title: Get bounding boxes of individual elements of a PathCollection from plt.scatter
body: <p>is there is a way to get bounding boxes of individual elements in the output of plt.scatter()? I can get offsets (i.e. x and y coordinates - which I have to begin with since I use them for plotting), and the sizes, but the sizes are not in data units, so even a hacky conversion from area to radius to get sizes of bboxes won't work...</p>
  
  <p>Is there a good way to do this?</p>
  
  <pre><code>tips = sns.load_dataset('tips')[:20]
  f, ax = plt.subplots()
  sc = ax.scatter(tips["total_bill"], y=tips["tip"], s=(tips["size"]*3)**2)
  plt.show()
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/7z2ck.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/7z2ck.png" alt="enter image description here"></a></p>
  
  <p><code>sc.properties()['offsets']</code></p>
  
  <pre><code>array([[ 16.99,   1.01],
         [ 10.34,   1.66],
         [ 21.01,   3.5 ],
         [ 23.68,   3.31],
         [ 24.59,   3.61],
         [ 25.29,   4.71],
         [  8.77,   2.  ],
         [ 26.88,   3.12],
         [ 15.04,   1.96],
         [ 14.78,   3.23],
         [ 10.27,   1.71],
         [ 35.26,   5.  ],
         [ 15.42,   1.57],
         [ 18.43,   3.  ],
         [ 14.83,   3.02],
         [ 21.58,   3.92],
         [ 10.33,   1.67],
         [ 16.29,   3.71],
         [ 16.97,   3.5 ],
         [ 20.65,   3.35]])
  </code></pre>
  
  <p><code>sc.get_sizes()</code></p>
  
  <p><code>array([ 36,  81,  81,  36, 144, 144,  36, 144,  36,  36,  36, 144,  36,
         144,  36,  36,  81,  81,  81,  81])</code></p>