graphviz-overlay

A templating tool for generating graphs using a structured data model.

The data model makes it possible to easily generate graphs directly from code and makes it possible produce different looking graphs from the same source.

Check out https://graphviz-overlay.readthedocs.io/ for more documentation.

Usage

The graphviz-overlay executable reads from stdin and produces dot source making it possible to produce a graph like this:

graphviz-overlay$ cat examples/hello_world.json | graphviz-overlay graph
graph G {
  hello -- world
}

or a directed graph:

cat examples/hello_world.json | graphviz-overlay digraph
digraph G {
  hello -> world
}

Features

Templating

You can define your own overlays:

import graphviz_overlay

class MyOverlay(graphviz_overlay.GraphOverlay):
    pass


ctx = graphviz_overlay.GraphContext()
overlay = MyOverlay(ctx)

model = {'edges': [{'from': 'hello', 'to': 'world'}]}
print(overlay.draw(model))

Enhanced Styling

You can style the graph using classes defined in the model or via a stylesheet specified as an argument making it possible to define all shared attributes between edges, nodes and graphs. You can of course also specify the attributes directly on each element.

Every overlay you define can also define

Classes are defined as part of the model or as a separate stylesheet.

Functionality exposed depends on the overlay and it is possible to define new ones. The basic overlays supports the followinggraph and digraph

Basic Overlay Support

The basic graph and digraph overlays add support for

Paths

It is possible to define paths (the term borrowed from graph theory).

By defining a path you can control how the final graph is created from the model.

Path selection syntax supports negation.

You can include nodes, edges and subgraphs as part of a path.

Selection

You can choose to include selected paths only, via the command-line.

You can also choose whether de-selected elements should be hidden (i.e. with style=invis, to maintain placement of other elements) or remove the elements entirely from the final dot-source.

Highlight/Shade Elements

You can choose to highlight and/or shade specific paths or subgraphs from the command line

These are really just built-in classes and can be customized any way you need.

Version History

0.1.1:

• Add initial documentation and project description

0.1.0:

• graph, digraph and er commands.
• Support for --select, --highlight and --shade via paths.
• Support for ranks
• External stylesheet definition.
• Nodes, edges, and graphs can have classes.