[ft-devel] auto-hinter has married HarfBuzz

[Werner LEMBERG]

Folks,


after intensive work in the last few weeks I can proudly announce that
the auto-hinter has been enhanced to access OpenType features using
the HarfBuzz library.

  1. There is now a separation between `writing systems' (this
     corresponds to the avaible auto-hinter submodules like `aflatin'
     or `afcjk', cf. file `afwrtsys.h'), `scripts' (in the
     OpenType/HarfBuzz sense, cf. file `afscript.h'), and `coverages'
     (a mixture between Unicode ranges and glyphs associated with
     OpenType features, cf. file `afcover.h').  A combination of these
     values is called a `style' (cf. file `afstyles.h'), and there are
     now separate hint sets for each style.

  2. A direct result of item 1 is that far more glyphs within an
     OpenType font can be correctly classified as belonging to a
     certain script to get proper hinting.

  3. Another corrolary of item 1 is that features like superscripts or
     small caps are far better hinted.

I'll fine-tune the details in the following weeks; similarly, the
results will be ported to ttfautohint in the next days (which gets
then released as version 1.0).

HarfBuzz support, however, is only available in `devel mode' right
now, since full integration into FreeType needs a split of the
HarfBuzz library into two parts to avoid a chicken-and-egg problem.

If you want to test, simply say

  make devel
  make

from a clean git repository, then `make' within the `freetype2-demos'
repository.

Attached you can find two snapshots from `pala.ttf' in light hinting
mode, with and without HarfBuzz support.


    Werner


PS: Behdad, please check `hbshim.c' whether everything is OK.