title: Flutter Layout Row / Column - share width, expand height
body: <p>I'm still having a bit of trouble with the layouting in Flutter.<br>
  Right now I want to have the available space shared between 3 widgets, in a quadrant layout.
  The width is evenly shared (this works fine via 2 <code>Expanded</code> widgets in a Row), but now I also want the height to adjust automatically so <code>widget3.height == widget1.height + widget2.height</code>.
  <a href="https://i.stack.imgur.com/jEtVl.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/jEtVl.jpg" alt="layout"></a>
  If the content of <code>widget3</code> is larger, I want <code>widget1</code> and <code>widget2</code> to adjust their height and vice versa.</p>
  
  <p>Is this even possible in Flutter?</p>