Merge pull request matplotlib#24812 from story645/pie-example

[Doc] expanded basic pie example

Author: QuLogic

examples/pie_and_polar_charts/pie_features.py

@@ -1,40 +1,100 @@
 """
-===============
-Basic pie chart
-===============
+==========
+Pie charts
+==========
 
-Demo of a basic pie chart plus a few additional features.
+Demo of plotting a pie chart.
 
-In addition to the basic pie chart, this demo shows a few optional features:
-
-* slice labels
-* auto-labeling the percentage
-* offsetting a slice with "explode"
-* drop-shadow
-* custom start angle
+This example illustrates various parameters of `~matplotlib.axes.Axes.pie`.
+"""
 
-Note about the custom start angle:
+# %%
+# Label slices
+# ------------
+#
+# Plot a pie chart of animals and label the slices. To add
+# labels, pass a list of labels to the *labels* parameter
 
-The default ``startangle`` is 0, which would start the "Frogs" slice on the
-positive x-axis. This example sets ``startangle = 90`` such that everything is
-rotated counter-clockwise by 90 degrees, and the frog slice starts on the
-positive y-axis.
-"""
 import matplotlib.pyplot as plt
-
-# Pie chart, where the slices will be ordered and plotted counter-clockwise:
 labels = 'Frogs', 'Hogs', 'Dogs', 'Logs'
 sizes = [15, 30, 45, 10]
+
+fig, ax = plt.subplots()
+ax.pie(sizes, labels=labels)
+
+# %%
+# Each slice of the pie chart is a `.patches.Wedge` object; therefore in
+# addition to the customizations shown here, each wedge can be customized using
+# the *wedgeprops* argument, as demonstrated in
+# :doc:`/gallery/pie_and_polar_charts/nested_pie`.
+#
+# Auto-label slices
+# -----------------
+#
+# Pass a function or format string to *autopct* to label slices.
+
+fig, ax = plt.subplots()
+ax.pie(sizes, labels=labels, autopct='%1.1f%%')
+
+# %%
+# By default, the label values are obtained from the percent size of the slice.
+#
+# Color slices
+# ------------
+#
+# Pass a list of colors to *colors* to set the color of each slice.
+
+fig, ax = plt.subplots()
+ax.pie(sizes, labels=labels,
+       colors=['olivedrab', 'rosybrown', 'gray', 'saddlebrown'])
+
+# %%
+# Hatch slices
+# ------------
+#
+# Pass a list of hatch patterns to *hatch* to set the pattern of each slice.
+
+fig, ax = plt.subplots()
+ax.pie(sizes, labels=labels, hatch=['**O', 'oO', 'O.O', '.||.'])
+
+# %%
+# Swap label and autopct text positions
+# -------------------------------------
+# Use the *labeldistance* and *pctdistance* parameters to position the *labels*
+# and *autopct* text respectively.
+
+fig, ax = plt.subplots()
+ax.pie(sizes, labels=labels, autopct='%1.1f%%',
+       pctdistance=1.25, labeldistance=.6)
+
+# %%
+# *labeldistance* and *pctdistance* are ratios of the radius; therefore they
+# vary between ``0`` for the center of the pie and ``1`` for the edge of the
+# pie, and can be set to greater than ``1`` to place text outside the pie.
+#
+# Explode, shade, and rotate slices
+# ---------------------------------
+#
+# In addition to the basic pie chart, this demo shows a few optional features:
+#
+# * offsetting a slice using *explode*
+# * add a drop-shadow using *shadow*
+# * custom start angle using *startangle*
+#
+# This example orders the slices, separates (explodes) them, and rotates them.
+
 explode = (0, 0.1, 0, 0)  # only "explode" the 2nd slice (i.e. 'Hogs')
 
-fig1, ax1 = plt.subplots()
-ax1.pie(sizes, explode=explode, labels=labels, autopct='%1.1f%%',
+fig, ax = plt.subplots()
+ax.pie(sizes, explode=explode, labels=labels, autopct='%1.1f%%',
         shadow=True, startangle=90)
-ax1.axis('equal')  # Equal aspect ratio ensures that pie is drawn as a circle.
-
 plt.show()
 
 # %%
+# The default *startangle* is 0, which would start the first slice ("Frogs") on
+# the positive x-axis. This example sets ``startangle = 90`` such that all the
+# slices are rotated counter-clockwise by 90 degrees, and the frog slice starts
+# on the positive y-axis.
 #
 # .. admonition:: References
 #