Merge pull request #10713 from salindersidhu/fixed-issue-8576

efiring · web-flow · commit b2782e0b3aa3 · 2018-03-13T16:24:33.000-10:00
Implemented support for 'markevery' in prop_cycle
diff --git a/doc/users/next_whats_new/markevery_prop_cycle.rst b/doc/users/next_whats_new/markevery_prop_cycle.rst
@@ -0,0 +1,7 @@
+Implemented support for axes.prop_cycle property markevery in rcParams
+----------------------------------------------------------------------
+
+The Matplotlib ``rcParams`` settings object now supports configuration
+of the attribute `axes.prop_cycle` with cyclers using the `markevery`
+Line2D object property. An example of this feature is provided at 
+`~matplotlib/examples/lines_bars_and_markers/markevery_prop_cycle.py`
diff --git a/examples/lines_bars_and_markers/markevery_prop_cycle.py b/examples/lines_bars_and_markers/markevery_prop_cycle.py
@@ -0,0 +1,67 @@
+"""
+=================================================================
+Implemented support for prop_cycle property markevery in rcParams
+=================================================================
+
+This example demonstrates a working solution to issue #8576, providing full
+support of the markevery property for axes.prop_cycle assignments through
+rcParams. Makes use of the same list of markevery cases from
+https://matplotlib.org/examples/pylab_examples/markevery_demo.html
+
+Renders a plot with shifted-sine curves along each column with
+a unique markevery value for each sine curve.
+"""
+from cycler import cycler
+import numpy as np
+import matplotlib as mpl
+import matplotlib.pyplot as plt
+
+# Define a list of markevery cases and color cases to plot
+cases = [None,
+         8,
+         (30, 8),
+         [16, 24, 30],
+         [0, -1],
+         slice(100, 200, 3),
+         0.1,
+         0.3,
+         1.5,
+         (0.0, 0.1),
+         (0.45, 0.1)]
+
+colors = ['#1f77b4',
+          '#ff7f0e',
+          '#2ca02c',
+          '#d62728',
+          '#9467bd',
+          '#8c564b',
+          '#e377c2',
+          '#7f7f7f',
+          '#bcbd22',
+          '#17becf',
+          '#1a55FF']
+
+# Create two different cyclers to use with axes.prop_cycle
+markevery_cycler = cycler(markevery=cases)
+color_cycler = cycler('color', colors)
+
+# Configure rcParams axes.prop_cycle with custom cycler
+custom_cycler = color_cycler + markevery_cycler
+mpl.rcParams['axes.prop_cycle'] = custom_cycler
+
+# Create data points and offsets
+x = np.linspace(0, 2 * np.pi)
+offsets = np.linspace(0, 2 * np.pi, 11, endpoint=False)
+yy = np.transpose([np.sin(x + phi) for phi in offsets])
+
+# Set the plot curve with markers and a title
+fig = plt.figure()
+ax = fig.add_axes([0.1, 0.1, 0.6, 0.75])
+
+for i in range(len(cases)):
+    ax.plot(yy[:, i], marker='o', label=str(cases[i]))
+    ax.legend(bbox_to_anchor=(1.05, 1), loc=2, borderaxespad=0.)
+
+plt.title('Support for axes.prop_cycle cycler with markevery')
+
+plt.show()
diff --git a/lib/matplotlib/rcsetup.py b/lib/matplotlib/rcsetup.py
@@ -534,7 +534,54 @@ def validate_ps_distiller(s):
 _validate_negative_linestyle = ValidateInStrings('negative_linestyle',
                                                  ['solid', 'dashed'],
                                                  ignorecase=True)
+def validate_markevery(s):
+    """
+    Validate the markevery property of a Line2D object.
+
+    Parameters
+    ----------
+    s : None, int, float, slice, length-2 tuple of ints,
+        length-2 tuple of floats, list of ints
+
+    Returns
+    -------
+    s : None, int, float, slice, length-2 tuple of ints,
+        length-2 tuple of floats, list of ints
+
+    """
+    # Validate s against type slice
+    if isinstance(s, slice):
+        return s
+    # Validate s against type tuple
+    if isinstance(s, tuple):
+        tupMaxLength = 2
+        tupType = type(s[0])
+        if len(s) != tupMaxLength:
+            raise TypeError("'markevery' tuple must have a length of "
+                            "%d" % (tupMaxLength))
+        if tupType is int and not all(isinstance(e, int) for e in s):
+            raise TypeError("'markevery' tuple with first element of "
+                            "type int must have all elements of type "
+                            "int")
+        if tupType is float and not all(isinstance(e, float) for e in s):
+            raise TypeError("'markevery' tuple with first element of "
+                            "type float must have all elements of type "
+                            "float")
+        if tupType is not float and tupType is not int:
+            raise TypeError("'markevery' tuple contains an invalid type")
+    # Validate s against type list
+    elif isinstance(s, list):
+        if not all(isinstance(e, int) for e in s):
+            raise TypeError("'markevery' list must have all elements of "
+                            "type int")
+    # Validate s against type float int and None
+    elif not isinstance(s, (float, int)):
+        if s is not None:
+            raise TypeError("'markevery' is of an invalid type")
+
+    return s
 
+validate_markeverylist = _listify_validator(validate_markevery)
 
 validate_legend_loc = ValidateInStrings(
     'legend_loc',
@@ -676,6 +723,7 @@ def validate_hatch(s):
         'markersize': validate_floatlist,
         'markeredgewidth': validate_floatlist,
         'markeredgecolor': validate_colorlist,
+        'markevery': validate_markeverylist,
         'alpha': validate_floatlist,
         'marker': validate_stringlist,
         'hatch': validate_hatchlist,
diff --git a/lib/matplotlib/tests/test_rcparams.py b/lib/matplotlib/tests/test_rcparams.py
@@ -23,6 +23,7 @@
                                 validate_cycler,
                                 validate_hatch,
                                 validate_hist_bins,
+                                validate_markevery,
                                 _validate_linestyle)
 
 
@@ -326,6 +327,35 @@ def generate_validator_testcases(valid):
                      ),
          'fail': (('aardvark', ValueError),
                   )
+         },
+         {'validator': validate_markevery,
+          'success': ((None, None),
+                      (1, 1),
+                      (0.1, 0.1),
+                      ((1, 1), (1, 1)),
+                      ((0.1, 0.1), (0.1, 0.1)),
+                      ([1, 2, 3], [1, 2, 3]),
+                      (slice(2), slice(None, 2, None)),
+                      (slice(1, 2, 3), slice(1, 2, 3))
+                      ),
+          'fail': (((1, 2, 3), TypeError),
+                   ([1, 2, 0.3], TypeError),
+                   (['a', 2, 3], TypeError),
+                   ([1, 2, 'a'], TypeError),
+                   ((0.1, 0.2, 0.3), TypeError),
+                   ((0.1, 2, 3), TypeError),
+                   ((1, 0.2, 0.3), TypeError),
+                   ((1, 0.1), TypeError),
+                   ((0.1, 1), TypeError),
+                   (('abc'), TypeError),
+                   ((1, 'a'), TypeError),
+                   ((0.1, 'b'), TypeError),
+                   (('a', 1), TypeError),
+                   (('a', 0.1), TypeError),
+                   ('abc', TypeError),
+                   ('a', TypeError),
+                   (object(), TypeError)
+                   )
          }
     )
 
