In typesetting, a strut is an invisible character or element, used to ensure that a text has a minimum height and depth, even if no other elements are included.
For example, LaTeX and plain TeX provide the command
\strut
to insert a font size-specific strut. In LaTeX it has a height of 70% of the baseline skip (the distance between the baselines of two consecutive lines of text) and a depth of 30% of the baseline skip. It ensures that two vertical stacked boxes which include such a strut have the same distance as two normal consecutive lines. LaTeX also supports the creation of general struts using the command:
\rule{0pt}{total height}
where \strut is equivalent in size to \rule{0pt}{\baselineskip}.
References
- Donald E. Knuth. The TeXbook (Computers and Typesetting, Volume A). Reading, Massachusetts: Addison-Wesley, 1984. ISBN 0-201-13448-9, page 82.
- Braams, J. and Carlisle, D. and Jeffrey, A. and Lamport, L. and Mittelbach, F. and Rowley, C. and Schöpf, R., The LaTeX2e Sources. 2009/09/24, pages 19 and 129. Available online as PDF and LaTeX source.