title: annotate in matplotlib places the number 1 off center when saved as a pdf
body: <p>I am finding that the annotate function in matplotlib places the number 1 off center when the figure is saved as a pdf.  All other numbers appear to be fine.  For example,</p>
  
  <pre><code>import matplotlib.pylab as plt
  fig = plt.figure(figsize = (5,5))
  ax = plt.subplot(111)
  ax.plot([0,1], [0,1])
  
  txts = ['1', '2', '3']
  y_coords = [0.9, 0.8, 0.7]
  for txt, y_coord in zip(txts, y_coords):
      ax.annotate(txt, xy = (0.25, y_coord), \
          size=36, va='center', ha='center', fontname = 'Helvetica', \
          bbox=dict(boxstyle='square', fc = 'w'))
  
  plt.savefig('Test.pdf', bbox_inches = 'tight', pad_inches = 0)
  plt.savefig('Test.jpg', bbox_inches = 'tight', pad_inches = 0)
  </code></pre>
  
  <p>produces a pdf file that looks like this</p>
  
  <p><img src="https://s7.postimg.org/w41b8tj6z/Test1_page_1.jpg" alt="pdf"></p>
  
  <p>and a jpg file that looks like this</p>
  
  <p><img src="https://s11.postimg.org/nldehvzgz/Test.jpg" alt="jpg"></p>
  
  <p>In the pdf, the 1 is not in the center of the rectangle, but the 2 and 3 are in the centers of their respective rectangles.  In the jpg, all three numbers are in the center of their respective rectangles.  If I was creating rasterized images I would be happy with the jpg, but I really want a pdf output.  </p>
  
  <p>Is this a bug?  Am I doing something wrong?</p>
  
  <p>I am using Matplotlib 1.2.1 on Python 2.7.3 under Mac OS X 10.8.5</p>