Re: [ft-devel] auto-hinter and base characters

[Werner LEMBERG]

> Right now, I'm working on slightly extending the auto-hinter to make
> a distinction between `base characters' and everything else.  The
> idea is that only base characters will use blue zones.  This should
> give more consistent vertical positions of e.g. diacritics since
> they won't be snapped to (incorrect) bluezones.

The code is now available in the git repositories of both FreeType and
ttfautohint.  Please test and comment!  Note that for coding reasons
there is now a distinction between `no-base characters' and everything
else.

> Note that ttfautohint will have more benefit than FreeType: The
> former normally hints diacritics and base characters separately,
> while the latter always decomposes composite characters.

I still have to investigate a minor issue: For no-base characters,
blue zones are not applied but snapping to the default stem width(s)
is executed for `strong auto-hinting' (this corresponds to using the
`-w' option in ttfautohint).  I wonder whether I should switch this
off also, given that diacritical symbols are usually smaller than base
glyphs.

> There are two drawbacks: Diacritics that have different shapes
> depending on the active features (e.g. special forms for smallcaps)
> won't be covered, and I have to increase the glyph style array from
> 8bit to 16bit.

While re-designing code ranges I've also added better support for
phonetic alphabets like the IPA that use superscript-like and
subscript-like characters; those characters are now using separate
blue zones, which greatly improves the visual result.

> As soon as I have something to show I'll post it here.

Here they are :-)


    Werner