* src/truetype/ttgload.c (TT_Load_Glyph): Use the glyph's (scaled)
`linearHoriAdvance' if the sbit's `horiAdvance' value is zero.
Cf. font `Fixedsys Excelsior' v3.01 (FSEX300.ttf), glyph A, 16ppem.
Some small enhancements have allowed the removal of many macros and
the simplification of existing rules in `ttsubpix.c'.
* src/truetype/ttsubpix.h (SPH_TWEAK_ALLOW_X_DMOVEX,
SPH_TWEAK_ALLOW_X_MOVE_ZP2,
SPH_TWEAK_DELTAP_SKIP_EXAGGERATED_VALUES,
SPH_TWEAK_SKIP_INLINE_DELTAS, SPH_TWEAK_MIRP_CVT_ZERO): Removed.
(SPH_TWEAK_SKIP_NONPIXEL_Y_MOVES_DELTAP): New rule macro.
* src/truetype/ttsubpix.c: Updated affected rules.
* src/truetype/ttinterp.c (Direct_Move_X): Updated.
(INS_FDEF): Add additional function detection.
(INS_ENDF): Set runtime flag.
(Ins_CALL): Skip the call under certain conditions.
Remove bad code.
(Ins_LOOPCALL): Skip the call under certain conditions.
Remove bad code.
(Move_Zp2_Point): Updated.
(Ins_SHPIX): Updated.
Skip the move under some situations.
(Ins_MIAP): Improve conditions.
(Ins_MIRP): Updated.
(Ins_DELTAP): Skip move under certain conditions.
Simplify conditions.
(TT_RunIns): Updated.
Add code to handle new function detection.
Trace messages.
This makes the option TT_CONFIG_OPTION_SUBPIXEL_HINTING controllable
at runtime.
* src/truetype/ttdriver.c: Include FT_TRUETYPE_DRIVER_H.
(tt_property_set, tt_property_get): Fill templates.
* src/truetype/ttobjs.h (TT_DriverRec): Add `interpreter_version'
member.
Remove unused `extension_component' member.
* src/truetype/ttgload.c: Include FT_TRUETYPE_DRIVER_H.
(tt_get_metrics, TT_Hint_Glyph, TT_Process_Simple_Glyph,
compute_glyph_metrics, tt_loader_init): Use `interpreter_version'.
* src/truetype/ttinterp.c: Include FT_TRUETYPE_DRIVER_H.
(SUBPIXEL_HINTING): New macro to check `interpreter_version' flag.
Update all affected functions to use it.
Use TT_INTERPRETER_VERSION_XXX where appropriate.
* src/truetype/ttobjs.c: Include FT_TRUETYPE_DRIVER_H.
(tt_driver_init): Initialize `interpreter_version'.
* src/truetype/ttsubpix.c: Include FT_TRUETYPE_DRIVER_H.
Use TT_INTERPRETER_VERSION_XXX where appropriate.
* src/truetype/ttdrivr.c: Include FT_SERVICE_PROPERTIES_H.
(tt_property_set, tt_property_get): New functions, still empty.
Define `tt_service_properties' service.
Update `tt_services'.
* src/truetype/ttpic.h: Include FT_SERVICE_PROPERTIES_H.
(TT_SERVICE_PROPERTIES_GET): New macro.
(TTModulePIC): Add `tt_service_properties'.
* src/base/ftcalc.c (FT_DivFix): Use unsigned values for
computations which use the left shift operator and convert to signed
as the last step.
* src/base/fttrigon.c (ft_trig_prenorm, FT_Vector_Rotate,
FT_Vector_Length, FT_Vector_Polarize): Ditto.
* src/cff/cffgload.c (cff_decoder_parse_charstrings): Simplify.
* src/cff/cffload.c (cff_subfont_load): Fix constant.
* src/cff/cffparse.c (cff_parse_integer, cff_parse_real, do_fixed,
cff_parse_fixed_dynamic): Use unsigned values for computations which
use the left shift operator and convert to signed as the last step.
* src/cid/cidload.c (cid_get_offset): Ditto.
* src/psaux/psconv.c (PS_Conv_ToFixed): Ditto.
* src/psaux/t1decode.c (t1_decoder_parse_charstrings): Ditto.
* src/truetype/ttinterp.c (TT_MulFix14, TT_DotFix14): Ditto.
This is essentially a mechanical conversion, adding inclusion of
`FT_INTERNAL_DEBUG_H' where necessary, and providing the macros for
stand-alone compiling modes of the rasterizer modules.
To convert the remaining occurrences of FT_Err_XXX and friends it is
necessary to rewrite the code. Note, however, that it doesn't harm
if some cases are not handled since FT_THROW is a no-op.
BTW, Greg agrees that the OpenType specification is missing the list
of GS variables which will always be reset to the default values
after the `prep' table has been executed.
