[Drup]

I'm surprised they chose that algorithm, it's fairly limited and not that efficient.

If your nodes have width, you should read "Improving Walker's Algorithm to Run in Linear Time" (I have an implementation here: https://github.com/Drup/tree_layout)

If your nodes have width and height, you need to read "Drawing Non-layered Tidy Trees in Linear Time"

If you want to go bananas visualizing n-ary trees: https://treevis.net/ :D