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Graph::Easy(3)	      User Contributed Perl Documentation	Graph::Easy(3)

NAME
       Graph::Easy - Convert or	render graphs (as ASCII, HTML, SVG or via
       Graphviz)

SYNOPSIS
	       use Graph::Easy;

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

	       # make a	fresh copy of the graph
	       my $new_graph = $graph->copy();

	       $graph->add_edge	('Bonn', 'Berlin');

	       # will not add it, since	it already exists
	       $graph->add_edge_once ('Bonn', 'Berlin');

	       print $graph->as_ascii( );	       # prints:

	       # +------+     +--------+
	       # | Bonn	| --> |	Berlin |
	       # +------+     +--------+

	       #####################################################
	       # alternatively,	let Graph::Easy	parse some text:

	       my $graph = Graph::Easy->new( '[Bonn] ->	[Berlin]' );

	       #####################################################
	       # slightly more verbose way:

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

	       my $bonn	= $graph->add_node('Bonn');
	       $bonn->set_attribute('border', 'solid 1px black');

	       my $berlin = $graph->add_node('Berlin');

	       $graph->add_edge	($bonn,	$berlin);

	       print $graph->as_ascii( );

	       # You can use plain scalars as node names and for the edge label:
	       $graph->add_edge	('Berlin', 'Frankfurt',	'via train');

	       # adding	edges with attributes:

	       my $edge	= Graph::Easy::Edge->new();
	       $edge->set_attributes( {
		       label =>	'train',
		       style =>	'dotted',
		       color =>	'red',
	       } );

	       # now with the optional edge object
	       $graph->add_edge	($bonn,	$berlin, $edge);

	       # raw HTML section
	       print $graph->as_html( );

	       # complete HTML page (with CSS)
	       print $graph->as_html_file( );

	       # Other possibilities:

	       # SVG (possible after you installed Graph::Easy::As_svg):
	       print $graph->as_svg( );

	       # Graphviz:
	       my $graphviz = $graph->as_graphviz();
	       open $DOT, '|dot	-Tpng -o graph.png' or die ("Cannot open pipe to dot: $!");
	       print $DOT $graphviz;
	       close $DOT;

	       # Please	see also the command line utility 'graph-easy'

DESCRIPTION
       "Graph::Easy" lets you generate graphs consisting of various shaped
       nodes connected by edges	(with optional labels).

       It can read and write graphs in a variety of formats, as	well as	render
       them via	its own	grid-based layouter.

       Since the layouter works	on a grid (manhattan layout), the output is
       most useful for flow charts, network diagrams, or hierarchy trees.

   Input
       Apart from driving the module with Perl code, you can also use
       "Graph::Easy::Parser" to	parse graph descriptions like:

	       [ Bonn ]	     --> [ Berlin ]
	       [ Frankfurt ] <=> [ Dresden ]
	       [ Bonn ]	     --	 [ Frankfurt ]

       See the "EXAMPLES" section below	for how	this might be rendered.

   Creating graphs
       First, create a graph object:

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

       Then add	a node to it:

	       my $node	= $graph->add_node('Koblenz');

       Don't worry, adding the node again will do nothing:

	       $node = $graph->add_node('Koblenz');

       You can get back	a node by its name with	"node()":

	       $node = $graph->node('Koblenz');

       You can either add another node:

	       my $second = $graph->node('Frankfurt');

       Or add an edge straight-away:

	       my ($first,$second,$edge) = $graph->add_edge('Mainz','Ulm');

       Adding the edge the second time creates another edge from 'Mainz' to
       'Ulm':

	       my $other_edge;
		($first,$second,$other_edge) = $graph->add_edge('Mainz','Ulm');

       This can	be avoided by using "add_edge_once()":

	       my $edge	= $graph->add_edge_once('Mainz','Ulm');
	       if (defined $edge)
		 {
		 # the first time the edge was added, do something with	it
		 $edge->set_attribute('color','blue');
		 }

       You can set attributes on nodes and edges:

	       $node->attribute('fill',	'yellow');
	       $edge->attribute('label', 'train');

       It is possible to add an	edge with a label:

	       $graph->add_edge('Cottbus', 'Berlin', 'my label');

       You can also add	self-loops:

	       $graph->add_edge('Bremen','Bremen');

       Adding multiple nodes is	easy:

	       my ($bonn,$rom) = Graph::Easy->add_nodes('Bonn','Rom');

       You can also have subgraphs (these are called groups):

	       my ($group) = Graph::Easy->add_group('Cities');

       Only nodes can be part of a group, edges	are automatically considered
       to be in	the group if they lead from one	node inside the	group to
       another node in the same	group. There are multiple ways to add one or
       more nodes into a group:

	       $group->add_member($bonn);
	       $group->add_node($rom);
	       $group->add_nodes($rom,$bonn);

       For more	options	please see the online manual:
       <http://bloodgate.com/perl/graph/manual/> .

   Output
       The output can be done in various styles:

       ASCII ART
	 Uses things like "+", "-" "<" and "|" to render the boxes.

       BOXART
	 Uses Unicode box art drawing elements to output the graph.

       HTML
	 HTML tables with CSS making everything	"pretty".

       SVG
	 Creates a Scalable Vector Graphics output.

       Graphviz
	 Creates graphviz code that can	be feed	to 'dot', 'neato' or similar
	 programs.

       GraphML
	 Creates a textual description of the graph in the GraphML format.

       GDL/VCG
	 Creates a textual description of the graph in the VCG or GDL (Graph
	 Description Language) format.

EXAMPLES
       The following examples are given	in the simple text format that is
       understood by Graph::Easy::Parser.

