When points are not touched by gvar interpolation deltas, FreeType
gave a slightly different result than Apple's CoreText.
The OpenType working group will update the specification to document
the following behaviour: If the two points with deltas to the `left'
and `right' of the untouched point have the same coordinate, then
the inferred delta for the untouched point should be zero.
* src/truetype/ttgxvar.c (tt_delta_interpolate): Implement new
behaviour.
* src/truetype/ttobs.h (TT_SizeRec): Add field `hinted_metrics' to
hold hinted metrics.
Make `metrics' a pointer so that `tt_glyph_load' can easily switch
between metrics.
* src/truetype/ttdriver.c (tt_size_request): Updated.
(tt_glyph_load): Use top-level metrics if FT_LOAD_NO_HINTING is
used.
* src/truetype/ttgload.c (TT_Hint_Glyph, TT_Process_Simple_Glyph,
TT_Process_Composite_Component, load_truetype_glyph,
compute_glyph_metrics, TT_Load_Glyph): Updated.
* src/truetype/ttinterp.c (TT_Load_Context): Updated.
* src/truetype/ttobjs.c (tt_size_reset): Updated.
* src/truetype/ttsubpix.c (sph_set_tweaks): Updated.
Reported as
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=981
* include/freetype/fterrdef.h (FT_Err_DEF_In_Glyf_Bytecode): New
error code.
* src/truetype/ttinterp.c (Ins_FDEF, Ins_IDEF): Prohibit execution
of these two opcodes in `glyf' bytecode.
(TT_RunIns): Don't enforce reexecution of `fpgm' and `prep' bytecode
in case of error since function tables can no longer be modified
(due to the changes in `Ins_FDEF' and `Ins_IDEF'). This change can
enormously speed up handling of broken fonts.
* src/truetype/ttdriver.c (tt_size_request): Revert change from
2011-07-16; the intended metrics fix seems now to be implemented in
a different way, making the patch unnecessary. Note that this
change was usually patched out by all major GNU/Linux distributions
due to heavy side effects.
* src/truetype/ttgload.c (compute_glyph_metrics, TT_Load_Glyph):
Refer to the metrics of the `TT_Size' object.
At least on FreeBSD there is a global declaration of `index' in file
`/usr/include/strings.h'.
* src/cff/cf2intrp.c, src/truetype/ttgload.c: s/index/idx/ where
appropriate.
Too much local variables holding different structures were called
`metrics'.
* src/truetype/ttdriver.c (tt_size_select): s/metrics/size_metrics/.
* src/truetype/ttgload.c (tt_get_metrics_incr_overrids,
compute_glyph_metrics): s/metrics/incr_metrics/.
(load_sbit_image): s/metrics/sbit_metrics/.
* src/truetype/ttobjs.c (tt_size_run_fpgm): s/metrics/size_metrics/.
(tt_size_init_bytecode): s/metrics/tt_metrics/.
(tt_size_reset): s/metrics/size_metrics/.
We have to make a separate case for Windows 64's LLP64 data model.
* builds/unix/ftconfig.in, builds/vms/ftconfig.h,
include/freetype/config/ftconfig.h (FT_UINT_TO_POINTER): New macro.
* src/truetype/ttgload.c (load_truetype_glyph): Use it.
* src/autofit/afcjk.c, src/autofit/afindic.c: Include `afcjk.h'
earlier.
* src/sfnt/sfobjs.c (sfnt_init_face): Put `memory' variable into
TT_CONFIG_OPTION_GX_VAR_SUPPORT block.
(sfnt_done_face): Protect some code with
TT_CONFIG_OPTION_GX_VAR_SUPPORT.
* src/sfnt/ttsbit.c (tt_face_load_sbix_image): Remove compiler
warning.
* src/truetype/ttgload.c (TT_Load_Simple_Glyph): Put `tmp' variable
into TT_USE_BYTECODE_INTERPRETER block.
(tt_loader_init): Put `error' variable into
TT_USE_BYTECODE_INTERPRETER block.
Everything is guarded with TT_CONFIG_OPTION_GX_VAR_SUPPORT.
* include/freetype/internal/tttypes.h (TT_FaceRec): New fields
`var_postscript_prefix' and `var_postscript_prefix_len'.
* src/sfnt/sfdriver.c: Include FT_TRUETYPE_IDS_H.
(sfnt_is_alphanumeric): New wrapperfunction for `ft_isalnum'.
(get_win_string, get_apple_string): Remove `const' from return
value.
(MAX_VALUE_DESCRIPTOR_LEN, MAX_PS_NAME_LEN): New macros.
(hexdigits): New array.
(sfnt_get_var_ps_name): New function, implementing Adobe TechNote
5902 to construct a PS name for a variation font instance.
(sfnt_get_ps_name): Call `sfnt_get_var_ps_name' for font instances.
* src/sfnt/sfobjs.c (sfnt_done_face): Updated.
* src/truetype/ttgxvar.c (tt_set_mm_blend): Reset
`face->postscript_name' to trigger recalculation for new instance
parameters.
* include/freetype/internal/services/svmm.h (FT_Get_Var_Blend_Func):
Add `normalizedcoords' argument.
* src/truetype/ttgxvar.h (GX_BlendRec): Add `coords' field to store
the design coordinates of the current instance.
Updated.
* src/truetype/ttgxvar.c (TT_Set_MM_Blend): Move functionality to...
(tt_set_mm_blend): ... New function.
Convert data in `normalizedcoords' array to `coords' array on
demand.
(TT_Set_Var_Design): Store argument data in `coords' array.
(TT_Get_Var_Design): Get data from `coords' array.
(tt_get_var_blend): Updated.
(tt_done_blend): Updated.
* src/cff/cffload.c, src/cff/cffload.h (cff_get_var_blend): Updated.
* src/cff/cf2ft.c (cf2_getNormalizedVector): Updated.
* src/cff/cffobjs.c (cff_face_init): Updated.
As documented in the OpenType specification, an entry for the
default instance may be omitted in the named instance table. In
particular this means that even if there is no named instance table
in the font we actually do have a named instance, namely the default
instance.
For consistency, we always want the default instance in our list of
named instances. If it is missing, we try to synthesize it.
* src/sfnt/sfobjs.c (sfnt_init_face): Check whether the default
instance is in the table of named instances. Otherwise adjust
number of instances.
* src/truetype/ttgxvar.c: Include FT_TRUETYPE_IDS_H.
(TT_Get_MM_Var): Use `face->root.style_flags' as the number of named
instances.
Sythesize a named instance entry if necessary.
(tt_done_blend): Free `normalized_stylecoords'.
* src/truetype/ttgxvar.h (GX_HVarTable): Renamed to...
(GX_HVVarTable): ...This.
(GX_Blend): Add fields for `VVAR' table handling.
Other minor updates.
* src/truetype/ttgxvar.c (ft_var_load_hvar): Renamed to...
(ft_var_load_hvvar): ...This.
Handle VVAR loading also (controlled by an additional parameter).
(tt_hadvance_adjust): Renamed to...
(tt_hvadvance_adjust): ...This.
Handle application of advance height also (controlled by an
additional parameter).
(tt_hadvance_adjust, tt_vadvance_adjust): Wrappers for
`tt_hvadvance_adjust'.
* src/truetype/ttdriver.c (tt_service_metrics_variations): Updated.
* src/truetype/ttgxvar.h (GX_MVarTable): `axisCount' has been
removed frem the specification; it is now reserved.
* src/truetype/ttgxvar.c (ft_var_load_mvar): Updated.
(GX_FVar_Head): Remove `countSizePairs'; the corresponding data
field in the `MVAR' table is now reserved.
(fvar_fields): Updated.
* src/base/ftmm.c: Include FT_SERVICE_METRICS_VARIATIONS_H.
(ft_face_get_mvar_service): New auxiliary function to look up
metrics variation service.
(FT_Set_Var_Design_Coordinates, FT_Set_MM_Blend_Coordinates,
FT_Set_Var_Blend_Coordinates): Call metrics variation service.
* src/truetype/ttobjs.c (tt_face_init): Use metrics variations for
named instances.
* src/truetype/ttgxvar.h (MVAR_TAG_XXX): New macros for MVAR tags.
(GX_Value, GX_MVarTable): New structures.
(GX_Blend): Add it.
* src/truetype/ttgxvar.c (GX_VALUE_SIZE, GX_VALUE_CASE,
GX_GASP_CASE): New macros.
(ft_var_get_value_pointer): New auxiliary function to get a pointer
to a value from various SFNT tables already stored in `TT_Face'.
(ft_var_load_mvar): New function.
(TT_Get_MM_Var): Call it.
(tt_done_blend): Updated.
* src/truetype/ttobjs.c (tt_size_reset): Add argument to make
function only recompute ascender, descender, and height.
* src/truetype/ttobjs.h: Updated.
* src/truetype/ttdriver.c (tt_size_select, tt_size_request):
Updated.
We need this later on for MVAR also.
* src/truetype/ttgxvar.c (tt_hadvance_adjust): Split off computing
an item store variation delta into...
(ft_var_get_item_delta): ...new function.
We need this later on for MVAR also.
* src/truetype/ttgxvar.c (tt_done_blend): Split off handling of item
variation store into...
(ft_var_done_item_variation_store): ...new function.
We need this later on for MVAR also.
* src/truetype/ttgxvar.c (ft_var_load_delta_set_index_mapping): Add
parameters for delta-set index mapping and item variation store.
(ft_var_load_item_variation_store): Add parameter for item variation
store.
s/hvarData/varData/.
Move allocation of `hvar_table' to...
(ft_var_load_hvar): ...this function.
Updated.
* src/truetype/ttgxvar.c (): Split off loading of item variation
store and delta set index mapping into...
(ft_var_load_item_variation_store,
ft_var_load_delta_set_index_mapping): ... new functions.
* src/truetype/ttgxvar.c (ft_var_load_hvar): Handle case where
`offsetToAdvanceWidthMapping' is zero.
(tt_hadvance_adjust): Implement direct deltaSet access by glyph
index.
* src/truetype/ttgload.c (TT_Load_Simple_Glyph): Check instruction
size only if we do native hinting.
(TT_Load_Glyph): Trace returned error code.
* src/truetype/ttobjs.c (tt_size_run_fpgm, tt_size_run_prep): Trace
returned error code.
(tt_size_ready_bytecode): Don't run `prep' table if `fpgm' table is
invalid.
* src/cff/cffload.c (FT_fdot14ToFixed): Fix casting.
(cff_blend_doBlend): Don't left-shift negative numbers.
Handle 5-byte numbers byte by byte to avoid alignment issues.
* src/cff/cffparse.c (cff_parse): Handle 5-byte numbers byte by byte
to avoid alignment issues.
* src/cid/cidload (cid_read_subrs): Do nothing if we don't have any
subrs.
* src/psaux/t1decode.c (t1_decode_parse_charstring): Fix tracing.
* src/tools/glnames.py (main): Put `DEFINE_PSTABLES' guard around
definition of `ft_get_adobe_glyph_index'.
* src/psnames/pstables.h: Regenerated.
* src/psnames/psmodule.c: Inlude `pstables.h' twice to get both
declaration and definition.
* src/truetype/ttgxvar.c (FT_fdot14ToFixed, FT_intToFixed): Fix
casting.
Make some functions work before a call to `TT_Set_MM_Blend'.
* src/truetype/ttgxvar.c (tt_hadvance_adjust): Exit immediately if
we don't blend.
(TT_Get_MM_Blend, TT_Get_Var_Design): Return default values if we
don't blend.
* src/cff/cffdrivr.c: Don't include
`FT_SERVICE_METRICS_VARIATIONS_H'.
(cff_get_advances): Use `ttface->variation_support'.
* src/truetype/ttdriver.c (tt_get_advances): Use
`ttface->variation_support'.
* src/truetype/ttgload.c (TT_Process_Simple_Glyph,
load_truetype_glyph): Use `ttface->variation_support'.
* include/freetype/internal/tttypes.h (TT_FACE_FLAG_VAR_XXX):
New macros describing available functionality of various OpenType
tables related to font variation.
(TT_Face): New fields `variation_support' and `mvar_support',
replacing and extending `use_fvar'.
* src/sfnt/sfobjs.c (sfnt_init_face, sfnt_load_face): Use
`variation_support'.
* src/truetype/ttgxvar.c (ft_var_load_hvar): Set `variation_support'
field.
(TT_Vary_Apply_Glyph_Deltas): Updated.
* src/cff/cffdrivr.c (cff_get_advances), src/truetype/ttdriver.c
(tt_get_advances): Use `is_default_instance' for test; this gets
recomputed after changing blend coordinates.
When asking for an unhinted non-default variations,
`linearVertAdvance' is currently the value from the `hmtx' table
instead of the actual value after applying the variation. `HVAR'
support fixes this, but fonts will exist without that table and will
need sane fallback.
* src/truetype/ttgload.c (TT_Process_Simple_Glyph,
load_truetype_glyph): Implement linear advance adjustments if `HVAR'
or `VVAR' tables are missing.
Everything is guarded with TT_CONFIG_OPTION_GX_VAR_SUPPORT.
* src/base/ftadvanc.c (LOAD_ADVANCE_FAST_CHECK): Don't handle MM.
* src/cff/cffdrivr.c: Include FT_SERVICE_METRICS_VARIATIONS_H.
(cff_get_advances): Test for HVAR and VVAR.
* src/truetype/ttdriver.c (tt_get_advances): Test for HVAR and VVAR.
In particular, we need access to named instance data.
* include/freetype/internal/services/svmm.h (FT_Get_Var_Blend_Func):
Add argument for `FT_MM_Var'.
* src/cff/cffload.c (cff_get_var_blend): Updated.
* src/cff/cffload.h: Updated.
* src/cff/cf2ft.c (cf2_getNormalizedVector): Updated.
* src/truetype/ttgxvar.c (tt_get_var_blend): Updated.
Accept value `NULL' for arguments.
* src/truetype/ttgxvar.h: Updated.
This is better behaviour than exiting with an error.
* include/freetype/internal/tttypes.h (TT_Face): Add `use_fvar'
field.
* src/sfnt/sfobjs.c (sfnt_init_face): Compute `use_fvar', also
updating the validation code.
Use `use_fvar' to compute FT_FACE_FLAG_MULTIPLE_MASTERS.
* src/truetype/ttgxvar.c (TT_Get_MM_Var): Remove `fvar' validation
code.
* include/freetype/internal/tttypes.h (TT_Face): Move
`is_default_instance' into TT_CONFIG_OPTION_GX_VAR_SUPPORT
block.
* src/sfnt/sfobjs.c (sfnt_init_face): Updated.
* src/truetype/ttgload.c (IS_DEFAULT_INSTANCE): New macro.
(TT_Load_Glyph): Use it.
* src/sfnt/sfobjs.c (sfnt_init_face): If the axis count in `fvar' is
zero, set `num_instances' to zero.
* src/truetype/ttgxvar.c (TT_Get_MM_Var): Handle `fvar' table with
zero axes as invalid.
* src/truetype/ttobjs.c (tt_face_init): Improve logic of loading
`loca', `cvt', `fpgm', and `prep' table.
* src/cff/cf2font.h: Include `cffload.h'.
* src/cff/cffload.c: Include FT_MULTIPLE_MASTERS_H and
FT_SERVICE_MULTIPLE_MASTERS_H.
(cff_vstore_load): Eliminate `vsSize'.
(cff_load_private_dict): Tag as `FT_LOCAL_DEF'.
* src/cff/cffload.h: Include `cffobjs.h'.
Provide declaration for `cff_load_private_dict'.
* src/truetype/ttgxvar.c (ft_var_load_hvar): Eliminate
`minorVersion' and `map_offset'.
The font variation code. All parts dependent on the GX code in the
`truetype' module are guarded with TT_CONFIG_OPTION_GX_VAR_SUPPORT.
In other words, you can still compile the `cff' module without
defining TT_CONFIG_OPTION_GX_VAR_SUPPORT (which brings you CFF2
support without font variation).
* src/cff/cf2font.c (cf2_font_setup): Add support for font
variation.
* src/cff/cf2font.h (CF2_Font): Add fields for variation data.
* src/cff/cf2ft.c (cf2_free_instance): Free blend data.
(cf2_getVStore, cf2_getNormalizedVector): New functions.
* src/cff/cf2ft.h: Updated.
* src/cff/cf2intrp.c: Include `cffload.h'.
(cf2_cmdRESERVED_15, cf2_cmdRESERVED_16): Replace with...
(cf2_cmdVSINDEX, cf2_cmdBLEND): ... this new enum values.
(cf2_doBlend): New function.
(cf2_interpT2CharString): Handle `vsindex' and `blend' opcodes.
* src/cff/cffload.c (FT_fdot14ToFixed): New macro.
(cff_vstore_done, cff_vstore_load): New functions.
(cff_blend_clear, cff_blend_doBlend, cff_blend_build_vector,
cff_blend_check_vector): New functions.
(cff_load_private_dict): Add arguments for blend vector.
Handle blend data.
(cff_subfont_load, cff_subfont_done): Updated.
(cff_font_load): Handle CFF2 variation store data.
(cff_font_done): Updated.
* src/cff/cffload.h: Include `cffparse.h'.
Updated.
* src/cff/cffobjs.c (cff_face_done): Updated.
* src/cff/cffparse.c: Include `cffload.h'.
(cff_parse_num): Handle internal value 255.
(cff_parse_vsindex, cff_parse_blend): New functions.
(CFF_FIELD_BLEND): New macro.
(cff_parser_run): Updated.
* src/cff/cffparse.h (cff_kind_blend): New enum value.
* src/cff/cfftoken.h: Handle `vstore', `vsindex', and `blend'
dictionary values.
* src/cff/cfftypes.h (CFF_VarData, CFF_AxisCoords, CFF_VarRegion,
CFF_VStore, CFF_Blend): New structures.
(CFF_FontRecDict): Add `vstore_offset' field.
(CFF_Private): Add `vsindex' field.
(CFF_SubFont): Add fields for blend data.
(CFF_Font): Add `vstore' field.
* src/truetype/ttgxvar.c (TT_Get_MM_Var): `CFF2' is equal to `gvar',
since glyph variation data is directly embedded.
(TT_Set_MM_Blend): Don't load `gvar' table for CFF2 fonts.
Note that this is not complete yet; it only handles advance width
variation.
Activation of the code follows in another commit.
* include/freetype/ftmm.h (FT_Var_Named_Style): Add `psid' member.
* src/truetype/ttgxvar.h (GX_HVarData, GX_AxisCoords, GX_HVarRegion,
GX_HVStore, GX_WidthMap): New auxiliary structures for...
(GX_HVarTable): ... HVAR main structure.
(GX_BlendRec): Add data for HVAR loading.
* src/truetype/ttgxvar.c (FT_FIXED_ONE, FT_fdot14ToFixed,
FT_intToFixed, FT_fixedToInt): New macros.
(ft_var_load_hvar): New function.
(TT_Get_MM_Var): Updated.
(tt_done_blend): Deallocate HVAR data.
No effect yet; service functions will be implemented later on.
Everything is guarded with TT_CONFIG_OPTION_GX_VAR_SUPPORT.
* include/freetype/internal/services/svmetric.h: New file.
* include/freetype/internal/ftserv.h
(FT_SERVICE_METRICS_VARIATIONS_H): New macro.
* include/freetype/internal/tttypes.h (TT_Face): New field `var'.
* src/sfnt/sfobjs.c: Include FT_SERVICE_METRICS_VARIATIONS_H.
(sfnt_init_face): Initialize `face->var'.
* src/truetype/ttdriver.c: Include FT_SERVICE_METRICS_VARIATIONS_H.
(tt_service_metrics_variations): New service.
(tt_services): Updated.
* src/truetype/ttpic.h: Updated.
For internal use; we want to share code between the forthcoming CFF2
support and TrueType.
* include/freetype/internal/services/svmm.h (FT_Get_Var_Blend_Func):
New typedef.
(MultiMasters): Add `get_var_blend'.
(FT_Service_MultiMasters): Updated.
* src/truetype/ttgxvar.c (tt_get_var_blend): New function.
* src/truetype/ttgxvar.h: Updated.
* src/truetype/ttdriver.c (tt_service_gx_multi_masters): Updated.
* src/type1/t1driver.c (t1_service_multi_masters): Updated.
For internal use; we want to share code between the forthcoming CFF2
support and TrueType.
* include/freetype/internal/services/svmm.h (FT_Done_Blend_Func):
New typedef.
(MultiMasters): Add `done_blend'.
(FT_Service_MultiMasters): Updated.
* src/truetype/ttgxvar.c (tt_done_blend): Use `TT_Face' as argument.
* src/truetype/ttgxvar.h: Updated.
* src/truetype/ttobjs.c (TT_Face_Done): Updated.
* src/truetype/ttdriver.c (tt_service_gx_multi_masters): Updated.
* src/type1/t1driver.c (t1_service_multi_masters): Updated.
Note that the low-level functions aren't implemented yet.
* include/freetype/ftmm.h: Declare.
* include/freetype/internal/services/svmm.h
(FT_Get_Var_Design_Func): New typedef.
(MultiMasters): New MM service function `get_var_design'.
(FT_DEFINE_SERVICE_MULTIMASTERSREC): Updated.
Update all callers.
* src/base/ftmm.c (FT_Get_Var_Design_Coordinates): Implement.
* src/truetype/ttdriver.c: Updated.
* src/truetype/ttgxvar.c (TT_Get_Var_Design): New dummy function to
handle `get_var_design' service.
* src/truetype/ttgxvar.h: Updated.
* src/type1/t1driver.c: Updated.
* src/type1/t1load.c (T1_Get_Var_Design): New dummp function to
handle `get_var_design' service.
* src/type1/t1load.h: Updated.
This is required by OpenType 1.8; it also avoids rounding surprises.
* src/truetype/ttgxvar.c (TT_Set_Var_Design): Clamp design coordinates
outside of the allowed range to always stay within the range instead
of producing an error.
* src/truetype/ttinterp.h (TT_ExecContextRec): Using `FT_ULong' for
loop counter handling.
* src/truetype/ttinterp.c: Updated.
(Ins_SCANTYPE): Use signed constant.
(TT_RunIns): Ensure `num_twilight_points' is 16bit.
* include/freetype/ftmm.h: Declare.
* include/freetype/internal/services/svmm.h (FT_Get_MM_Blend_Func):
New typedef.
(MultiMasters): New MM service function `get_mm_blend'.
(FT_DEFINE_SERVICE_MULTIMASTERSREC): Updated.
Update all callers.
* src/base/ftmm.c (FT_Get_MM_Blend_Coordinates,
FT_Get_Var_Blend_Coordinates): Implement.
* src/truetype/ttdriver.c: Updated.
* src/truetype/ttgxvar.c (TT_Get_MM_Blend): New function to handle
`get_mm_blend' service.
* src/truetype/ttgxvar.h: Updated.
* src/type1/t1driver.c: Updated.
* src/type1/t1load.c (T1_Get_MM_Blend): New function to handle
`get_mm_blend' service.
* src/type1/t1load.h: Updated.
* docs/CHANGES: Document.
This avoids additional calls to `tt_face_lookup_table' for the
`glyf' table, which can be expensive.
* include/freetype/internal/tttypes.h (TT_LoaderRec): Move
`glyf_offset' field to ...
(TT_FaceRec): ... this structure.
* src/truetype/ttgload.c (load_truetype_glyph): Updated.
(tt_loader_init): Move initialization of `glyf_offset' to ...
* src/truetype/ttpload.c (tt_face_load_loca): .. this function.
This speeds up FreeType's handling of malformed fonts.
* src/truetype/ttinterp.c (TT_RunIns): Set up limits for the number
of twilight points, the total number of negative jumps, and the
total number of loops in LOOPCALL opcodes. The values are based on
the number of points and entries in the CVT table.
(Ins_JMPR): Test negative jump counter.
(Ins_LOOPCALL): Test loopcall counter.
* src/truetype/ttinterp.h (TT_ExecContext): Updated.
* docs/CHANGES: Updated.
Without this patch, a loca sequence like `0 100000 0 100000 ...',
where value 100000 is larger than the `glyf' table size, makes
FreeType handle the whole `glyf' table as a single glyph again and
again, which is certainly invalid (and can be very slow, too).
* src/truetype/ttpload.c (tt_face_get_location): Implement.
Improve tracing messages.
Problems reported as
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=40
We now map the strike index right before accessing the physical
data, not earlier.
* src/sfnt/sfobjs.c (sfnt_load_face): Set `face->sbit_strike_map'
after creating the map so that...
* src/sfnt/ttsbit.c (tt_face_load_strike_metrics): ... this function
can be used before and after setting up `sbit_strike_map'.
(tt_face_set_sbit_strike): Revert change.
(tt_sbit_decoder_init, tt_face_load_sbix_image): Map strike index.
* src/truetype/ttdriver.c (tt_size_select): Revert change.
FreeType tries to sanitize strike header data; we now reject
completely broken ones.
* include/freetype/internal/tttypes.h (TT_FaceRec): New
`sbit_strike_map' array pointer.
* src/base/ftobjs.c (FT_Match_Size): Reject matches where either
width or height would be zero.
Add tracing message in case of error.
* src/sfnt/sfobjs.c (sfnt_load_face): Populate `sbit_strike_map',
only using (more or less) valid strike header data for
FT_Face's `available_sizes' array.
(sfnt_done_face): Updated.
* src/sfnt/ttsbit.c (tt_face_set_sbit_strike): Use
`sbit_strike_map'.
(tt_face_load_strike_metrics): Improve tracing.
* src/truetype/ttdriver.c (tt_size_select): Use `sbit_strike_map'.
Problems reported by Bob Taylor <Bob.Taylor@monotype.com>.
* src/truetype/ttgxvar.c (TT_Vary_Apply_Glyph_Deltas): Fix rough
sanity test for glyph variation array header size.
Always set stream position before reading packed x and y deltas.
Fix thinko w.r.t. `localpoints' array.
Since 2016-05-16 we detect infinite recursion directly.
* src/sfnt/ttload.c (tt_face_load_maxp): Don't adjust
`maxComponentDepth'.
* src/truetype/ttgload.c (load_truetype_glyph): Don't abort if
`maxComponentDepth' is not valid. Instead, simply adjust its value
and emit a tracing message.
To match the logic in FDEF. The value of the end is only used for
bound-checking in `Ins_JMPR', so it may not have been obvious that
it was not recorded. Tested (as part of Font Validator 2.0) all the
fonts on Fedora and did not see any change.
* src/truetype/ttinterp.c (Ins_IDEF): Updated.
GETDATA[], opcode 0x92
bytecode instruction. It always returns 17, and we have absolutely
no idea what it is good for...
* src/truetype/ttinterp.c (Pop_Push_Count, opcode_name): Updated.
(Ins_GETDATA): New function.
(TT_RunIns): Add it.
This commit implements undocumented (but confirmed) stuff from
Apple's old bytecode engine.
GETVARIATION[], opcode 0x91
This opcode pushes normalized variation coordinates for all axes
onto the stack (in 2.14 format). Coordinate of first axis gets
pushed first.
GETINFO[], selector bit 3
If GX variation support is enabled, bit 10 of the result is set
to 1.
* src/truetype/ttinterp.c: Include FT_MULTIPLE_MASTERS_H.
(opcode_name) [TT_CONFIG_OPTION_GX_VAR_SUPPORT]: Updated.
(Ins_GETINFO) [TT_CONFIG_OPTION_GX_VAR_SUPPORT]: Handle selector
bit 3, checking support for variation glyph hinting.
(Ins_GETVARIATION) [TT_CONFIG_OPTION_GX_VAR_SUPPORT]: New function
to implement opcode 0x91.
(TT_RunIns) [TT_CONFIG_OPTION_GX_VAR_SUPPORT]: Handle opcode 0x91.
This finally fixes the rendering of the cyclist and the lizard in
the `Zycon' font.
* src/truetype/ttgxvar.c (ft_var_readpackedpoints): `first' point
index is always cumulative.
(tt_handle_deltas): Rename to...
(tt_interpolate_deltas): ... This.
Add new parameter for output point array.
Update caller.
(TT_Vary_Apply_Glyph_Deltas): Add `points_out' array; it now holds
the intermediate results of `tt_interpolate_deltas' that are to be
added to `outline->points'.
The coordinates of the base font should be used for interpolation
purposes, NOT the current points (i.e., the result of accumulation
of previous deltas).
* src/truetype/ttgxvar.c (TT_Vary_Apply_Glyph_Deltas): Initialize
`points_org' before looping over all tuples.
This commit covers the most important one.
* src/autofit/afmodule.c (af_property_set): Handle `warping',
`darkening-parameters', and `no-stem-darkening'.
* src/cff/cffdrivr.c (cff_property_set): Handle
`darkening-parameters', `hinting-engine', and `no-stem-darkening'.
* src/truetype/ttdriver.c (tt_property_set): Handle
`interpreter-version'.
This is a preparation for handling an `FREETYPE_PROPERTIES'
environment variable to control (some) driver properties.
No change in functionality.
* src/base/ftobjs.c (ft_property_do): Add `value_is_string'
parameter.
(ft_property_string_set): New function.
(FT_Property_Set, FT_Property_Get): Updated.
* include/freetype/internal/ftobjs.h: Updated.
* include/freetype/internal/services/svprop.h
(FT_Properties_SetFunc): Add `value_is_string' parameter.
* src/autofit/afmodule.c (af_property_set), src/cff/cffdrivr.c
(cff_property_set), src/truetype/ttdriver.c (tt_property_set):
Updated, emitting an error currently if `value_is_string' is set.
* src/truetype/ttinterp.c (Ins_SHPIX): Allow SHPIX to move points in
the twilight zone. Otherwise, treat SHPIX the same as DELTAP.
Unbreaks various fonts such as older versions of Rokkitt and DTL
Argo T Light that would glitch severly after calling ALIGNRP after a
blocked SHPIX.
This patch prepares data structures and the like.
See added comments in `ttinterp.h' for more information on this and
the following commits in the series.
* devel/ftoption.h, include/freetype/config/ftoption.h
(TT_CONFIG_OPTION_SUBPIXEL_HINTING): Assign values to differentiate
between subpixel versions.
(TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY,
TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL): New macros.
* include/freetype/ftttdrv.h (TT_INTERPRETER_VERSION_40): New macro.
* include/freetype/internal/tttypes.h (TT_FaceRec): Updated.
* src/truetype/ttinterp.h (TT_ExecContextRec): Define new fields
`subpixel_hinting_lean', `vertical_lcd_lean',
`backwards_compatibility', `iupx_called', iupy_called', and
`grayscale_cleartype' for new hinting mode.
* src/truetype/ttdriver.c (tt_property_set): Handle v38 and v40
interpreters conditionally.
* src/truetype/ttgload.c (TT_Hint_Glyph): Save phantom points unless
in v38 backwards compatibility mode.
Updated.
(compute_glyph_metrics): Add v38 backwards compatibility mode
constraint for adjusting advance widths.
Updated.
(tt_loader_init): Handle new flags `subpixel_hinting_lean',
`grayscale_cleartype', and `vertical_lcd_lean'.
Updated.
(tt_get_metrics, TT_Process_Simple_Glyph, TT_LOADER_SET_PP):
Updated.
* src/truetype/ttobjs.c (tt_driver_init): Conditionally set
default interpreter version number.
* src/truetype/ttsubpix.c, src/truetype/ttsubpix.h: Updated.
The previous fix for #46372 misunderstood a composite glyph referring
same component twice as a recursive reference. See the discussion
http://lists.gnu.org/archive/html/freetype/2016-05/msg00000.html
Thanks to Khaled Hosny for finding this issue.
* src/truetype/ttgload.c (ft_list_get_node_at): A function to get
the i-th node from FT_List. (load_truetype_glyph): In the traversal
scan of the reference tree in the composite glyph, we clear the
nodes filled by previous sibling chain.
Otherwise some properties could be set to arbitrary values, which is
harmless, but querying could give wrong positive results.
* src/cff/cffdrivr.c (cff_property_set) [hinting-engine],
* src/truetype/ttdriver.c (tt_property_set) [interpreter-version]:
Only allow defined values.
We probably did not notice this as all fonts we tested had only
tuple_coords[i] be +1 or -1 for non-intermediate tuples.
* src/truetype/ttgxvar.c (ft_var_apply_tuple): Implement it.
* include/freetype/internal/tttypes.h (TT_LoaderRec): New field
`composites'.
* src/truetype/ttgload.c: Include FT_LIST_H.
(load_truetype_glyph): Add composite subglyph index to a list;
abort if index is already in list.
(tt_loader_init): Updated.
(tt_loader_done): New function.
(TT_Load_Glyph): Call `tt_loader_done'.
Use the `gvar' table size instead of the remaining bytes in the
stream.
* src/truetype/ttgxvar.h (GX_BlendRec): New field `gvar_size'.
* src/truetype/ttgxvar.c (ft_var_load_gvar): Set `gvar_size'.
(ft_var_readpackedpoints, ft_var_readpackeddeltas: New argument
`size'.
(tt_face_vary_cvt, TT_Vary_Apply_Glyph_Deltas): Updated.
These tests should mainly help avoid unnecessarily large memory
allocations in case of malformed fonts.
* src/truetype/ttgxvar.c (ft_var_readpackedpoints,
ft_var_readpackeddeltas): Check number of points against stream
size.
(ft_var_load_avar): Check `pairCount' against table length.
(ft_var_load_gvar): Check `globalCoordCount' and `glyphCount'
against table length.
(tt_face_vary_cvt): Check `tupleCount' and `offsetToData'.
Fix trace.
(TT_Vary_Apply_Glyph_Deltas): Fix trace.
Free `sharedpoints' to avoid memory leak.
For functions querying a face, bits 16-30 of the face index can hold
the named instance index if we have a GX font. The indices start
with value 1; value 0 indicates font access without GX variation
data.
* include/freetype/freetype.h (FT_FaceRec): Update documentation.
* include/freetype/internal/sfnt.h: Ditto.
* src/sfnt/sfobjs.c (sfnt_init_face)
[TT_CONFIG_OPTION_GX_VAR_SUPPORT]: Get number of named instances and
do argument checks.
(sfnt_load_face): Updated.
* src/truetype/ttobjs.c (tt_face_init)
[TT_CONFIG_OPTION_GX_VAR_SUPPORT]: Use named instance, overwriting
the style name.
* src/base/ftobjs.c (open_face_from_buffer,
open_face_PS_from_sfnt_stream): Updated.
* src/bdf/bdfdrivr.c (BDF_Face_Init): Updated.
* src/cff/cffload.c (cff_font_load): Updated.
* src/cff/cffobjs.c (cff_face_init): Make function exit early for
pure CFF fonts if `font_index < 0'.
Updated.
* src/cid/cidobjs.c (cid_face_init): Updated.
* src/pcf/pcfdrivr.c (PCF_Face_Init): Updated.
* src/pfr/pfrobjs.c (pfr_face_init): Updated.
* src/type1/t1objs.c (T1_Face_Init): Updated.
* src/type42/t42objs.c (T42_Face_Init): Updated.
* src/winfonts/winfnt.c (fnt_face_get_dll_font, FNT_Face_Init):
Updated.
* docs/CHANGES: Updated.
* src/pfr/pfrgload.c (pfr_glyph_load_compound): Use multiplication,
not left-shift.
* src/truetype/ttgxvar.c (ft_var_load_avar, ft_var_load_gvar,
tt_face_vary_cvt, TT_Vary_Apply_Glyph_Deltas): Use multiplication,
not left-shift.
* src/base/ftrfork.c (FT_Raccess_Get_HeaderInfo): Only accept
positive values from header.
Check overflow.
* src/base/ftoutln.c (SCALED): Correctly handle left-shift of
negative values.
* src/bdf/bdf.h (_bdf_glyph_modified, _bdf_set_glyph_modified,
_bdf_clear_glyph_modified): Use unsigned long constant.
* src/bdf/bdfdrivr.c (BDF_Size_Select, BDF_Glyph_Load): Don't
left-shift values that can be negative.
* src/pcf/pcfdrivr.c (PCF_Size_Select, PCF_Glyph_Load): Don't
left-shift values that can be negative.
* src/raster/ftraster.c (SCALED): Correctly handle left-shift of
negative values.
* src/sfnt/ttsbit.c (tt_face_load_strike_metrics): Don't left-shift
values that can be negative.
* src/truetype/ttgload.c (TT_Load_Composite_Glyph,
compute_glyph_metrics, load_sbit_image): Don't left-shift values
that can be negative.
See
http://lists.nongnu.org/archive/html/freetype-devel/2015-07/msg00008.html
for a rationale.
* src/autofit/afpic.h, src/base/basepic.h, src/cff/cffpic.h,
src/pshinter/pshpic.h, src/psnames/pspic.h, src/raster/rastpic.h,
src/sfnt/sfntpic.h, src/smooth/ftspic.h, src/truetype/ttpic.h
(FT_BEGIN_HEADER, FT_END_HEADER): Move macro calls to not enclose
header files that contain FT_{BEGIN,END}_HEADER macros by
themselves.
* src/autofit/aftypes.h [FT_DEBUG_AUTOFIT]: Include
FT_CONFIG_STANDARD_LIBRARY_H earlier.
* src/truetype/ttpic.h: Include FT_INTERNL_PIC_H.
This is just very basic stuff and just a little bit tested on
GNU/Linux only. I won't delve into this since I'm not a Jam user.
* Jamfile: Call `HDRMACRO' for `ftserv.h' also.
(DEFINES): Replace with...
(CCFLAGS): ... this.
* src/Jamfile: Don't call `HDRMACRO' for `internal.h'; this is
already handled in the top-level Jamfile.
* src/autofit/Jamfile (DEFINES): Replace with...
(CCFLAGS): ... this.
(_sources): Add missing files.
* src/cache/Jamfile: Don't call `HDRMACRO' for `ftcache.h'; it no
longer contains macro header definitions.
* src/base/Jamfile, src/cff/Jamfile, src/sfnt/Jamfile,
src/truetype/Jamfile (_sources): Add missing files.
=======================
Tag sources with `VER-2-6'.
* docs/VERSION.DLL: Update documentation and bump version number to
2.6.
* README, Jamfile (RefDoc), builds/windows/vc2005/freetype.vcproj,
builds/windows/vc2005/index.html,
builds/windows/vc2008/freetype.vcproj,
builds/windows/vc2008/index.html,
builds/windows/vc2010/freetype.vcxproj,
builds/windows/vc2010/index.html,
builds/windows/visualc/freetype.dsp,
builds/windows/visualc/freetype.vcproj,
builds/windows/visualc/index.html,
builds/windows/visualce/freetype.dsp,
builds/windows/visualce/freetype.vcproj,
builds/windows/visualce/index.html,
builds/wince/vc2005-ce/freetype.vcproj,
builds/wince/vc2005-ce/index.html,
builds/wince/vc2008-ce/freetype.vcproj,
builds/wince/vc2008-ce/index.html: s/2.5.5/2.6/, s/255/26/.
* include/freetype/freetype.h (FREETYPE_MINOR): Set to 6.
(FREETYPE_PATCH): Set to 0.
* builds/unix/configure.raw (version_info): Set to 18:0:12.
* CMakeLists.txt (VERSION_MINOR): Set to 0.
(VERSION_PATCH): Set to 6.
* src/autofit/afmodule.c [!FT_MAKE_OPTION_SINGLE_OBJECT]: Add
declarations for dumping functions.
* src/truetype/ttinterp.c (TT_New_Context): Pacify compiler.
* builds/toplevel.mk: Use `freetype.mk's code to compute the version
string.
Don't include a zero patch level in version string.
* builds/freetype.mk: Remove code for computing the version string.
Problem reported by Grissiom <chaos.proton@gmail.com>; in
http://lists.nongnu.org/archive/html/freetype/2015-05/msg00013.html
there is an example code to trigger the bug.
* src/truetype/ttobjs.c (tt_size_init_bytecode): Free old `size'
data before allocating again. Bug most probably introduced four
years ago in version 2.4.3.
* src/truetype/ttinterp.c: Change all existing TRACE7 calls to
TRACE6.
(opcode_name): Add string lengths.
(TT_RunIns): Implement display of code position and stack.
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.
* src/truetype/ttgload.c, src/truetype/ttinterp.c: Guard new code
with `TT_CONFIG_OPTION_SUBPIXEL_HINTING'.
Problem reported by Nikolaus Waxweiler <madigens@gmail.com>.
This flag activates `native ClearType hinting', disabling backwards
compatibility mode as described in Greg Hitchcocks whitepaper. In
other words, it enables unrestricted functionality of all TrueType
instructions in ClearType.
* src/truetype/ttgload.c (tt_get_metrics): Call `sph_set_tweaks'
unconditionally.
(tt_loader_init): Unset `ignore_x_mode' flag if bit 2 of
`GS.instruct_control' is active.
* src/truetype/ttinterp.c (Ins_INSTCTRL): Handle selector index 3.
(Ins_GETINFO): Updated.
* docs/CHANGES: Document it.
* src/truetype/ttgload.c (TT_Load_Composite_Glyph): If the
ARGS_ARE_XY_VALUES flag is not set, handle argument values as
unsigned. I trust `ttx' (which has exactly such code) that it does
the right thing here...
The reason that noone has ever noticed this bug is probably the fact
that point-aligned subglyphs are rare, as are subglyphs with a
number of points in the range [128;255], which is quite large (or
even in the range [32768;65535], which is extremely unlikely).
This commit allows `num_coords' to be larger or smaller than the
number of available axes while selecting a design instance, either
ignoring excess data or using defaults if data is missing.
* src/truetype/ttgxvar.c (TT_Set_MM_Blend, TT_Set_Var_Design):
Implement it.
* src/type1/t1load.c (T1_Set_MM_Blend, T1_Set_MM_Design,
T1_Set_Var_Design): Ditto.
* src/truetype/ttgxvar.c (ft_var_readpackedpoints): Correctly handle
single-element runs. Cf. glyph `Q' in Skia.ttf with weights larger
than the default.
* src/truetype/ttgxvar.c (ft_var_readpackedpoints): Fix return value
of `point_cnt' if two bytes are read.
Use a more vertical coding style.
(ft_var_readpackeddeltas): Use FT_UInt for `delta_cnt' parameter.
Use a more vertical coding style.
This is hard-coded to value 2 in `fvar' version 1.0 (and no newer
version exists), but some fonts set it incorrectly.
Problem reported by Adam Twardoch <adam@fontlab.com>.
* src/truetype/ttgload.c (load_truetype_glyph): For incremental
fonts, the glyph index may be greater than the number of glyphs
indicated, so guard the check with a preprocessor conditional.
Previously the code had stipulation for using a per-TT_Size exec
context if `size->debug' was true. But there was no way that
`size->debug' could *ever* be true. As such, the code was always
using the singleton `TT_ExecContext' that was stored in `TT_Driver'.
This was, clearly, not threadsafe.
With this patch, loading glyphs from different faces from different
threads doesn't crash in the bytecode loader code.
* src/truetype/ttobjs.h (TT_SizeRec): Remove `debug' member.
(TT_DriverRec): Remove `context' member.
* src/truetype/ttobjs.c (tt_size_run_fpgm, tt_size_run_prep): Remove
`TT_ExecContext' code related to a global `TT_Driver' object.
(tt_driver_done): Don't remove `TT_ExecContext' object here but ...
(tt_size_done_bytecode): ... here.
(tt_driver_init): Don't create `TT_ExecContext' object here but ...
(tt_size_init_bytecode): ... here, only on demand.
* src/truetype/ttinterp.c (TT_Run_Context): Remove defunct debug
code.
(TT_New_Context): Remove `TT_ExecContext' code related to a global
`TT_Driver' object.
* src/truetype/ttinterp.h: Updated.
* src/truetype/ttgload.c (TT_Hint_Glyph, tt_loader_init): Updated.
Assure that FreeType's internal include directories are found before
`CPPFLAGS' (which might be set by the user in the environment), and
`CPPFLAGS' before `CFLAGS'.
* builds/freetype.mk (FT_CFLAGS): Don't add `INCLUDE_FLAGS'.
(FT_COMPILE): Make this a special variable for compiling only the
files handled in `freetype.mk'.
(.c.$O): Removed, unused.
* src/*/rules.mk (*_COMPILE): Fix order of include directories.
Based on a patch from Behdad.
* src/truetype/ttinterp.c (DO_*): Expand macros into corresponding
`Ins_*' functions.
(TT_RunIns): Replace `DO_*' macros with `Ins_*' function calls.
(ARRAY_BOUND_ERROR): Remove second definition, which is no longer
needed.
(Ins_SVTCA, Ins_SPVTCA, Ins_SFVTCA): Replaced with...
(Ins_SxyTCA): New function.
This is a follow-up patch.
* src/truetype/ttinterp.c, src/truetype/ttinterp.h
[TT_CONFIG_OPTION_STATIC_INTERPRETER,
TT_CONFIG_OPTION_STATIC_RASTER]: Remove macros and related code.
`API functions' are functions tagged with `FT_EXPORT_DEF'.
Besides trivial fixes, the following changes are included, too.
* src/base/ftbdf.c (FT_Get_BDF_Charset_ID, FT_Get_BDF_Property): Set
error code if no service is available.
* src/base/ftinit.c (FT_Done_FreeType): Change return value for
invalid `library' parameter to `Invalid_Library_Handle'.
* src/base/ftobjs.c (FT_New_Size): Change return value for invalid
`asize' parameter to `Invalid_Argument'.
* src/base/ftoutln.c (FT_Outline_Copy): Change return value for
invalid `source' and `target' parameters to `Invalid_Outline'.
(FT_Outline_Done_Internal): Change return value for invalid
`outline' parameter to `Invalid_Outline'.
The functions in this patch *do* return non-trivial errors that must
be taken care of.
* src/autofit/afloader.c (af_loader_load_g), src/base/ftobjs.c
(FT_Render_Glyph_Internal), src/base/ftoutln.c (FT_Outline_Render),
src/cff/cffgload.c (cff_decoder_parse_charstrings) <cff_op_endchar>,
src/psaux/psobjs.c (ps_parser_load_field_table), src/psaux/t1decode
(t1_decoder_parse_charstrings) <op_endchar>, src/truetype/ttgload.c
(load_truetype_glyph <subglyph loop>, tt_loader_init,
TT_Load_Glyph), src/truetype/ttgxvar.c (TT_Set_MM_Blend),
src/truetype/ttobjs.c (tt_size_run_fpgm, tt_size_run_prep): Do it.
We use a cast to indicate that we intentionally ignore a function's
return value. However, this doesn't apply to API functions where
errors can only happen for trivially invalid input.
* src/base/ftstroke.c (FT_Glyph_Stroke, FT_Glyph_StrokeBorder),
src/base/ftsynth.c (FT_GlyphSlot_Embolden), src/cff/cffgload.c
(cff_slot_load), src/pfr/pfrdrivr.c (pfr_get_kerning),
src/type1/t1load.c (parse_encoding), src/type42/t42parse.c
(t42_parse_encoding): Do it.
Before this patch, it was impossible to ever call DELTAP[123] in
subpixel hinting mode as described in the ClearType whitepaper; it
only worked if in `compatibility mode'. However, compatibility mode
essentially disables SHPIX, completely ruining hinting of
ttfautohint output, for example.
We now follow the whitepaper more closely so that DELTAP[123]
instructions for touched points in the non-subpixel direction are
executed.
Zero distance does not have to be treated specially if you follow
specifications and check the sign as the very last step of rounding.
* src/truetype/ttinterp.c (Round_None, Round_To_Grid,
Round_Down_To_Grid, Round_Up_To_Grid, Round_To_Double_Grid): Use
macros when available, do not check for non-zero distance.
(Round_To_Half_Grid, Round_Super, Round_Super_45): Ditto, return phase
if sign changed.
Suggested by Doug Felt <dougfelt@gmail.com>.
* src/sfnt/ttsbit.c (tt_sbit_decoder_load_metrics): Set
`vertAdvance' to zero...
* src/truetype/ttgload.c (TT_Load_Glyph): ... and set here a default
value for `vertAdvance' based on `linearVertAdvance' in case
`vertAdvance' is zero. Note that the previous computed ad-hoc value
for `linearVertAdvance' was apparently not tested in a real-life
situation.
The legal range for delta shift is zero through six. Negative values
are illegal according to
https://developer.apple.com/fonts/TrueType-Reference-Manual/RM04/Chap4.html#delta%20shift
* src/truetype/ttobjs.h (delta_shift, delta_base): Make unsigned.
* src/truetype/ttinterp.h (DO_SDS): Throw an error if delta_shift
out of range.
(Ins_DELTAP, Ins_DELTAC): Optimize for legal delta_shift.
* src/truetype/ttinterp.h (TT_ExecContextRec): New field
`cur_ppem_func' with a function pointer.
* src/truetype/ttinterp.c (TT_RunIns): Initialize `cur_ppem_func'
depending on the pixel geometry to either...
(Current_Ppem_Stretched): ... this for stretched pixels.
(Current_Ppem): ... or this for square pixels.
(DO_MPPEM, DO_MPS, Ins_DELTAP, Ins_DELTAC): Use `cur_ppem_func'.