Example of LaTeX snippet that keeps text on a single line, but resizes it to fit the width, if it would otherwise wrap.

oneline.tex

\documentclass{article}
\usepackage{xifthen}
\usepackage{graphicx}
 
\newcommand{\oneline}[1]{%
  \newdimen{\namewidth}%
  \setlength{\namewidth}{\widthof{#1}}%
  \ifthenelse{\lengthtest{\namewidth < \textwidth}}%
  {#1}% do nothing if shorter than text width
  {\resizebox{\textwidth}{!}{#1}}% scale down
}
 
\begin{document}
 
\oneline{\Huge{The no-wrap text to scale}}
 
\oneline{\Huge{The quick brown fox jumped over the lazy dog, over and over and over and over again.}}
 
\end{document}