       You can also see	many more examples at:

       <http://bloodgate.com/perl/graph/>

   One node
       The most	simple graph (apart from the empty one :) is a graph
       consisting of only one node:

	       [ Dresden ]

   Two nodes
       A simple	graph consisting of two	nodes, linked together by a directed
       edge:

	       [ Bonn ]	-> [ Berlin ]

   Three nodes
       A graph consisting of three nodes, and both are linked from the first:

	       [ Bonn ]	-> [ Berlin ]
	       [ Bonn ]	-> [ Hamburg ]

   Three nodes in a chain
       A graph consisting of three nodes, showing that you can chain
       connections together:

	       [ Bonn ]	-> [ Berlin ] -> [ Hamburg ]

   Two not connected graphs
       A graph consisting of two separate parts, both of them not connected to
       each other:

	       [ Bonn ]	-> [ Berlin ]
	       [ Freiburg ] -> [ Hamburg ]

   Three nodes,	interlinked
       A graph consisting of three nodes, and two of the are connected from
       the first node:

	       [ Bonn ]	-> [ Berlin ]
	       [ Berlin	] -> [ Hamburg ]
	       [ Bonn ]	-> [ Hamburg ]

   Different edge styles
       A graph consisting of a couple of nodes,	linked with the	different
       possible	edge styles.

	       [ Bonn ]	<-> [ Berlin ]	       # bidirectional
	       [ Berlin	] ==> [	Rostock	]      # double
	       [ Hamburg ] ..> [ Altona	]      # dotted
	       [ Dresden ] - > [ Bautzen ]     # dashed
	       [ Leipzig ] ~~> [ Kirchhain ]   # wave
	       [ Hof ] .-> [ Chemnitz ]	       # dot-dash
	       [ Magdeburg ] <=> [ Ulm ]       # bidrectional, double etc
	       [ Magdeburg ] --	[ Ulm ]	       # arrow-less edge

       More examples at: <http://bloodgate.com/perl/graph/>

ANIMATION SUPPORT
       Note: Animations	are not	yet implemented!

       It is possible to add animations	to a graph. This is done by adding
       steps via the pseudo-class "step":

	       step.0 {
		 target: Bonn;	       # find object with id=Bonn, or
				       # if this fails,	the node named
				       # "Bonn".
		 animate: fill:	       # animate this attribute
		 from: yellow;	       # start value (0% of duration)
		 via: red;	       # at 50%	of the duration
		 to: yellow;	       # and 100% of duration
		 wait: 0;	       # after triggering, wait	so many	seconds
		 duration: 5;	       # entire	time to	go from	"from" to "to"
		 trigger: onload;      # when to trigger this animation
		 repeat: 2;	       # how often to repeat ("2" means	two times)
				       # also "infinite", then "next" will be ignored
		 next: 1;	       # which step to take after repeat is up
	       }
	       step.1 {
		 from: white;	       # set to	white
		 to: white;
		 duration: 0.1;	       # 100ms
		 next: 0;	       # go back to step.0
	       }

       Here two	steps are created, 0 and 1 and the animation will be going
       like this:

				      0.1s
				    +-------------------------------+
				    v				    |
	       +--------+  0s	+--------+  5s	 +--------+  5s	  +--------+
	       | onload	| ---->	| step.0 | ----> | step.0 | ----> | step.1 |
	       +--------+	+--------+	 +--------+	  +--------+

       You can generate	a a graph with the animation flow via
       "animation_as_graph()".

   Output
       Currently no output formats supports animations yet.

METHODS
       "Graph::Easy" supports the following methods:

   new()
	       use Graph::Easy;

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

       Creates a new, empty "Graph::Easy" object.

       Takes optional a	hash reference with a list of options. The following
       are valid options:

	       debug		       if true,	enables	debug output
	       timeout		       timeout (in seconds) for	the layouter
	       fatal_errors	       wrong attributes	are fatal errors, default: true
	       strict		       test attribute names for	being valid, default: true
	       undirected	       create an undirected graph, default: false

   copy()
	   my $copy = $graph->copy( );

       Create a	copy of	this graph and return it as a new Graph::Easy object.

   error()
	       my $error = $graph->error();

       Returns the last	error or '' for	none.  Optionally, takes an error
       message to be set.

	       $graph->error( 'Expected	Foo, but found Bar.' );

       See warn() on how to catch error	messages. See also non_fatal_errors()
       on how to turn errors into warnings.

   warn()
	       my $warning = $graph->warn();

       Returns the last	warning	or '' for none.	 Optionally, takes a warning
       message to be output to STDERR:

	       $graph->warn( 'Expected Foo, but	found Bar.' );

       If you want to catch warnings from the layouter,	enable catching	of
       warnings	or errors:

	       $graph->catch_messages(1);

	       # Or individually:
	       # $graph->catch_warnings(1);
	       # $graph->catch_errors(1);

	       # something which warns or throws an error:
	       ...

	       if ($graph->error())
		 {
		 my @errors = $graph->errors();
		 }
	       if ($graph->warning())
		 {
		 my @warnings =	$graph->warnings();
		 }

       See Graph::Easy::Base for more details on error/warning message
       capture.

   add_edge()
	       my ($first, $second, $edge) = $graph->add_edge( 'node 1', 'node 2');

   add_edge()
	       my ($first, $second, $edge) = $graph->add_edge( 'node 1', 'node 2');
	       my $edge	= $graph->add_edge( $x,	$y, $edge);
	       $graph->add_edge( $x, $y);

       Add an edge between nodes X and Y. The optional edge object defines the
       style of	the edge, if not present, a default object will	be used.

       When called in scalar context, will return $edge. In array/list context
       it will return the two nodes and	the edge object.

       $x and $y should	be either plain	scalars	with the names of the nodes,
       or objects of Graph::Easy::Node,	while the optional $edge should	be
       Graph::Easy::Edge.

       Note: "Graph::Easy" graphs are multi-edged, and adding the same edge
       twice will result in two	edges going from $x to $y! See
       "add_edge_once()" on how	to avoid that.

       You can also use	"edge()" to check whether an edge from X to Y already
       exists in the graph.

   add_edge_once()
	       my ($first, $second, $edge) = $graph->add_edge_once( 'node 1', 'node 2');
	       my $edge	= $graph->add_edge_once( $x, $y, $edge);
	       $graph->add_edge_once( $x, $y);

	       if (defined $edge)
		 {
		 # got added once, so do something with	it
		 $edge->set_attribute('label','unique');
		 }

       Adds an edge between nodes X and	Y, unless there	exists already an edge
       between these two nodes.	See "add_edge()".

