title: How to get matplotlib text(x, y, "String", bbox=...) axis coordinates
body: <p>For example, I can create a text with rounded box using</p>
  
  <pre><code>fig, ax = plt.subplots(1,1)
  obj = ax.text(0.2, 0.6, "something", bbox = dict(boxstyle = 'round'))
  </code></pre>
  
  <p>Now I would like to get the rounded box corner points in the plot. I have tried using</p>
  
  <p><code>obj.clipbox.corners()</code></p>
  
  <p>But it does not return the points of the plot, it does not match the points in the plot. Also have tried using</p>
  
  <p><code>obj.clipbox.transformed(...)</code></p>
  
  <p>still not work. May I ask for help on this? Thanks.</p>