viz.js

Viz.js

This project is a Makefile for building Graphviz with Emscripten and a simple wrapper for using it in the browser.

Getting Viz.js

Install with Bower:

bower install viz.js

Or with npm:

npm install viz.js

Or download the viz.js "binary" from the releases page.

API

Viz.js defines a single function to handle most cases:

Viz(src, options={ format="svg", engine="dot", scale })

• src is a string representing the graph to render in the DOT language.
• options
  • format sets the output format, and may be one of "svg", "xdot", "plain", "ps", or "png-image-element".
  • engine sets the Graphviz engine to use, and may be one of "circo", "dot", "neato", "osage", or "twopi".
  • scale sets the scale factor for the "png-image-element" format. If this is not specified, window.devicePixelRatio will be used if available, and 1 if not.

Output is returned as a string, except when using the "png-image-element" format, when it is returned as an instance of HTMLImageElement.

For example:

result = Viz("digraph { a -> b; }");
result = Viz("digraph { a -> b; }", { format: "png-image-element", scale: 2 });
result = Viz("graph { n0 -- n1 -- n2 -- n3 -- n0; }", { engine: "neato" });
result = Viz("digraph { x -> y -> z; }", { format: "plain" });

If Graphviz encounters an error, the error message will be thrown as an exception.

Supported Graphviz features

These engines are supported:

• circo
• dot
• fdp
• neato
• osage
• twopi

These formats are supported:

• svg
• xdot
• plain
• ps

PNG output

Viz.js provides the "png-image-element" format in addition to the regular Graphviz formats. This returns an HTMLImageElement which can be inserted into the document.

image = Viz("digraph g { a -> b; }", { format: "png-image-element" });
document.body.appendChild(image);

However, this won't work in a Web Worker context. In that case, ask for the "svg" format in the worker and convert using the accessory function Viz.svgXmlToPngImageElement in the window context. See tests/png.js for an example.

Internet Explorer support

Internet Explorer 10 and 11 require Fabric.js as an optional dependency for PNG output. Viz.js will look for a fabric object as a member of the global object with a loadSVGFromString() function and use that if present.

Build

To build from source, you will need to install the Emscripten SDK.

To download the sources and build everything:

make

Support Viz.js

If you find Viz.js useful, please consider a donation. Thank you!