--- name: "Graph::Easy::Edge" section: "3pm" platform: "linux" package: "libgraph-easy-perl" version: "0.76-3" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/Graph::Easy::Edge" --- # Graph::Easy::Edge(3pm) An edge (a path connecting one ore more nodes) ## 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 \. See the LICENSE file for more details.