=======================================
dot2tex - A Graphviz to LaTeX converter
=======================================

A tool for converting graphs generated by Graphviz_ to formats suitable for use with LaTeX.

:Author: Kjell Magne Fauske
:Version: 2.8.7
:Licence: MIT_

.. _Graphviz: http://www.graphviz.org/
.. _PSTricks: http://tug.org/PSTricks/main.cgi/
.. _PGF/TikZ: http://www.ctan.org/tex-archive/help/Catalogue/entries/pgf.html
.. _MIT: http://www.opensource.org/licenses/mit-license.php

The purpose of dot2tex is to give graphs a more LaTeX look and feel. This is accomplished by:

- Typesetting labels with LaTeX, allowing mathematical notation.
- Using native PSTricks_ and `PGF/TikZ`_ commands for drawing arrows, edges
  and nodes.
- Using output specific styles to customize the output.

Dependencies
============

The following software and modules are required to run dot2tex:

- Python_ 2.4+
- pyparsing_. Version 1.4.8 or later is recommended.
- Graphviz_. A recent version is required.
- preview_. A LaTeX package for extracting parts of a document. A free-standing part of the `preview-latex`_/`AUCTeX`_ bundle.
- `PGF/TikZ`_ version 2.0 or later.

Users have reported problems using dot2tex with old versions of pyparsing and Graphviz.

A natural companion to dot2tex is `the dot2texi LaTeX package`_ for embedding graphs directly in your LaTeX source code.

Dot2tex was developed and tested using Python_ 2.4 and 2.5. However, dot2tex will probably run fine using Python 2.3.


.. _Python: http://www.python.org
.. _pyparsing: http://pyparsing.wikispaces.com/
.. _pydot: http://dkbza.org/pydot.html
.. _preview: http://www.ctan.org/tex-archive/help/Catalogue/entries/preview.html
.. _preview-latex: http://www.gnu.org/software/auctex/preview-latex.html
.. _AUCTeX: http://www.gnu.org/software/auctex/

Installation
============

From source
-----------

Download a zip or a tarball from the download_ page. It is also available on CTAN_. Unpack the file to a directory and run ``python`` on the ``setup.py`` file::

    $ python setup.py install

This will create a dot2tex module in your Python module directory and a wrapper script in your ``SCRIPTS`` directory. Note that a few warnings will be displayed. You can safely ignore them. The warnings are shown because there is some extra information in the ``setup.py`` file that distutils does not understand.

Using easy_install
------------------

The easiest way to install dot2tex is to use `easy_install`_::

    $ easy_install dot2tex

The command will locate dot2tex and download it automatically. Note that documentation and examples are not installed by default. `Easy_install`_ will also create a wrapper script or EXE file for you and install dependencies if necessary.


.. _download: http://www.fauskes.net/code/dot2tex/download/
.. _CTAN: http://www.ctan.org/tex-archive/help/Catalogue/entries/dot2tex.html
.. _easy_install: http://peak.telecommunity.com/DevCenter/EasyInstall

Binary packages
---------------

Binary packages are available for Debian_ and OpenSUSE_.

Development version
-------------------

The development version of ``dot2tex`` is  available from a `Subversion repository`_ hosted at Google code. To get the code you can use the following command::

    svn checkout http://dot2tex.googlecode.com/svn/trunk/ dot2tex


.. _Debian: http://packages.qa.debian.org/d/dot2tex.html
.. _OpenSUSE: http://download.opensuse.org/repositories/home:/jimfunk/
.. _Subversion repository: http://code.google.com/p/dot2tex/source

Usage
=====

Syntax::

    dot2tex [options] [inputfile]


Input data is read from standard input if no input file is specified. Output is written to standard output unless a destination file is set with the ``-o`` option.

Dot2tex can also be loaded as a module for use in other Python program. See the `Using dot2tex as a module`_ section for more details.

Dot2tex relies on the `xdot format`_ generated by Graphviz. Dot2tex will automatically run ``dot`` on the input data if it is in the plain dot format. If you want to use other layout tools like ``neato`` and ``circo``, use the ``--prog`` option.

.. _xdot format: http://www.graphviz.org/doc/info/output.html#d:xdot

A few examples on how to invoke dot2tex:

Read a file from standard input and write the result to the file ``test.tex``::

    $ dot -Txdot test.dot | dot2tex > test.tex
    $ neato -Txdot -Gstart=rand test.dot | dot2tex > test.tex

Load ``test.dot``, convert it to xdot format and output the resulting graph using the ``tikz`` output format to ``testpgf.tex``::

    $ dot2tex -ftikz test.dot > testtikz.tex

The same as above, but use neato for graph layout::

    $ dot2tex --prog=neato -ftikz test.dot > testtikz.tex


.. admonition:: Invoking dot2tex

   Windows users you have to type ``python dot2tex`` to invoke the program.
   If you find this annoying, try the `ExeMaker`_ tool from `effbot.org`_, or better, use `easy_install`_ to install dot2tex.



   .. _ExeMaker: http://effbot.org/zone/exemaker.htm
   .. _effbot.org: http://effbot.org
   .. _easy_install: http://peak.telecommunity.com/DevCenter/EasyInstall


Options
-------

The following options are available:

-h, --help
    Display help message.
-f fmt, --format fmt
    Set output format. The following values of `fmt` are supported:

    ``pgf``
        PGF/TikZ. Default.
    ``pstricks`` or ``pst``
        Use PSTricks.
    ``tikz``
        TikZ format.

-t mode, --texmode mode
    Text mode. Specify how text is converted.

    ``verbatim``
        Text is displayed with all special TeX chars escaped (default).
    ``math``
        Output all text in math mode $$.
    ``raw``
        Output text without any processing.

    Note that you can locally override the text mode by assigning a special ``texlbl`` attribute to a graph element, or by using the ``texmode`` attribute.

-s, --straightedges
    Draw edges using straight lines. Graphviz uses bezier curves to draw straight edges. Use this option to force the use of line to operations instead of curves. Does not work in ``duplicate`` mode.

