Merge pull request matplotlib#24470 from story645/pie

[ENH] hatch keyword for pie + some pie documentation

Author: jklymak

doc/users/next_whats_new/pie_hatch.rst

@@ -0,0 +1,18 @@
+``hatch`` parameter for pie
+-------------------------------------------
+
+`~matplotlib.axes.Axes.pie` now accepts a *hatch* keyword that takes as input
+a hatch or list of hatches:
+
+.. plot::
+    :include-source: true
+    :alt: Two pie charts, identified as ax1 and ax2, both have a small blue slice, a medium orange slice, and a large green slice. ax1 has a dot hatching on the small slice, a small open circle hatching on the medium slice, and a large open circle hatching on the large slice. ax2 has the same large open circle with a dot hatch on every slice.
+
+    fig, (ax1, ax2) = plt.subplots(ncols=2)
+    x = [10, 30, 60]
+
+    ax1.pie(x, hatch=['.', 'o', 'O'])
+    ax2.pie(x, hatch='.O')
+
+    ax1.set_title("hatch=['.', 'o', 'O']")
+    ax2.set_title("hatch='.O'")

lib/matplotlib/axes/_axes.py

@@ -3075,7 +3075,7 @@ def pie(self, x, explode=None, labels=None, colors=None,
             autopct=None, pctdistance=0.6, shadow=False, labeldistance=1.1,
             startangle=0, radius=1, counterclock=True,
             wedgeprops=None, textprops=None, center=(0, 0),
-            frame=False, rotatelabels=False, *, normalize=True):
+            frame=False, rotatelabels=False, *, normalize=True, hatch=None):
         """
         Plot a pie chart.
 
@@ -3101,29 +3101,34 @@ def pie(self, x, explode=None, labels=None, colors=None,
             A sequence of colors through which the pie chart will cycle.  If
             *None*, will use the colors in the currently active cycle.
 
+        hatch : str or list, default: None
+            Hatching pattern applied to all pie wedges or sequence of patterns
+            through which the chart will cycle. For a list of valid patterns,
+            see :doc:`/gallery/shapes_and_collections/hatch_style_reference`.
+
+            .. versionadded:: 3.7
+
         autopct : None or str or callable, default: None
-            If not *None*, is a string or function used to label the wedges
-            with their numeric value.  The label will be placed inside the
-            wedge.  If it is a format string, the label will be ``fmt % pct``.
-            If it is a function, it will be called.
+            If not *None*, *autopct* is a string or function used to label the
+            wedges with their numeric value. The label will be placed inside
+            the wedge. If *autopct* is a format string, the label will be
+            ``fmt % pct``. If *autopct* is a function, then it will be called.
 
         pctdistance : float, default: 0.6
-            The ratio between the center of each pie slice and the start of
-            the text generated by *autopct*.  Ignored if *autopct* is *None*.
+            The relative distance along the radius at which the the text
+            generated by *autopct* is drawn. To draw the text outside the pie,
+            set *pctdistance* > 1. This parameter is ignored if *autopct* is
+            ``None``.
+
+        labeldistance : float or None, default: 1.1
+            The relative distance along the radius at which the labels are
+            drawn. To draw the labels inside the pie, set  *labeldistance* < 1.
+            If set to ``None``, labels are not drawn but are still stored for
+            use in `.legend`.
 
         shadow : bool, default: False
             Draw a shadow beneath the pie.
 
-        normalize : bool, default: True
-            When *True*, always make a full pie by normalizing x so that
-            ``sum(x) == 1``. *False* makes a partial pie if ``sum(x) <= 1``
-            and raises a `ValueError` for ``sum(x) > 1``.
-
-        labeldistance : float or None, default: 1.1
-            The radial distance at which the pie labels are drawn.
-            If set to ``None``, label are not drawn, but are stored for use in
-            ``legend()``
-
         startangle : float, default: 0 degrees
             The angle by which the start of the pie is rotated,
             counterclockwise from the x-axis.
@@ -3135,11 +3140,11 @@ def pie(self, x, explode=None, labels=None, colors=None,
             Specify fractions direction, clockwise or counterclockwise.
 
