Merge pull request #20084 from Carloscerq/add_legend_labelcolor_rcParam

tacaswell · web-flow · commit 9b9c42dcf137 · 2021-05-22T18:07:42.000-04:00
ENH: Add legend.labelcolor in rcParams
diff --git a/doc/users/next_whats_new/rcparams_legend.rst b/doc/users/next_whats_new/rcparams_legend.rst
@@ -0,0 +1,25 @@
+New rcParams for legend: set legend labelcolor globally
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+A new :rc:`legend.labelcolor` sets the default *labelcolor* argument for
+`.Figure.legend`.  The special values  'linecolor', 'markerfacecolor'
+(or 'mfc'), or 'markeredgecolor' (or 'mec') will cause the legend text to match 
+the corresponding color of marker. 
+
+
+.. plot::
+
+    plt.rcParams['legend.labelcolor'] = 'linecolor'
+
+    # Make some fake data.
+    a = np.arange(0, 3, .02)
+    c = np.exp(a)
+    d = c[::-1]
+
+    fig, ax = plt.subplots()
+    ax.plot(a, c, 'g--', label='Model length')
+    ax.plot(a, d, 'r:', label='Data length')
+
+    ax.legend()
+
+    plt.show()
diff --git a/lib/matplotlib/legend.py b/lib/matplotlib/legend.py
@@ -173,12 +173,15 @@ def _update_bbox_to_anchor(self, loc_in_canvas):
     absolute font size in points. String values are relative to the current
     default font size. This argument is only used if *prop* is not specified.
 
-labelcolor : str or list
+labelcolor : str or list, default: :rc:`legend.labelcolor`
     The color of the text in the legend. Either a valid color string
     (for example, 'red'), or a list of color strings. The labelcolor can
     also be made to match the color of the line or marker using 'linecolor',
     'markerfacecolor' (or 'mfc'), or 'markeredgecolor' (or 'mec').
 
+    Labelcolor can be set globally using :rc:`legend.labelcolor`. If None,
+    use :rc:`text.color`.
+
 numpoints : int, default: :rc:`legend.numpoints`
     The number of marker points in the legend when creating a legend
     entry for a `.Line2D` (line).
@@ -539,8 +542,11 @@ 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:
+            if mpl.rcParams['legend.labelcolor'] is not None:
+                labelcolor = mpl.rcParams['legend.labelcolor']
+            else:
+                labelcolor = mpl.rcParams['text.color']
+        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:    None
 #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 +289,27 @@ 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, 'markeredgecolor'):
+        return 'markeredgecolor'
+    elif s is None:
+        return None
+    elif isinstance(s, str) and len(s) == 6 or len(s) == 8:
+        stmp = '#' + s
+        if is_color_like(stmp):
+            return stmp
+        if s.lower() == 'none':
+            return None
+    elif is_color_like(s):
+        return s
+
+    raise ValueError(f'{s!r} does not look like a color arg')
+
+
 def validate_color(s):
     """Return a valid color arg."""
     if isinstance(s, str):
@@ -1017,6 +1038,8 @@ def _convert_validator_spec(key, conv):
     "legend.scatterpoints":  validate_int,
     "legend.fontsize":       validate_fontsize,
     "legend.title_fontsize": validate_fontsize_None,
+     # color of the legend
+    "legend.labelcolor":     _validate_color_or_linecolor,
      # the relative size of legend markers vs. original
     "legend.markerscale":    validate_float,
     "legend.shadow":         validate_bool,
diff --git a/lib/matplotlib/tests/test_legend.py b/lib/matplotlib/tests/test_legend.py
@@ -644,6 +644,85 @@ def test_legend_labelcolor_markerfacecolor():
         assert mpl.colors.same_color(text.get_color(), color)
 
