\documentclass[beamer,multi]{standalone}
---PREAMBLE---
\begin{document}
\setlength\fboxsep{0pt}
\begin{standaloneframe}%
\fbox{%
\pgfmathsetmacro\progress{---PROGRESS---}%
---STILL---%
}%
\end{standaloneframe}%
\end{document}

