UK TeX FAQ -- question label baselinepar

### Only one `\``baselineskip` per paragraph

The `\``baselineskip`, which determines the space between lines, is not (as one might hope) a property of a line, but of a paragraph. As a result, in a `10pt` (nominal) document (with a default `\``baselineskip` of `12pt`), a single character with a larger size, as:

>     {\Huge A}

will be squashed into the paragraph: TeX will make sure it doesn’t scrape up against the line above, but won’t give it “room to breathe”, as it does the text at standard size; that is, its size (`24.88pt`) is taken account of, but its `\``baselineskip` (`30pt`) isn’t. This problem may be solved by a strut: the name comes from movable metal typography, and refers to a spacer that held the boxes (that contained the metal character shapes) apart. Every time you change font size, LaTeX redefines the command `\``strut` to provide the equivalent of a metal-type strut for the size chosen. So for the example above, we would type

>     Paragraph text ...
>        {\Huge A\strut}
>        ... paragraph continues ...

This technique only works for such very short intrusions; if you need several lines, you should convert your intrusion into a `quote` environment, since it’s not possible to provide a `\``strut` command for every line of the intrusion, in a sensible way, so proceed by:

>     \begin{quote}
>       \Huge A LENGTHY TEXT ...
>       SHOUTING AT THE READER!
>     \end{quote}

The contrary case:

>     Paragraph text ...
>     {\footnotesize Extended interjection ...
>        ... into the paragraph.}
>           ... paragraph continues ...

will look wrong, since the `8pt` interjection will end up set on the `12pt` `\``baselineskip` of the paragraph, rather than its preferred `8.5pt`. A `\``strut` here is no help: there is no such thing as a “negative strut”, that draws lines together, so once more, one falls back on the `quote` to separate the interjection:

>     Paragraph text ...
>     \begin{quote}
>       \footnotesize Extended interjection ...
>       ... into the paragraph.
>     \end{quote}
>     ... paragraph continues ...

The same effect is at work when we have something like:

>     Paragraph text ...
>       ... paragraph body ends.
>     {\footnotesize Comment on the paragraph.}

>     Next paragraph starts...

which will set the body of the first paragraph on the constricted `\``baselineskip` of the `\``footnotesize` comment. Solve this problem by ending the initial paragraph before starting the comment:

>     Paragraph text ...
>       ... paragraph body ends.
>     \par\nothtml{\noindent}
>     {\footnotesize Comment on the paragraph.}

>     Next paragraph starts...

(We suggest `\``noindent` to make the comment look as if it is part of the paragraph it discusses; omit `\``noindent` if that is inappropriate.)

A variation of the previous issue arises from a paragraph whose size is different from those around it:

>     {\Large (Extended) IMPORTANT DETAILS ...}

>     Main body of text...

Again, the problem is solved by ending the paragraph in the same group as the text with a different size:

>     {\Large (Extended) IMPORTANT DETAILS ...\par}

>     Main body of text...

This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=baselinepar