 
+@pytest.mark.parametrize('color', ('red', 'none', (.5, .5, .5)))
+def test_legend_labelcolor_rcparam_single(color):
+    # test the rcParams legend.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')
+
+    mpl.rcParams['legend.labelcolor'] = color
+    leg = ax.legend()
+    for text in leg.get_texts():
+        assert mpl.colors.same_color(text.get_color(), color)
+
+
+def test_legend_labelcolor_rcparam_linecolor():
+    # test the rcParams legend.labelcolor for a linecolor
+    fig, ax = plt.subplots()
+    ax.plot(np.arange(10), np.arange(10)*1, label='#1', color='r')
+    ax.plot(np.arange(10), np.arange(10)*2, label='#2', color='g')
+    ax.plot(np.arange(10), np.arange(10)*3, label='#3', color='b')
+
+    mpl.rcParams['legend.labelcolor'] = 'linecolor'
+    leg = ax.legend()
+    for text, color in zip(leg.get_texts(), ['r', 'g', 'b']):
+        assert mpl.colors.same_color(text.get_color(), color)
+
+
+def test_legend_labelcolor_rcparam_markeredgecolor():
+    # test the labelcolor for labelcolor='markeredgecolor'
+    fig, ax = plt.subplots()
+    ax.plot(np.arange(10), np.arange(10)*1, label='#1', markeredgecolor='r')
+    ax.plot(np.arange(10), np.arange(10)*2, label='#2', markeredgecolor='g')
+    ax.plot(np.arange(10), np.arange(10)*3, label='#3', markeredgecolor='b')
+
+    mpl.rcParams['legend.labelcolor'] = 'markeredgecolor'
+    leg = ax.legend()
+    for text, color in zip(leg.get_texts(), ['r', 'g', 'b']):
+        assert mpl.colors.same_color(text.get_color(), color)
+
+
+def test_legend_labelcolor_rcparam_markeredgecolor_short():
+    # test the labelcolor for labelcolor='markeredgecolor'
+    fig, ax = plt.subplots()
+    ax.plot(np.arange(10), np.arange(10)*1, label='#1', markeredgecolor='r')
+    ax.plot(np.arange(10), np.arange(10)*2, label='#2', markeredgecolor='g')
+    ax.plot(np.arange(10), np.arange(10)*3, label='#3', markeredgecolor='b')
+
+    mpl.rcParams['legend.labelcolor'] = 'mec'
+    leg = ax.legend()
+    for text, color in zip(leg.get_texts(), ['r', 'g', 'b']):
+        assert mpl.colors.same_color(text.get_color(), color)
+
+
+def test_legend_labelcolor_rcparam_markerfacecolor():
+    # test the labelcolor for labelcolor='markeredgecolor'
+    fig, ax = plt.subplots()
+    ax.plot(np.arange(10), np.arange(10)*1, label='#1', markerfacecolor='r')
+    ax.plot(np.arange(10), np.arange(10)*2, label='#2', markerfacecolor='g')
+    ax.plot(np.arange(10), np.arange(10)*3, label='#3', markerfacecolor='b')
+
+    mpl.rcParams['legend.labelcolor'] = 'markerfacecolor'
+    leg = ax.legend()
+    for text, color in zip(leg.get_texts(), ['r', 'g', 'b']):
+        assert mpl.colors.same_color(text.get_color(), color)
+
+
+def test_legend_labelcolor_rcparam_markerfacecolor_short():
+    # test the labelcolor for labelcolor='markeredgecolor'
+    fig, ax = plt.subplots()
+    ax.plot(np.arange(10), np.arange(10)*1, label='#1', markerfacecolor='r')
+    ax.plot(np.arange(10), np.arange(10)*2, label='#2', markerfacecolor='g')
+    ax.plot(np.arange(10), np.arange(10)*3, label='#3', markerfacecolor='b')
+
+    mpl.rcParams['legend.labelcolor'] = 'mfc'
+    leg = ax.legend()
+    for text, color in zip(leg.get_texts(), ['r', 'g', 'b']):
+        assert mpl.colors.same_color(text.get_color(), color)
+
+
 def test_get_set_draggable():
     legend = plt.legend()
     assert not legend.get_draggable()
diff --git a/lib/matplotlib/tests/test_rcparams.py b/lib/matplotlib/tests/test_rcparams.py
@@ -17,6 +17,7 @@
     validate_bool,
     validate_color,
     validate_colorlist,
+    _validate_color_or_linecolor,
     validate_cycler,
     validate_float,
     validate_fontweight,
@@ -329,6 +330,17 @@ def generate_validator_testcases(valid):
                   ('(0, 1, "0.5")', ValueError),  # last one not a float
                   ),
          },
+        {'validator': _validate_color_or_linecolor,
+         'success': (('linecolor', 'linecolor'),
+                     ('markerfacecolor', 'markerfacecolor'),
+                     ('mfc', 'markerfacecolor'),
+                     ('markeredgecolor', 'markeredgecolor'),
+                     ('mec', 'markeredgecolor')
+                     ),
+         'fail': (('line', ValueError),
+                  ('marker', ValueError)
+                  )
+         },
         {'validator': validate_hist_bins,
          'success': (('auto', 'auto'),
                      ('fd', 'fd'),
