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<h1>Graph::Easy - Manual</h1>
<h2>F.A.Q. - Frequently Asked Questions</h2>
<div class="text">
<p>
This document tried to answer the most frequently asked questions in relation
to Graph::Easy, as well as for the MediaWiki integration.
</p>
</div>
<a name="general"></a>
<h2>General</h2>
<div class="text">
<span class="q">Question:</span>
<p>
Is there an interactive editor or GUI for Graph::Easy?
</p>
<span class="a">Answer: <small>[2007-09-1]</small></span>
<p>
Yes, read its <a href="editor.html">manual page</a> or go straight to
<a href="http://bloodgate.com/graph-easy/">interactive graph editor</a>.
</p>
<span class="q">Question:</span>
<p>
What extension should Graph::Easy files have?
</p>
<span class="a">Answer: <small>[2006-12-17]</small></span>
<p>
The <i>native</i> format of Graph::Easy is called "txt", as can be seen on the
method names (<code>as_txt()</code>) as well as the converter options. And
since a graph description in Graph::Easy is just this, text, the file
extension used should be <code><b>.txt</b></code>.
<br>
Some people like to invent their own extension for Graph::Easy files, but this
just is a solution in search for a problem, and actually causes more problems,
namely:
</p>
<ul>
<li>There aren't enough two- and three-letter combinations available, so
name clashes are unavoidable</li>
<li>All current modern operating systems know how to handle .txt files, but
for an unknown extension no handler is setup/installed</li>
<li>Likewise, sending .txt files via email etc. already works</li>
</ul>
<p>
Therefore, Graph::Easy textual descriptions should be called what they are:
<code><b>.txt</b></code>.
</p>
</div>
<a name="graphviz"></a>
<h2>Graphviz</h2>
<div class="text">
<span class="q">Question:</span>
<p>
What are the main differences between <code>Graph::Easy</code> and Graphviz?
</p>
<span class="a">Answer: <small>[2006-08-20]</small></span>
<p>
<code>Graph::Easy</code> has:
</p>
<ul>
<li>an easier syntax, that is very human readable/writable and makes thus maintance easier,
especially for people unfamiliar with graphviz, HTML or similar languages
<li>a grid based layouter, which is suited for flowcharts. For complex graphs it can also
use graphviz as backend, giving you the best of both worlds.
<li>is easier to install, needs no compiler, just Perl
<li>Can output HTML, and ASCII art
<li>Sizes, widths, lengths and offsets are all given relative, either to some point
of reference or the current font-size. This makes the output resolution independend
and freely scalable.
</ul>
<span class="q">Question:</span>
<p>
What can Graphviz, that <code>Graph::Easy</code> cannot do?
</p>
<span class="a">Answer: <small>[2006-08-06]</small></span>
<p>
Here is a list of things that <code>Graph::Easy</code> has difficulties with, or that are
not yet implemented:
</p>
<ul>
<li>For complex layouts, the layouter easily breaks down.
<li>The layouter only has one overall strategy (unlike graphviz, where dot, neato and circo all implement wildly different strategies)
<li>One cannot define a starting point on an edge, edges always start with a plain line.
<li>Groups (aka subgraphs) cannot yet be nested.
<li>Some shapes and options (node shape egg, edge lines with more than two lines f.i.) are not yet possible
<li>There are only 3 different arrow shapes (open, closed and filled triangles)
<li>Not as many layout influencing options (margins, paddings and spacings are generally missing)
<li>It is not yet possible to specify transparency for colors (especially fill/background).
</ul>
<span class="q">Question:</span>
<p>
What can <code>Graph::Easy</code>, that Graphviz cannot do?
</p>
<span class="a">Answer: <small>[2006-11-18]</small></span>
Apart from the IMHO easier for humans syntax of the input format, here are the key points:
<ul>
<li>Full <a href="http://unicode.org/">Unicode</a> support on both input
and output (when supported by the output format, all native ones like
HTML, SVG and ASCII/Unicode output do). Graphviz has problems
when you include "foreign" characters, then you must set the proper
font (and hope that it is portable and contains all glyphs your label has)
<li>Grid-based layouter
<li>Support for HTML, ASCII and boxart drawing (Unicode) output formats
<li>You can set text-styles on labels like <span style="text-decoration: underline">underline</span>,
<span style="text-decoration: overline">overline</span>, <b>bold</b>, <i>italic</i> etc
<li>You can even set these text-styles for parts of a label and mix them, even nest them like
so:
<span style="text-decoration: underline">underline<b>bold</b> and <i>italic</i></span> (<font color="green">Implemented in v0.43</font>)
<li><code>text-wrap: auto</code> automatically wraps labels (<font color="green">Implemented in v0.43</font>)
<li>You can set the flow (direction of layout) for the entire graph, and change it
on an per-node or even per-edge basis.
<li>Graphviz doesn't implement the border or edge style "wave". Edge styles involving double
lines are non-obvious to create in Graphviz.
<li>Links are build from two parts, a <code>linkbase</code> and a <code>link</code>. Thus you
can easily set a common base part and put the rest per node on it. There are even attributes
than build links or titles automatically.
<li>You can restrict the node length automatically, and make a title automatically show the
full node text.
