Label on edges

[gijsdh]

How would I show a graph in kotlin notebooks with labels on verteces but also on edges?

[breandan]

Hi @gijsdh, thanks for your question. This library is basically a wrapper for graphviz-java.

The default visualization for a graph is done here:

galoisenne/src/jvmMain/kotlin/ai/hypergraph/kaliningraph/visualization/Utils.kt

Lines 111 to 125 in ba7886a

	fun <G : IGraph<G, E, V>, E : IEdge<G, E, V>, V : IVertex<G, E, V>>
	IGraph<G, E, V>.toGraphviz(): MutableGraph =
	graph(directed = true, strict = true) {
	val color = if (DARKMODE) WHITE else BLACK
	edge[color, NORMAL, lineWidth(THICKNESS)]
	graph[CONCENTRATE, Rank.dir(LEFT_TO_RIGHT),
	TRANSPARENT.background(), margin(0.0),
	COMPOUND, Attributes.attr("nslimit", "20")]
	node[color, color.font(), Font.config("JetBrains Mono", 15),
	lineWidth(THICKNESS), Attributes.attr("shape", "Mrecord")]
	for (vertex in vertices) vertex.render()
	for ((vertex, edge) in edgList)
	edge.render().also { if (vertex is LGVertex && vertex.occupied) it.add(RED) }
	}

It is called by .html() like so:

galoisenne/src/jvmMain/kotlin/ai/hypergraph/kaliningraph/visualization/Utils.kt

Line 41 in ba7886a

fun IGraph<*, *, *>.html() = toGraphviz().render(SVG).toString()

Alternatively, you can also output it as a PNG, which is one of the output formats supported by Kotlin Notebooks.

You can add a vertex and edge labels to a custom graph by converting it to a graphviz MutableGraph like so:

galoisenne/src/jvmMain/kotlin/ai/hypergraph/kaliningraph/visualization/Utils.kt

Line 104 in ba7886a

for (vertex in states) Factory.mutNode(vertex).add(Label.of(toString()))

galoisenne/src/jvmMain/kotlin/ai/hypergraph/kaliningraph/visualization/Utils.kt

Line 108 in ba7886a

(a.render() - b.render()).add(Label.of(""))

The visualization API is a bit clunky, but should do the job. Let me know if you have trouble getting it to work.

[gijsdh]

Wow thanks for the detailed answer :)