-o filename, --output filename
    Write output to file.

-d, --duplicate
    Duplicate the xdot output. Uses the drawing information embedded in the xdot output to draw nodes and edges.

--template filename
    Use template from file. See the `templates`_ section for more details.

-V, --version
    Print version information and exit.

-w, --switchdraworder
    Switch drawing order of nodes and edges. By default edges are drawn before nodes.

-c, --crop
    Use ``preview.sty`` to crop the graph. Currently only implemented for the ``pgf`` and ``tikz`` output format.

--figonly
    Output the graph without a document preamble. Useful if the graph is to be included in a master document.

--codeonly
    Output only the drawing commands, without wrapping it in a ``tikzpicture`` or ``pspicture`` environment. Useful when used with the dot2texi package.

--preproc
    Preprocess the graph through LaTeX using the preview_ package. Will generate a new dot file where the height and widths of nodes and edge labels are set based on the results from preview_.

--autosize
    Preprocess the graph and run Graphviz on the output. Equivalent to::

        $ dot2tex --preproc ex1.dot | dot2tex

--prog program
    Set graph layout program to use when the input is in plain dot format. Allowed values:

    - ``dot`` (default)
    - ``neato``
    - ``circo``
    - ``fdp``
    - ``twopi``


--usepdflatex
    Use pdflatex instead of latex for preprocessing the graph.

--nominsize
    Ignore minimum node sizes during preprocessing.

--valignmode mode
    Vertical alignment of node labels, where ``mode`` can have the values:

    ``center``
        Labels are placed in the middle of the node (default).
    ``dot``
        Use the coordinate given by the xdot output from Graphviz.

    (``pgf`` and ``pstricks`` only)

--alignstr
    Used to pass a default alignment string to the PSTricks ``\rput`` command::

        \rput[alignstr] ...

    Only works for the PSTricks format. PGF/TikZ users can instead pass an ``anchor=...`` style using the ``graphstyle`` option.

--tikzedgelabels
    Bypass Graphviz' edge label placement and use PGF/TikZ instead (``tikz`` and ``pgf`` formats only).

--styleonly
    Use TikZ only styles when drawing nodes. No ``draw`` or ``shape`` option is added (``tikz`` format only).

--nodeoptions tikzoptions
    Wrap node code in a ``scope`` environment with ``tikzoptions`` as parameter (``tikz`` format only).

--edgeoptions tikzoptions
    Wrap edge code in a ``scope`` environment with ``tikzoptions`` as parameter (``tikz`` format only).

--debug
    Write detailed debug information to the file dot2tex.log in the current directory.
    
--pgf118
    Generate code compatible with PGF 1.18 and earlier. 

The following options are used by the output templates_.

-e encoding, --encoding encoding
    Set text encoding. Supported encodings are:

    - ``utf8``
    - ``latin1``

--docpreamble TeXcode
    Insert TeX code in the document preamble.

--figpreamble TeXcode
    Insert TeX code in the figure preamble.

--figpostamble TeXcode
    Insert TeX code in the figure postamble.

--graphstyle style
    Sets the ``<<graphstyle>>`` tag.

--margin margin
    Set margin around the graph when using ``preview.sty``. ``margin`` must be a valid TeX unit. By default ``margin`` is set to ``0pt``.


Output formats
==============

The output format is specified with the ``-f fmt`` or  ``--format fmt`` command line option.

PGF
---

This is the default output format. Generates code for the `Portable Graphics Format`_ (PGF) package . Mixes both PGF and TikZ commands.

.. _Portable Graphics Format: http://www.ctan.org/tex-archive/help/Catalogue/entries/pgf.html

PSTricks
--------

Generates code for the PSTricks_ package.

TikZ
----

The ``tikz`` output format also uses the PGF and TikZ package. However, it relies on TikZ node and edge mechanisms to draw nodes and edges, instead of using the drawing information provided by Graphviz. This allows much tighter integration with TikZ and in some cases prettier results.

Advantages of the ``tikz`` format:

- The generated code is very compact and clean.
- Easy to modify the output.
- Labels will fit inside nodes without preprocessing.
- Full access to the power of PGF and TikZ.

You can find more details in the section: `Use the tikz output format for maximum flexibility`_.

.. note:: The ``tikz`` output format requires detailed knowledge of the PGF and TikZ package. Some of Graphviz' features will not work with this output format.


Labels
======

The main purpose of dot2tex is to allow text and labels to be typeset by LaTeX. Labels are  treated differently according to the current TeX mode:

``verbatim``
    Text is displayed with all special TeX chars escaped (default).
``math``
    Output all text in math mode $$.
``raw``
    Output text without any processing.

The TeX mode can be set on the command line using the ``-t`` option. It can also be set locally in a graph by using the special ``texmode`` attribute.

You can also use the special ``texlbl`` attribute on a graph element, which is interpreted as ``raw`` TeX string. If a ``texlbl`` attribute is found, it will be used regardless of the current TeX mode. It also has precedence over the ``label`` attribute.

.. note:: The ``\`` character needs to be escaped with ``\\`` if used in the ``label`` attribute.

Note that only position and alignment information is converted. Any font information is lost. This may result in some odd behavior. Some tweaking may be necessary to get it right.

.. note:: If you use ``texlbl`` for edges, you have to provide a dummy ``label`` attribute. Otherwise Graphviz will not generate the necessary code for placing edge labels.

Label examples
--------------

Consider the following graph:

.. sourcecode:: dot

    digraph G {
        a_1-> a_2 -> a_3 -> a_1;
    }

Converting the graph using::

    $ dot2tex -tmath ex1.dot > ex1.tex

gives the result shown in the left hand side of the figure below. The default rendering is shown to the right. Using the ``raw`` mode will result in a compilation error because of the underscore character.