       Returns undef when an edge between X and	Y already exists.

       When called in scalar context, will return $edge. In array/list context
       it will return the two nodes and	the edge object.

   flip_edges()
	       my $graph = Graph::Easy->new();
	       $graph->add_edge('Bonn','Berlin');
	       $graph->add_edge('Berlin','Bonn');

	       print $graph->as_ascii();

	       #   +--------------+
	       #   v		  |
	       # +--------+	+------+
	       # | Berlin | -->	| Bonn |
	       # +--------+	+------+

	       $graph->flip_edges('Bonn', 'Berlin');

	       print $graph->as_ascii();

	       #   +--------------+
	       #   |		  v
	       # +--------+	+------+
	       # | Berlin | -->	| Bonn |
	       # +--------+	+------+

       Turn around (transpose) all edges that are going	from the first node to
       the second node.

   add_node()
	       my $node	= $graph->add_node( 'Node 1' );
	       # or if you already have	a Graph::Easy::Node object:
	       $graph->add_node( $x );

       Add a single node X to the graph. $x should be either a
       "Graph::Easy::Node" object, or a	unique name for	the node. Will do
       nothing if the node already exists in the graph.

       It returns an Graph::Easy::Node object.

   add_anon_node()
	       my $anon_node = $graph->add_anon_node( );

       Creates a single, anonymous node	and adds it to the graph, returning
       the "Graph::Easy::Node::Anon" object.

       The created node	is equal to one	created	via " [	] " in the Graph::Easy
       text description.

   add_nodes()
	       my @nodes = $graph->add_nodes( 'Node 1',	'Node 2' );

       Add all the given nodes to the graph. The arguments should be either a
       "Graph::Easy::Node" object, or a	unique name for	the node. Will do
       nothing if the node already exists in the graph.

       It returns a list of Graph::Easy::Node objects.

   rename_node()
	       $node = $graph->rename_node($node, $new_name);

       Changes the name	of a node. If the passed node is not part of this
       graph or	just a string, it will be added	with the new name to this
       graph.

       If the node was part of another graph, it will be deleted there and
       added to	this graph with	the new	name, effectively moving the node from
       the old to the new graph	and renaming it	at the same time.

   del_node()
	       $graph->del_node('Node name');
	       $graph->del_node($node);

       Delete the node with the	given name from	the graph.

   del_edge()
	       $graph->del_edge($edge);

       Delete the given	edge object from the graph. You	can use	"edge()" to
       find an edge from Node A	to B:

	       $graph->del_edge( $graph->edge('A','B') );

   merge_nodes()
	       $graph->merge_nodes( $first_node, $second_node );
	       $graph->merge_nodes( $first_node, $second_node, $joiner );

       Merge two nodes.	Will delete all	connections between the	two nodes,
       then move over any connection to/from the second	node to	the first,
       then delete the second node from	the graph.

       Any attributes on the second node will be lost.

       If present, the optional	$joiner	argument will be used to join the
       label of	the second node	to the label of	the first node.	If not
       present,	the label of the second	node will be dropped along with	all
       the other attributes:

	       my $graph = Graph::Easy->new('[A]->[B]->[C]->[D]');

	       # this produces "[A]->[C]->[D]"
	       $graph->merge_nodes( 'A', 'B' );

	       # this produces "[A C]->[D]"
	       $graph->merge_nodes( 'A', 'C', '	' );

	       # this produces "[A C \n	D]", note single quotes	on the third argument!
	       $graph->merge_nodes( 'A', 'C', '	\n ' );

   get_attribute()
	       my $value = $graph->get_attribute( $class, $name	);

       Return the value	of attribute $name from	class $class.

       Example:

	       my $color = $graph->attribute( 'node', 'color' );

       You can also call all the various attribute related methods on members
       of the graph directly, for instance:

	       $node->get_attribute('label');
	       $edge->get_attribute('color');
	       $group->get_attribute('fill');

   attribute()
	       my $value = $graph->attribute( $class, $name );

       Is an alias for get_attribute.

   color_attribute()
	       # returns f.i. #ff0000
	       my $color = $graph->get_color_attribute(	'node',	'color'	);

       Just like get_attribute(), but only for colors, and returns them	as
       hex, using the current colorscheme.

   get_color_attribute()
       Is an alias for color_attribute().

   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.

       Note that this does not include custom attributes.

       See also	get_custom_attributes and raw_attributes().

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

       Return all the custom attributes	on this	object (graph/node/group/edge)
       as an anonymous hash ref.

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

       "custom_attributes()" is	an alias for get_custom_attributes.

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

       Return all set attributes on this object	(graph,	node, group or edge)
       as an anonymous hash ref. Thus you get all the locally active
       attributes for this object.

       Inheritance is respected, e.g. attributes that have the value "inherit"
       and are inheritable, will be inherited from the base class.

       But default values for unset attributes are skipped. Here is an
       example:

	       node { color: red; }

	       [ A ] { class: foo; color: inherit; }

       This will return:

	       { class => foo, color =>	red }

       As you can see, attributes like "background" etc. are not included,
       while the color value was inherited properly.

       See also	get_attributes().

   default_attribute()
	       my $def = $graph->default_attribute($class, 'fill');

       Returns the default value for the given attribute in the	class of the
       object.

       The default attribute is	the value that will be used if the attribute
       on the object itself, as	well as	the attribute on the class is unset.

