matplotlib · mdboom · Nov 17, 2015 · Dec 14, 2015 · Dec 14, 2015 · Dec 14, 2015
diff --git a/examples/pylab_examples/color_demo.py b/examples/pylab_examples/color_demo.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 """
-matplotlib gives you 4 ways to specify colors,
+matplotlib gives you 5 ways to specify colors,
 
     1) as a single letter string, ala MATLAB
 
@@ -11,6 +11,10 @@
     4) as a string representing a floating point number
        from 0 to 1, corresponding to shades of gray.
 
+    5) as a string representing the Nth color in the
+       currently active color cycle, e.g. "[0]"
+       represents the first color in the color cycle.
+
 See help(colors) for more info.
 """
 import matplotlib.pyplot as plt
@@ -20,8 +24,8 @@
 #subplot(111, facecolor='#ababab')
 t = np.arange(0.0, 2.0, 0.01)
 s = np.sin(2*np.pi*t)
-plt.plot(t, s, 'y')
-plt.xlabel('time (s)', color='r')
+plt.plot(t, s, '[0]')
+plt.xlabel('time (s)', color='[0]')
 plt.ylabel('voltage (mV)', color='0.5')  # grayscale color
 plt.title('About as silly as it gets, folks', color='#afeeee')
 plt.show()
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -4,6 +4,7 @@
 from matplotlib.externals import six
 from matplotlib.externals.six.moves import reduce, xrange, zip, zip_longest
 
+import itertools
 import math
 import warnings
 
@@ -2452,7 +2453,7 @@ def pie(self, x, explode=None, labels=None, colors=None,
         Call signature::
 
           pie(x, explode=None, labels=None,
-              colors=('b', 'g', 'r', 'c', 'm', 'y', 'k', 'w'),
+              colors=None,
               autopct=None, pctdistance=0.6, shadow=False,
               labeldistance=1.1, startangle=None, radius=None,
               counterclock=True, wedgeprops=None, textprops=None,
@@ -2471,8 +2472,9 @@ def pie(self, x, explode=None, labels=None, colors=None,
             fraction of the radius with which to offset each wedge.
 
           *colors*: [ *None* | color sequence ]
-            A sequence of matplotlib color args through which the pie chart
-            will cycle.
+            A sequence of matplotlib color args through which the pie
+            chart will cycle.  If `None`, will use the colors in the
+            default property cycle.
 
           *labels*: [ *None* | len(x) sequence of strings ]
             A sequence of strings providing the labels for each wedge
@@ -2561,7 +2563,12 @@ def pie(self, x, explode=None, labels=None, colors=None,
         if len(x) != len(explode):
             raise ValueError("'explode' must be of length 'x'")
         if colors is None:
-            colors = ('b', 'g', 'r', 'c', 'm', 'y', 'k', 'w')
+            get_next_color = self._get_patches_for_fill.get_next_color
+        else:
+            color_cycle = itertools.cycle(colors)
+
+            def get_next_color():
+                return six.next(color_cycle)
 
         if radius is None:
             radius = 1
@@ -2597,7 +2604,7 @@ def pie(self, x, explode=None, labels=None, colors=None,
 
             w = mpatches.Wedge((x, y), radius, 360. * min(theta1, theta2),
                             360. * max(theta1, theta2),
-                            facecolor=colors[i % len(colors)],
+                            facecolor=get_next_color(),
                             **wedgeprops)
             slices.append(w)
             self.add_patch(w)
@@ -3017,8 +3024,8 @@ def xywhere(xs, ys, mask):
             l0, = self.plot(x, y, fmt, label='_nolegend_', **kwargs)
 
         if ecolor is None:
-            if l0 is None and 'color' in self._get_lines._prop_keys:
-                ecolor = six.next(self._get_lines.prop_cycler)['color']
+            if l0 is None:
+                ecolor = self._get_lines.get_next_color()
             else:
                 ecolor = l0.get_color()
 
