-The `graph` directive supports the following parameters:
-
-- `src` - The graphviz source to render.
-- `type` - The type of graph to render: `graph` or `digraph`. Defaults to
- `digraph`.
-- `prog` - The graphviz program to render with: `dot`, `neato`, `fdp`, `twopi`,
- or `circo`. Defaults to `dot`.
-- `height`, `width` - Limit the size of the graph to a given height and width,
- in inches. You must specify both to limit the size; otherwise, graphviz will
- choose a size, without any limit.
-