       To find out what	attribute is on	the class, use the three-arg form of
       attribute on the	graph:

	       my $g = Graph::Easy->new();
	       my $node	= $g->add_node('Berlin');

	       print $node->attribute('fill'), "\n";	       # print "white"
	       print $node->default_attribute('fill'), "\n";   # print "white"
	       print $g->attribute('node','fill'), "\n";       # print "white"

	       $g->set_attribute('node','fill','red');	       # class is "red"
	       $node->set_attribute('fill','green');	       # this object is	"green"

	       print $node->attribute('fill'), "\n";	       # print "green"
	       print $node->default_attribute('fill'), "\n";   # print "white"
	       print $g->attribute('node','fill'), "\n";       # print "red"

       See also	raw_attribute().

   raw_attribute()
	       my $value = $object->raw_attribute( $name );

       Return the value	of attribute $name from	the object it this method is
       called on (graph, node, edge, group etc.). If the attribute is not set
       on the object itself, returns undef.

       This method respects inheritance, so an attribute value of 'inherit' on
       an object will make the method return the inherited value:

	       my $g = Graph::Easy->new();
	       my $n = $g->add_node('A');

	       $g->set_attribute('color','red');

	       print $n->raw_attribute('color');	       # undef
	       $n->set_attribute('color','inherit');
	       print $n->raw_attribute('color');	       # 'red'

       See also	attribute().

   raw_color_attribute()
	       # returns f.i. #ff0000
	       my $color = $graph->raw_color_attribute('color' );

       Just like raw_attribute(), but only for colors, and returns them	as
       hex, using the current colorscheme.

       If the attribute	is not set on the object, returns "undef".

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

       Returns a hash with all the raw attributes of that object.  Attributes
       that are	no set on the object itself, but on the	class this object
       belongs to are not included.

       This method respects inheritance, so an attribute value of 'inherit' on
       an object will make the method return the inherited value.

   set_attribute()
	       # Set the attribute on the given	class.
	       $graph->set_attribute( $class, $name, $val );

	       # Set the attribute on the graph	itself.	This is	synonymous
	       # to using 'graph' as class in the form above.
	       $graph->set_attribute( $name, $val );

       Sets a given attribute named $name to the new value $val	in the class
       specified in $class.

       Example:

	       $graph->set_attribute( 'graph', 'gid', '123' );

       The class can be	one of "graph",	"edge",	"node" or "group". The last
       three can also have subclasses like in "node.subclassname".

       You can also call the various attribute related methods on members of
       the graph directly, for instance:

	       $node->set_attribute('label', 'my node');
	       $edge->set_attribute('color', 'red');
	       $group->set_attribute('fill', 'green');

   set_attributes()
	       $graph->set_attributes( $class, $att );

       Given a class name in $class and	a hash of mappings between attribute
       names and values	in $att, will set all these attributes.

       The class can be	one of "graph",	"edge",	"node" or "group". The last
       three can also have subclasses like in "node.subclassname".

       Example:

	       $graph->set_attributes( 'node', { color => 'red', background => 'none' }	);

   del_attribute()
	       $graph->del_attribute('border');

       Delete the attribute with the given name	from the object.

       You can also call the various attribute related methods on members of
       the graph directly, for instance:

	       $node->del_attribute('label');
	       $edge->del_attribute('color');
	       $group->del_attribute('fill');

   unquote_attribute()
	       # returns '"Hello World!"'
	       my $value = $self->unquote_attribute('node','label','"Hello World!"');
	       # returns 'red'
	       my $color = $self->unquote_attribute('node','color','"red"');

       Return the attribute unquoted except for	labels and titles, that	is it
       removes double quotes at	the start and the end of the string, unless
       these are escaped with a	backslash.

   border_attribute()
	       my $border = $graph->border_attribute();

       Return the combined border attribute like "1px solid red" from the
       border(style|color|width) attributes.

   split_border_attributes()
	       my ($style,$width,$color) = $graph->split_border_attribute($border);

       Split the border	attribute (like	"1px solid red") into the three
       different parts.

   quoted_comment()
	       my $cmt = $node->comment();

       Comment of this object, quoted suitable as to be	embedded into
       HTML/SVG.  Returns the empty string if this object doesn't have a
       comment set.

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

       Returns the flow	of the graph, as absolute number in degress.

   source_nodes()
	       my @roots = $graph->source_nodes();

       Returns all nodes that have only	outgoing edges,	e.g. are the root of a
       tree, in	no particular order.

       Isolated	nodes (no edges	at all)	will not be included, see
       predecessorless_nodes() to get these, too.

       In scalar context, returns the number of	source nodes.

   predecessorless_nodes()
	       my @roots = $graph->predecessorless_nodes();

       Returns all nodes that have no incoming edges, regardless of whether
       they have outgoing edges	or not,	in no particular order.

       Isolated	nodes (no edges	at all)	will be	included in the	list.

       See also	source_nodes().

       In scalar context, returns the number of	predecessorless	nodes.

   root_node()
	       my $root	= $graph->root_node();

       Return the root node as Graph::Easy::Node object, if it was set with
       the 'root' attribute.

   timeout()
	       print $graph->timeout(),	" seconds timeout for layouts.\n";
	       $graph->timeout(12);

       Get/set the timeout for layouts in seconds. If the layout process did
       not finish after	that time, it will be stopped and a warning will be
       printed.

       The default timeout is 5	seconds.

   strict()
	       print "Graph has	strict checking\n" if $graph->strict();
	       $graph->strict(undef);	       # disable strict	attribute checks

       Get/set the strict option. When set to a	true value, all	attribute
       names and values	will be	strictly checked and unknown/invalid one will
       be rejected.

       This option is on by default.

   type()
	       print "Graph is " . $graph->type() . "\n";

       Returns the type	of the graph as	string,	either "directed" or
       "undirected".

   layout()
	       $graph->layout();
	       $graph->layout( type => 'force',	timeout	=> 60 );

       Creates the internal structures to layout the graph.

       This method will	be called automatically	when you call any of the
       "as_FOO"	methods	or "output()" as described below.

