NAME
Map::Tube::Plugin::Graph - Graph plugin for Map::Tube.
VERSION
Version v1.1.0
DESCRIPTION
This is a graph plugin for Map::Tube to create maps of individual tube lines or of a complete tube network. This module is defined as a Moo Role. Once installed, it gets plugged into the Map::Tube::* family.
SYNOPSIS
use strict; use warnings;
use MIME::Base64;
use Map::Tube::London;
my $tube = Map::Tube::London->new;
# Entire map image to STDOUT
binmode(STDOUT);
print STDOUT $tube->as_png();
# Entire binary map image
my (undef, $name_bin) = $tube->render( output_file => undef );
# print "Image written to $name_bin";
# Entire base64-encoded map image
my ($base64_string, $name_txt) = $tube->render( output_file => undef, base64 => 1 );
# Just a particular line map image in binary format
my (undef, $name_lin) = $tube->render( 'Bakerloo', output_file => undef );
# print "Image written to $name_lin";INSTALLATION
The plugin primarily depends on the GraphViz2 library, which provides an interface to the external GraphViz tool. GraphViz2 as of 2.61 can only be installed on Perl v5.008008 or above.
For example, on my Windows 11 box running WSL2 (Ubuntu 24.04 LTS), try this:
$ sudo apt install libgraphviz2-perlMETHODS
as_graph
Returns a multiedged, directed Graph object with the entire map. You can do graph-theory stuff with it yourself, or even control a visualisation using the "from_graph" in GraphViz2 API:
use Map::Tube::London;
# a convention with GraphViz2 is to have a separate decorating function:
sub graphvizify {
my ($g) = @_;
my $l2c = $g->get_graph_attribute('line2colour');
for my $ft ($g->edges) {
$g->set_edge_attribute_by_id(@$ft, $_, graphviz=>{color=>$l2c->{$_}})
for $g->get_multiedge_ids(@$ft);
}
}
$tube = Map::Tube::London->new;
$g = $tube->as_graph->undirected_copy_attributes; # make undirected version
graphvizify($g);
binmode STDOUT;
print +GraphViz2->from_graph($g)
->run(format=>"png",driver=>"neato") # neato, because dot is bad undirected
->dot_output;Or you can show only two lines using "filter_edges" in Graph:
# uses same graphvizify as above
$g = $tube->as_graph->undirected_copy_attributes; # make undirected version
my %keep = map +($_=>1), qw(Central Northern);
$g->filter_edges(sub { $keep{$_[3]} });
$g->filter_vertices(sub { !$_[0]->is_isolated_vertex($_[1]) });
graphvizify($g);
# binmode and print as aboverender([ $line_name] [, more_parameters...] )
All parameters are optional. If the $line_name is passed in, the method returns a map for the given line. Otherwise you get the entire tube map.
There are a number of parameters that influence the rendering process and the result:
format => ...By default, output is in the PNG bitmap format. This can be changed by passing the
format=parameter. GraphViz supports many output formats, among them SVG and PDF and the native GraphViz DOT (or GV) format. While DOT and GV are formally identical, there is an important difference: GV yields the raw, un-layouted graph description, whereas DOT yields a graph description where each element is already precisely placed. -- For a list of supported formats, see the list_formats() method.driver => ...GraphViz also supports a number of layout engines, or drivers, which can be customised through the
driver=parameter. Usually, thedotdriver (which is the default) or theneatodriver will produce good results. -- For a list of supported drivers, see the list_drivers() method.output_file => ...If the
output_fileparameter passes in the name of a file, output will be written to a file of this name. If its value isundef, a name is automatically chosen, based on the name of the map or the chosen line. If the parameter is missing, no output will be written. In this case, the calling software is responsible for further processing of the output. In particular, when writing binary output, care must be taken to open the output file in binary mode on systems (like Windows) that differentiate between text and binary files.base64 => 0|1Most of the output formats will produce a binary stream. If the output is meant to be embedded in a text file (like a web page source), it is useful to transform it into a purely textual representation. This can be achieved by passing
base64 => 1.line_name => ...The name of the tube line (if any) may be given as the first parameter, as shown above, but also, alternatively, as a named parameter
line_name=. If both are given, the value of the first parameter will take precedence.
In scalar context, the method will return the representation of the graph in the desired format (which may be binary). In array context, the method will return an array of two elements: first the repesentation of the graph, then the name of the output file (or undef if no file output was requested).
See "SYNOPSIS" for more details on how this method can be used.
as_png($line_name [, ...])
The $line_name parameter is optional. If it is passed, the method returns the given line map as a PNG bitmap. Otherwise you get the entire map.
(In fact, this method is almost an alias for the render() method. However, it always returns only the graph representation, never an output file name.)
See "SYNOPSIS" for more details on how it can be used.
as_image($line_name, [, ...])
The $line_name parameter is optional. If it is passed, the method returns the base64 encoded string of a PNG bitmap showing the given line map. Otherwise you get the entire map as a base64 encoded string.
(In fact, this method is almost an alias for the render() method. One difference is that the base64= parameter is set to TRUE. And it always returns only the graph representation, never an output file name.)
See "SYNOPSIS" for more details on how it can be used.
list_drivers()
Returns a list of drivers (formatters) that GraphViz supports on your machine. The basic dot driver must be available via the search path for executables.
list_formats()
Returns a list of output formats that GraphViz supports on your machine.
AUTHOR
Mohammad Sajid Anwar, <mohammad.anwar at yahoo.com>
REPOSITORY
https://github.com/manwar/Map-Tube-Plugin-Graph
SEE ALSO
CONTRIBUTORS
Gisbert W. Selke
Ed J
BUGS
Please report any bugs or feature requests through the web interface at https://github.com/manwar/Map-Tube-Plugin-Graph/issues. I will be notified and then you'll automatically be notified of progress on your bug as I make changes.
SUPPORT
You can find documentation for this module with the perldoc command.
perldoc Map::Tube::Plugin::GraphYou can also look for information at:
BUG Report
Search MetaCPAN
LICENSE AND COPYRIGHT
Copyright (C) 2015 - 2026 Mohammad Sajid Anwar.
This program is free software; you can redistribute it and / or modify it under the terms of the the Artistic License (2.0). You may obtain a copy of the full license at:
http://www.perlfoundation.org/artistic_license_2_0
Any use, modification, and distribution of the Standard or Modified Versions is governed by this Artistic License.By using, modifying or distributing the Package, you accept this license. Do not use, modify, or distribute the Package, if you do not accept this license.
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This license includes the non-exclusive, worldwide, free-of-charge patent license to make, have made, use, offer to sell, sell, import and otherwise transfer the Package with respect to any patent claims licensable by the Copyright Holder that are necessarily infringed by the Package. If you institute patent litigation (including a cross-claim or counterclaim) against any party alleging that the Package constitutes direct or contributory patent infringement,then this Artistic License to you shall terminate on the date that such litigation is filed.
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