NAME

       Graph::Easy::Edge - An edge (a path connecting one ore more nodes)

SYNOPSIS

               use Graph::Easy;

               my $ssl = Graph::Easy::Edge->new(
                       label => 'encrypted connection',
                       style => 'solid',
               );
               $ssl->set_attribute('color', 'red');

               my $src = Graph::Easy::Node->new('source');

               my $dst = Graph::Easy::Node->new('destination');

               $graph = Graph::Easy->new();

               $graph->add_edge($src, $dst, $ssl);

               print $graph->as_ascii();

DESCRIPTION

       A "Graph::Easy::Edge" represents an edge between two (or more) nodes in a simple graph.

       Each edge has a direction (from source to destination, or back and forth), plus a style
       (line width and style), colors etc. It can also have a label, e.g. a text associated with
       it.

       During the layout phase, each edge also contains a list of path-elements (also called
       cells), which make up the path from source to destination.

METHODS

   error()
               $last_error = $edge->error();

               $cvt->error($error);                    # set new messages
               $cvt->error('');                        # clear error

       Returns the last error message, or '' for no error.

   as_ascii()
               my $ascii = $edge->as_ascii();

       Returns the edge as a little ascii representation.

   as_txt()
               my $txt = $edge->as_txt();

       Returns the edge as a little Graph::Easy textual representation.

   label()
               my $label = $edge->label();

       Returns the label (also known as 'name') of the edge.

   name()
               my $label = $edge->name();

       To make the interface more consistent, the "name()" method of an edge can also be called,
       and it will returned either the edge label, or the empty string if the edge doesn't have a
       label.

   style()
               my $style = $edge->style();

       Returns the style of the edge, like 'solid', 'dotted', 'double', etc.

   nodes()
               my @nodes = $edge->nodes();

       Returns the source and target node that this edges connects as objects.

   bidirectional()
               $edge->bidirectional(1);
               if ($edge->bidirectional())
                 {
                 }

       Returns true if the edge is bidirectional, aka has arrow heads on both ends.  An optional
       parameter will set the bidirectional status of the edge.

   undirected()
               $edge->undirected(1);
               if ($edge->undirected())
                 {
                 }

       Returns true if the edge is undirected, aka has now arrow at all.  An optional parameter
       will set the undirected status of the edge.

   has_ports()
               if ($edge->has_ports())
                 {
                 ...
                 }

       Return true if the edge has restriction on the starting or ending port, e.g. either the
       "start" or "end" attribute is set on this edge.

   start_port()
               my $port = $edge->start_port();

       Return undef if the edge does not have a fixed start port, otherwise returns the port as
       "side, number", for example "south, 0".

   end_port()
               my $port = $edge->end_port();

       Return undef if the edge does not have a fixed end port, otherwise returns the port as
       "side, number", for example "south, 0".

   from()
               my $from = $edge->from();

       Returns the node that this edge starts at. See also "to()".

   to()
               my $to = $edge->to();

       Returns the node that this edge leads to. See also "from()".

   start_at()
               $edge->start_at($other);
               my $other = $edge->start_at('some node');

       Set the edge's start point to the given node. If given a node name, will add that node to
       the graph first.

       Returns the new edge start point node.

   end_at()
               $edge->end_at($other);
               my $other = $edge->end_at('some other node');

       Set the edge's end point to the given node. If given a node name, will add that node to
       the graph first.

       Returns the new edge end point node.

   flip()
               $edge->flip();

       Swaps the "start" and "end" nodes on this edge, e.g. reverses the direction of the edge.

   flow()
               my $flow = $edge->flow();

       Returns the flow for this edge, honoring inheritance. An edge without a specific flow set
       will inherit the flow from the node it comes from.

   edge_flow()
               my $flow = $edge->edge_flow();

       Returns the flow for this edge, or undef if it has none set on either the object itself or
       its class.

   port()
               my ($side, $number) = $edge->port('start');
               my ($side, $number) = $edge->port('end');

       Return the side and port number where this edge starts or ends.

       Returns undef for $side if the edge has no port restriction. The returned side will be one
       absolute direction of "east", "west", "north" or "south", depending on the port
       restriction and flow at that edge.

   get_attributes()
               my $att = $object->get_attributes();

       Return all effective attributes on this object (graph/node/group/edge) as an anonymous
       hash ref. This respects inheritance and default values.

       See also raw_attributes().

   raw_attributes()
               my $att = $object->get_attributes();

       Return all set attributes on this object (graph/node/group/edge) as an anonymous hash ref.
       This respects inheritance, but does not include default values for unset attributes.

       See also get_attributes().

   attribute related methods
       You can call all the various attribute related methods like "set_attribute()",
       "get_attribute()", etc. on an edge, too. For example:

               $edge->set_attribute('label', 'by train');
               my $attr = $edge->get_attributes();
               my $raw_attr = $edge->raw_attributes();

       You can find more documentation in Graph::Easy.

EXPORT

       None by default.

SEE ALSO

       Graph::Easy.

AUTHOR

       Copyright (C) 2004 - 2008 by Tels <http://bloodgate.com>.

       See the LICENSE file for more details.