       The options are:

	       type	       the type	of the layout, possible	values:
			       'force'	       - force based layouter
			       'adhoc'	       - the default layouter
	       timeout	       timeout in seconds

       See also: timeout().

   output_format()
	       $graph->output_format('html');

       Set the outputformat. One of 'html', 'ascii', 'graphviz', 'svg' or
       'txt'.  See also	output().

   output()
	       my $out = $graph->output();

       Output the graph	in the format set by "output_format()".

   as_ascii()
	       print $graph->as_ascii();

       Return the graph	layout in ASCII	art, in	utf-8.

   as_ascii_file()
	       print $graph->as_ascii_file();

       Is an alias for as_ascii.

   as_ascii_html()
	       print $graph->as_ascii_html();

       Return the graph	layout in ASCII	art, suitable to be embedded into an
       HTML page. Basically it wraps the output	from as_ascii()	into "<pre>
       </pre>" and inserts real	HTML links. The	returned string	is in utf-8.

   as_boxart()
	       print $graph->as_box();

       Return the graph	layout as box drawing using Unicode characters (in
       utf-8, as always).

   as_boxart_file()
	       print $graph->as_boxart_file();

       Is an alias for "as_box".

   as_boxart_html()
	       print $graph->as_boxart_html();

       Return the graph	layout as box drawing using Unicode characters,	as
       chunk that can be embedded into an HTML page.

       Basically it wraps the output from as_boxart() into "<pre> </pre>" and
       inserts real HTML links.	The returned string is in utf-8.

   as_boxart_html_file()
	       print $graph->as_boxart_html_file();

       Return the graph	layout as box drawing using Unicode characters,	as a
       full HTML page complete with header and footer.

   as_html()
	       print $graph->as_html();

       Return the graph	layout as HTML section.	See css() to get the CSS
       section to go with that HTML code. If you want a	complete HTML page
       then use	as_html_file().

   as_html_page()
	       print $graph->as_html_page();

       Is an alias for "as_html_file".

   as_html_file()
	       print $graph->as_html_file();

       Return the graph	layout as HTML complete	with headers, CSS section and
       footer. Can be viewed in	the browser of your choice.

   add_group()
	       my $group = $graph->add_group('Group name');

       Add a group to the graph	and return it as Graph::Easy::Group object.

   group()
	       my $group = $graph->group('Name');

       Returns the group with the name "Name" as Graph::Easy::Group object.

   rename_group()
	       $group =	$graph->rename_group($group, $new_name);

       Changes the name	of the given group. If the passed group	is not part of
       this graph or just a string, it will be added with the new name to this
       graph.

       If the group was	part of	another	graph, it will be deleted there	and
       added to	this graph with	the new	name, effectively moving the group
       from the	old to the new graph and renaming it at	the same time.

   groups()
	       my @groups = $graph->groups();

       Returns the groups of the graph as Graph::Easy::Group objects, in
       arbitrary order.

   groups_within()
	       # equivalent to $graph->groups():
	       my @groups = $graph->groups_within();	       # all
	       my @toplevel_groups = $graph->groups_within(0); # level 0 only

       Return the groups that are inside this graph, up	to the specified
       level, in arbitrary order.

       The default level is -1,	indicating no bounds and thus all contained
       groups are returned.

       A level of 0 means only the direct children, and	hence only the
       toplevel	groups will be returned. A level 1 means the toplevel groups
       and their toplevel children, and	so on.

   anon_groups()
	       my $anon_groups = $graph->anon_groups();

       In scalar context, returns the number of	anon groups (aka
       Graph::Easy::Group::Anon) the graph has.

       In list context,	returns	all anon groups	as objects, in arbitrary
       order.

   del_group()
	       $graph->del_group($name);

       Delete the group	with the given name.

   edges(), edges_within()
	       my @edges = $graph->edges();

       Returns the edges of the	graph as Graph::Easy::Edge objects, in
       arbitrary order.

       edges_within() is an alias for "edges()".

   is_simple_graph(), is_simple()
	       if ($graph->is_simple())
		 {
		 }

       Returns true if the graph does not have multiedges, e.g.	if it does not
       have more than one edge going from any node to any other	node or	group.

       Since this method has to	look at	all edges, it is costly	in terms of
       both CPU	and memory.

   is_directed()
	       if ($graph->is_directed())
		 {
		 }

       Returns true if the graph is directed.

   is_undirected()
	       if ($graph->is_undirected())
		 {
		 }

       Returns true if the graph is undirected.

   parent()
	       my $parent = $graph->parent();

       Returns the parent graph, for graphs this is undef.

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

       Returns the label of the	graph.

   title()
	       my $title = $graph->title();

       Returns the (mouseover) title of	the graph.

   link()
	       my $link	= $graph->link();

       Return a	potential link (for the	graphs label), build from the
       attributes "linkbase" and "link"	(or autolink). Returns '' if there is
       no link.

   as_graphviz()
	       print $graph->as_graphviz();

       Return the graph	as graphviz code, suitable to be feed to a program
       like "dot" etc.

   as_graphviz_file()
	       print $graph->as_graphviz_file();

       Is an alias for as_graphviz().

   angle()
	       my $degrees = Graph::Easy->angle( 'south' );
	       my $degrees = Graph::Easy->angle( 120 );

       Check an	angle for being	valid and return a value between -359 and 359
       degrees.	The special values "south", "north", "west", "east", "up" and
       "down" are also valid and converted to degrees.

   nodes()
	       my $nodes = $graph->nodes();

       In scalar context, returns the number of	nodes/vertices the graph has.

       In list context,	returns	all nodes as objects, in arbitrary order.

   anon_nodes()
	       my $anon_nodes =	$graph->anon_nodes();

       In scalar context, returns the number of	anon nodes (aka
       Graph::Easy::Node::Anon)	the graph has.

       In list context,	returns	all anon nodes as objects, in arbitrary	order.

   html_page_header()
	       my $header = $graph->html_page_header();
	       my $header = $graph->html_page_header($css);

       Return the header of an HTML page. Used together	with html_page_footer
       by as_html_page to construct a complete HTML page.

