GraphViz(3) User Contributed Perl Documentation GraphViz(3)NAMETk::GraphViz - Render an interactive GraphViz graph
SYNOPSIS
use Tk::GraphViz;
my $gv = $mw->GraphViz ( qw/-width 300 -height 300/ )
->pack ( qw/-expand yes -fill both/ );
$gv->show ( $dotfile );
DESCRIPTION
The GraphViz widget is derived from Tk::Canvas. It adds the ability to
render graphs in the canvas. The graphs can be specified either using
the DOT graph-description language, or using via a GraphViz object.
When show() is called, the graph is passed to the dot command to
generate the layout info. That info is then used to create rectangles,
lines, etc in the canvas that reflect the generated layout.
Once the items have been created in the graph, they can be used like
any normal canvas items: events can be bound, etc. In this way,
interactive graphing applications can be created very easily.
METHODS
$gv->show ( graph, ?opt => val, ...? )
Renders the given graph in the canvas. The graph itself can be
specified in a number of formats. 'graph' can be one of the following:
- An instance of the GraphViz class (or subclass thereof)
- A scalar containing a graph in DOT format. The scalar must match
/^\s*(?:di)?graph /.
- An instance of the IO::Handle class (or subclass thereof), from which
to read a graph in DOT format.
- The name / path of a file that contains a graph in DOT format.
show() will recognize some options that control how the graph is
rendered, etc. The recognized options:
layout => CMD
Specifies an alternate command to invoke to generate the layout of
the graph. If not given, then default is 'dot'. This can be used,
for example, to use 'neato' instead of 'dot'.
graphattrs => [ name => value, ... ]
Allows additional default graph attributes to be specified. Each
name => value pair will be passed to dot as '-Gname=value' on the
command-line.
nodeattrs => [ name => value, ... ]
Allows additional default node attributes to be specified. Each
name => value pair will be passed to dot as '-Nname=value' on the
command-line.
edgeattrs => [ name => value, ... ]
Allows additional default edge attributes to be specified. Each
name => value pair will be passed to dot as '-Ename=value' on the
command-line.
For example, to use neato to generate a layout with non-overlapping
nodes and spline edges:
$gv->show ( $file, layout => 'neato',
graphattrs => [qw( overlap false spline true )] );
$gv->createBindings ( ?option => value? )
The Tk::GraphViz canvas can be configured with some bindings for
standard operations. If no options are given, the default bindings for
zooming and scrolling will be enabled. Alternative bindings can be
specified via these options:
-zoom => true
Creates the default bindings for zooming. Zooming in or out in the
canvas will be bound to <Shift-2> (Shift + mouse button 2). To
zoom in, click and drag out a zoom rectangle from top left to
bottom right. To zoom out, click and drag out a zoom rectangle
from bottom left to top right.
-zoom => spec
This will bind zooming to an alternative event sequence. Examples:
-zoom => '<1>' # Zoom on mouse button 1
-zoom => '<Ctrl-3>' # Zoom on Ctrl + mouse button 3
-scroll => true
Creates the default bindings for scrolling / panning. Scrolling
the canvas will be bound to <2> (Mouse button 2).
-scroll => spec
This will bind scrolling to an alternative event sequence.
Examples:
-scroll => '<1>' # Scroll on mouse button 1
-scroll => '<Ctrl-3>' # Scroll on Ctrl + mouse button 3
-keypad => true
Binds the keypad arrow / number keys to scroll the canvas, and the
keypad +/- keys to zoom in and out. Note that the canvas must have
the keyboard focus for these bindings to be activated. This is
done by default when createBindings() is called without any
options.
$gv->fit()
Scales all of the elements in the canvas to fit the canvas' width and
height.
$gv->zoom( -in => factor )
Zoom in by scaling everything up by the given scale factor. The factor
should be > 1.0 in order to get reasonable behavior.
$gv->zoom( -out => factor )
Zoom out by scaling everything down by the given scale factor. This is
equivalent to
$gv->zoom ( -in => 1/factor )
The factor show be > 1.0 in order to get reasonable behavior.
TAGS
In order to facilitate binding, etc, all of the graph elements (nodes,
edges, subgraphs) that a created in the cavas. Specific tags are given
to each class of element. Additionally, all attributes attached to an
element in the graph description (e.g. 'color', 'style') will be
included as tags.
Nodes
Node elements are identified with a 'node' tag. For example, to bind
something to all nodes in a graph:
$gv->bind ( 'node', '<Any-Enter>', sub { ... } );
The value of the 'node' tag is the name of the node in the graph (which
is not equivalent to the node label -- that is the 'label' tag)
Edges
Edge elements are identified with a 'edge' tag. For example, to bind
something to all edges in a graph:
$gv->bind ( 'edge', '<Any-Enter>', sub { ... } );
The value of the 'edge' tag is an a string of the form "node1 node2",
where node1 and node2 are the names of the respective nodes. To make
it convenient to get the individual node names, the edge also has tags
'node1' and 'node2', which give the node names separately.
Subgraphs
Subgraph elements are identified with a 'subgraph' tag. The value of
the 'subgraph' is the name of the subgraph / cluster.
EXAMPLES
The following example creates a GraphViz widgets to display a graph
from a file specified on the command line. Whenever a node is clicked,
the node name and label are printed to stdout:
use GraphViz;
use Tk;
my $mw = new MainWindow ();
my $gv = $mw->Scrolled ( 'GraphViz',
-background => 'white',
-scrollbars => 'sw' )
->pack ( -expand => '1', -fill => 'both' );
$gv->bind ( 'node', '<Button-1>', sub {
my @tags = $gv->gettags('current');
push @tags, undef unless (@tags % 2) == 0;
my %tags = @tags;
printf ( "Clicked node: '%s' => %s\n",
$tags{node}, $tags{label} );
} );
$gv->show ( shift );
MainLoop;
BUGS AND LIMITATIONS
Lots of DOT language features not yet implemented
Various node shapes and attributes: polygon, skew, ...
Edge arrow head types
ACKNOWLEDGEMENTS
See http://www.graphviz.org/ for more info on the graphviz tools.
AUTHOR
Jeremy Slade <jeremy@jkslade.net>
Other contributors: Mike Castle, John Cerney, Phi Kasten, Jogi
Kuenstner Tobias Lorenz, Charles Minc, Reinier Post, Slaven Rezic
COPYRIGHT AND LICENSE
Copyright 2003-2008 by Jeremy Slade
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
POD ERRORS
Hey! The above document had some coding errors, which are explained
below:
Around line 2294:
You forgot a '=back' before '=head1'
perl v5.14.1 2008-12-09 GraphViz(3)