.. figure:: img/ex1comb.png
   :alt: Difference between math and verbatim mode

Example of using ``texlbl``:

.. sourcecode:: dot

    digraph G {
        a_1 [texlbl="$\frac{\gamma}{x^2}$"];
        a_1-> a_2 -> a_3 -> a_1;
    }

.. figure:: img/ex2.png
   :alt: Using the special texlbl attribute

Example of using the ``texmode`` attribute:

.. sourcecode:: dot

    digraph G {
        a_1 [texlbl="$\frac{\gamma}{2x^2+y^3}$"];
        a_1 -> a_2 -> a_3 -> a_1
        node [texmode="math"];
        a_1 -> b_1 -> b_2 -> a_3;
        b_1 [label="\\frac{\\gamma}{x^2}"];
        node [texmode="verbatim"]
        b_4 [label="\\beta"]
        a_3 -> b_4 -> a_1;
    }

.. figure:: img/texmode.png
   :alt: Using the special texmode attribute

The above example shows two important things:

- The backslash ``\`` character needs to be written as ``\\`` in the ``label`` attribute.
- Using LaTeX markup in the ``label`` attribute gives oversized nodes. A workaround  is to use the ``texlbl`` attribute, and manually pad the ``label`` attribute to an appropriate length. A much better solution is to use the ``--preproc`` option.

Preprocessing the above graph with::

    $ dot2tex --preproc ex4.dot | dot2tex > ex4.tex

gives correctly sized nodes:

.. figure:: img/texmodeb.png
   :alt: Preprocessing the graph to get correct node sizes.

Read more about preprocessing in the `Preprocessing graphs`_ section.


Vertical label alignment
------------------------

Dot2tex relies on the xdot format for drawing nodes and placing node labels. The fonts that Graphviz and LaTeX use are different, so using the label coordinates from Graphviz does not always give good results. Dot2tex's default behavior is to place node labels in the middle of the node. However, you can change this behavior by setting the ``valignmode`` option to ``dot``. Labels will then be placed using the coordinates supplied by Graphviz.

Here is an example graph where it is necessary to use the ``valignmode`` option:

.. sourcecode:: dot

    digraph G {
        node0 [label="{left|right}", shape=record];
        node1 [shape=rectangle, label="node 1"];
        node0 -> node1;
        rankdir=LR;
    }

For record nodes dot2tex has to use Graphviz coordinates. This is shown in the following figure rendered with::

    $ dot2tex valign.dot

.. figure:: img/valignmode0.png
   :alt: Vertical alignment for record shapes

To get the same vertical alignment for both nodes, you can use::

    $ dot2tex --valignmode=dot valign.dot

.. figure:: img/valignmode1.png
   :alt: Vertical alignment with --valignmode=dot

Now the labels are aligned, but the labels are still placed too low. The reason for this is that both PSTricks and PGF by default centers text vertically on the current coordinate. The alignment point should in this case be set to the baseline. For PGF/TikZ you can use the ``--graphstyle`` option like this::

    $ dot2tex --valignmode=dot --graphstyle="anchor=base" valign.dot

PSTricks users have to use the ``--alingstr`` option::

    $ dot2tex --valignmode=dot --alignstr=B valign.dot

.. figure:: img/valignmode2.png
   :alt: blabla

The result is better, but to get even better alignment you have to change the node font size. Graphviz' default font size is 14pt, which is larger than the typical 10pt or 11pt used in LaTeX documents. By changing the node font size to 10pt we can trick Graphviz to give us a better alignment:

.. sourcecode:: dot

    digraph G {
        node [fontsize=10];
        node0 [label="{left|right}", shape=record];
        node1 [shape=rectangle, label="node 1"];
        node0 -> node1;
        rankdir=LR;
    }

.. figure:: img/valignmode3.png
   :alt: blabla

Preprocessing graphs
====================

A problem with using LaTeX for typesetting node and edge labels, is that Graphviz does not know the sizes of the resulting labels. To circumvent this problem, you can use the ``--preproc`` or ``--autosize`` option. The following will then happen:

1. Node and edge labels are extracted and the corresponding LaTeX markup is saved to a temporary file.
2. The file is typeset with LaTeX and information about sizes is extracted using the preview_ package.
3. A new dot file is created where node and edge label sizes are set using the dot language's ``width`` and ``height`` attributes.
4. The generated graph can now be processed using Graphviz and dot2tex. Label sizes will now correspond with the output from LaTeX.

Widths and heights of nodes are handled the in same way as Graphviz does it. The ``width`` and ``height`` attributes set the minimum size of the node. If label size + margins is larger that the minimum size, the node size will grow accordingly. Default values are width=0.75in and height=0.5in.

Node margins are set using the `margin`_ attribute. This also works for edge labels. ``margin==value`` sets both the horizontal and vertical margin to ``value``, ``margin=="hvalue,vvalue"`` sets the horizontal and vertical margins respectively.

.. note:: All sizes are given in inches.

If you do not want a minimum node size, you can use the '--nominsize' option. Dot2tex will then use size of label + margins as node size.

Nodes with ``fixedsize=True`` attributes are not processed.

Limitations:

- Does not work for HTML-labels
- Does not work for record-based nodes


Examples
--------

Consider the following graph:

.. sourcecode:: dot

    digraph G {
        node [shape=circle];
        a_1 [texlbl="$x^2+\frac{\sin y}{y^2+\cos \beta}+\gamma_3$"];
        a_1 -> a_2 [label=" ", texlbl="$x_1+x_3^2+z+c+v~~$"];
        a_2 -> a_1;
    }

Rendered with::

    $ dot2tex -tmath example.dot > example.tex

the graph will look like this:

.. figure:: img/preproc1a.png
   :alt: Graph with oversized edge and node labels

You could improve the result by adding a longer ``label`` attribute or setting a fixed width. A better solution is to preprocess the graph like this::

    $ dot2tex -tmath --preproc example.dot > exampletmp.dot
    $ dot2tex exampletmp.dot > example.tex

You can also chain the commands::

    $ dot2tex -tmath --preproc example.dot | dot2tex > example.tex

A shorter alternative is::

    $ dot2tex -tmath --autosize example.dot > example.tex

The resulting graph now has correctly sized nodes and edge labels:

.. figure:: img/preproc1b.png
   :alt: Graph with preprocessed labels

Modifying node sizes using the ``widht/height`` and ``margin`` attributes can be a bit counterintuitive. A few examples will hopefully make it clearer:

.. sourcecode:: dot

    digraph G {
        node [shape=rectangle];
        a_1 [margin="0"];
        a_2 [margin="0.7,0.4"];
        a_3 [width="2",height="1"];
        a_1-> a_2 -> a_3 -> a_1;
    }

Processing the graph with::

    $ dot2tex -tmath --preproc example.dot | dot2tex > example.tex

gives

.. figure:: img/nodewidth1.png
   :alt: Graph with preprocessed labels

Setting the margin of ``a_1`` to 0 has no effect because of the minimum node width. Processing the graph with::

    $ dot2tex -tmath --preproc --nominsize example.dot | dot2tex > example.tex

gives a different graph, where only label widths and margins affect the node sizes:

.. figure:: img/nodewidth2.png
   :alt: Graph with preprocessed labels


.. _margin: http://graphviz.org/doc/info/attrs.html#d:margin




Customizing the output
======================

Dot2tex offers a few ways of modifying the generated output.

Using styles
------------

The dot language defines the ``style`` attribute that can be used to modify the appearance of graphs, nodes, and edges. The ``style`` attribute is passed to the rendering backend, and is a powerful and flexible way of customizing the look and feel of your graphs. Using styles requires detailed knowledge of the output format.

The following example shows how interesting visual results can be achieved with the PGF/TikZ output format. The styles are PGF/TikZ specific. See the user guide for details:

.. sourcecode:: dot

    graph G {
        node [shape=circle, fixedsize=True, width="0.2",
              style="ball color =green", label=""];
        edge [style="snake=zigzag, green"];
        a_1 -- c -- a_2;
        c [style="ball color=black"];
        edge [style="snake=snake, blue"];
        node [style="ball color = red", label=""];
        a_3 -- c -- a_4 --a_3;
    }

The ``snake`` styles only work on straight lines. We therefore have to use the ``-s`` option. ``fdp`` is used to lay out the graph::

    $ fdp -TXdot ball.dot | dot2tex -fpgf -s > balls.tex

The resulting graph is shown below.

.. figure:: img/balls.png
   :alt: Using styles to style the PGF/TikZ output.

.. note:: Use the straight edge option ``-s`` to force the use of straight lines. Otherwise curves will be used to draw even straight lines.


Changing arrow types
~~~~~~~~~~~~~~~~~~~~

The style attribute can be used to change arrow types. A PGF/TikZ example:

.. sourcecode:: dot

    digraph G {
        graph [mindist=0.5];
        node [fixedsize=true, shape=circle, width=0.4, style="fill=green!20"];
        c -> n_1 [style="-stealth"];
        c -> n_2 [style="-to"];
        c -> n_3 [style="-latex"];
        c -> n_4 [style="-diamond"];
        c -> n_5 [style="-o"];
        c -> n_6 [style="{-]}"];
        c -> n_7 [style="-triangle 90"];
        c -> n_8 [style="-hooks"];
        c -> n_9 [style="->>"];
        c [style="fill=red!80"];
    }

Rendered with::

    $ circo -Txdot pgfarrows.dot | dot2tex -tmath > pgfarrows.tex

.. figure:: img/pgfarrows.png
   :alt: PGF/TikZ style arrows.

You can also set the default arrow style by using the ``--graphstyle`` option or ``d2tgraphstyle`` attribute::

    $ dot2tex -tmath --graphstyle=">=diamond" ex1.dot > ex1gstyle.tex

.. figure:: img/ex1gstyle.png
   :alt: Setting default PGF/TikZ arrows.

A PSTricks example:

.. sourcecode:: dot

    digraph G {
        d2tdocpreamble="\usepackage{pstricks-add}";
        graph [mindist=0.5];
        node [texmode="math", fixedsize=true, shape=circle, width=0.4];
        c -> n_1 [style="arrows=->"];
        c -> n_2 [style="arrows=->>"];
        c -> n_3 [style="arrows=-<"];
        c -> n_4 [style="arrows=-*"];
        c -> n_5 [style="arrows=-{]}"];
        c -> n_6 [style="arrows=-o"];
        c -> n_7 [style="arrows=-H"];
    }

Rendered with::

    $ circo -Txdot pstarrows.dot | dot2tex -fpst > pstarrows.tex


.. figure:: img/pstarrows.png
   :alt: PSTricks style arrows

The above example shows how the ``d2tdocpreamble`` attribute can be used to load additional LaTeX packages. You could also use the ```--docpreamble`` option::

    $ ... | dot2tex -fpst --docpreamble="\usepackage{pstricks-add}" ...


Label styles
~~~~~~~~~~~~

Node, edge and graph labels can be styled using the special ``lblstyle`` attribute. However, this only works for the ``pgf`` and ``tikz`` output formats.

Labels are drawn using code like:

.. sourcecode:: latex

    \draw (157bp,52bp) node {label};

When you specify a ``lblstyle`` attribute, the style will be given as a parameter to the node like this:

.. sourcecode:: latex

    \draw (157bp,52bp) node[lblstyle] {label};

Example:

.. sourcecode:: dot

    digraph G {
        node [shape=circle];
        a -> b [label="label",lblstyle="draw=red,cross out"];
        b -> c [label="test",lblstyle="below=0.5cm,rotate=20,fill=blue!20"];
        a [label="aa",lblstyle="blue"];
        b [lblstyle="font=\Huge"];
        c [label="ccc", lblstyle="red,rotate=90"];
        label="Graph label";
        lblstyle="draw,fill=red!20";
        rankdir=LR;
    }


.. figure:: img/lblstyle.png
   :alt: Label styles

See the PGF and TikZ documentation for more information about styles.

.. note:: You can use the ``exstyle`` attribute in addition to ``lblstyle``. The difference is that ``exstyle`` is ignored in preprocessing mode. Useful when using TikZ' ``pin`` and ``label`` options and you do not want them to influence the graph layout.