       Takes an	optional parameter with	the CSS	styles to be inserted into the
       header. If $css is not defined, embedds the result of "$self->css()".

   html_page_footer()
	       my $footer = $graph->html_page_footer();

       Return the footer of an HTML page. Used together	with html_page_header
       by as_html_page to construct a complete HTML page.

   css()
	       my $css = $graph->css();

       Return CSS code for that	graph. See as_html().

   as_txt()
	       print $graph->as_txt();

       Return the graph	as a normalized	textual	representation,	that can be
       parsed with Graph::Easy::Parser back to the same	graph.

       This does not call layout() since the actual text representation	is
       just a dump of the graph.

   as_txt_file()
	       print $graph->as_txt_file();

       Is an alias for as_txt().

   as_svg()
	       print $graph->as_svg();

       Return the graph	as SVG (Scalable Vector	Graphics), which can be
       embedded	into HTML pages. You need to install Graph::Easy::As_svg first
       to make this work.

       See also	as_svg_file().

       Note: You need Graph::Easy::As_svg installed for	this to	work!

   as_svg_file()
	       print $graph->as_svg_file();

       Returns SVG just	like "as_svg()", but this time as standalone SVG,
       suitable	for storing it in a file and referencing it externally.

       After calling "as_svg_file()" or	"as_svg()", you	can retrieve some SVG
       information, notable "width" and	"height" via "svg_information".

       Note: You need Graph::Easy::As_svg installed for	this to	work!

   svg_information()
	       my $info	= $graph->svg_information();

	       print "Size: $info->{width}, $info->{height}\n";

       Return information about	the graph created by the last "as_svg()" or
       "as_svg_file()" call.

       The following fields are	set:

	       width	       width of	the SVG	in pixels
	       height	       height of the SVG in pixels

       Note: You need Graph::Easy::As_svg installed for	this to	work!

   as_vcg()
	       print $graph->as_vcg();

       Return the graph	as VCG text. VCG is a subset of	GDL (Graph Description
       Language).

       This does not call layout() since the actual text representation	is
       just a dump of the graph.

   as_vcg_file()
	       print $graph->as_vcg_file();

       Is an alias for as_vcg().

   as_gdl()
	       print $graph->as_gdl();

       Return the graph	as GDL (Graph Description Language) text. GDL is a
       superset	of VCG.

       This does not call layout() since the actual text representation	is
       just a dump of the graph.

   as_gdl_file()
	       print $graph->as_gdl_file();

       Is an alias for as_gdl().

   as_graphml()
	       print $graph->as_graphml();

       Return the graph	as a GraphML representation.

       This does not call layout() since the actual text representation	is
       just a dump of the graph.

       The output contains only	the set	attributes, e.g. default attribute
       values are not specifically mentioned. The attribute names and values
       are the in the format that "Graph::Easy"	defines.

   as_graphml_file()
	       print $graph->as_graphml_file();

       Is an alias for as_graphml().

   sorted_nodes()
	       my $nodes =
		$graph->sorted_nodes( );	       # default sort on 'id'
	       my $nodes =
		$graph->sorted_nodes( 'name' );	       # sort on 'name'
	       my $nodes =
		$graph->sorted_nodes( 'layer', 'id' ); # sort on 'layer', then on 'id'

       In scalar context, returns the number of	nodes/vertices the graph has.
       In list context returns a list of all the node objects (as reference),
       sorted by their attribute(s) given as arguments.	The default is 'id',
       e.g. their internal ID number, which amounts more or less to the	order
       they have been inserted.

       This routine will sort the nodes	by their group first, so the requested
       sort order will be only valid if	there are no groups or inside each
       group.

   as_debug()
	       print $graph->as_debug();

       Return debugging	information like version numbers of used modules, and
       a textual representation	of the graph.

       This does not call layout() since the actual text representation	is
       more a dump of the graph, than a	certain	layout.

   node()
	       my $node	= $graph->node('node name');

       Return node by unique name (case	sensitive). Returns undef if the node
       does not	exist in the graph.

   edge()
	       my $edge	= $graph->edge(	$x, $y );

       Returns the edge	objects	between	nodes $x and $y. Both $x and $y	can be
       either scalars with names or "Graph::Easy::Node"	objects.

       Returns undef if	the edge does not yet exist.

       In list context it will return all edges	from $x	to $y, in scalar
       context it will return only one (arbitrary) edge.

   id()
	       my $graph_id = $graph->id();
	       $graph->id('123');

       Returns the id of the graph. You	can also set a new ID with this
       routine.	The default is ''.

       The graph's ID is used to generate unique CSS classes for each graph,
       in the case you want to have more than one graph	in an HTML page.

   seed()
	       my $seed	= $graph->seed();
	       $graph->seed(2);

       Get/set the random seed for the graph object. See randomize() for a
       method to set a random seed.

       The seed	is used	to create random numbers for the layouter. For the
       same graph, the same seed will always lead to the same layout.

   randomize()
	       $graph->randomize();

       Set a random seed for the graph object. See seed().

   debug()
	       my $debug = $graph->debug();    # get
	       $graph->debug(1);	       # enable
	       $graph->debug(0);	       # disable

       Enable, disable or read out the debug status. When the debug status is
       true, additional	debug messages will be printed on STDERR.

   score()
	       my $score = $graph->score();

       Returns the score of the	graph, or undef	if layout() has	not yet	been
       called.

       Higher scores are better, although you cannot compare scores for
       different graphs. The score should only be used to compare different
       layouts of the same graph against each other:

	       my $max = undef;

	       $graph->randomize();
	       my $seed	= $graph->seed();

	       $graph->layout();
	       $max = $graph->score();

	       for (1..10)
		 {
		 $graph->randomize();		       # select	random seed
		 $graph->layout();		       # layout	with that seed
		 if ($graph->score() > $max)
		   {
		   $max	= $graph->score();	       # store the new max store
		   $seed = $graph->seed();	       # and it's seed
		   }
		 }

	       # redo the best layout
	       if ($seed ne $graph->seed())
		 {
		 $graph->seed($seed);
		 $graph->layout();
		 }
	       # output	graph:
	       print $graph->as_ascii();	       # or as_html() etc

   valid_attribute()
	       my $graph = Graph::Easy->new();
	       my $new_value =
		 $graph->valid_attribute( $name, $value, $class	);

	       if (ref($new_value) eq 'ARRAY' && @$new_value ==	0)
		 {
		 # throw error
		 die ("'$name' is not a	valid attribute	name for '$class'")
		       if $self->{_warn_on_unused_attributes};
		 }
	       elsif (!defined $new_value)
		 {
		 # throw error
		 die ("'$value'	is no valid '$name' for	'$class'");
		 }

       Deprecated, please use validate_attribute().