         wedgeprops : dict, default: None
-            Dict of arguments passed to the wedge objects making the pie.
-            For example, you can pass in ``wedgeprops = {'linewidth': 3}``
-            to set the width of the wedge border lines equal to 3.
-            For more details, look at the doc/arguments of the wedge object.
-            By default, ``clip_on=False``.
+            Dict of arguments passed to each `.patches.Wedge` of the pie.
+            For example, ``wedgeprops = {'linewidth': 3}`` sets the width of
+            the wedge border lines equal to 3. By default, ``clip_on=False``.
+            When there is a conflict between these properties and other
+            keywords, properties passed to *wedgeprops* take precedence.
 
         textprops : dict, default: None
             Dict of arguments to pass to the text objects.
@@ -3153,6 +3158,11 @@ def pie(self, x, explode=None, labels=None, colors=None,
         rotatelabels : bool, default: False
             Rotate each label to the angle of the corresponding slice if true.
 
+        normalize : bool, default: True
+            When *True*, always make a full pie by normalizing x so that
+            ``sum(x) == 1``. *False* makes a partial pie if ``sum(x) <= 1``
+            and raises a `ValueError` for ``sum(x) > 1``.
+
         data : indexable object, optional
             DATA_PARAMETER_PLACEHOLDER
 
@@ -3207,6 +3217,8 @@ def pie(self, x, explode=None, labels=None, colors=None,
             def get_next_color():
                 return next(color_cycle)
 
+        hatch_cycle = itertools.cycle(np.atleast_1d(hatch))
+
         _api.check_isinstance(Number, radius=radius, startangle=startangle)
         if radius <= 0:
             raise ValueError(f'radius must be a positive number, not {radius}')
@@ -3233,6 +3245,7 @@ def get_next_color():
             w = mpatches.Wedge((x, y), radius, 360. * min(theta1, theta2),
                                360. * max(theta1, theta2),
                                facecolor=get_next_color(),
+                               hatch=next(hatch_cycle),
                                clip_on=False,
                                label=label)
             w.set(**wedgeprops)

lib/matplotlib/pyplot.py

@@ -2779,15 +2779,15 @@ def pie(
         pctdistance=0.6, shadow=False, labeldistance=1.1,
         startangle=0, radius=1, counterclock=True, wedgeprops=None,
         textprops=None, center=(0, 0), frame=False,
-        rotatelabels=False, *, normalize=True, data=None):
+        rotatelabels=False, *, normalize=True, hatch=None, data=None):
     return gca().pie(
         x, explode=explode, labels=labels, colors=colors,
         autopct=autopct, pctdistance=pctdistance, shadow=shadow,
         labeldistance=labeldistance, startangle=startangle,
         radius=radius, counterclock=counterclock,
         wedgeprops=wedgeprops, textprops=textprops, center=center,
         frame=frame, rotatelabels=rotatelabels, normalize=normalize,
-        **({"data": data} if data is not None else {}))
+        hatch=hatch, **({"data": data} if data is not None else {}))
 
 
 # Autogenerated by boilerplate.py.  Do not edit as changes will be lost.

lib/matplotlib/tests/test_axes.py

@@ -5744,6 +5744,24 @@ def test_normalize_kwarg_pie():
     assert abs(t2[0][-1].theta2 - 360.) > 1e-3
 
 
+@check_figures_equal()
+def test_pie_hatch_single(fig_test, fig_ref):
+    x = [0.3, 0.3, 0.1]
+    hatch = '+'
+    fig_test.subplots().pie(x, hatch=hatch)
+    wedges, _ = fig_ref.subplots().pie(x)
+    [w.set_hatch(hatch) for w in wedges]
+
+
+@check_figures_equal()
+def test_pie_hatch_multi(fig_test, fig_ref):
+    x = [0.3, 0.3, 0.1]
+    hatch = ['/', '+', '.']
+    fig_test.subplots().pie(x, hatch=hatch)
+    wedges, _ = fig_ref.subplots().pie(x)
+    [w.set_hatch(hp) for w, hp in zip(wedges, hatch)]
+
+
 @image_comparison(['set_get_ticklabels.png'])
 def test_set_get_ticklabels():
     # test issue 2246