draw

Documentation

Overview

Package draw provides functions for visualizing graph structures. At this time, draw supports the DOT language which can be interpreted by Graphviz, Grappa, and others.

Index

• func DOT[K comparable, T any](g graph.Graph[K, T], w io.Writer, options ...func(*description)) error
• func GraphAttribute(key, value string) func(*description)

Functions

func DOT

func DOT[K comparable, T any](g graph.Graph[K, T], w io.Writer, options ...func(*description)) error

DOT renders the given graph structure in DOT language into an io.Writer, for example a file. The generated output can be passed to Graphviz or other visualization tools supporting DOT.

The following example renders a directed graph into a file my-graph.gv:

g := graph.New(graph.IntHash, graph.Directed())

_ = g.AddVertex(1)
_ = g.AddVertex(2)
_ = g.AddVertex(3, graph.VertexAttribute("style", "filled"), graph.VertexAttribute("fillcolor", "red"))

_ = g.AddEdge(1, 2, graph.EdgeWeight(10), graph.EdgeAttribute("color", "red"))
_ = g.AddEdge(1, 3)

file, _ := os.Create("./my-graph.gv")
_ = draw.DOT(g, file)

To generate an SVG from the created file using Graphviz, use a command such as the following:

dot -Tsvg -O my-graph.gv

Another possibility is to use os.Stdout as an io.Writer, print the DOT output to stdout, and pipe it as follows:

go run main.go | dot -Tsvg > output.svg

DOT also accepts the GraphAttribute functional option, which can be used to add global attributes when rendering the graph:

_ = draw.DOT(g, file, draw.GraphAttribute("label", "my-graph"))

func GraphAttribute

func GraphAttribute(key, value string) func(*description)

GraphAttribute is a functional option for the DOT method.