[ft-devel] ttfautohint: twilight points

[Werner LEMBERG]

The last two days I've rewritten a large part of the bytecode in
ttfautohint to use twilight points for representing segments.

FreeType's autohinter treats segments as if they were a single point,
located in the middle of the maximum and minimum coordinate value.
The previous code in ttfautohint simplified this by using the first
point of a segment (pars pro toto), and its location was saved in a
storage area location.  However, the deviation compared to the
autohinter results was rather large.

I've now fixed this by properly computing the middle positions for
each segment, and I use two sets of twilight points to store these
representations: The first set holds the original coordinates, the
second one the hinted values.

The reason for this is that all twilight points are originally located
at (0,0), thus instructions like `MD[orig]' to access the original
coordinates would always refer to (0,0) which is not really helpful.

Unfortunately, I'm still behind my schedule, but there actually is a
lot of progress!

  http://repo.or.cz/w/ttfautohint.git


    Werner