What am I doing wrong with vspace

Question

In the MWE below (LuaLaTex), why \vspace*{1pt} causes such a huge vertical space?

\documentclass[12pt, oneside]{book}
\usepackage[showframe, paperwidth=30pc, paperheight=30pc, margin=5pc]{geometry}
\begin{document}
% \vspace*{1pt}
\begin{center}
    \Huge{Test text.}
\end{center}
\end{document}

Because \begin{center} introduces vertical padding which is however ignored at the start of a page. — campa, Feb 08 '24 at 11:49
\vspace* inserts an invisible rule and so your center is no longer at the begin of the page. — Ulrike Fischer, Feb 08 '24 at 11:50
Unrelated to the question, but \Huge is a switch and does not take an argument. Use \Huge Test text. or {\Huge Test text.} if you want to restrict the change to a certain group. — samcarter_is_at_topanswers.xyz, Feb 08 '24 at 11:54
You can avoid the problem by moving \vspace*{1pt} into the center environment. — samcarter_is_at_topanswers.xyz, Feb 08 '24 at 11:57

score 3 · Accepted Answer · answered Feb 08 '24 at 14:18

If you want exactly one point of space above the title, then you need some deeper control on spacing.

With \vspace*{1pt}\begin{center} the standard space above center is not removed because it's preceded by something that must not be removed at a page break (the start of a document counts as a page break). Thus you get the total of 1pt plus the \topsep.

On the other hand, you probably don't actually want center, but only centering the title.

\documentclass{article}
\usepackage{showframe}
\begin{document}
\vspace*{1pt}% the space you want
\vspace{-\topskip}% remove the topskip
\begingroup\centering\Huge
Test text\par
\endgroup
\addvspace{\topsep}% or what you need
Some other text follows.
\end{document}

Note that you need something more than just \vspace*{1pt}.

What am I doing wrong with vspace

1 Answers1