Graphviz ++

This is a small and simple C++ library to produce .gv files for GraphViz. It support both narrow and wide character strings.

Usage

Creating elements

In the following, str means string if chartype == char, or wstring if chartype == wchar_t

Every class is templated by the char type of the strings it will hold, though using <> will default to char. The only class instanciable by the user is Graph, which has corresponding methods to create child elements. Those are:

• addNode(str id, str label = "", bool forcenew=false) creates a node with the corresponding id, or returns it if there already is one. If forcenew == true, an error will be thrown if the node already exists.
• addEdge(Node &node1, Node &node2, str label = "") creates an edge node1 --> node2
• addSubGraph(str name, bool cluster = false, str label = "") creates a subgraph. If cluster is true and name doesn't start with "cluster_", it is prepended.

Setting attributes

All elements have a set method to set element values, as well as corresponding get and has methods. set also always return a reference to the element it was called upon, as to allow for method chaining.

Node and Edge only have one type of Element, so set just takes a key and a value:

• Node/Edge &set(str key, str value)

Graph can have Graph attributes for itself, or Edge/Node attributes that act as default for its children, thus it takes a type as first argument:

• Graph &set(AttrType type, str key, str value) with type one of: {AttrType::GRAPH, AttrType::NODE, AttrType::EDGE}

And finally, SubGraph being both a Graph (inherits AbstractGraph) and a graph element, it has both signatures. The type-less one defaults to AttrType::GRAPH.

Printing

To output the graph as a .gv file, just pass it to an output stream through <<. The stream's chartype has to match the Graph's, obviously. Additionally, gvpp also provides renderToFile(Graph &g, string layout, string format, string file) which calls graphviz to render the graph file directly, and save it as a file, or display it if the format specifies it. renderToScreen(Graph &g, string layout) is a shortcut for renderToFile with format="x11".