2. Usage guide

2.1. Invoking dot2tex from the command line

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 section Using dot2tex as a module 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. You can pass options to the layout program with the --progoptions option.

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

Invoking dot2tex

If you are on Windows and have installed dot2tex from source, you have to type python dot2tex to invoke the program.

2.2. Command line 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. See Labels for details.
-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
--progoptions options
	Pass options to graph layout program.
--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.
--pgf210	Generate code compatible with PGF 2.10.

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.

2.3. Output formats

The output format is specified with the -f fmt or --format fmt command line option. The following output formats are available form the command line. Additionally there is a special positions output format only available when using dot2tex as Python module.

2.3.1. PGF

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

2.3.2. PSTricks

Generates code for the PSTricks package.

2.3.3. 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.

2.4. 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. See the section Vertical label alignment for tips.

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.

2.4.1. Label examples

Consider the following graph:

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.

Example of using texlbl:

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

Example of using the texmode attribute:

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;
}

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:

Read more about preprocessing in the Preprocessing graphs section.

2.4.2. 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:

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

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

$ dot2tex --valignmode=dot valign.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

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:

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

2.5. 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

2.5.1. Examples

Consider the following graph:

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:

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:

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

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

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: