.TH gv 3perl "13 April 2024"

.SH NAME

gv_perl - graph manipulation in perl

.SH SYNOPSIS

#!/usr/bin/perl
.br
use gv;

.SH USAGE



.SH INTRODUCTION

.B gv_perl
is a dynamically loaded extension for
.B perl
that provides access to the graph facilities of
.B graphviz.

.SH COMMANDS

.TP
\fBNew graphs\fR
.br
.TP
New empty graph
.br
\fIgraph_handle\fR \fBgv::graph\fR \fI(name);\fR
.br
\fIgraph_handle\fR \fBgv::digraph\fR \fI(name);\fR
.br
\fIgraph_handle\fR \fBgv::strictgraph\fR \fI(name);\fR
.br
\fIgraph_handle\fR \fBgv::strictdigraph\fR \fI(name);\fR
.br
.TP
New graph from a dot-syntax string or file
.br
\fIgraph_handle\fR \fBgv::readstring\fR \fI(string);\fR
.br
\fIgraph_handle\fR \fBgv::read\fR \fI(string filename);\fR
.br
\fIgraph_handle\fR \fBgv::read\fR \fI(channel);\fR
.br
.TP
Add new subgraph to existing graph
.br
\fIgraph_handle\fR \fBgv::graph\fR \fI(graph_handle, name);\fR
.br
.TP
\fBNew nodes\fR
.br
.TP
Add new node to existing graph
.br
\fInode_handle\fR \fBgv::node\fR \fI(graph_handle, name);\fR
.br
.TP
\fBNew edges\fR
.br
.TP
Add new edge between existing nodes
.br
\fIedge_handle\fR \fBgv::edge\fR \fI(tail_node_handle, head_node_handle);\fR
.br
.TP
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
.br
\fIedge_handle\fR \fBgv::edge\fR \fI(tail_node_handle, head_name);\fR
.br
.TP
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
.br
\fIedge_handle\fR \fBgv::edge\fR \fI(tail_name, head_node_handle);\fR
.br
.TP
Add a new edge between named tail  and head nodes which will be induced in the graph if they don't already exist
.br
\fIedge_handle\fR \fBgv::edge\fR \fI(graph_handle, tail_name, head_name);\fR
.br
.TP
\fBSetting attribute values\fR
.br
.TP
Set value of named attribute of graph/node/edge - creating attribute if necessary
.br
\fIstring\fR \fBgv::setv\fR \fI(graph_handle, attr_name, attr_value);\fR
.br
\fIstring\fR \fBgv::setv\fR \fI(node_handle, attr_name, attr_value);\fR
.br
\fIstring\fR \fBgv::setv\fR \fI(edge_handle, attr_name, attr_value);\fR
.br
.TP
Set value of existing attribute of graph/node/edge (using attribute handle)
.br
\fIstring\fR \fBgv::setv\fR \fI(graph_handle, attr_handle, attr_value);\fR
.br
\fIstring\fR \fBgv::setv\fR \fI(node_handle, attr_handle, attr_value);\fR
.br
\fIstring\fR \fBgv::setv\fR \fI(edge_handle, attr_handle, attr_value);\fR
.br
.TP
\fBGetting attribute values\fR
.br
.TP
Get value of named attribute of graph/node/edge
.br
\fIstring\fR \fBgv::getv\fR \fI(graph_handle, attr_name);\fR
.br
\fIstring\fR \fBgv::getv\fR \fI(node_handle, attr_name);\fR
.br
\fIstring\fR \fBgv::getv\fR \fI(edge_handle, attr_name);\fR
.br
.TP
Get value of attribute of graph/node/edge (using attribute handle)
.br
\fIstring\fR \fBgv::getv\fR \fI(graph_handle, attr_handle);\fR
.br
\fIstring\fR \fBgv::getv\fR \fI(node_handle, attr_handle);\fR
.br
\fIstring\fR \fBgv::getv\fR \fI(edge_handle, attr_handle);\fR
.br
.TP
\fBObtain names from handles\fR
.br
\fIstring\fR \fBgv::nameof\fR \fI(graph_handle);\fR
.br
