Graphviz

Graphviz (short for Graph Visualization Software) is a package of open-source tools initiated by AT&T Labs Research for drawing graphs (as in nodes and edges, not as in bar charts) specified in DOT language scripts having the file name extension "gv". It also provides libraries for software applications to use the tools. Graphviz is free software licensed under the Eclipse Public License.

Tools

 * dot : a command-line tool to produce layered graph drawings in a variety of output formats, such as (PostScript, PDF, SVG, annotated text and so on).
 * neato : useful for undirected graphs up to about 1000 nodes. "Spring model" layout minimizes global energy.
 * fdp : force-directed graph drawing similar to "spring model", but minimizes forces instead of energy. Useful for undirected graphs.
 * sfdp : multiscale version of fdp for the layout of large undirected graphs.
 * twopi : for radial graph layouts. Nodes are placed on concentric circles depending on their distance from a given root node.
 * circo : circular layout. Suitable for certain diagrams of multiple cyclic structures, such as certain telecommunications networks.
 * dotty : a graphical user interface to visualize and edit graphs.
 * lefty : a programmable (in a language inspired by EZ ) widget that displays DOT graphs and allows the user to perform actions on them with the mouse. Therefore, Lefty can be used as the view in a model–view–controller GUI application that uses graphs.
 * gml2gv, gv2gml: convert to/from GML, another graph file format.
 * graphml2g: convert a GraphML file to the DOT format.
 * gxl2gv, gv2gxl: convert to/from GXL, another graph file format.

Applications that use Graphviz
Notable applications of Graphviz include:
 * ArgoUML's alternative UML diagram rendering called argouml-graphviz.
 * AsciiDoc can embed Graphviz syntax as a diagram.
 * Bison is able to output the grammar as dot for visualization of the language.
 * Confluence has a Graphviz plugin to render diagrams from text descriptions.
 * ConnectedText has a Graphviz plugin.
 * Doxygen uses Graphviz to generate diagrams, including class hierarchies, collaboration and call trees for source code.
 * FreeCAD uses Graphviz to display the dependencies between objects in documents.
 * Gephi has a Graphviz plugin.
 * Gramps uses Graphviz to create genealogical (family tree) diagrams.
 * Graph-tool a Python library for graph manipulation and visualization.
 * OmniGraffle version 5 and later uses the Graphviz engine, with a limited set of commands, for automatically laying out graphs.
 * Org-mode can work with DOT source code blocks.
 * PlantUML uses Graphviz to generate UML diagrams from text descriptions.
 * Puppet can produce DOT resource graphs that can be viewed with Graphviz.
 * Scribus is an open-source DTP program that can use Graphviz to render graphs by using its internal editor in a special frame type called render frame.
 * Sphinx is a documentation generator that can use Graphviz to embed graphs in documents.
 * TOra a free-software database development and administration GUI, available under the GNU GPL.
 * Trac wiki has a Graphviz plugin.
 * Zim includes a plugin that allows adding and editing in-page diagrams using the Graphviz dot language.