       Check that a "$name,$value" pair	is a valid attribute in	class $class,
       and returns a new value.

       It returns an array ref if the attribute	name is	invalid, and undef if
       the value is invalid.

       The return value	can differ from	the passed in value, f.i.:

	       print $graph->valid_attribute( 'color', 'red' );

       This would print	'#ff0000';

   validate_attribute()
	       my $graph = Graph::Easy->new();
	       my ($rc,$new_name, $new_value) =
		 $graph->validate_attribute( $name, $value, $class );

       Checks a	given attribute	name and value (or values, in case of a	value
       like "red|green") for being valid. It returns a new attribute name (in
       case of "font-color" => "fontcolor") and	either a single	new attribute,
       or a list of attribute values as	array ref.

       If $rc is defined, it is	the error number:

	       1		       unknown attribute name
	       2		       invalid attribute value
	       4		       found multiple attributes, but these arent
				       allowed at this place

   color_as_hex()
	       my $hexred   = Graph::Easy->color_as_hex( 'red' );
	       my $hexblue  = Graph::Easy->color_as_hex( '#0000ff' );
	       my $hexcyan  = Graph::Easy->color_as_hex( '#f0f'	);
	       my $hexgreen = Graph::Easy->color_as_hex( 'rgb(0,255,0)'	);

       Takes a valid color name	or definition (hex, short hex, or RGB) and
       returns the color in hex	like "#ff00ff".

   color_value($color_name, $color_scheme)
	       my $color = Graph::Easy->color_name( 'red' );   # #ff0000
	       print Graph::Easy->color_name( '#ff0000'	);     # #ff0000

	       print Graph::Easy->color_name( 'snow', 'x11' );

       Given a color name, returns the color in	hex. See color_name for	a list
       of possible values for the optional $color_scheme parameter.

   color_name($color_value, $color_scheme)
	       my $color = Graph::Easy->color_name( 'red' );   # red
	       print Graph::Easy->color_name( '#ff0000'	);     # red

	       print Graph::Easy->color_name( 'snow', 'x11' );

       Takes a hex color value and returns the name of the color.

       The optional parameter is the color scheme, where the following values
       are possible:

	w3c		       (the default)
	x11		       (what graphviz uses as default)

       Plus the	following ColorBrewer schemes are supported, see the online
       manual for examples and their usage:

	accent3	accent4	accent5	accent6	accent7	accent8

	blues3 blues4 blues5 blues6 blues7 blues8 blues9

	brbg3 brbg4 brbg5 brbg6	brbg7 brbg8 brbg9 brbg10 brbg11

	bugn3 bugn4 bugn5 bugn6	bugn7 bugn8 bugn9 bupu3	bupu4 bupu5 bupu6 bupu7
	bupu8 bupu9

	dark23 dark24 dark25 dark26 dark27 dark28

	gnbu3 gnbu4 gnbu5 gnbu6	gnbu7 gnbu8 gnbu9

	greens3	greens4	greens5	greens6	greens7	greens8	greens9

	greys3 greys4 greys5 greys6 greys7 greys8 greys9

	oranges3 oranges4 oranges5 oranges6 oranges7 oranges8 oranges9

	orrd3 orrd4 orrd5 orrd6	orrd7 orrd8 orrd9

	paired3	paired4	paired5	paired6	paired7	paired8	paired9	paired10 paired11
	paired12

	pastel13 pastel14 pastel15 pastel16 pastel17 pastel18 pastel19

	pastel23 pastel24 pastel25 pastel26 pastel27 pastel28

	piyg3 piyg4 piyg5 piyg6	piyg7 piyg8 piyg9 piyg10 piyg11

	prgn3 prgn4 prgn5 prgn6	prgn7 prgn8 prgn9 prgn10 prgn11

	pubu3 pubu4 pubu5 pubu6	pubu7 pubu8 pubu9

	pubugn3	pubugn4	pubugn5	pubugn6	pubugn7	pubugn8	pubugn9

	puor3 puor4 puor5 puor6	puor7 puor8 puor9 puor10 puor11

	purd3 purd4 purd5 purd6	purd7 purd8 purd9

	purples3 purples4 purples5 purples6 purples7 purples8 purples9

	rdbu3 rdbu4 rdbu5 rdbu6	rdbu7 rdbu8 rdbu9 rdbu10 rdbu11

	rdgy3 rdgy4 rdgy5 rdgy6	rdgy7 rdgy8 rdgy9

	rdpu3 rdpu4 rdpu5 rdpu6	rdpu7 rdpu8 rdpu9 rdgy10 rdgy11

	rdylbu3	rdylbu4	rdylbu5	rdylbu6	rdylbu7	rdylbu8	rdylbu9	rdylbu10 rdylbu11

	rdylgn3	rdylgn4	rdylgn5	rdylgn6	rdylgn7	rdylgn8	rdylgn9	rdylgn10 rdylgn11

	reds3 reds4 reds5 reds6	reds7 reds8 reds9

	set13 set14 set15 set16	set17 set18 set19

	set23 set24 set25 set26	set27 set28

	set33 set34 set35 set36	set37 set38 set39 set310 set311	set312

	spectral3 spectral4 spectral5 spectral6	spectral7 spectral8 spectral9
	spectral10 spectral11

	ylgn3 ylgn4 ylgn5 ylgn6	ylgn7 ylgn8 ylgn9

	ylgnbu3	ylgnbu4	ylgnbu5	ylgnbu6	ylgnbu7	ylgnbu8	ylgnbu9

	ylorbr3	ylorbr4	ylorbr5	ylorbr6	ylorbr7	ylorbr8	ylorbr9

	ylorrd3	ylorrd4	ylorrd5	ylorrd6	ylorrd7	ylorrd8	ylorrd9

   color_names()
	       my $names = Graph::Easy->color_names();

