Prohibit edge node intersections

Question

my question is how to prevent my edge crossing its node, when rendering a DoT file using Graphviz. I have seen various questions on StackOverflow regarding my question, which eventually boiled down to setting overlap=false or setting the anchor (see :n, :s in minimal example below) in combination with rank and splines properly. However, I still get an edge crossing my node. Setting the anchors even makes it worse. I don't get what I am doing wrong. I have read and tried several things from the docs like scalexy, overlap_scaling, etc. and none of them worked or even had an effect. Could someone explain me what I am doing wrong. Is there probably a setting I made, which is not compatible with the overlap=false setting?

You find a minimal example below:

digraph minimal_example {
  overlap=false;
  overlap_scaling=5;
  rankdir=RL;
  splines=line;

 "a" 
 "g" [shape=diamond, color=red] 

 "a" -> "f"; {rank=same; "f"; "a"}
 "g":n -> "b":s; {rank=same; "b"; "g"}
 "f" -> { "d" "b" }
 "b" -> { "c" }
 "c" -> { "d" }
 "d" -> { "e" }
 "e" -> {  }
}

Rendering via: `dot -Tsvg -Nshape=rect -o output.svg

Desired outcome: Move node g below node b. The idea was to achieve this main goal by prohibiting these ugly intersection between nodes and edges.

Version: dot - graphviz version 2.43.0 (0)

System: Ubuntu 20.04.4 LTS

Answer 1

• rankdir=RL; makes an interesting graph
• overlap (and overlap_scaling) do not apply to dot, only to the other engines (https://graphviz.org/docs/attrs/overlap/)
• "e" -> { } does nothing
• "d" -> { "e" } (and similar) can be rewritten as d -> e (braces do nothing here)
• as you noted, ports do not solve this problem
• FYI, your Ubuntu version is pretty old. But that is not causing your problems.
• relationships (->) in the same rank are normally shown downward, thus g->b is shown downward (and not where you want it)
• you might also try the other engines (neato, fdp, circo, twopi - all mad interesting output)

OK, two solutions:

digraph minimal_example {
  rankdir=RL;
  //splines=line;  // defaults to splines=true
  node [shape=rect]
// "a"  // oddly, removing this declaration mad a difference
 "g" [shape=diamond, color=red] 

 "a" -> "f"; {rank=same; "f"; "a"}
 "g" -> "b"; {rank=same; "b"; "g"}
 "f" -> { "d" "b" }
 "b" -> { "c" }
 "c" -> { "d" }
 "d" -> { "e" }
}

Giving:

Or

digraph minimal_example {
  rankdir=RL;
  splines=line;
  node [shape=rect]

 "g" [shape=diamond, color=red] 

 "a" -> "f"; {rank=same; "f"; "a"}
 "g" -> "b"  {rank=same; "b"; "g"}
 "f" -> { "d" "b" }
 "b" -> { "c" }
 "c" -> { "d" }
 "d" -> { "e" }
}

Giving: