%%
%% The LaTeX Companion, 3ed
%%
%% Example 7-4-3 on page I-543 in "Standard customization possibilities for \protect \nxLcs  {caption}".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{123.0pt}
%
  \setlength\intextsep{6pt}
  \addtolength\textwidth{-4pt}

% Not shown here since explained later in the
% book:
  \AtBeginDocument{\captionsetup{skip=8pt}}

%StartShownPreambleCommands
\usepackage{graphicx,float}
\floatstyle{boxed} \restylefloat{table}
\usepackage[font={sf,bf,footnotesize},
            textfont={md,smaller}]{caption}
%StopShownPreambleCommands

\begin{document}
\begin{figure}[ht] \centering
  \includegraphics[width=10mm]{Escher}
  \caption{Short caption}
\end{figure}
\begin{table}[ht]  \centering Let there be a table
  \caption{A caption that runs over more than one line}
\end{table}
\end{document}