<li>Edge arrows can have their arrows filled with a different color
<li>Graph::Easy supports an additional color scheme, <code>w3c</code>. This is also the default. (<font color="green">Color scheme support is implemented in v0.46</font>)
<li>Animations are possible (even w/o knowledge of scripting languages) (<font color="red">Will be implemented in v0.60</font>)
</ul>
<span class="q">Question:</span>
<p>
Are there other differences between <code>Graph::Easy</code> and Graphviz?
</p>
<span class="a">Answer: <small>[2006-03-12]</small></span>
<p>
There are other differences which have mainly to do with the output formats and their
limitations or advantages. For instance:
<ul>
<li>HTML allows text zoom (good for people with bad eyesight, or big monitors), while f.i.
raster image formats like PNG only support one fixed size
<li>Plain text formats like HTML or SVG allow easy indexing of the contents.
<li>SVG files are truly resolution independend.
<li>ASCII output lacks many things, but can be read even on a terminal or by
a screen reader.
</ul>
<p>
Since Graph::Easy's own layouter can only output HTMl, ASCII or SVG, other formats like PNG or PDF
must be created by either using the graphviz backend, or by outputting SVG and then converting
this. In the future SVG support by viewing and printer subsystems will hopefully be so good
that such "hacks" are no longer required, though.
</p>
<span class="q">Question:</span>
<p>
Is there a speed difference?
</p>
<span class="a">Answer: <small>[2006-03-12]</small></span>
<p>
<code>Graph::Easy</code> might be a bit slower for some things, but is faster for others.
In praxis this only matters for huge graphs. For details, please see the <a href="benchmark.html">benchmark page</a>.
</p>
</div>
<a name="svg"></a>
<h2>SVG (Scalable Vector Graphic) Problems</h2>
<div class="text">
<h3>Links open inside the SVG</h3>
<span class="q">Question:</span>
<p class="ind">
When I click a link in an SVG graph, the new page is opened inside the graph,
instead of in a new window/tab or even in the same window.
</p>
<span class="a">Answer:</span>
<p class="ind">
This is a Firefox 1.5 bug. Firefox will open links in SVGs by default "inline", and
it even ignores attributes like "xlink:show" and "xlink:target".
<br>
The bug is reportedly already
fixed in the Mozilla codebase, so it should work in the near future in a browser
on your system.
<br>
In the meantime upgrade <a href="http://search.cpan.org/~tels/Graph-Easy-As_svg">Graph::Easy::As_svg</a>,
as newer versions contain a workaround for this bug.
<br>
See also <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=315389">bug #315389</a> in the bugzilla.
</p>
<h3>Text too big</h3>
<span class="q">Question:</span>
<p class="ind">
The text on nodes is to small, or to big, and sometimes even crosses the node
border.
</p>
<span class="a">Answer:</span>
<p class="ind">
Please upgrade <a href="
">Graph::Easy::As_svg</a>, this bug has been fixed in v0.18.
<br>
You still might see text that is either too big or too small if you
use the text-zoom (<code>CTRL</code> plus <code>+</code> or <code>-</code>),
Firefox will zoom the font/text, but not the rest of the SVG, thus the graphic quickly
becomes garbled.
</p>
<h3>Graphic corruptions</h3>
<span class="q">Question:</span>
<p class="ind">
I see only garbled graphs, f.i. it has black rectangles or
the labels are not properly centered.
</p>
<span class="a">Answer:</span>
<p class="ind">
Make sure you are using the latest version of your browser. Opera 8.5 does only
support SVG Tiny, which is not enough to properly display the SVG generated
by Graph::Easy. Likewise, Opera 9.0 only supports SVG Basic, which sadly
also misses key features like centered text.
<br>
Other browsers seem to lack support for CSS-styles inside SVG, and thus will
render the fillcolor inside nodes wrongly (the default is black, and the
overriden color from the CSS is ignored by these buggy browsers).
</p>
</div>
<a name="windows"></a>
<h2>Windows</h2>
<div class="text">
<h3>Install under Windows</h3>
<span class="q">Question:</span>
<p class="ind">
Can I install and use Graph::Easy under Windows?
</p>
<span class="a">Answer:</span>
<p class="ind">
Yes. You need two things:
</p>
<ul class="ind">
<li>Perl, you can get it from <a href="http://activestate.com/store/activeperl/download">Activestate</a>
<li>nmake, see here for how to <a href="http://johnbokma.com/perl/make-for-windows.html">get and install nmake</a>
</ul>
<p class="ind">
After installing Perl and nmake, you can install Graph::Easy normally, just replacing "make" with "nmake" in
the install instructions:
</p>
<pre class="ind">
perl Makefile.PL
nmake
nmake test
nmake install
</pre>
</div>
<h2>Contact and Bugreports</h2>
<div class="text">
<p>
If you have questions, or found an error on this page, feel free to send me an
<a href="http://bloodgate.com/mail.html">email</a>
<small>(<a href="http://bloodgate.com/tels.asc">Gnupg key</a>)</small>.
<b>Bugreports</b> should go to <a href="http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Graph-Easy">rt.cpan.org</a>.
</p>
</div>
<div class="footer">
Page created <span class="date">2005-01-11</span> by <a href="http://bloodgate.com/mail.html">Tels</a>.
Last update: <span class="date">2007-09-02</span>
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