@@ -5966,9 +5973,8 @@ def hist(self, x, bins=None, range=None, normed=False, weights=None,
 
         nx = len(x)  # number of datasets
 
-        if color is None and 'color' in self._get_lines._prop_keys:
-            color = [six.next(self._get_lines.prop_cycler)['color']
-                     for i in xrange(nx)]
+        if color is None:
+            color = [self._get_lines.get_next_color() for i in xrange(nx)]
         else:
             color = mcolors.colorConverter.to_rgba_array(color)
             if len(color) != nx:

diff --git a/lib/matplotlib/axes/_base.py b/lib/matplotlib/axes/_base.py
@@ -10,6 +10,7 @@
 import warnings
 import math
 from operator import itemgetter
+import re
 
 import numpy as np
 from numpy import ma
@@ -94,6 +95,17 @@ def _process_plot_format(fmt):
         linestyle = 'None'
         fmt = fmt.replace(' ', '')
 
+    # handle the N-th color in the color cycle
+    matches = re.findall('\[[0-9]+\]', fmt)
+    if len(matches) == 1:
+        color = mcolors.colorConverter._get_nth_color(
+            int(matches[0][1:-1]))
+        fmt = fmt.replace(matches[0], '')
+    elif len(matches) != 0:
+        if color is not None:
+            raise ValueError(
+                'Illegal format string "%s"; two color symbols' % fmt)
+
     chars = [c for c in fmt]
 
     for c in chars:
@@ -160,6 +172,10 @@ def set_prop_cycle(self, *args, **kwargs):
         else:
             prop_cycler = cycler(*args, **kwargs)
 
+        # Make sure the cycler always has at least one color
+        if 'color' not in prop_cycler.keys:
+            prop_cycler = prop_cycler * cycler('color', ['k'])
+
         self.prop_cycler = itertools.cycle(prop_cycler)
         # This should make a copy
         self._prop_keys = prop_cycler.keys
@@ -185,6 +201,12 @@ def __call__(self, *args, **kwargs):
         ret = self._grab_next_args(*args, **kwargs)
         return ret
 
+    def get_next_color(self):
+        """
+        Return the next color in the cycle.
+        """
+        return six.next(self.prop_cycler)['color']
+
     def set_lineprops(self, line, **kwargs):
         assert self.command == 'plot', 'set_lineprops only works with "plot"'
         line.set(**kwargs)

diff --git a/lib/matplotlib/colors.py b/lib/matplotlib/colors.py
@@ -31,6 +31,14 @@
     - k: black
     - w: white
 
+To use the colors that are part of the active color cycle in the
+current style, use a string with a positive index in square brackets.
+If the index is larger than the color cycle, it is wrapped around.
+For example:
+
+    - `[0]`: The first color in the cycle
+    - `[1]`: The second color in the cycle
+
 Gray shades can be given as a string encoding a float in the 0-1 range, e.g.::
 
     color = '0.75'
@@ -213,6 +221,18 @@
 
 def is_color_like(c):
     'Return *True* if *c* can be converted to *RGB*'
+    # Special-case the N-th color cycle syntax, because it's parsing
+    # needs to be deferred.  We may be reading a value from rcParams
+    # here before the color_cycle rcParam has been parsed.
+    if isinstance(c, bytes):
+        match = re.match(b'^\[[0-9]\]$', c)
+        if match is not None:
+            return True
+    elif isinstance(c, six.text_type):
+        match = re.match('^\[[0-9]\]$', c)
+        if match is not None:
+            return True
+
     try:
         colorConverter.to_rgb(c)
         return True
@@ -260,8 +280,35 @@ class ColorConverter(object):
         'k': (0.0, 0.0, 0.0),
         'w': (1.0, 1.0, 1.0), }
 
