py
@@ -544,8 +544,8 @@ def __init__(self, parent, handles, labels,
             'mec':             ['get_markeredgecolor', 'get_edgecolor'],
         }
         if labelcolor is None:
-            pass
-        elif isinstance(labelcolor, str) and labelcolor in color_getters:
+            labelcolor = mpl.rcParams['legend.labelcolor']
+        if isinstance(labelcolor, str) and labelcolor in color_getters:
             getter_names = color_getters[labelcolor]
             for handle, text in zip(self.legendHandles, self.texts):
                 for getter_name in getter_names:
diff --git a/lib/matplotlib/mpl-data/matplotlibrc b/lib/matplotlib/mpl-data/matplotlibrc
@@ -530,6 +530,7 @@
 #legend.scatterpoints: 1        # number of scatter points
 #legend.markerscale:   1.0      # the relative size of legend markers vs. original
 #legend.fontsize:      medium
+#legend.labelcolor:    black
 #legend.title_fontsize: None    # None sets to the same as the default axes.
 
 ## Dimensions as fraction of font size:
diff --git a/lib/matplotlib/rcsetup.py b/lib/matplotlib/rcsetup.py
@@ -289,6 +289,17 @@ def validate_color_for_prop_cycle(s):
     return validate_color(s)
 
 
+def validate_color_or_linecolor(s):
+    if cbook._str_equal(s, 'linecolor'):
+        return s
+    elif cbook._str_equal(s, 'mfc') or cbook._str_equal(s, 'markerfacecolor'):
+        return 'markerfacecolor'
+    elif cbook._str_equal(s, 'mec') or cbook._str_equal(s, 'markerfacecolor'):
+        return 'markeredgecolor'
+
+    return validate_color(s)
+
+
 def validate_color(s):
     """Return a valid color arg."""
     if isinstance(s, str):
@@ -1017,6 +1028,7 @@ def _convert_validator_spec(key, conv):
     "legend.scatterpoints":  validate_int,
     "legend.fontsize":       validate_fontsize,
     "legend.title_fontsize": validate_fontsize_None,
+    "legend.labelcolor":     validate_color_or_linecolor, #color of the legend
      # the relative size of legend markers vs. original
     "legend.markerscale":    validate_float,
     "legend.shadow":         validate_bool,
