graphviz.pl -- Render data using graphviz

This renderer exploits graphviz to render graphs from Prolog data. It takes two representations. The first is a straightforward term Program(String), e.g.,

dot("digraph G {Hello->World}")

The second takes a Prolog term as input. The dot language is represented as follows:

Graph      := graph(Statements)
            | graph(Options, Statements)
            | digraph(Statements)
            | digraph(Options, Statements)
Options    := ID | [ID] | [strict, ID]
Statements := List of statements
Statement  := NodeStm | EdgeStm | AttrStm | Name = Value | SubGraph
NodeStm    := NodeID | node(NodeID, AttrList)
NodeID     := ID | ID:Port | ID:Port:CompassPT
CompassPT  := n | ne | e | se | s | sw | w | nw | c | _
EdgeStm    := (NodeID|SubGraph) (EdgeOp (NodeID|SubGraph))+
EdgeStm     | edge(NodeID|SubGraph) (EdgeOp (NodeID|SubGraph))+), AttrList)
EdgeOp     := - | ->
AttrStm    := graph(AttrList)
            | node(AttrList)
            | edge(AttrList)
AttrList   := List of attributes
Attribute  := Name = Value
            | Name(Value)
SubGraph   := subgraph(ID, Statements)

 term_rendering(+Term, +Vars, +Options)//

Renders data using graphviz. Options:

svg(+Mode)

One of inline (default) or object, rendering the SVG using an HTML <object> element.

 render_dot(+DotString, +Program, +Options)// is det[private]

Render a dot program. First checks whether Program is available. It has two modes, producing inline SVG or producing an HTML <object> element, which calls the server again to fetch the SVG.

 svg(+SVG:string, +Options:list)//

Include SVG as pan/zoom image. Must be embedded in a <div> with class 'reactive-size'.

 data_to_graphviz_string(+Data, -DOTString, -Program) is semidet[private]

Extract the DOT data and graphviz program to run on the data.

 swish_send_graphviz(+Request)[private]

HTTP handler to send a GraphViz graph

 remove_old_data(+Now)[private]

Remove data that are older than 15 minutes.

 add_defaults(Statements0, Statements) is det[private]

 value(+Name, +Value)//[private]

Emit a GraphViz value.

 is_graphviz_id(+AtomOrString) is semidet[private]

True if AtomOrString is a valid Graphviz ID, i.e., a value that does not need to be quoted.

 gv_attr(?AttrName, ?Element, ?Type) is nondet[private]

Name and type-declarations for GraphViz attributes. Types are defined my must_be/2.

See also

- http://www.graphviz.org/doc/info/shapes.html

 cstring(+Codes)//[private]

Create a C-string. dot uses UTF-8 encoding.