Node and edge options
~~~~~~~~~~~~~~~~~~~~~

The ``tikz`` output format offers an additional way of customizing the output by using the ``--nodeoptions`` and ``--edgeoptions`` options, or the ``d2tnodeoptions`` and ``d2tedgeoptions`` graph attributes. The code for generating nodes and edges will then be wrapped in a ``scope`` environment like this:

.. sourcecode:: latex

    ...
    \begin{scope}[nodeoptions]
    % code for drawing nodes
    \end{scope}
    \begin{scope}[edgeoptions]
    % code for drawing edges
    \end{scope}
    ...


Customizing edges
=================

The ``tikz`` and ``pgf`` output formats offers a few additional ways of customizing how edges are drawn and how edge edge labels are placed. These features are tightly integrated with TikZ and detailed knowledge of the output format is therefore necessary.

TikZ edge labels
----------------

With the ``--tikzedgelabel`` option you can bypass the XDOT edge label placement and let PGF and TikZ do the job instead. This can be useful in some cases. However, this only works properly for straight edges and ``to`` paths.

Example:

.. sourcecode:: dot

    graph G {
        mindist = 0.5;
        node [shape="circle"];
        edge [lblstyle="mystyle"];
        a -- b [label="ab"];
        b -- c [label="bc"];
        c -- a [label="ca"];
    }

Without the ``--tikzedgelabel`` option the code for placing edges will look something like this:

.. sourcecode:: latex

    % Edge: a -- b
    \draw [] (28bp,55bp) -- (28bp,75bp);
    \draw (40bp,65bp) node[mystyle] {ab};
    % Edge: b -- c
    \draw [] (51bp,88bp) -- (68bp,78bp);
    \draw (66bp,96bp) node[mystyle] {bc};
    % Edge: c -- a
    \draw [] (69bp,51bp) -- (52bp,41bp);
    \draw (53bp,57bp) node[mystyle] {ca};

With the ``tikzedgelabels`` option the output is simply:

.. sourcecode:: latex

    \draw [] (a) -- node[mystyle] {ab} (b);
    \draw [] (b) -- node[mystyle] {bc} (c);
    \draw [] (c) -- node[mystyle] {ca} (a);

The placement of the edge labels depends on the options passed to the edge label node (in this case ``mystyle``), and the curve used to connect the nodes. Some examples of ``mystyle`` values are shown in the figure below. The leftmost graph is rendered without the ``tikzedgelabels`` option.

.. figure:: img/tikzedgelabels.png
   :alt: blabla

Limitations:

- Works best with straight edges and ``to`` paths
- The ``headlabel`` and ``taillabel`` attributes are currently not affected by the ``tikzedgelabels`` option.

To paths
--------

The ``topath`` edge attribute offers a way to override the edges drawn by Graphviz. When a ``topath`` attribute is encountered, dot2tex inserts a so called ``to`` path operation to connect the nodes. A number of predefined to paths are defined by TikZ, and you can create your own.

Example:

.. sourcecode:: dot

    digraph G {
        mindist = 0.5;
        node [shape="circle"];
        a -> b [topath="bend right"];
        c -> b [topath="bend left"];
        c -> a [topath="out=10,in=-90"];
        b -> b [topath="loop above"];
    }

Generating the graph with::

    $ circo -Txdot topaths1.dot | dot2tex -ftikz > topaths1.tex

yields:

.. figure:: img/topaths1.png


The generated edge drawing code is:

.. sourcecode:: latex

    \draw [->] (a) to[bend right] (b);
    \draw [->] (c) to[bend left] (b);
    \draw [->] (c) to[out=10,in=-90] (a);
    \draw [->] (b) to[loop above] (b);

.. note:: To paths works best with layout tools that generate straight edges (neato, fdp, circo, twopi). The ``topath`` attribute overrides the edge routing done by Graphviz. You may therefore end up with overlapping edges.

Here is a larger example that uses the ``automata`` library:

.. sourcecode:: dot

    digraph G {
        d2tdocpreamble = "\usetikzlibrary{automata}";
        d2tfigpreamble = "\tikzstyle{every state}= \
        [draw=blue!50,very thick,fill=blue!20]";
        node [style="state"];
        edge [lblstyle="auto",topath="bend left"];
        A [style="state, initial"];
        A -> B [label=2];
        A -> D [label=7];
        B -> A [label=1];
        B -> B [label=3,topath="loop above"];
        B -> C [label=4];
        C -> F [label=5];
        F -> B [label=8];
        F -> D [label=7];
        D -> E [label=2];
        E -> A [label="1,6"];
        F [style="state,accepting"];
    }

Generated with::

    neato -Txdot fsm1.dot | dot2tex -ftikz --tikzedgelabels --styleonly

.. figure:: img/fsm1.png
   :alt: blabla



Color support
=============

All Graphviz `color formats`_ are supported, including the RGBA format. Transparency will however only work when using the PGF/TikZ output format.

.. _color formats: http://www.graphviz.org/doc/info/attrs.html#k:color

Named colors are supported, but you have to ensure that the colors are defined in the resulting LaTeX file. The default PSTricks and PGF/TikZ templates load the ``X11names`` color scheme defined in the xcolor_ package. Note that color names in the xcolor_ package are case sensitive. This is not the case with Graphviz's `color names`_. Use CamelCase_  names in your graphs to ensure compatibility with xcolor_.

.. _CamelCase: http://en.wikipedia.org/wiki/CamelCase
.. _xcolor: http://www.ctan.org/tex-archive/help/Catalogue/entries/xcolor.html
.. _color names: http://www.graphviz.org/doc/info/colors.html

For convenience, a color definition file ``gcols.tex`` is distributed with dot2tex. You can find it in the ``examples`` directory. This file defines most of Graphviz's named colors as lower case. Include this file in the preamble if you need it.


Templates
=========

The output from dot2tex is a list of drawing commands. To render the graphics with LaTeX there's a need for some boiling plate code. This code can be customized using simple templates. If no template is specified with the ``--template`` option, a default template will be used.

The following template tags are available:

``<<drawcommands>>``
  The actual list of drawing commands.

``<<figcode>>``
  Drawing commands wrapped in a figure environment. Note that several important style options are set in the figure environment.

``<<bbox>>``
  Bounding box. Example: ``(0bp,0bp)(100bp,100bp)``
  The individual parts of the bounding box are available with the tags:

  - ``<<bbox.x0>>``
  - ``<<bbox.y0>>``
  - ``<<bbox.x1>>``
  - ``<<bbox.y1>>``

  Note that the bounding box parts are given without any units.

``<<textencoding>>``
  The text encoding used for the output file. Current values are:
  - ``utf8``
  - ``latin1``

``<<docpreamble>>``
  Document preamble. The content of this tag is set by the ``--docpreamble`` option or ``d2tdocpreamble`` graph attribute. Useful for including packages and such.

``<<figpreamble>>``
  Figure preamble. The content of this tag is set by the ``--figpreamble`` option or ``d2tfigpreamble`` graph attribute. Useful for setting font sizes and such.

``<<preproccode>>``
  Code generated for preprocessing labels.

Three different templates are used by dot2tex for the preprocessing mode, output mode and figure only mode respectively. The following template tags make it possible to use the same template file for all modes.

``<<startoutputsection>>`` and ``<<endoutputsection>>``
  Code between these tags is ignored in preprocessing mode.


``<<startpreprocsection>>`` and ``<<endpreprocsection>>``
  Code between these tags is ignored in output mode.

``<<startfigonlysection>>`` and ``<<endfigonlysection>>``
  Code between these tags is used as a template when using the ``--figonly`` option. Ignored in preprocessing and output mode.


.. note:: Tags that have no value are replaced with an empty string. Insert a ``%`` character after a template tag to avoid unwanted line breaks.

Default PGF/TikZ template
-------------------------

.. sourcecode:: latex

    \documentclass{article}
    \usepackage[x11names, rgb]{xcolor}
    \usepackage[<<textencoding>>]{inputenc}
    \usepackage{tikz}
    \usetikzlibrary{snakes,arrows,shapes}
    \usepackage{amsmath}
    <<startpreprocsection>>%
    \usepackage[active,auctex]{preview}
    <<endpreprocsection>>%
    <<gvcols>>%
    <<cropcode>>%
    <<docpreamble>>%

    \begin{document}
    \pagestyle{empty}
    %
    <<startpreprocsection>>%
    <<preproccode>>
    <<endpreprocsection>>%
    %
    <<startoutputsection>>
    \enlargethispage{100cm}
    % Start of code
    % \begin{tikzpicture}[anchor=mid,>=latex',join=bevel,<<graphstyle>>]
    \begin{tikzpicture}[>=latex',join=bevel,<<graphstyle>>]
    \pgfsetlinewidth{1bp}
    <<figpreamble>>%
    <<drawcommands>>
    <<figpostamble>>%
    \end{tikzpicture}
    % End of code
    <<endoutputsection>>
    %
    \end{document}
    %
    <<startfigonlysection>>
    \begin{tikzpicture}[>=latex,join=bevel,<<graphstyle>>]
    \pgfsetlinewidth{1bp}
    <<figpreamble>>%
    <<drawcommands>>
    <<figpostamble>>%
    \end{tikzpicture}
    <<endfigonlysection>>


The ``<<cropcode>>`` template tag is available when the ``--preview`` option is used. The contents will then be:

.. sourcecode:: latex

    \usepackage[active,tightpage]{preview}
    \PreviewEnvironment{tikzpicture}
    \setlength\PreviewBorder{<<margin>>}



Default pstricks template
-------------------------

.. sourcecode:: latex

    \documentclass{article}
    % <<bbox>>
    \usepackage[x11names]{xcolor}
    \usepackage[<<textencoding>>]{inputenc}
    \usepackage{graphicx}
    \usepackage{pstricks}
    \usepackage{amsmath}
    <<startpreprocsection>>%
    \usepackage[active,auctex]{preview}
    <<endpreprocsection>>%
    <<gvcols>>%
    <<docpreamble>>%


    \begin{document}
    \pagestyle{empty}
    <<startpreprocsection>>%
    <<preproccode>>%
    <<endpreprocsection>>%
    <<startoutputsection>>%
    \enlargethispage{100cm}

    % Start of code
    \begin{pspicture}[linewidth=1bp<<graphstyle>>]<<bbox>>
    \pstVerb{2 setlinejoin} % set line join style to 'mitre'
    <<figpreamble>>%
    <<drawcommands>>
    <<figpostamble>>%
    \end{pspicture}
    % End of code
    <<endoutputsection>>%
    \end{document}
    %
    <<startfigonlysection>>
    \begin{pspicture}[linewidth=1bp<<graphstyle>>]<<bbox>>
    \pstVerb{2 setlinejoin} % set line join style to 'mitre'
    <<figpreamble>>%
    <<drawcommands>>
    <<figpostamble>>%
    \end{pspicture}
    <<endfigonlysection>>


Special attributes
==================

Dot2tex defines several special graph, node and edge attributes. Most of them are not part of the DOT language.

``texmode``
  Changes locally how labels_ are interpreted.

``texlbl``
  Overrides the current node or edge label.

``d2tdocpreamble``
  Sets the ``<<docpreamble>>`` tag.

``d2tfigpreamble``
  Sets the ``<<figpreamble>>`` tag.

``d2tfigpostamble``
  Sets the ``<<figpostable>>`` tag.

``d2tgraphstyle``
  Sets the ``<<graphstyle>>`` tag.

``d2ttikzedgelabels``
  Sets the ``--tikzedgelabels`` option.

``d2tnodeoptions``
  Sets the ``--nodeoptions`` option.

``d2tedgeoptions``
  Sets the ``--edgeoptions`` option.

``style``
  Used to pass styles to the backend. Styles are output format specific, with the exception of the styles defined by the DOT language.

``lblstyle``
  Used to set styles for drawing graph, node and edge labels. Only works for the ``pgf`` and ``tikz`` output formats.

``exstyle``
  The same as ``lblstyle``, except that ``exstyle`` is ignored in preprocessing mode.

``topath``
  Used to set a ``to`` path operation for connecting nodes. Only works for the ``tikz`` output format.

``d2talignstr``
  Used to pass a default alignment string to the PSTricks ``\rput`` command::

    \rput[d2talignstr] ...

``d2toptions``
  Allows you to pass options to dot2tex in the same format as from the command line. The ``d2toptions`` value is parsed in the same way as ordinary command line options.


