=pod

To better view this file, use:

	perldoc README

=head1 graphcnv

Take textual graph descriptions and turn them into nice drawings.

This package is intended to integrate Graph::Easy into Wikimedia, the software
behind popular wikis like http://en.wikipedia.org/.

For instance this input:

	[ Bonn ] -> [ Berlin ]
	[ Berlin -> [ Frankfurt ] { border: 1px dotted black; }
	[ Frankfurt ] -> [ Dresden ]
	[ Berlin ] -> [ Potsdam ]
	[ Potsdam ] => [ Cottbus ]

would be rendered in ASCII as:

	+------+     +--------+      .............     +---------+
	| Bonn | --> | Berlin |  --> : Frankfurt : --> | Dresden |
	+------+     +--------+      .............     +---------+
	               |
	               |
	               v
	             +---------+     +---------+
	             | Potsdam | ==> | Cottbus |
	             +---------+     +---------+

The HTML, SVG or PNG output would look similiar, except be more pretty :o)

This extension can output either inline "drawings" using HTML, Boxart or
ASCII output, or create an external SVG file and then link it in.

In addition, it is possible to output graphviz code, and when you have
graphviz (including dot) installed, you can generate PNG files.

=head1 Check the Signature

First you need to check the signature on the package to verify that
it is untampered and intact. To do this you have to:

=over 2

=item *

Install the Perl module Module::Signature from http://search.cpan.org

=item *

Get my key from http://bloodgate.com/tels.asc, import it into
GnuPG with:

	gpg --import tels.asc

You may also let the C<cpansign> utility fetch it automatically
from a keyserver, if that works for you.

=item *

Extract the package to a directory, change there and then:

=item *

Type on a console:

	cpansign --verify

inside the unpacked directory. 

=back

If the last step says "good signature" or "SIGNATURE VERIFIED OK",
everything is all right.

Note that if you C<cpansign> let GnuPG download my key from a keyserver,
it might put a C<tels.asc> file in the package directory, and then afterward
complain that "tels.asc" is not in the MANIFEST:

 Not in MANIFEST: tels.asc
 ==> MISMATCHED content between MANIFEST and distribution files! <==

You can safely ignore this warning.

B<NOTE:> Please notify me immidiately if the signature
does not verify. In that case do B<NOT> install this software, your system
might get compromised!

=head1 Installation

Install the following Perl modules into your system:

	Config-Tiny
	Graph-Easy
	Graph-Easy-As_svg	(optional, for SVG output)

You can get these modules from C<http://search.cpan.org/>.

Afterwards, you should be able to run this on any command line:

	perl -MGraph::Easy\ 99

and it should report your installed Graph::Easy version (like v0.34).

	Graph::Easy version 99 required--this is only version 0.34.
	BEGIN failed--compilation aborted.

If it says something about "Graph::Easy" not being found, you need to
install it first as root (see above!).

Note: You do NOT need to install Graph::Simple (the former name of
Graph::Easy), nor Graph (formerly used by Graph::Easy). If they are already
installed, that will not do any harm, however.

=head2 Installation on a shared host

On a shared host you typically do not have the rights to install Perl
modules. An easy way around that limitation is to place the modules
inside a directory called C<lib/> in the C<wiki/graph> directory:

	http_docroot
		\ - cgi-bin			etc
		\ - wiki
			\ - graph
				\ - lib		<-- here
			\ - extensions		etc

Untar Graph::Easy, Graph::Easy::As_svg and maybe Config::Tiny into
this directory so that it looks like that:

	\ - wiki
		\ - graph
			\ - lib
				\ - Graph
					\ - Easy.pm
					\ - Layout	etc
				\ - Config
					\ - Tiny.pm	etc

=head2 Run the testsuite

If you are on a shared host, skip this step.

Otherwise, after installing the Perl modules from above into the system,
then run in the directory of this package:

	perl Makefile.PL
	make test

All tests should pass. If not, please notify me.

=head2 Copy the files

Then place the contents of this mediawiki-graph.tar.gz file so that it
is a subdirectory named 'graph' of your wiki installation like this:

	http_docroot
		\ - cgi-bin			etc
		\ - wiki
			\ - graph		<-- here
			\ - math		etc

You need the following files inside C<wiki/graph>:

	graphcnv
	.htaccess
	graph.cfg		(there is a .sample file in the distribution)

Make a backup of your wiki directory! I repeat, MAKE A BACKUP! You have been
warned!

Now copy B<all> the files from the C<extensions/> subdirectory of C<graph> to
to the extension dir of your wiki, like so:

	http_docroot
		\ - cgi-bin			etc
		\ - wiki
			\ - graph
				\ - extensions	<-- from here
			\ - extensions		<-- to here

At present this is only one file, C<Graph.php>.

Then include the following line at the bottom of your C<LocalSettings.php>,
but before the "?>" line:

	include('extensions/Graph.php');

=head2 Manual test

Change the permissions of graphcnv to be executable:

	chmod a+x graph/graphcnv

Now you should be able to run manually (from your wiki directory):

	./graph/graphcnv '[ Bonn ] -> [ Berlin ]' 'ascii'

and get a pretty ASCII art back on the console.

=head2 Wiki test

Finally you should be able to edit any page of the wiki and insert:

	<graph>
	[ Bonn ] -> [ Berlin ]
	</graph>

and hit preview.

If you get an error messages like:

	Error running graphcnv.

make sure that you followed the steps above correctly.

=head1 CONFIGURATION

Inside the C<graph> subdirectory there is a file called C<graph.cfg.sample>.
If you haven't done already, copy it to C<graph.cfg> like so:

	http_docroot
		\ - cgi-bin			etc
		\ - wiki
			\ - graph
				graph.cfg.sample	<-- from here
				graph.cfg		<-- to here

Then edit the C<graph.cfg> file to your match your settings.

For more information please see L<http://bloodgate.com/perl/graph/>
or send me an email.

=head1 SVG AND PNG OUTPUT

To enable SVG/PNG etc. output, you need to create a directory for the
files that will be generated for the graphs. (Inlining the SVG code in
the HTML page directly does not work, since no browser seesm to support
this properly at this time).

The C<.svg> (or C<.png>) files are written to the output directory
set in the config file, which defaults to C<./images/graph/>.
So you need to make sure that this directory exists and is writable by the
web server process:

	http_docroot
		\ - cgi-bin			etc
		\ - wiki
			\ - images
				\ - graph	<-- create this directory
			\ - extensions		etc

You need also make sure that you web server process can write to this
directory, so you might need to give it the same user/group as the
process is using, f.i. C<chmod nobody.nogroup images/graph>.

=head2 Caveats

At the moment, each edit of a page containing a graph with SVG or PNG
output results some of the time in one leaked file in the
C<images/graph/> directory, e.g. there is a file created which
is no longer referenced by any article. This happens when you delete
articles with graphs in them or edit graphs heavily while using
preview.

To stop the ever growing archive, you could simple delete all files
and directories in that directory. Afterwards you might need to do
null-edits on pages containing such diagrams. Although this also
means you loose graphs embedded into older revisions, so this
is not really recommended.

I am currently trying to find a way around that leak, or to
clean up that directory.

=head1 AUTHOR

Copyright (C) 2004 - 2006 by Tels http://bloodgate.com/

Contact: <nospam-abuse@bloodgate.com> (literally :)

This library is free software; you can redistribute it and/or modify
it under the same terms of the GPL version 2.

