[truetype] In GX, make private point numbers work correctly.
This is completely missing in Apple's documentation: If a `gvar'
tuple uses private point numbers (this is, deltas are specified for
some points only), the uncovered points must be interpolated for
this tuple similar to the IUP bytecode instruction. Examples that
need this functionality are glyphs `Oslash' and `Q' in Skia.ttf.
* src/truetype/ttgxvar.c (tt_delta_shift, tt_delta_interpolate,
tt_handle_deltas): New functions.
(TT_Vary_Get_Glyph_Deltas): Renamed to...
(TT_Vary_Apply_Glyph_Deltas): ... this; it directly processes the
points and does no longer return an array of deltas.
Add tracing information.
Call `tt_handle_deltas' to interpolate missing deltas.
Also fix a minor memory leak in case of error.
* src/truetype/ttgxvar.h: Updated.
* src/truetype/ttgload.c (TT_Process_Simple_Glyph,
load_truetype_glyph): Updated.
4 files changed
