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.
* src/base/ftcalc.c (FT_Matrix_Check): New base function to properly
reject degenerate font matrices.
* include/freetype/internal/ftcalc.h: Updated.
* src/cff/cffparse.c (cff_parse_font_matrix), src/cid/cidload.c
(cid_parse_font_matrix), src/type1/t1load.c (t1_parse_font_matrix),
src/type42/t42parse.c (t42_parse_font_matrix): Use
`FT_Matrix_Check'.
Reported by Alexei.
* src/sfnt/ttcolr.c (tt_face_get_colr_layer): Return immediately if
`colr' is NULL.
* src/sfnt/ttcpal.c (tt_face_palette_set): Return immediately, if
`cpal' is NULL.
This function facilitates access to full capabilities of FreeType
rendering engine for custom glyphs. This can be quite useful for
consistent rendering of mathematical and chemical formulas, e.g.
https://bugs.chromium.org/p/chromium/issues/detail?id=757078
* include/freetype/ftglyph.h, src/base/ftglyph.c (FT_New_Glyph): New
function.
bdflib.c:1562 could be reached with `font->glyphs_used == 0'. That
caused an underflow of the unsigned value which results in undefined
behaviour.
* src/bdf/bdflib.c (src/bdf/bdflib.c): Bail out earlier than before
if the `ENCODING' keyword cannot be found.
Still missing: Support for negative bitmap pitch and subpixel offset
of source bitmap.
* include/freetype/ftbitmap.h, src/base/ftbitmap.c
(FT_Bitmap_Blend): New function.
This solution doesn't store any data in an `FT_GlyphSlot' object.
* include/freetype/freetype.h (FT_LayerIterator): New structure.
(FT_Get_Color_Glyph_Layer): New function.
* include/freetype/internal/sfnt.h (TT_Get_Colr_Layer_Func): New
function type.
(SFNT_Interface, FT_DEFINE_SFNT_INTERFACE): Add it.
* src/base/ftobjs.c (FT_Get_Color_Glyph_Layer): Implement it.
* src/sfnt/ttcolr.c (tt_face_get_colr_layer): New function.
* src/sfnt/ttcolr.h: Updated.
* src/sfnt/sfdriver.c (sfnt_interface): Updated.
* src/sfnt/sfdriver.c: Include `ttcpal.h'.
* src/sfnt/sfnt.c: Include `ttcpal.c'.
* src/sfnt/ttcolr.c, src/sfnt/ttcolr.h: Move CPAL stuff to ...
* src/sfnt/ttcpal.c, src/sfnt/ttcpal.c: ... these new files.
* src/sfnt/Jamfile (_sources), src/sfnt/rules.mk (SFNT_DRV_SRC):
Updated.
* include/freetype/internal/fttrace.h: Add support for `colr' and
`cpal'.
Sort entries.
* src/sfnt/ttcolr.c (tt_face_find_color): Removed.
(tt_face_colr_blend_layer): Use `face->palette' instead of calling
`tt_face_find_color'.
Use and set text foreground color.
* src/sfnt/ttcolr.c (tt_face_palette_set): New function.
(tt_face_load_colr): Allocate `face->palette' and call
`tt_face_palette_set'.
Adjust return error code in case of error.
* src/sfnt/ttcolr.h: Updated.
* include/freetype/internal/sfnt.h (TT_Set_Palette_Func): New
function type.
(SFNT_Interface, FT_DEFINE_SFNT_INTERFACE): Add it.
* src/sfnt/sfdriver.c (sfnt_interface), src/sfnt/sfobjs.c
(sfnt_done_face): Updated.
* src/raster/ftraster.c (black_TWorker, SCALED, Set_High_Precision):
Clean up after 5-level gray removal (8dc8635874).
(Vertical_Sweep_Span): Be brief.
Werner Lemberg