Including external dot files
============================

If your input file contains the single line

.. sourcecode:: latex

    \input{filename.dot}

dot2tex will load the ``filename.dot`` file and convert it. This feature is useful when you want to use `the dot2texi LaTeX package`_, but don't want to include your dot code directly in your document.


Using dot2tex as a module
=========================

It is possible to load dot2tex as a module for use in other Python programs. Here is a basic example:

.. sourcecode:: python

    import dot2tex
    testgraph = """
    digraph G {
        a -> b -> c -> a;
    }
    """
    texcode = dot2tex.dot2tex(testgraph, format='tikz', crop=True)

The ``dot2tex`` function is the main interface:

.. sourcecode:: python

    dot2tex(dotsource,**kwargs)

It takes the following input arguments:

    ======================  ===================================================
    Argument                Description
    ======================  ===================================================
    ``dotsource``           A string containing a DOT or XDOT graph.
    ``**kwargs``            An arbitrary number of conversion options passed as
                            keyword arguments
    ======================  ===================================================

The function returns the resulting LaTeX code as a string.

The supported options are the same as the command line options_ (long version). Here are a few examples:

.. sourcecode:: python

    import dot2tex as d2t
    texcode = d2t.dot2tex(testgraph, format='tikz', crop=True)
    texcode = d2t.dot2tex(testgraph, preproc=True,figonly=True)
    texcode = d2t.dot2tex(testgraph, debug=True)

Option values are either strings or booleans. Note that some of the command line options are not relevant when using dot2tex as a module.

To specify a template you can use the ``template`` option like this:

.. sourcecode:: python

    import dot2tex
    mytemplate = "<<drawcommands>>"
    texcode = dot2tex.dot2tex(graph, template = mytemplate)



Debugging
---------

You can set ``debug=True`` to create a detailed log useful for debugging. To retrieve the content of the log you can use the ``get_logstream`` function. It will return a ``StringIO`` instance. You can then use the ``getvalue()`` class method to get the actual text. Example:

.. sourcecode:: python

    import dot2tex
    texcode = dot2tex.dot2tex(testgraph, debug=True)
    logstream = dot2tex.get_logstream()
    print logstream.getvalue()



Issues and limitations
======================

The purpose of dot2tex is to give graphs a more LaTeX friendly look, not to create exact duplicates. However, the program does a descent duplication job when it comes to drawing nodes and edges, but it does not try to duplicate label and annotation formatting.

A list of known limitations:

- Parallel edges are only supported in the ``duplicate`` mode.
- Concentrated edges are not render properly when using the tikz output format.
- Pyparsing sometimes choke on valid dot files. If this happen you could try to feed xdot data directly to dot2tex like this::

    $ dot -Txdot example.dot | dot2tex -o example.tex

- Graphviz sometimes complain about nodes being too small to fit the content. This typically happens after the graph has been preprocessed with the preview package. You can usually ignore this warning. However, if edges are routed poorly, it may help increasing the size of the nodes.
- If a dot file contains more than one graph, only the first graph will be converted.
- Background color of page is currently not set.
- The ``fontcolor`` attribute is not supported yet.
- The ``setlinewidth(.)`` attribute is not supported yet.


Text encoding
-------------

Graphviz's default text encoding is ``utf8``. The ``latin1`` encoding can also be used. Utf8 is an unicode encoding and can in theory handle any international characters. However, LaTeX's unicode support is somewhat limited.

Tips and tricks
===============

Fonts
-----

No font information in the DOT file is preserved by dot2tex. However, there are several ways of  modifying the generated LaTeX code to achieve some control of fonts and font sizes.

- Modifying the templates.
- Using the ``d2tdocpreamble`` and ``d2tfigpreamble`` attributes or command line options.
- Using the ``lblstyle`` attribute.

To increase the font size you can for instance insert a ``\Huge`` command in the figure preamble::

    $ dot2tex -tmath --figpreamble="\Huge" ex1.dot > ex1huge.tex

.. figure:: img/ex1huge.png
   :alt: Setting label font size to \Huge

Debugging
---------

When making your own templates it is easy to make mistakes, and LaTeX markup in graphs may fail to compile. To make it easier to find errors, invoke dot2tex with the ``--debug`` option::

    $ dot2tex --preproc --debug test.dot

A dot2tex.log file will then be generated with detailed information. In the log file you will find the generated LaTeX code, as well as well as the compilation log.

Be consistent
-------------

Be aware of differences between the template you use for preprocessing and code used to generate final output. This is especially important if you use the ``--figonly`` option and include the code in a master document. If a 10pt font is used during preprocessing, the result may not be optimal if a 12pt font is used in the final output.

Example. A graph is generated with::

    $ dot2tex --preproc -tmath --nominsize ex1.dot > ex1tmp.dot

Running through dot2tex again with::

    $ dot2tex --figpreamble="\Huge" ex1tmp.dot > ex1huge.tex

gives labels that do not fit properly inside the nodes.

.. figure:: img/consistent.png
   :alt: Inconsistence between preproc mode and output mode

Postprocessing
--------------