+    _prop_cycler = None
+
     cache = {}
 
+    @classmethod
+    def _get_nth_color(cls, val):
+        """
+        Get the Nth color in the current color cycle.  If N is greater
+        than the number of colors in the cycle, it is wrapped around.
+        """
+        from matplotlib.rcsetup import cycler
+        from matplotlib import rcParams
+
+        prop_cycler = rcParams['axes.prop_cycle']
+        if prop_cycler is None and 'axes.color_cycle' in rcParams:
+            clist = rcParams['axes.color_cycle']
+            prop_cycler = cycler('color', clist)
+
+        colors = prop_cycler._transpose()['color']
+        return colors[val % len(colors)]
+
+    @classmethod
+    def _parse_nth_color(cls, val):
+        match = re.match('^\[[0-9]\]$', val)
+        if match is not None:
+            return cls._get_nth_color(int(val[1:-1]))
+
+        raise ValueError("Not a color cycle color")
+
     def to_rgb(self, arg):
         """
         Returns an *RGB* tuple of three floats from 0-1.
@@ -299,6 +346,10 @@ def to_rgb(self, arg):
                 argl = arg.lower()
                 color = self.colors.get(argl, None)
                 if color is None:
+                    try:
+                        argl = self._parse_nth_color(argl)
+                    except ValueError:
+                        pass
                     str1 = cnames.get(argl, argl)
                     if str1.startswith('#'):
                         color = hex2color(str1)

diff --git a/lib/matplotlib/rcsetup.py b/lib/matplotlib/rcsetup.py
@@ -827,7 +827,7 @@ def validate_hist_bins(s):
     # line props
     'lines.linewidth':       [1.0, validate_float],  # line width in points
     'lines.linestyle':       ['-', six.text_type],             # solid line
-    'lines.color':           ['b', validate_color],  # blue
+    'lines.color':           ['[0]', validate_color],  # blue
     'lines.marker':          ['None', six.text_type],     # black
     'lines.markeredgewidth': [1.0, validate_float],
     'lines.markersize':      [6, validate_float],    # markersize, in points
@@ -843,7 +843,7 @@ def validate_hist_bins(s):
     ## patch props
     'patch.linewidth':   [None, validate_float_or_None],  # line width in points
     'patch.edgecolor':   ['k', validate_color],  # black
-    'patch.facecolor':   ['b', validate_color],  # blue
+    'patch.facecolor':   ['[0]', validate_color],  # blue
     'patch.antialiased': [True, validate_bool],  # antialiased (no jaggies)
 
     ## Histogram properties
@@ -992,14 +992,15 @@ def validate_hist_bins(s):
     'axes.formatter.use_mathtext': [False, validate_bool],
     'axes.formatter.useoffset': [True, validate_bool],
     'axes.unicode_minus': [True, validate_bool],
-    'axes.color_cycle': [['b', 'g', 'r', 'c', 'm', 'y', 'k'],
-                         deprecate_axes_colorcycle],  # cycle of plot
-                                                      # line colors
     # This entry can be either a cycler object or a
     # string repr of a cycler-object, which gets eval()'ed
     # to create the object.
-    'axes.prop_cycle': [ccycler('color', 'bgrcmyk'),
-                        validate_cycler],
+    'axes.prop_cycle': [
+        ccycler('color',
+                ['#1f77b4', '#ff7f0e', '#2ca02c', '#d62728',
+                 '#9467bd', '#8c564b', '#e377c2', '#7f7f7f',
+                 '#bcbd22', '#17becf']),
+        validate_cycler],
     # If 'data', axes limits are set close to the data.
     # If 'round_numbers' axes limits are set to the nearest round numbers.
     'axes.autolimit_mode': [

diff --git a/lib/matplotlib/sankey.py b/lib/matplotlib/sankey.py
@@ -7,6 +7,7 @@
 
 from matplotlib.externals import six
 from matplotlib.externals.six.moves import zip
+from matplotlib import rcParams
 
