[Fontinst] Interword shrink vs thinspace

[Plamen Tanovski]

Hi,

here ist the next thing: the thinspace (as in \,) is used widely by
varios packages, i.e. for typesetting units like 3\,mm and it is
usually equal to thinmuskip in math mode. It is defined as 3/18 from
the quad (= 0.1667em). I think, it is generally a bad idea to change
this amount. At least, fontinst and the one who creates the TeX font
metrics, can not influence that space.

Let's look at the min. interword space. It is the difference between
interword space (\fontdimen2) and shrink (\fontdimen4). Fontinst sets
by default first dimen to the width of the space glyph and the second
one to 0.24 of the first width.

Now, things get ugly on a narrow typesetted line in case that the min.
interword space is narrower than the thinspace. The thinspace then
doesn't look thin at all compared to the interword space. This is the
situation i.e. with the MinionPro fonts (not fontinst's fault ;) where
at 10pt the min. interword space is 1.513pt but the \thinspace is
1.667pt.

So, I think fontinst should check both dimensions and guarantee that
the default min. interword space is always slightly (whatever that
means) bigger then \thinspace, or if the dimension is set explicitly,
fontinst should issue a warning.

best regards

-- 
Plamen Tanovski
Prager Str. 125
04317 Leipzig, Germany
Tel. +49 341 3085760