How to use \newline in a macro?

Question

I want to introduce \newline after the figure label instead of :. I am aware that caption package does this via \captionsetup. However, I would like to do it without it.

I read from the memoir class manual (page no - 214) about the trick of declaring an extra argument for \fnum@figure and not using it, which gobbles the undesired colon from \@makecaption. Now, for memoir class I can introduce \newline instead of : as the label separator. It works.

Original caption:

Modified in Memoir class:

This trick also works for scrreprt. However, for scrreprt, : disappears but \newline is not introduced. I have also tried \\, \\* and \vspace{\baselineskip}. None of them work.

Modified caption without ":" but no \newline

Introducing \newline at the start of the \caption also doesn't work.

I think that I am making some rookie mistake here. I have read that most macros do not distinguish between spaces and \newlines. Is this the reason why this won't work?

Please let me know a workaround.

%\documentclass{memoir}
\documentclass{scrreprt}

%Memoir manual page no - 214
%Note the extra unused argument.
\makeatletter
\renewcommand{\fnum@figure}[1]{\textsc{\figurename~\thefigure} \newline \sffamily}
\makeatother
%
\begin{document}
  \begin{figure}
    \centering
    \rule{3cm}{2cm}
    \caption{A Caption}
    %\caption{\newline A Caption}
  \end{figure}
\end{document}

Answer 1

As an example this is a simple caption handler that makes a two line layout (if your captions may be long you could change ll to lp{5cm} or whatever you need for multi-line version) it does not respect all the options the class may have controlling caption positioning.

\documentclass{scrreprt}

%Memoir manual page no - 214
%Note the extra unused argument.
\makeatletter
\renewcommand{\fnum@figure}[1]{\textsc{\figurename~\thefigure}}
\def\@@makecaption#1#2#3{%
{\centering\begin{tabular}{@{}ll@{}}
\csname fnum@\@captype\endcsname&{}\tabularnewline
&#3\end{tabular}\par}
}
\makeatother
%
\begin{document}
  \begin{figure}
    \centering
    \rule{3cm}{2cm}
    \caption{A Caption}
    %\caption{\newline A Caption}
  \end{figure}
\end{document}