title: How to make invisible nodes occupy space in graphviz?
body: <p>I want to plot a binary tree using graphviz, and it is important that the left child of a node appear to the left (duh) of the right child. If there is no left child, I want an empty space on the left, to make it visually clear that the right child is the right child. I want to do the same if there is no right child (on the right there should be an empty space).</p>
  
  <p>For instance, I want something like:</p>
  
  <pre><code>A                     A
    \     instead of    |
      B                 B
  </code></pre>
  
  <p>I can make sure Graphviz will place the left child before the right by using ordering = "out", but if there is no left child, then the right child might appear right below its parent. </p>
  
  <p>If I add dummy nodes where a child is missing, I get the correct layout, but the dummy nodes are then on the picture (and I don't want them). I tried using style = "invis" for the dummy nodes and edges connecting to them, but then it is as if they didn't exist for graphviz. How can I get around this problem?</p>