       Return a	hash with name => value	mapping	for all	known colors.

   text_style()
	       if ($graph->text_style('bold, italic'))
		 {
		 ...
		 }

       Checks the given	style list for being valid.

   text_styles()
	       my $styles = $graph->text_styles();     # or $edge->text_styles() etc.

	       if ($styles->{'italic'})
		 {
		 print 'is italic\n';
		 }

       Return a	hash with the given text-style properties, aka 'underline',
       'bold' etc.

   text_styles_as_css()
	       my $styles = $graph->text_styles_as_css();      # or $edge->...() etc.

       Return the text styles as a chunk of CSS	styling	that can be embedded
       into a "	style="" " parameter.

   use_class()
	       $graph->use_class('node', 'Graph::Easy::MyNode');

       Override	the class to be	used to	constructs objects when	calling
       "add_edge()", "add_group()" or "add_node()".

       The first parameter can be one of the following:

	       node
	       edge
	       group

       Please see the documentation about "use_class()"	in
       "Graph::Easy::Parser" for examples and details.

   animation_as_graph()
	       my $graph_2 = $graph->animation_as_graph();
	       print $graph_2->as_ascii();

       Returns the animation of	$graph as a graph describing the flow of the
       animation. Useful for debugging animation flows.

   add_cycle()
	       $graph->add_cycle('A','B','C');	       # A -> B	-> C ->	A

       Compatibility method for	Graph, adds the	edges between each node	and
       back from the last node to the first. Returns the graph.

   add_path()
	       $graph->add_path('A','B','C');	       # A -> B	-> C

       Compatibility method for	Graph, adds the	edges between each node.
       Returns the graph.

   add_vertex()
	       $graph->add_vertex('A');

       Compatibility method for	Graph, adds the	node and returns the graph.

   add_vertices()
	       $graph->add_vertices('A','B');

       Compatibility method for	Graph, adds these nodes	and returns the	graph.

   has_edge()
	       $graph->has_edge('A','B');

       Compatibility method for	Graph, returns true if at least	one edge
       between A and B exists.

   vertices()
       Compatibility method for	Graph, returns in scalar context the number of
       nodes this graph	has, in	list context a (arbitrarily sorted) list of
       node objects.

   set_vertex_attribute()
	       $graph->set_vertex_attribute( 'A', 'fill', '#deadff' );

       Compatibility method for	Graph, set the named vertex attribute.

       Please note that	this routine will only accept Graph::Easy attribute
       names and values. If you	want to	attach custom attributes, you need to
       start their name	with 'x-':

	       $graph->set_vertex_attribute( 'A', 'x-foo', 'bar' );

   get_vertex_attribute()
	       my $fill	= $graph->get_vertex_attribute(	'A', 'fill' );

       Compatibility method for	Graph, get the named vertex attribute.

       Please note that	this routine will only accept Graph::Easy attribute
       names. See set_vertex_attribute().

EXPORT
       Exports nothing.

SEE ALSO
       Graph, Graph::Convert, Graph::Easy::As_svg, Graph::Easy::Manual and
       Graph::Easy::Parser.

   Related Projects
       Graph::Layout::Aesthetic, Graph and Text::Flowchart.

       There is	also an	very old, unrelated project from ca. 1995, which does
       something similar.  See
       <http://rw4.cs.uni-sb.de/users/sander/html/gsvcg1.html>.

       Testcases and more examples under:

       <http://bloodgate.com/perl/graph/>.

LIMITATIONS
       This module is now quite	complete, but there are	still some
       limitations.  Hopefully further development will	lift these.

   Scoring
       Scoring is not yet implemented, each generated graph will be the	same
       regardless of the random	seed.

   Layouter
       The layouter can	not yet	handle links between groups (or	between	a
       group and a node, or vice versa). These links will thus only appear in
       as_graphviz() or	as_txt() output.

   Paths
       No optimizations
	 In complex graphs, non-optimal	layout part like this one might
	 appear:

		 +------+     +--------+
		 | Bonn	| --> |	Berlin | --> ...
		 +------+     +--------+
				^
				|
				|
		 +---------+	|
		 | Kassel  | ---+
		 +---------+

	 A second-stage	optimizer that simplifies these	layouts	is not yet
	 implemented.

	 In addition the general placement/processing strategy as well as the
	 local strategy	might be improved.

       attributes
	 The following attributes are currently	ignored	by the layouter:

		 undirected graphs
		 autosplit/autojoin for	edges
		 tail/head label/title/link for	edges

       groups
	 The layouter is not fully recursive yet, so groups do not properly
	 nest.

	 In addition, links to/from groups are missing,	too.

   Output formats
       Some output formats are not yet complete	in their implementation.
       Please see the online manual at
       <http://bloodgate.com/perl/graph/manual>	under "Output" for details.

LICENSE
       This library is free software; you can redistribute it and/or modify it
       under the terms of the GPL 2.0 or a later version.

       See the LICENSE file for	a copy of the GPL.

       This product includes color specifications and designs developed	by
       Cynthia Brewer (http://colorbrewer.org/). See the LICENSE file for the
       full license text that applies to these color schemes.

NAME CHANGE
       The package was formerly	known as "Graph::Simple". The name was changed
       for two reasons:

       o In graph theory, a "simple" graph is a	special	type of	graph. This
	 software, however, supports more than simple graphs.

       o Creating graphs should	be easy	even when the graphs are quite
	 complex.

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

perl v5.32.1			  2016-06-06			Graph::Easy(3)

NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | ANIMATION SUPPORT | METHODS | EXPORT | SEE ALSO | LIMITATIONS | LICENSE | NAME CHANGE | AUTHOR

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