initial commit, fixes to formatting and squashing of commits

.flake8

@@ -182,6 +182,7 @@ per-file-ignores =
     examples/misc/table_demo.py: E201
     examples/mplot3d/voxels.py: E501
     examples/mplot3d/wire3d_zero_stride.py: E501
+    examples/pie_and_polar_charts/bar_of_pie.py: E402
     examples/pie_and_polar_charts/nested_pie.py: E402
     examples/pie_and_polar_charts/pie_and_donut_labels.py: E402
     examples/pie_and_polar_charts/pie_demo2.py: E402

examples/pie_and_polar_charts/bar_of_pie.py

+"""
+==========
+Bar of pie
+==========
+Make a "bar of pie" chart where the first slice of the pie is
+"exploded" into a bar chart with a further breakdown of said slice's
+characteristics. The example demonstrates using a figure with multiple
+sets of axes and using the axes patches list to add two ConnectionPatches
+to link the subplot charts.
+"""
+
+import matplotlib.pyplot as plt
+from matplotlib.patches import ConnectionPatch
+import numpy as np
+
+# make figure and assign axis objects
+fig = plt.figure(figsize=(9, 5.0625))
+ax1 = fig.add_subplot(121)
+ax2 = fig.add_subplot(122)
+fig.subplots_adjust(wspace=0)
+
+# pie chart parameters
+ratios = [.27, .56, .17]
+labels = ['Approve', 'Disapprove', 'Undecided']
+explode = [0.1, 0, 0]
+# rotate so that first wedge is split by the x-axis
+angle = -180 * ratios[0]
+ax1.pie(ratios, autopct='%1.1f%%', startangle=angle,
+        labels=labels, explode=explode)
+
+# bar chart parameters
+
+xpos = 0
+bottom = 0
+ratios = [.33, .54, .07, .06]
+width = .2
+colors = [[.1, .3, .5], [.1, .3, .3], [.1, .3, .7], [.1, .3, .9]]
+
+for j in range(len(ratios)):
+    height = ratios[j]
+    ax2.bar(xpos, height, width, bottom=bottom, color=colors[j])
+    ypos = bottom + ax2.patches[j].get_height() / 2
+    bottom += height
+    ax2.text(xpos, ypos, "%d%%" % (ax2.patches[j].get_height() * 100),
+             ha='center')
+
+ax2.set_title('Age of approvers')
+ax2.legend(('50-65', 'Over 65', '35-49', 'Under 35'))
+ax2.axis('off')
+ax2.set_xlim(- 2.5 * width, 2.5 * width)
+
+# use ConnectionPatch to draw lines between the two plots
+# get the wedge data
+theta1, theta2 = ax1.patches[0].theta1, ax1.patches[0].theta2
+center, r = ax1.patches[0].center, ax1.patches[0].r
+bar_height = sum([item.get_height() for item in ax2.patches])
+
+# draw top connecting line
+x = r * np.cos(np.pi / 180 * theta2) + center[0]
+y = np.sin(np.pi / 180 * theta2) + center[1]
+con = ConnectionPatch(xyA=(- width / 2, bar_height), xyB=(x, y),
+                      coordsA="data", coordsB="data", axesA=ax2, axesB=ax1)
+con.set_color([0, 0, 0])
+con.set_linewidth(4)
+ax2.add_artist(con)
+
+# draw bottom connecting line
+x = r * np.cos(np.pi / 180 * theta1) + center[0]
+y = np.sin(np.pi / 180 * theta1) + center[1]
+con = ConnectionPatch(xyA=(- width / 2, 0), xyB=(x, y), coordsA="data",
+                      coordsB="data", axesA=ax2, axesB=ax1)
+con.set_color([0, 0, 0])
+ax2.add_artist(con)
+con.set_linewidth(4)
+
+plt.show()
+
+#############################################################################
+#
+# ------------
+#
+# References
+# """"""""""
+#
+# The use of the following functions, methods, classes and modules is shown
+# in this example:
+
+import matplotlib
+matplotlib.axes.Axes.pie
+matplotlib.axes.Axes.bar
+matplotlib.pyplot
+matplotlib.patches.ConnectionPatch