title: Coordinates of box of annotations in matplotlib
body: <p>How can I get the coordinates of the box displayed in the following plot?</p>
  
  <p><img src="https://i.stack.imgur.com/89DNz.png" alt="enter image description here"></p>
  
  <pre><code>fig, ax = subplots()
  x = ax.annotate('text', xy=(0.5, 0), xytext=(0.0,0.7), 
                  ha='center', va='bottom',
                  bbox=dict(boxstyle='round', fc='gray', alpha=0.5),
                  arrowprops=dict(arrowstyle='-&gt;', color='blue'))
  </code></pre>
  
  <p>I tried to inspect the properties of this object, but I couldn't find something suited to this purpose. There is a property called <code>get_bbox_patch()</code> which could be on the right track, however, I get results in a different coordinate system (or associated to a different property)</p>
  
  <pre><code>y = x.get_bbox_patch()
  y.get_width()
  63.265625
  </code></pre>
  
  <p>Thanks  a lot!</p>