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.
This monster commit was created by applying Nikhil's scripts
`docconverter.py' and `markify.py' to all C header and source files,
followed up by minor manual clean-up.
No change in functionality, of course.
I used commit f7419907bc6044b9b7057f9789866426c804ba82 from
https://github.com/nikramakrishnan/freetype-docs.git.
* include/freetype/internal/ftobjs.h (FT_Glyph_LayerRec): Move this
structure to...
* include/freetype/freetype.h (FT_Glyph_LayerRec): ... this
header file.
(FT_Glyph_Layer): New typedef.
Update code to use it where appropriate.
* src/base/ftobjs.c (FT_Get_GlyphLayers): New function.
* src/truetype/ttgload.c (TT_Load_Glyph): Free old `layers' array
before reassigning allocated memory.
Only allocate `color_layers' if we don't have one already.
* src/sfnt/ttcolr.c (tt_face_load_colr_layers): Return FT_Err_Ok if
current glyph is not a `COLR' base glyph.
* src/truetype/ttgload.c (TT_Load_Glyph): Don't allocate
`color_layers' if there are no color layers.
This commit enables OpenType's COLR/CPAL table handling; a typical
application are color emojis that can be scaled to any size.
If the color palette does not exist or is invalid, the rendering
step rasterizes the outline instead. The current implementation
assumes that the foreground is black.
Enable this by defining option TT_CONFIG_OPTION_COLOR_LAYERS.
There are still some issues with metrics; additionally, an API to
fetch color layers is missing.
* devel/ftoption.h, include/freetype/config/ftoption.h
(TT_CONFIG_OPTION_COLOR_LAYERS): New macro.
* include/freetype/internal/ftobjs.h (FT_Glyph_LayerRec,
FT_Colr_InternalRec): New structures.
(FT_Slot_InternalRec): Add `color_layers' field.
* include/freetype/internal/sfnt.h (TT_Load_Colr_Layer_Func,
TT_Blend_Colr_Func): New function types.
(SFNT_Interface): Add `load_colr', `free_colr', `load_colr_layer',
and `colr_blend' fields.
* include/freetype/internal/tttypes.h (TT_FaceRec): Add
`colr_and_cpal' field.
* include/freetype/internal/tttags. (TTAG_COLR, TTAG_CPAL): New
macros.
* src/sfnt/ttcolr.c, src/sfnt/ttcolr.h: New files.
* src/base/ftobjs.c (ft_glyphslot_done, FT_Render_Glyph_Internal):
Handle glyph color layers.
* src/sfnt/Jamfile (_sources), src/sfnt/rules.mk (SFNT_DRV_SRC): Add
`ttcolr.c'.
* src/sfnt/sfdriver.c: Include `ttcolr.h'.
(PUT_COLOR_LAYERS): New macro.
Update call to `FT_DEFINE_SFNT_INTERFACE'.
* src/sfnt/sfnt.c: Include `ttcolr.c'.
* src/sfnt/sfobjs.c (sfnt_load_face): Load `COLR' and `CPAL' tables.
(sfnt_done_face): Updated.
* src/truetype/ttgload.c (TT_Load_Glyph): Handle color layers.
*/* [FT_CONFIG_OPTION_PIC]: Remove all code guarded by this
preprocessor symbol.
*/*: Replace `XXX_GET' macros (which could be either a function in
PIC mode or an array in non-PIC mode) with `xxx' arrays.
* include/freetype/internal/ftpic.h, src/autofit/afpic.c,
src/autofit/afpic.h, src/base/basepic.c, src/base/basepic.h,
src/base/ftpic.c, src/cff/cffpic.c, src/cff/cffpic.h,
src/pshinter/pshpic.c, src/pshinter/pshpic.h, src/psnames/pspic.c,
src/psnames/pspic.h, src/raster/rastpic.c, src/raster/rastpic.h,
src/sfnt/sfntpic.c, src/sfnt/sfntpic.h, src/smooth/ftspic.c,
src/smooth/ftspic.h, src/truetype/ttpic.c, src/truetype/ttpic.h:
Removed.
* src/truetype/ttgxvar.c (ft_var_to_normalized): Don't emit number
of coordinates.
(TT_Get_MM_Var): Trace instance indices names.
(TT_Set_Var_Design): Updated.
Behdad reported that setting blend coordinates, then getting design
coordinates did incorrectly return the default instance's
coordinates.
* src/truetype/ttgxvar.c (tt_set_mm_blend): Fix it.
We exit early if the current design or blend coordinates are
identical to the new ones.
* src/truetype/ttgxvar.c (tt_set_mm_blend, TT_Set_Var_Design):
Implement it, returning internal error code -1 if there will be no
variation change.
* src/type1/t1load.c (t1_set_mm_blend): Ditto.
* src/base/ftmm.c (FT_Set_Var_Design_Coordinates,
FT_Set_MM_Blend_Coordinates, FT_Set_Var_Blend_Coordinates): Updated.
* src/truetype/ttgload.c (TT_Process_Simple_Glyph): Always adjust
`pp1' to `pp4', except if we have an HVAR and/or VVAR table.
* src/truetype/ttgxvar.c (TT_Vary_Apply_Glyph_Deltas): Handle
alternative code branch identically w.r.t. presence of an HVAR
and/or VVAR table.
This reduces redundancy and increases synergy; it also reduces the
number of header files.
* include/freetype/config/ftheader.h (FT_DRIVER_H): New macro.
(FT_AUTOHINTER_H, FT_CFF_DRIVER_H, FT_TRUETYPE_DRIVER_H,
FT_PCF_DRIVER_H, FT_TYPE1_DRIVER_H): Make them aliases to
FT_DRIVER_H.
* include/freetype/ftautoh.h, include/freetype/ftcffdrv.h,
include/freetype/ftpcfdrv.h, include/freetype/ftt1drv.h,
include/freetype/ftttdrv.h: Replaced with...
* include/freetype/ftdriver.h: ...this new file.
(FT_CFF_HINTING_ADOBE, FT_T1_HINTING_ADOBE): Renamed to...
(FT_HINTING_ADOBE): ... this new macro.
(FT_CFF_HINTING_FREETYPE, FT_T1_HINTING_FREETYPE): Renamed to...
(FT_HINTING_FREETYPE): ... this new macro.
* src/*/*: Updated accordingly.
Some static function declarations cause unused function warnings if
certain config options are turned off via `ftoption.h'.
* src/base/ftbase.h, src/base/ftrfork.c, src/sfnt/ttbdf.h,
src/truetype/ttgxvar.h: Add #ifdef guards around these sections.
