# Unable to show a derivative with \dot in gfsartemisia-euler font (inside TikZ figure)

I'm trying to make a figure using a font that has support for mathematics. The aim here is to enhance the visual appeal of the figure compared to what could be achieved with one of the plainer standard LaTeX fonts. After some experimentation I have chosen gfsartemisia-euler. I have the problem that the \dot{x} command is processed to give a result more like \underline{x}. Here's an example:

\documentclass[a4paper]{article}

\usepackage{mathtools, color,tikz}

\usetikzlibrary{positioning,shapes}
\usetikzlibrary{fit}
\usetikzlibrary{calc}

\usepackage{gfsartemisia-euler}
\usepackage[T1]{fontenc}

\begin{document}

\pagestyle{empty}

\begin{figure}[c]

\centering
\begin{tikzpicture}

\begin{scope}[font=\large, color=black, ultra thick, node distance=19mm, text centered,text=black]

\node[text width=80mm]  (SE-PE) {$\displaystyle \frac{ \partial } { \partial t} A_{n r} = [B_{0}, A_{nr} ] + \sum_{\substack{s \neq r \\ s=1}}^{M} \frac{ \dot{x}_{r} - \dot{x}_{s} } { x_{r} - x_{s} } [ A_{ns}, A_{nr}]$ \\[+5pt]  Schlesinger Equations/ Painlev\'e Equations};

\node[minimum height=47mm, minimum width=87mm, rounded rectangle, draw,red] at (SE-PE) {};

\end{scope}

\end{tikzpicture}
\end{figure}

\end{document}


with result

I have looked at various pages on changing fonts in documents without success, but I don't often have to play with fonts so it appears that I'm missing some crucial piece of information on how to proceed. Suggestions will be appreciated.

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This has nothing to do with tikz. The font files for gfsartemisia-euler lack any commands for defining the math accents, and the accents are in non-standard places. To fix this issue an appropriate \DeclareMathAccent command as follows:

\documentclass{article}

\usepackage{gfsartemisia-euler}
\usepackage[T1]{fontenc}
\DeclareMathAccent{\dot}{\mathalpha}{artemisiaeulernumbers}{"01}

\begin{document}

$$\dot x \dot A$$

\end{document}


How do you get to the right math accent command? Well the log file, tells you the path to the package file for the font, namely .../gfsartemisia-euler.sty. In this file you find that there is only one symbol font defined, namely via the line

\DeclareSymbolFont{artemisiaeulernumbers}{OT1}{artemisiaeuler}{m}{n}


which tells us that artemisiauelernumbers is set up to be used as math symbols, and that it is really artemisiaeuler in the OT1 encoding. That font is loaded via the file ot1artemisiaeuler.fd, which lies in the same directory and contains the declaration

\DeclareFontShape{OT1}{artemisiaeuler}{m}{n}{<-> s * [0.98] artemisiarg8a}{}


telling us that the font used is artemisiarg8a Now you can get a table of the characters in the relevant font by using the fonttable package as follows:

\documentclass{article}

\usepackage{fonttable}
\usepackage[T1]{fontenc}

\begin{document}

\fonttable{artemisiarg8a}

\end{document}


The resulting table shows that the dot accent lies in position "01, and that is the argument we use in the math accent command. Now one should treat the other accents in a similar way...

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thanks for the thorough and speedy response, this has fixed the problem (and most likely some potential future problems) very simply. –  Jason Whyte Oct 26 '12 at 0:43