setspace with non standard point sizes.

[davidcarlisle]

https://tex.stackexchange.com/questions/734794/spurious-text-when-using-setspace-and-scrextend-with-decimal-font-size

here \@ptsize is 0.5 we could avoid the issue by rounding up(?) to the nearest integer before doing the \ifcase but if changing this area we might also want to support other values eg extsizes which leaves this command with its "natural" value rather than ten less.

\documentclass{article}\usepackage[fontsize=10.5pt]{scrextend}% 0.5 10.5, 12.59996

%\documentclass{article}\usepackage[fontsize=14.5pt]{scrextend}% 4.5, 14.5, 17.39995

%\documentclass[14pt]{extarticle} % 14, 14.4, 17
%\documentclass[12pt]{extarticle} % 12, 12, 14.5

\makeatletter
\show\@ptsize
\show\f@size
\showthe\baselineskip
\usepackage{setspace}

\begin{document}
\onehalfspacing
text
\end{document}