Graphvix

Graphviz in Elixir

Installation

If available in Hex, the package can be installed as:

1. Add graphvix to your list of dependencies in mix.exs:

def deps do
  [{:graphvix, "~> 1.0.0"}]
end

Usage

See the wiki for examples.

API Overview

• Create a new graph

  Graphvix.Graph.new/0

• Add a vertex to a graph

  Graphvix.Graph.add_vertex/2Graphvix.Graph.add_vertex/3

• Add an edge between two vertices

  Graphvix.Graph.add_edge/3Graphvix.Graph.add_edge/4

• Create a vertex with type record

  Graphvix.Record.new/1Graphvix.Record.new/2

• Add a record vertex to a graph

  Graphvix.Graph.add_record/2

• Create a vertex using HTML table markup

  Graphvix.HTMLRecord.new/1Graphvix.HTMLRecord.new/2

• Add an HTML table vertex to a graph

  Graphvix.Graph.add_html_record/2

• Save a graph to disk in .dot format

  Graphvix.Graph.write/2

• Save and compile a graph (defaults to .png)

  Graphvix.Graph.compile/2Graphvix.Graph.compile/3

• Save, compile and open a graph (defaults to .png and your OS's default image viewer)

  Graphvix.Graph.graph/2Graphvix.Graph.graph/3

Basic Usage

1. Alias the necessary module for ease of use

    alias Graphvix.Graph

2. Create a new graph.

    graph = Graph.new()

3. Add a simple vertex with a label

    {graph, vertex_id} = Graph.add_vertex(graph, "vertex label")

4. Add a vertex with a label and attributes

    {graph, vertex2_id} = Graph.add_vertex(
      graph,
      "my other vertex",
      color: "blue", shape: "diamond"
    )

5. Add an edge between two existing vertices

    {graph, edge_id} = Graph.add_edge(
      graph,
      vertex_id, vertex2_id,
      label: "Edge", color: "green"
    )

6. Add a cluster containing one or more nodes

    {graph, cluster_id} = Graph.add_cluster(graph, [vertex_id, vertex2_id])

Records

1. Alias the necessary module for ease of use

    alias Graphvix.Record

2. Create a simple record that contains only a row of cells

    record = Record.new(Record.row(["a", "b", "c"]))

   • A record with a top-level row can also be created by just passing a list

     record = Record.new(["a", "b", "c"])

3. Create a record with a single column of cells

    record = Record.new(Record.column(["a", "b", "c"]))

4. Create a record with nested rows and columns

    import Graphvix.Record, only: [column: 1, row: 1]
   
    record = Record.new(row([
      "a",
      column([
        "b",
        row(["c", "d", "e"]),
        "f"
      ]),
      "g"
    ])

Ports

1. Ports can be attached to record cells by passing a tuple of {port_name, label}

    import Graphvix.Record, only: [column: 1, row: 1]
   
    record = Record.new(row([
      {"port_a", "a"},
      column([
        "b",
        row(["c", {"port_d", "d"}, "e"]),
        "f"
      ]),
      "g"
    ])

2. Edges can be drawn from specific ports on a record

    {graph, record_id} = Graph.add_record(graph, record)
   
    {graph, _edge_id} = Graph.add_edge({record_id, "port_a"}, vertex_id)
   

HTML Table Records

1. Alias the necessary modules for ease of use

    alias Graphvix.HTMLRecord

2. Create a simple table

    record = HTMLRecord.new([
      tr([
        td("a"),
        td("b"),
        td("c")
      ]),
      tr([
        td("d", port: "port_d"),
        td("e"),
        td("f")
      ])
    ])

3. Or a more complex table

    record = HTMLRecord.new([
      tr([
        td("a", rowspan: 3),
        td("b", colspan: 2),
        td("f", rowspan: 3)
      ]),
      tr([
        td("c"),
        td("d")
      ])
      tr([
        td("e", colspan: 2)
      ])
    ])

Cells can also use the font/2 and br/0 helper methods to add font styling and forced line breaks. See the documentation for Graphvix.HTMLRecord for examples.

Output

1. Convert the graph to DOT format

    Graph.to_dot(graph)
    """
    digraph G {
      cluster c0 {
        v0 [label="vertex label"]
        v1 [label="my other vertex",color="blue",shape="diamond"]
   
        v0 -> v1 [label="Edge",color="green"]
      }
    }
    """

2. Save the graph to a .dot file, with an optional filename

    Graph.write(graph, "first_graph") #=> creates "first_graph.dot"

3. Compile the graph to a .png or .pdf using the dot command

    ## creates first_graph.dot and first_graph.png
    Graph.compile(graph, "first_graph")
   
    ## creates first_graph.dot and first_graph.pdf
    Graph.compile(graph, "first_graph", :pdf)

4. Compile the graph using the dot command and open the resulting file

    ## creates first_graph.dot and first_graph.pdf; opens first_graph.png
    Graph.graph(graph, "first_graph")
   
    ## creates first_graph.dot and first_graph.pdf; opens first_graph.pdf
    Graph.graph(graph, "first_graph", :pdf)