Provided by: libgv-ruby_2.36.0-0ubuntu3_amd64 bug

NAME

       gv_ruby - graph manipulation in ruby

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 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, ruby.

                                         20 February 2014                               gv(3ruby)