The output from Graphviz and dot2tex is not perfect. Manual adjustments are sometimes necessary to get the right results for use in a publication. For final and cosmetic adjustments, it is often easier to edit the generated code than to hack the dot source. This is especially true when using the ``tikz`` output format.

Use the special graph attributes
--------------------------------

Dot2tex has many options for customizing the output. Sometimes is is impractical or boring to type the various options at the command line each time you want to create the graph. To avoid this, you can use the special graph attributes. The ``d2toptions`` attribute is handy because it is interpreted as command line options.

So instead of typing::

    $ dot2tex -tikz -tmath --tikzedgelabels ex1.dot

each time, use ``d2toptions`` like this:

.. sourcecode:: dot

    digraph G {
        d2toptions ="-tikz -tmath --tikzedgelabels";
        ...
    }



Use the tikz output format for maximum flexibility
--------------------------------------------------

The difference between the ``pgf`` and ``tikz`` output formats is best shown with an example. Consider the following graph:

.. sourcecode:: dot

    graph G {
        mindist = 0.5;
        node [shape=circle];
        a -- b -- c -- a;
    }

Rendering the graph using ``circo`` and the ``pgf`` and ``tikz`` output formats::

    $ circo -Txdot simple.dot | dot2tex -tmath -fpgf -s
    $ circo -Txdot simple.dot | dot2tex -tmath -ftikz -s

gives visually different graphs:

.. figure:: img/pgftikzsimple.png
   :alt: Difference between pgf and tikz output format

However, the main difference is in the generated code. Here is the ``pgf`` output:

.. sourcecode:: latex

    % Edge: a -- b
    \draw [] (19bp,38bp) -- (19bp,60bp);
    % Edge: b -- c
    \draw [] (35bp,70bp) -- (55bp,58bp);
    % Edge: c -- a
    \draw [] (55bp,40bp) -- (35bp,28bp);
    % Node: a
    \begin{scope}
    \pgfsetstrokecolor{black}
    \draw (19bp,19bp) ellipse (18bp and 19bp);
    \draw (19bp,19bp) node {$a$};
    \end{scope}
    % Node: b
    \begin{scope}
    \pgfsetstrokecolor{black}
    \draw (19bp,79bp) ellipse (18bp and 19bp);
    \draw (19bp,79bp) node {$b$};
    \end{scope}
    % Node: c
    \begin{scope}
    \pgfsetstrokecolor{black}
    \draw (71bp,49bp) ellipse (18bp and 19bp);
    \draw (71bp,49bp) node {$c$};
    \end{scope}

Compare the above code with the ``tikz`` output:

.. sourcecode:: latex

    \node (a) at (19bp,19bp) [draw,circle,] {$a$};
    \node (b) at (19bp,79bp) [draw,circle,] {$b$};
    \node (c) at (71bp,49bp) [draw,circle,] {$c$};
    \draw [] (a) -- (b);
    \draw [] (b) -- (c);
    \draw [] (c) -- (a);

The code is much more compact and it is quite easy to modify the graph.

The dot2texi LaTeX package
--------------------------

The dot2texi package allows you to embed DOT graphs directly in you LaTeX document. The package will automatically run ``dot2tex`` for you and include the generated code. Example:

.. sourcecode:: latex

    \documentclass{article}
    \usepackage{dot2texi}

    \usepackage{tikz}
    \usetikzlibrary{shapes,arrows}

    \begin{document}
    \begin{dot2tex}[neato,options=-tmath]
    digraph G {
        node [shape="circle"];
        a_1 -> a_2 -> a_3 -> a_4 -> a_1;
        }
    \end{dot2tex}

    \end{document}

When the above code is run through LaTeX, the following will happen is shell escape is enabled:

- The graph is written to file.
- ``dot2tex`` is run on the DOT file.
- The generated code is included in the document.

The whole process is completely automated. The generated graph will look like this:

.. figure:: img/dot2texiex1.png
   :alt: Graph generated with dot2texi

The ``codeonly`` option is useful in conjunction with ``dot2texi``, especially when used with the ``tikz`` output format. Here is an example that shows how to annotate a graph:

.. sourcecode:: latex

    \documentclass{article}
    \usepackage{tikz}
    \usetikzlibrary{arrows,shapes}
    \usepackage{dot2texi}
    \begin{document}
    % Define layers
    \pgfdeclarelayer{background}
    \pgfdeclarelayer{foreground}
    \pgfsetlayers{background,main,foreground}

    % The scale option is useful for adjusting spacing between nodes.
    % Note that this works best when straight lines are used to connect
    % the nodes.
    \begin{tikzpicture}[>=latex',scale=0.8]
        % set node style
        \tikzstyle{n} = [draw,shape=circle,minimum size=2em,
                            inner sep=0pt,fill=red!20]
        \begin{dot2tex}[dot,tikz,codeonly,styleonly,options=-s -tmath]
            digraph G  {
                node [style="n"];
                A_1 -> B_1; A_1 -> B_2; A_1 -> B_3;
                B_1 -> C_1; B_1 -> C_2;
                B_2 -> C_2; B_2 -> C_3;
                B_3 -> C_3; B_3 -> C_4;
            }
        \end{dot2tex}
        % annotations
        \node[left=1em] at (C_1.west)  (l3) {Level 3};
        \node at (l3 |- B_1) (l2){Level 2};
        \node at (l3 |- A_1) (l1) {Level 1};
        % Draw lines to separate the levels. First we need to calculate
        % where the middle is.
        \path (l3) -- coordinate (l32) (l2) -- coordinate (l21) (l1);
        \draw[dashed] (C_1 |- l32) -- (l32 -| C_4);
        \draw[dashed] (C_1 |- l21) -- (l21 -| C_4);
        \draw[<->,red] (A_1) to[out=-120,in=90] (C_2);
        % Highlight the A_1 -> B_1 -> C_2 path. Use layers to draw
        % behind everything.
        \begin{pgfonlayer}{background}
            \draw[rounded corners=2em,line width=3em,blue!20,cap=round]
                    (A_1.center) -- (B_1.west) -- (C_2.center);
        \end{pgfonlayer}
    \end{tikzpicture}
    \end{document}

.. figure:: img/dot2texiex2.png
   :alt: Annotated graph

.. note::

    If you don't want to include the dot directly in your document, you can use the ``\input{..}`` command. See the section `Including external dot files`_ for more details.

Acknowledgements
================

The dot parser used by dot2tex is based on code from the pydot_ project.

