[Groff] Re: Composed glyphs - quick and dirty solution

[Werner LEMBERG]

> A modern font may contain instrucions on composing glyphs from parts
> (GSUB table), but it is likely to have most of the popular glyphs
> precomposed.

GSUB can't be used for composing glyphs from parts.  It can be used to
create ligatures.  What you probably mean is the GPOS table.  I'll
post a query on the fontforge list whether it is possible (and whether
it makes sense) to have fontforge emit `CC' lines in the AFM file.

> For rarely used composed glyphs or old fonts, "ps-achar" request
> (from ps.tmac) can be used, that creates a fall-back glyph by
> overprinting accent centered above the base glyph.  It provides
> reasonable quality, but "ps-achar" has to be explicitly called for
> each composed glyph.  If ps-achar is to be used once for every
> composed glyph from unicode in ps.tmac, that file will be HUGE.

Indeed.  There are about 2000 composite characters in the current
Unicode version -- see file uniuni.cpp.  Theoretically, we could add a
request to groff to activate an option so that it tries to compose
missing glyphs automatically if both the base and accent characters
are available.  On the other hand I'm not sure whether this is a good
thing from the typographical point of view.

> It would be nice to have some magic hardcoded in grops to do
> something similar to ps-achar for composed glyphs that were really
> [rarely] used only.

Why restricting this to grops?

> For base-3 PS fonts (Courier, Helvetica, Times) accent placement may
> be somewhat improved, since there are hand-made tables for accent
> placement, that may result in better positions than just centering
> the accent.  That tables originate from second millenium attempts to
> "add more characters" to base PS fonts (ogonkify project).
>
> If there is some interest in that - I'll do it this weekend.

Hmm, I'm not happy about a PS-only solution.  If any, than support for
the CC keyword would help to handle the ogonkify solution, I think.


    Werner