\fIstring\fR \fBgv::nameof\fR \fI(node_handle);\fR
.br
\fIstring\fR \fBgv::nameof\fR \fI(attr_handle);\fR
.br
.TP
\fBFind handles from names\fR
.br
\fIgraph_handle\fR \fBgv::findsubg\fR \fI(graph_handle, name);\fR
.br
\fInode_handle\fR \fBgv::findnode\fR \fI(graph_handle, name);\fR
.br
\fIedge_handle\fR \fBgv::findedge\fR \fI(tail_node_handle, head_node_handle);\fR
.br
\fIattribute_handle\fR \fBgv::findattr\fR \fI(graph_handle, name);\fR
.br
\fIattribute_handle\fR \fBgv::findattr\fR \fI(node_handle, name);\fR
.br
\fIattribute_handle\fR \fBgv::findattr\fR \fI(edge_handle, name);\fR
.br
.TP
\fBMisc graph navigators returning handles\fR
.br
\fInode_handle\fR \fBgv::headof\fR \fI(edge_handle);\fR
.br
\fInode_handle\fR \fBgv::tailof\fR \fI(edge_handle);\fR
.br
\fIgraph_handle\fR \fBgv::graphof\fR \fI(graph_handle);\fR
.br
\fIgraph_handle\fR \fBgv::graphof\fR \fI(edge_handle);\fR
.br
\fIgraph_handle\fR \fBgv::graphof\fR \fI(node_handle);\fR
.br
\fIgraph_handle\fR \fBgv::rootof\fR \fI(graph_handle);\fR
.br
.TP
\fBObtain handles of proto node/edge for setting default attribute values\fR
.br
\fInode_handle\fR \fBgv::protonode\fR \fI(graph_handle);\fR
.br
\fIedge_handle\fR \fBgv::protoedge\fR \fI(graph_handle);\fR
.br
.TP
\fBIterators\fR
.br
.TP
Iteration termination tests
.br
\fIbool\fR \fBgv::ok\fR \fI(graph_handle);\fR
.br
\fIbool\fR \fBgv::ok\fR \fI(node_handle);\fR
.br
\fIbool\fR \fBgv::ok\fR \fI(edge_handle);\fR
.br
\fIbool\fR \fBgv::ok\fR \fI(attr_handle);\fR
.br
.TP
Iterate over subgraphs of a graph
.br
\fIgraph_handle\fR \fBgv::firstsubg\fR \fI(graph_handle);\fR
.br
\fIgraph_handle\fR \fBgv::nextsubg\fR \fI(graph_handle, subgraph_handle);\fR
.br
.TP
Iterate over supergraphs of a graph (obscure and rarely useful)
.br
\fIgraph_handle\fR \fBgv::firstsupg\fR \fI(graph_handle);\fR
.br
\fIgraph_handle\fR \fBgv::nextsupg\fR \fI(graph_handle, subgraph_handle);\fR
.br
.TP
Iterate over edges of a graph
.br
\fIedge_handle\fR \fBgv::firstedge\fR \fI(graph_handle);\fR
.br
\fIedge_handle\fR \fBgv::nextedge\fR \fI(graph_handle, edge_handle);\fR
.br
.TP
Iterate over outedges of a graph
.br
\fIedge_handle\fR \fBgv::firstout\fR \fI(graph_handle);\fR
.br
\fIedge_handle\fR \fBgv::nextout\fR \fI(graph_handle, edge_handle);\fR
.br
.TP
Iterate over edges of a node
.br
\fIedge_handle\fR \fBgv::firstedge\fR \fI(node_handle);\fR
.br
\fIedge_handle\fR \fBgv::nextedge\fR \fI(node_handle, edge_handle);\fR
.br
.TP
Iterate over out-edges of a node
.br
\fIedge_handle\fR \fBgv::firstout\fR \fI(node_handle);\fR
.br
\fIedge_handle\fR \fBgv::nextout\fR \fI(node_handle, edge_handle);\fR
.br
.TP
Iterate over head nodes reachable from out-edges of a node
.br
\fInode_handle\fR \fBgv::firsthead\fR \fI(node_handle);\fR
.br
\fInode_handle\fR \fBgv::nexthead\fR \fI(node_handle, head_node_handle);\fR
.br
.TP
Iterate over in-edges of a graph
.br
\fIedge_handle\fR \fBgv::firstin\fR \fI(graph_handle);\fR
.br
\fIedge_handle\fR \fBgv::nextin\fR \fI(node_handle, edge_handle);\fR
.br
.TP
Iterate over in-edges of a node
.br
