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I didn't realize graphviz could do graphs of that quality. I'm used to graphviz's examples of DAGs and badly formatted text. Can you tell us more of how you're using graphviz? Wouldn't you need to move away from it as you move towards an interactive editor, in favor of other more javascript-based layout algorithms? What path do you think you'd follow for that?



Graphviz is only used to find the positions for the nodes using Graphviz's Neato algorithm. The nodes and the lines themselves are all rendered using the Haskell library Diagrams [0].

The next step for the project is to improve graph layout (see Glance issue here [1]), which likely means moving away from Graphviz.

What tools to use for interactivity or an editor is still up in the air.

[0] http://projects.haskell.org/diagrams/

[1] https://github.com/rgleichman/glance/issues/1


Why are the nodes rotated like that? It seems very distracting, and I think that might also be partly causing your "layout is too spread out" issue? [1] It could also be exacerbating your second issue of crossing edges - you are getting crossing edges in even the simplest graphs (e.g. your "f1" function example, with 5 nodes).

GraphViz's "dot" algorithm (i.e., Sugiyama-style graph drawing algorithm) [2] should give a fairly compact representation that is organized into layers, and avoids crossing edges in at least simple cases, but rotating the nodes would again "spread out" the layout by forcing increasing height of each layer.

Under "Possible solutions" you mention "create a better graph layout algorithm" - that sounds quite ambitious, wouldn't this be a PhD-thesis-level research task in itself?

The only graph drawing library I'm aware of that might be competitive with GraphViz's algorithms is MSAGL [3] but that's a .NET library.

[1] https://github.com/rgleichman/glance/issues/1

[2] https://en.wikipedia.org/wiki/Layered_graph_drawing

[3] https://www.microsoft.com/en-us/research/project/microsoft-a...


Rotating nodes is an easy way to reduce line crossings. Here's a comparison [0].

However, it does seem that vertical and angled text is harder to read than horizontal text, so there is room to improve here.

[0] https://gist.github.com/rgleichman/f812150151b549ca9f634832c...




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