SYNOPSIS

#!/usr/bin/ruby
require 'gv'

USAGE

INTRODUCTION

gv_ruby is a dynamically loaded extension for ruby that provides access to the graph facilities of graphviz.

COMMANDS

New graphs

New empty graph

graph_handle Gv.graph (name);
graph_handle Gv.digraph (name);
graph_handle Gv.strictgraph (name);
graph_handle Gv.strictdigraph (name);

New graph from a dot-syntax string or file

graph_handle Gv.readstring (string);
graph_handle Gv.read (string filename);
graph_handle Gv.read (channel);

Add new subgraph to existing graph

graph_handle Gv.graph (graph_handle, name);

New nodes

Add new node to existing graph

node_handle Gv.node (graph_handle, name);

New edges

Add new edge between existing nodes

edge_handle Gv.edge (tail_node_handle, head_node_handle);

Add a new edge between an existing tail node, and a named head node which will be induced in the graph if it doesn't already exist

edge_handle Gv.edge (tail_node_handle, head_name);

Add a new edge between an existing head node, and a named tail node which will be induced in the graph if it doesn't already exist

edge_handle Gv.edge (tail_name, head_node_handle);

Add a new edge between named tail and head nodes which will be induced in the graph if they don't already exist

edge_handle Gv.edge (graph_handle, tail_name, head_name);

Setting attribute values

Set value of named attribute of graph/node/edge - creating attribute if necessary

string Gv.setv (graph_handle, attr_name, attr_value);
string Gv.setv (node_handle, attr_name, attr_value);
string Gv.setv (edge_handle, attr_name, attr_value);

Set value of existing attribute of graph/node/edge (using attribute handle)

string Gv.setv (graph_handle, attr_handle, attr_value);
string Gv.setv (node_handle, attr_handle, attr_value);
string Gv.setv (edge_handle, attr_handle, attr_value);

Getting attribute values

Get value of named attribute of graph/node/edge

string Gv.getv (graph_handle, attr_name);
string Gv.getv (node_handle, attr_name);
string Gv.getv (edge_handle, attr_name);

Get value of attribute of graph/node/edge (using attribute handle)

string Gv.getv (graph_handle, attr_handle);
string Gv.getv (node_handle, attr_handle);
string Gv.getv (edge_handle, attr_handle);

Obtain names from handles

string Gv.nameof (graph_handle);
string Gv.nameof (node_handle);
string Gv.nameof (attr_handle);

Find handles from names

graph_handle Gv.findsubg (graph_handle, name);
node_handle Gv.findnode (graph_handle, name);
edge_handle Gv.findedge (tail_node_handle, head_node_handle);
attribute_handle Gv.findattr (graph_handle, name);
attribute_handle Gv.findattr (node_handle, name);
attribute_handle Gv.findattr (edge_handle, name);

Misc graph navigators returning handles

node_handle Gv.headof (edge_handle);
node_handle Gv.tailof (edge_handle);
graph_handle Gv.graphof (graph_handle);
graph_handle Gv.graphof (edge_handle);
graph_handle Gv.graphof (node_handle);
graph_handle Gv.rootof (graph_handle);

Obtain handles of proto node/edge for setting default attribute values

node_handle Gv.protonode (graph_handle);
edge_handle Gv.protoedge (graph_handle);

Iterators

Iteration termination tests

bool Gv.ok (graph_handle);
bool Gv.ok (node_handle);
bool Gv.ok (edge_handle);
bool Gv.ok (attr_handle);

Iterate over subgraphs of a graph

graph_handle Gv.firstsubg (graph_handle);
graph_handle Gv.nextsubg (graph_handle, subgraph_handle);

Iterate over supergraphs of a graph (obscure and rarely useful)

graph_handle Gv.firstsupg (graph_handle);
graph_handle Gv.nextsupg (graph_handle, subgraph_handle);

Iterate over edges of a graph

edge_handle Gv.firstedge (graph_handle);
edge_handle Gv.nextedge (graph_handle, edge_handle);

Iterate over outedges of a graph

edge_handle Gv.firstout (graph_handle);
edge_handle Gv.nextout (graph_handle, edge_handle);

Iterate over edges of a node

edge_handle Gv.firstedge (node_handle);
edge_handle Gv.nextedge (node_handle, edge_handle);

Iterate over out-edges of a node

edge_handle Gv.firstout (node_handle);
edge_handle Gv.nextout (node_handle, edge_handle);

Iterate over head nodes reachable from out-edges of a node

node_handle Gv.firsthead (node_handle);
node_handle Gv.nexthead (node_handle, head_node_handle);

Iterate over in-edges of a graph

edge_handle Gv.firstin (graph_handle);
edge_handle Gv.nextin (node_handle, edge_handle);

Iterate over in-edges of a node

edge_handle Gv.firstin (node_handle);
edge_handle Gv.nextin (graph_handle, edge_handle);

Iterate over tail nodes reachable from in-edges of a node

node_handle Gv.firsttail (node_handle);
node_handle Gv.nexttail (node_handle, tail_node_handle);

Iterate over nodes of a graph

node_handle Gv.firstnode (graph_handle);
node_handle Gv.nextnode (graph_handle, node_handle);

Iterate over nodes of an edge

node_handle Gv.firstnode (edge_handle);
node_handle Gv.nextnode (edge_handle, node_handle);

Iterate over attributes of a graph

attribute_handle Gv.firstattr (graph_handle);
attribute_handle Gv.nextattr (graph_handle, attr_handle);

Iterate over attributes of an edge

attribute_handle Gv.firstattr (edge_handle);
attribute_handle Gv.nextattr (edge_handle, attr_handle);

Iterate over attributes of a node

attribute_handle Gv.firstattr (node_handle);
attribute_handle Gv.nextattr (node_handle, attr_handle);

Remove graph objects

bool Gv.rm (graph_handle);
bool Gv.rm (node_handle);
bool Gv.rm (edge_handle);

Layout

Annotate a graph with layout attributes and values using a specific layout engine

bool Gv.layout (graph_handle, string engine);

Render

Render a layout into attributes of the graph

bool Gv.render (graph_handle);

Render a layout to stdout

bool Gv.render (graph_handle, string format);

Render to an open file

bool Gv.render (graph_handle, string format, channel fout);

Render a layout to an unopened file by name

bool Gv.render (graph_handle, string format, string filename);

Render to a string result

string Gv.renderresult (graph_handle ing, string format);
Gv.renderresult (graph_handle, string format, string outdata);

Render to an open channel

bool Gv.renderchannel (graph_handle, string format, string channelname);

Render a layout to a malloc'ed string, to be free'd by the caller

(deprecated - too easy to leak memory)

(still needed for "eval [gv::renderdata $G tk]" )

string Gv.renderdata (graph_handle, string format);

Writing graph back to file

bool Gv.write (graph_handle, string filename);
bool Gv.write (graph_handle, channel);

KEYWORDS

graph, dot, neato, fdp, circo, twopi, ruby.