How can I make Sphinx's inheritance_diagram readable?

Question

Similar to this chap's post, I'm seeing Sphinx generate unreadable graphviz output: How can I generate readable output? - Nothing happens if I add `-Gfontsize=140` - If I tell it to use `neato` instead of `dot` it produces readable output, but the graphs aren't tree-like.

Accepted Answer

I figured out the answer from this thread. In the `graphviz.py` code, they have a default value for the size of the graph at 8.0x12.0. If you want to allow Graphviz to determine the size you need to put this in `conf.py` so the Sphinx graphviz extension uses your empty string instead of its default:

```
inheritance_graph_attrs = dict(size='""')
```

Also, if you're hitting this issue then the graph may be too wide once you allow the size to be determined by Graphviz. You'll additionally want attribute `rankdir="TB"` so the tree goes from top to bottom instead of left to right:

```
inheritance_graph_attrs = dict(rankdir="TB", size='""')
```

How can I make Sphinx's inheritance_diagram readable?

Solution

Problem