added pie labeling example (rev1)

ImportanceOfBeingErnest · ImportanceOfBeingErnest · commit df2c889c1be6 · 2018-04-05T00:41:35.000+02:00
diff --git a/examples/pie_and_polar_charts/pie_and_donut_labels.py b/examples/pie_and_polar_charts/pie_and_donut_labels.py
@@ -6,14 +6,14 @@
 Welcome to the matplotlib bakery. We will create a pie and a donut
 chart through the :meth:`pie method <matplotlib.axes.Axes.pie>` and
 show how to label them with a :meth:`legend <matplotlib.axes.Axes.legend>`
-as well as with :meth:`annotations <matplotlib.axes.Axes.annotation>`.
+as well as with :meth:`annotations <matplotlib.axes.Axes.annotate>`.
 """
 
 ###############################################################################
 # As usual we would start by defining the imports and create a figure with
 # subplots. To have some space for the big cake, we use
-# :meth:`subplots_adjust <matplotlib.figure.subplots_adjust>` to adjust the
-# spacings.
+# :meth:`subplots_adjust <matplotlib.figure.Figure.subplots_adjust>` to
+# adjust the spacings.
 
 import numpy as np
 import matplotlib.pyplot as plt
@@ -22,25 +22,24 @@
 fig.subplots_adjust(top=0.92, bottom=0.08)
 plt.setp((ax, ax2), aspect="equal")
 
-
 ###############################################################################
 # Now it's time for the pie. Starting with a pie recipe, we create the data
 # and a list of labels from it.
 #
-# We can `provide a function to the ``autopct`` argument, which will expand
-# automatic percentage labeling by the absolute values, which we calculate 
-# back from realtive data and the known sum of all values.
+# We can provide a function to the ``autopct`` argument, which will expand
+# automatic percentage labeling by showing absolute values; we calculate
+# the latter back from realtive data and the known sum of all values.
 #
-# We then create the pie and store the tuple of returned objects in a
-# variable ``pie``.
-# The first returned element of that tuple is a list of the wedges. Those are
+# We then create the pie and store the returned objects for later.
+# The first returned element of the returned tuple is a list of the wedges.
+# Those are
 # :class:`matplotlib.patches.Wedge <matplotlib.patches.Wedge>` patches, which
-# can directly be used as the handles for a legend. We can use the 
+# can directly be used as the handles for a legend. We can use the
 # legend's ``bbox_to_anchor`` argument to position the legend outside of
-# the pie. Here we use the axes coordinates ``(1, 0, 0.5, 1)`` together 
+# the pie. Here we use the axes coordinates ``(1, 0, 0.5, 1)`` together
 # with the location ``"center left"``; i.e.
 # the left central point of the legend will be at the left central point of the
-# bounding box, spanning from ``(1,0)`` to ``(1.5,1)`` in axes coordinates. 
+# bounding box, spanning from ``(1,0)`` to ``(1.5,1)`` in axes coordinates.
 
 
 recipe = ["375 g flour",
@@ -51,44 +50,47 @@
 data = [float(x.split()[0]) for x in recipe]
 ingredients = [x.split()[-1] for x in recipe]
 
+
 def func(pct, allvals):
     absolute = int(pct/100.*np.sum(allvals))
     return "{:.1f}%\n({:d} g)".format(pct, absolute)
 
-pie = ax.pie(data, autopct=lambda pct: func(pct, data),
-             textprops=dict(color="w"))
 
-ax.legend(pie[0], ingredients,
+wedges, texts, autotexts = ax.pie(data, autopct=lambda pct: func(pct, data),
+                                  textprops=dict(color="w"))
+
+ax.legend(wedges, ingredients,
           title="Ingredients",
           loc="center left",
           bbox_to_anchor=(1, 0, 0.5, 1))
 
-plt.setp(pie[2], size=8, weight="bold")
+plt.setp(autotexts, size=8, weight="bold")
 
 ax.set_title("Matplotlib bakery: A pie")
 
 
-
 ###############################################################################
 # Now it's time for the donut. Starting with a donut recipe, we transcribe
 # the data to numbers (converting 1 egg to 50 g), and directly plot the pie.
-# The pie? Wait... it's going to be donut, is it not? 
+# The pie? Wait... it's going to be donut, is it not?
 # Well, as we see here, the donut is a pie, having a certain ``width`` set to
 # the wedges, which is different from its radius. It's as easy as it gets.
 # This is done via the ``wedgeprops`` argument.
 #
-# Labeling the wedges is done via ``annotate``. We first create some
+# We then want to label the wedges via
+# :meth:`annotations <matplotlib.axes.Axes.annotate>`. We first create some
 # dictionaries of common properties, which we can later pass as keyword
 # argument. We then iterate over all wedges and for each
 #
-# * calcualte the angle of the wedge's center
-# * from that obtain the coordinates of the point at that angle on the 
-#   circonference
+# * calculate the angle of the wedge's center,
+# * from that obtain the coordinates of the point at that angle on the
+#   circumference,
 # * determine the horizontal alignment of the text, depending on which side
-#   of the circle the point lies.
+#   of the circle the point lies,
 # * update the connection style with the obtained angle to have the annotation
-#   arrow point outwards from the donut
-# * finally create the annotation with all the previously determined parameters
+#   arrow point outwards from the donut,
+# * finally, create the annotation with all the previously
+#   determined parameters.
 
 recipe = ["225 g flour",
           "90 g sugar",
@@ -99,23 +101,22 @@ def func(pct, allvals):
 
 data = [225, 90, 50, 60, 100, 5]
 
-donut = ax2.pie(data, radius=1, wedgeprops=dict(width=0.5), startangle=-40)
+wedges, texts = ax2.pie(data, wedgeprops=dict(width=0.5), startangle=-40)
 
 bbox_props = dict(boxstyle="square,pad=0.3", fc="w", ec="k", lw=0.72)
-kw = dict(xycoords='data',textcoords='data',arrowprops=dict(arrowstyle="-"),
+kw = dict(xycoords='data', textcoords='data', arrowprops=dict(arrowstyle="-"),
           bbox=bbox_props, zorder=0, va="center")
 
-for i, p in enumerate(donut[0]):
+for i, p in enumerate(wedges):
     ang = (p.theta2 - p.theta1)/2. + p.theta1
     y = np.sin(np.deg2rad(ang))
     x = np.cos(np.deg2rad(ang))
     horizontalalignment = ["", "left", "right"][int(np.sign(x))]
     connectionstyle = "angle,angleA=0,angleB={}".format(ang)
-    kw["arrowprops"].update({"connectionstyle" :  connectionstyle})
+    kw["arrowprops"].update({"connectionstyle":connectionstyle})
     ax2.annotate(recipe[i], xy=(x, y), xytext=(1.35*np.sign(x), 1.4*y),
                  horizontalalignment=horizontalalignment, **kw)
-    
-ax2.set_title("Matplotlib bakery: A donut")
 
-plt.show()
+ax2.set_title("Matplotlib bakery: A donut")
 
+plt.show()
