[truetype] Increase precision while applying VF deltas.
It turned out that we incorrectly round CVT and glyph point deltas
before accumulation, leading to severe positioning errors if there
are many delta values to sum up.
Problem reported by Akiem Helmling <akiem@underware.nl> and analyzed
by Behdad.
* src/truetype/ttgxvar.c (ft_var_readpackeddelta): Return deltas in
16.16 format.
(tt_face_var_cvt): Collect deltas in `cvt_deltas', which is a 16.16
format array, and add the accumulated values to the CVT at the end
of the function.
(TT_Vary_Apply_Glyph_Deltas): Store data in `points_org' and
`points_out' in 16.16 format.
Collect deltas in `point_deltas_x' and `point_deltas_y', which are
16.16 format arrays, and add the accumulated values to the glyph
coordinates at the end of the function.
2 files changed