 # Original version by Yannick Copin (ycopin@ipnl.in2p3.fr) 10/2/2010, available
 # at:
@@ -770,11 +771,15 @@ def _get_angle(a, r):
             print("lrpath\n", self._revert(lrpath))
             xs, ys = list(zip(*vertices))
             self.ax.plot(xs, ys, 'go-')
-        patch = PathPatch(Path(vertices, codes),
-                          fc=kwargs.pop('fc', kwargs.pop('facecolor',
-                                        '#bfd1d4')),  # Custom defaults
-                          lw=kwargs.pop('lw', kwargs.pop('linewidth', 0.5)),
-                          **kwargs)
+        if rcParams['_internal.classic_mode']:
+            fc = kwargs.pop('fc', kwargs.pop('facecolor', '#bfd1d4'))
+            lw = kwargs.pop('lw', kwargs.pop('linewidth', 0.5))
+        else:
+            fc = kwargs.pop('fc', kwargs.pop('facecolor', None))
+            lw = kwargs.pop('lw', kwargs.pop('linewidth', None))
+        if fc is None:
+            fc = six.next(self.ax._get_patches_for_fill.prop_cycler)['color']
+        patch = PathPatch(Path(vertices, codes), fc=fc, lw=lw, **kwargs)
         self.ax.add_patch(patch)
 
         # Add the path labels.

diff --git a/lib/matplotlib/stackplot.py b/lib/matplotlib/stackplot.py
@@ -108,10 +108,7 @@ def stackplot(axes, x, *args, **kwargs):
         raise ValueError(errstr)
 
     # Color between x = 0 and the first array.
-    if 'color' in axes._get_lines._prop_keys:
-        color = six.next(axes._get_lines.prop_cycler)['color']
-    else:
-        color = None
+    color = axes._get_lines.get_next_color()
     r.append(axes.fill_between(x, first_line, stack[0, :],
                                facecolor=color,
                                label= six.next(labels, None),
@@ -120,10 +117,7 @@ def stackplot(axes, x, *args, **kwargs):
 
     # Color between array i-1 and array i
     for i in xrange(len(y) - 1):
-        if 'color' in axes._get_lines._prop_keys:
-            color = six.next(axes._get_lines.prop_cycler)['color']
-        else:
-            color = None
+        color = axes._get_lines.get_next_color()
         r.append(axes.fill_between(x, stack[i, :], stack[i + 1, :],
                                    facecolor=color,
                                    label= six.next(labels, None),

diff --git a/lib/matplotlib/streamplot.py b/lib/matplotlib/streamplot.py
@@ -82,8 +82,8 @@ def streamplot(axes, x, y, u, v, density=1, linewidth=None, color=None,
     if transform is None:
         transform = axes.transData
 
-    if color is None and 'color' in axes._get_lines._prop_keys:
-        color = six.next(axes._get_lines.prop_cycler)['color']
+    if color is None:
+        color = axes._get_lines.get_next_color()
 
     if linewidth is None:
         linewidth = matplotlib.rcParams['lines.linewidth']

diff --git a/lib/matplotlib/tests/baseline_images/test_artist/default_edges.png b/lib/matplotlib/tests/baseline_images/test_artist/default_edges.png
diff --git a/lib/matplotlib/tests/baseline_images/test_cycles/lineprop_cycle_basic.png b/lib/matplotlib/tests/baseline_images/test_cycles/lineprop_cycle_basic.png
diff --git a/matplotlibrc.template b/matplotlibrc.template
@@ -314,7 +314,10 @@ backend      : %(backend)s
 #axes.unicode_minus  : True    # use unicode for the minus symbol
                                # rather than hyphen.  See
                                # http://en.wikipedia.org/wiki/Plus_and_minus_signs#Character_codes
-#axes.prop_cycle    : cycler('color', 'bgrcmyk')
+#axes.prop_cycle    : cycler('color',
+#                            ['#1f77b4', '#ff7f0e', '#2ca02c', '#d62728',
+#                             '#9467bd', '#8c564b', '#e377c2', '#7f7f7f',
+#                             '#bcbd22', '#17becf'])
                                             # color cycle for plot lines
                                             # as list of string colorspecs:
                                             # single letter, long name, or