gv(3perl)

NAME
gv_perl - graph manipulation in perl

SYNOPSIS
#!/usr/bin/perl
use gv;

USAGE

INTRODUCTION
gv_perl is a dynamically loaded extension for perl 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 an open channel
    bool gv::renderchannel (graph_handle, string format, string channelname);

Render to a string result
    gv::renderresult (graph_handle, string format, string outdata);

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, perl.