title: Gradient facecolor matplotlib bar plot
body: <p>How do I add a gradient <code>facecolor</code> to my bar plots? I want to know how to use simple one-color gradients to complex multicolor gradients. Here is some example code:</p>
  
  <pre><code>import numpy as np
  import matplotlib.pyplot as plt
  
  plt.figure(figsize=(1,5))
  plt.axis([0,1,-50,200])
  plt.xticks([])
  plt.yticks([-40,180])
  plt.bar(left=0, width=1, bottom=-40, height=220, color='r')
  plt.subplots_adjust(left=0.4, right=0.8)
  plt.savefig("test.png")
  </code></pre>