Graphviz

This package facilitates the creation of graph descriptions in the DOT language of the Graphviz graph drawing software from Python.

Create a graph object, assemble the graph by adding nodes and edges, and retrieve its DOT source code string. Save the source code to a file and render it with the Graphviz installation of your system.

Use the view option/method to directly inspect the resulting (PDF, PNG, SVG, etc.) file with its default application.

Installation

This package runs under Python 2.7 and 3.3+, use pip to install:

$ pip install graphviz

To render the generated DOT source code, you also need to install Graphviz (download page).

Make sure that the dot executable is on your systems' path.

Usage

Create a graph object:

>>> from graphviz import Digraph

>>> dot = Digraph(comment='The Round Table')

>>> dot  #doctest: +ELLIPSIS
<graphviz.dot.Digraph object at 0x...>

Add nodes and edges:

>>> dot.node('A', 'King Arthur')
>>> dot.node('B', 'Sir Bedevere the Wise')
>>> dot.node('L', 'Sir Lancelot the Brave')

>>> dot.edges(['AB', 'AL'])
>>> dot.edge('B', 'L', constraint='false')

Check the generated source code:

>>> print(dot.source)  # doctest: +NORMALIZE_WHITESPACE
// The Round Table
digraph {
    A [label="King Arthur"]
    B [label="Sir Bedevere the Wise"]
    L [label="Sir Lancelot the Brave"]
        A -> B
        A -> L
        B -> L [constraint=false]
}

Save and render the source code, optionally view the result:

>>> dot.render('test-output/round-table.gv', view=True)
'test-output/round-table.gv.pdf'

Formats

To use a different output file format than the default PDF, set the format argument when creating your Graph or Digraph object:

>>> from graphviz import Graph

>>> g = Graph(format='png')

You can also change the format attribute on an existing graph object:

>>> dot.format = 'svg'

>>> dot.render()
'test-output/round-table.gv.svg'

Styling

Use the graph_attr, node_attr, and edge_attr arguments to change the default appearance of your graph, nodes, and edges.

>>> dot = Digraph(name='pet-shop', node_attr={'shape': 'plaintext'})

>>> dot.node('parrot')
>>> dot.node('dead')
>>> dot.edge('parrot', 'dead')

After creation, they can be edited on the graph object:

>>> dot.graph_attr['rankdir'] = 'LR'
>>> dot.edge_attr.update(arrowhead='vee', arrowsize='2')

>>> print(dot.source)  # doctest: +NORMALIZE_WHITESPACE
digraph "pet-shop" {
    graph [rankdir=LR]
    node [shape=plaintext]
    edge [arrowhead=vee arrowsize=2]
        parrot
        dead
            parrot -> dead
}

Engines

To use a different layout command than the default dot when rendering your graph, set the engine argument on graph creation.

>>> g = Graph(engine='neato')

You can also change the engine attribute of an existing instance:

>>> dot.engine = 'circo'

See also

• pygraphviz – full-blown interface wrapping the Graphviz C library with SWIG
• graphviz-python – official Python bindings (documentation)
• pydot – stable pure-Python approach, requires pyparsing

License

This package is distributed under the MIT license.