How long is 1quad?

jingkaimori · June 5, 2024, 4:20pm

Manual of texmacs mentioned that 1fn is 1quad by default, but length of 1quad is not specified in that document.

texmacs/texmacs/blob/master/TeXmacs/doc/devel/format/basics/lengths.en.tm#L95




  <item*|<verbatim|ex>>The height of the ``x'' character in the current
  font.


  <item*|<verbatim|emunit>>The width of the ``M'' character in the current
  font.
</description>


<paragraph*|Stretchable font-dependent length units>


<\description>
  <item*|<code*|fn>>This is a stretchable variant of <verbatim|1quad>. The
  default length of <verbatim|1fn> is <verbatim|1quad>. When stretched,
  <verbatim|1fn> may be reduced to <verbatim|0.5fn> and extended to
  <verbatim|1.5fn>.


  <item*|<verbatim|fns>>This length defaults to zero, but it may be
  stretched up till <verbatim|1fn>.


  <item*|<verbatim|bls>>The ``base line skip'' is the sum of
  <verbatim|1quad> and <src-var|par-sep>. It corresponds to the distance

xuyiqi1 · June 5, 2024, 5:00pm

1 quad space is the fixed width of the “M” character in the current font, see The Jolly Writer Page 62 and 141.