[Fontinst] Dashes and monospaced fonts

[Lars Hellström]

At 15.32 +0200 2005-06-18, Peter Dyballa wrote:
>Hello!
>
>Why is fontinst creating for monospaced fonts an endash like '--' and
>an emdash like '---'?

As usual, you haven't got your facts right. The _emdash_ is like `--',
whereas the endash is like `-'. The reason Alan chose this default is that
the endashes of most monowidth fonts look awful.

The reasoning of the foundries seems to be that since all glyphs have the
same advance width, that width must be the em of the font, and the emdash
is made to fit. Then the endash is made half as long as the emdash, i.e.,
half that of its advance width. This reasoning is fundamentally flawed
because dashes are normally compared not to each other but to the
surrounding text, and in that comparison both dashes are too short to be
recognisable.

In order to do better (i.e., make things more readable), the default in
fontinst is to build glyphs that instead emulate the typewriter style for
writing en- and emdashes. Quoting ltpunct.mtx:

\texttt{rangedash} and \texttt{punctdash} are mostly two traditional
aliases for \texttt{endash} and \texttt{emdash}. The problem with the
latter two ``original'' glyphs is that they in monowidth fonts
usually are much shorter than one would expect, whereas the hyphen
combinations look quite good.
\endcomment

\setglyph{rangedash}
   \ifisint{monowidth}\then
      \glyph{hyphen}{1000}
   \Else
      \glyph{endash}{1000}
   \Fi
\endsetglyph

\setglyph{punctdash}
   \ifisint{monowidth}\then
      \glyph{hyphen}{1000}
      \glyph{hyphen}{1000}
   \Else
      \glyph{emdash}{1000}
   \Fi
\endsetglyph


Lars Hellström