Yeah when you have requirements around layout graphviz gets a bit hairy. It's still doable with rank directives and invisible nodes, but that's the point where I start to think if I shouldn't do it another way (e.g. in this case I'd probably have done an ascii diagram rendered).
digraph G {
rankdir=LR
node [shape=rectangle]
// nodes declared in order of horizontal position ("rank")
exciter
filter
subgraph H {
// nodes at the same horizontal rank
rank=same
plus [label="+"]
// invisible node for layout purposes
p1 [width=0, height=0, margin=0, label=""]
}
subgraph I {
rank=same
delay
nl
}
subgraph J {
rank=same
filter_ [label="filter"]
p2 [width=0, height=0, margin=0, label=""]
}
out
exciter -> filter -> plus -> delay -> filter_ -> out
filter_ -> p2 [arrowhead=none]
p2 -> nl -> p1 [arrowhead=none]
p1 -> plus
}
Nice! Thanks for sharing your graphviz-fu, that's actually not as hairy as I thought it would be, and the result is neat enough. I do remember playing with subgraphs and ranks when testing graphviz, but I gave up before getting this far. I'll try applying those techniques to more complex diagrams, and if I find it workable, I might just switch to that.