\fIedge_handle\fR \fBgv::firstin\fR \fI(node_handle);\fR
.br
\fIedge_handle\fR \fBgv::nextin\fR \fI(graph_handle, edge_handle);\fR
.br
.TP
Iterate over tail nodes reachable from in-edges of a node
.br
\fInode_handle\fR \fBgv::firsttail\fR \fI(node_handle);\fR
.br
\fInode_handle\fR \fBgv::nexttail\fR \fI(node_handle, tail_node_handle);\fR
.br
.TP
Iterate over nodes of a graph
.br
\fInode_handle\fR \fBgv::firstnode\fR \fI(graph_handle);\fR
.br
\fInode_handle\fR \fBgv::nextnode\fR \fI(graph_handle, node_handle);\fR
.br
.TP
Iterate over nodes of an edge
.br
\fInode_handle\fR \fBgv::firstnode\fR \fI(edge_handle);\fR
.br
\fInode_handle\fR \fBgv::nextnode\fR \fI(edge_handle, node_handle);\fR
.br
.TP
Iterate over attributes of a graph
.br
\fIattribute_handle\fR \fBgv::firstattr\fR \fI(graph_handle);\fR
.br
\fIattribute_handle\fR \fBgv::nextattr\fR \fI(graph_handle, attr_handle);\fR
.br
.TP
Iterate over attributes of an edge
.br
\fIattribute_handle\fR \fBgv::firstattr\fR \fI(edge_handle);\fR
.br
\fIattribute_handle\fR \fBgv::nextattr\fR \fI(edge_handle, attr_handle);\fR
.br
.TP
Iterate over attributes of a node
.br
\fIattribute_handle\fR \fBgv::firstattr\fR \fI(node_handle);\fR
.br
\fIattribute_handle\fR \fBgv::nextattr\fR \fI(node_handle, attr_handle);\fR
.br
.TP
\fBRemove graph objects\fR
.br
\fIbool\fR \fBgv::rm\fR \fI(graph_handle);\fR
.br
\fIbool\fR \fBgv::rm\fR \fI(node_handle);\fR
.br
\fIbool\fR \fBgv::rm\fR \fI(edge_handle);\fR
.br
.TP
\fBLayout\fR
.br
.TP
Annotate a graph with layout attributes and values using a specific layout engine
.br
\fIbool\fR \fBgv::layout\fR \fI(graph_handle, string engine);\fR
.br
.TP
\fBRender\fR
.br
.TP
Render a layout into attributes of the graph
.br
\fIbool\fR \fBgv::render\fR \fI(graph_handle);\fR
.br
.TP
Render a layout to stdout
.br
\fIbool\fR \fBgv::render\fR \fI(graph_handle, string format);\fR
.br
.TP
Render to an open file
.br
\fIbool\fR \fBgv::render\fR \fI(graph_handle, string format, channel fout);\fR
.br
.TP
Render a layout to an unopened file by name
.br
\fIbool\fR \fBgv::render\fR \fI(graph_handle, string format, string filename);\fR
.br
.TP
Render to a string result
.br
\fIstring\fR \fBgv::renderresult\fR \fI(graph_handle ing, string format);\fR
.br
\fBgv::renderresult\fR \fI(graph_handle, string format, string outdata);\fR
.br
.TP
Render to an open channel
.br
\fIbool\fR \fBgv::renderchannel\fR \fI(graph_handle, string format, string channelname);\fR
.br
.TP
Render a layout to a malloc'ed string, to be free'd by the caller
.br
.TP
(deprecated - too easy to leak memory)
.br
.TP
(still needed for "eval [gv::renderdata $G tk]" )
.br
\fIstring\fR \fBgv::renderdata\fR \fI(graph_handle, string format);\fR
.br
.TP
Writing graph back to file
.br
\fIbool\fR \fBgv::write\fR \fI(graph_handle, string filename);\fR
.br
\fIbool\fR \fBgv::write\fR \fI(graph_handle, channel);\fR
.br
.TP
Graph transformation tools
.br
\fIbool\fR \fBgv::tred\fR \fI(graph_handle);\fR
.br

.SH KEYWORDS

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