Putting LaTeX into Xfig figures

Thousands of people, particularly those using UNIX (or LINUX or MAC OS X) computers, use the Xfig program to produce diagrams to be included in their LaTeX documents. Frequently, one needs to put mathematical symbols or expressions in their diagrams. Instructions found on the internet are often vague on how to do this. Here is an easy solution, which I make available to you. Please send me a "thank you" email if this solution has proved helpful, or send me any suggestions or comments.

NOTICE: A much fancier and robust version of this is now available at Sourceforge. It is called fig2ps.

How to set it up (do this only once):

Copy the /bin/sh shell script (text file) called fig2eps (which I made up) into a directory (such as ~/bin) where you put executable files. Name the file fig2eps.
Ensure fig2eps is executable via the UNIX command chmod u+x fig2eps.
The script relies on the following programs which are commonly found in UNIX (or LINUX, MAC OSX) setups: fig2dev, latex, dvips and ps2eps. You might need to install them, or modify the script if your instillation uses alternative, equivalent, programs.

How to make diagram:

Set the Special Flag when writing text containing LaTeX commands (such as "$\int f(x) \; dx$") within the xfig program. You can set this via the Text Flags button that appears at the bottom of the xfig panel when you are in text-entry mode. The Special Flag can be set automatically by starting xfig via the UNIX command xfig -specialtext.
Save your diagram as an xfig file, say mydiagram.fig.
Run the script via the UNIX command fig2eps mydiagram.fig or simply fig2eps mydiagram. This should create a new file called mydiagram.eps in the same directory as mydiagram.fig.
(Optional) If your diagram has a complicated or recurring mathematical construct, then you can create a file called mydiagram.preamble where you may place LaTeX preamble commands such as
```
\newcommand{\myint}{ \int_{a}^{b} f(x) \; dx }
```
The shell script will include mydiagram.preamble when TeX-processing mydiagram.fig. Now, within xfig, you can typeset the whole integral via the text "$\myint$".

How to place diagram into LaTeX document:

Include the line
```
\usepackage{graphicx}
```
in your LaTeX source-file preamble (before "\begin{document}").

Use something like the following to put the diagram into a figure. Of course you can change the width to scale the diagram.

\begin{figure}[htb]
  \begin{center}
    \includegraphics[height=3.0cm]{mydiagram.eps}
  \end{center}
  \caption{This is my fabulous xfig-generated diagram with embedded LaTeX commands.}
\label{fig:figWithLatexDiagram}
\end{figure}

Typeset your .tex file using standard latex, NOT pdflatex.
If you must use pdflatex, be aware that it expects diagrams to be in PDF format. You must convert mydiagram.eps to mydiagram.pdf using a program like ps2pdf or pstopdf. You can automate this by uncommenting some lines in the fig2eps script. However, this can screw up BoundingBox information, resulting in diagrams which are not well centred or too small. You are on your own here, but this website might prove helpful. Alternatively, try omitting the .eps extension in the .tex file, like
```
    \includegraphics[height=3.0cm]{mydiagram}
```
You are on your own here!

Problems I have seen

Sometimes ps2eps has trouble calculating the BoundingBox dimensions of a .ps diagram. This problem is documented in its man pages and there is nothing I can do about that. Let me know if you have a solution! However, a BoundingBox problem is usually easy to fix. For example, there may be a small or invisible graphic item which is far down the page in xfig, causing the BoundingBox to be too big, and the diagram has a huge empty white space. In any case, one can easily modify the BoundingBox in an .eps file using your favourite text editor. Simply change the numbers on the line which looks something like
```
%%BoundingBox: 149 445 452 667
```
This line is usually near the top of any .eps or .ps file. The first two numbers are the (x,y)-coordinates of the SW corner of the box. The final two numbers are the (x,y)-coordinates of the NE corner of the box.

Side Effects

The fig2eps script creates a few temporary files in your /tmp/ directory, and reports what it is doing in the command window. The script normally deletes these temporary files during cleanup. If the script fails and the cleanup does not proceed, then do not worry. The /tmp/ directory is wiped out each time you reboot a UNIX machine.

Disclaimer

The usual disclaimers hold, as detailed in the file fig2eps. You may have to slightly modify the file, such as the location of your temporary directory, and program names. The script is not terribly robust against program errors etc (volunteers?). Have fun with it!

Modified: 2009.11.25 by goddyn@sfu.ca (Luis Goddyn)