title: Missing labels in matplotlib pie chart
body: <p>I try to plot a pie chart using Python 3 Matplotlib v2.2.2-4build1 on Ubuntu 18.10. Everything seems to be ok except labels - they are missing. Tried to add it according to official documentation (<a href="https://matplotlib.org/api/_as_gen/matplotlib.pyplot.pie.html" rel="nofollow noreferrer">https://matplotlib.org/api/_as_gen/matplotlib.pyplot.pie.html</a>), tried to use an example from the web (<a href="https://pythonspot.com/matplotlib-pie-chart/" rel="nofollow noreferrer">https://pythonspot.com/matplotlib-pie-chart/</a>) - same result, no labels.</p>
  
  <p>Here is a simplified version of my code:</p>
  
  <pre><code>import numpy as np
  import matplotlib.pyplot as plt
  import sys
  
  headers = ['a', 'b', 'c', 'd', 'e']
  values = [5, 4, 3, 2, 1]
  sum = sum(values)
  labels = []
  for v in values:
      labels.append('{:.1f}%'.format(100 * v / sum))
  fig, ax = plt.subplots(figsize=(6, 3), subplot_kw=dict(aspect="equal"))
  wedges, texts = ax.pie(values, labels=labels, textprops=dict(color="w"))
  plt.show()
  </code></pre>
  
  <p>Here is what I see - no labels:</p>
  
  <p><a href="https://i.stack.imgur.com/FJGwI.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/FJGwI.png" alt="Pie chart with no labels"></a></p>
  
  <p>Tried to use a tuple instead of a list - same thing.</p>
  
  <p>Could anybody help me?</p>