Up to now, we simply took a snapshot of the Graphics State after the
`prep' table has been executed, and right before a glyph's bytecode
was run it got reloaded. However, as Greg Hitchcock has told us in
private communication, reference points get reset to zero in the MS
rasterizer and we follow in due course. While reasonable, this is
undocumented behaviour.
Most notably, this fixes the rendering of Arial's `x' glyph in
subpixel hinting mode.
* src/truetype/ttsubpix.h: Updated.
(SPH_X_SCALING_RULES_SIZE): Moved and renamed to...
* src/truetype/ttsubpix.c (X_SCALING_RULES_SIZE): This.
(sph_X_SCALING_Rules): Removed.
(scale_test_tweak): Make function static.
(sph_test_tweak_x_scaling): New function.
* src/truetype/ttgload.c (TT_Process_Simple_Glyph): Updated.
* include/freetype/fttrigon.h (FT_Hypot): Declare it.
* src/base/fttrigon.c (FT_Hypot): Define it.
* src/truetype/ttgload.c (TT_Process_Composite_Component): Use it
instead of explicit expressions.
* src/truetype/ttinterp.c (Current_Ratio, Normalize): Use it instead
of TT_VecLen.
(TT_VecLen): Removed.
* src/truetype/ttobjs.c (tt_size_reset): The Windows rendering
engine uses rounded values of the ascender and descender to compute
the TrueType font height.
This patches fixes many issues with the ttsubpix implementation.
1. Data tables are defined, instead of declared, in the header, and
thus copied into each source file that includes it.
2. These tables were defined as global, mutable, visible variables,
and thus costing private RAM to every process that loads the
library (> 50 KB / process, this is huge!).
Additionally, this also made the library export the symbols
completely needlessly.
3. Missing `sph_' and `SPH_' prefixes to some of the definitions.
Note that this doesn't try to fix the incredibly inefficient storage
format for the data tables used by the code. This one will require
another pass in the future.
* src/truetype/ttinterp.h (MAX_NAME_SIZE, MAX_CLASS_MEMBERS):
Renamed to...
(SPH_MAX_NAME_SIZE, SPH_MAX_CLASS_MEMBERS): This.
Update all users.
(SPH_TweakRule, SPH_ScaleRule): Decorate with `const' where
appropriate.
(Font_Class): Rename to...
(SPH_Font_Class): This. Decorate with `const' where appropriate.
* src/truetype/ttsubpix.h (scale_test_tweak, sph_test_tweak):
Decorate arguments with `const' where appropriate.
Move font tweaking tables to...
* src/truetype/ttsubpic.c: This file and decorate them with `static'
and `const' where appropriate.
(X_SCALING_Rules, X_SCALING_RULES_SIZE): Renamed to...
(spu_X_SCALING_Rules, SPH_X_SCALING_RULES_SIZE): This.
Update all users.
Unit vector components are stored as 2.14 fixed-point numbers. In
order to calculate all 14 bits accurately, a short vector to be
normalized has to be upscaled to at least 14 bits before its length
is calculated. This has been safe since accurate CORDIC algorithms
were adopted.
* src/truetype/ttinterp.c (Normalize): Scale short vectors by 0x4000.
Back in the days, vector length calculations were not very accurate
and the vector normalization function, Normalize, had to meticulously
correct the errors for long vectors [commit b7ef2b096867]. It was no
longer necessary after accurate CORDIC algorithms were adopted, but
the code remained. It is time to kill it.
* src/truetype/ttinterp.c (Normalize): Remove error compensation.
(TT_VecLen): Remove any mention of old less accurate implementation.
* include/freetype/internal/ftserv.h (FT_SERVICE_UNAVAILABLE): Use
`logical not' operator instead of negation. The idea is that `~'
returns exactly the data type enforced by the cast to a pointer (be
it 32bit or 64bit or whatever), while a negative integer has not
this flexibility.
* src/cache/ftccmap.c (FTC_CMAP_UNKNOWN): Ditto.
* src/truetype/ttgxvar.c (ALL_POINTS, TT_Get_MM_Var): Ditto.
* src/type/t1load.c (T1_Get_MM_Var): Ditto.
(parse_blend_axis_types): Use cast.
* src/bdf/bdflib.c (_bdf_readstream): Use cast.
The dot product between freeVector and projVector or cosine of
the angle between these FT_F2Dot14 unit vectors used to be scaled up
by 4 and routinely occupied 32 bits in an FT_Long field F_dot_P.
This patch scales the value down by 2^14 instead, which simplifies
its use throughout the bytecode interpreter.
This does not lead to the loss of precision because the lower bits
are unreliable anyway. Consider two unit vectors (1,0) and (.6,.8)
for which the true value of F_dot_P is .6 * 0x40000000 = 0x26666666.
These vectors are stored as (0x4000,0) and (0x2666,0x3333) after
rounding and F_dot_P is assigned 0x26660000. The lower bits were
already lost while rounding the unit vector components.
Besides code simplification, this change can lead to better
performance when FT_MulDiv with the scaled-down F_dot_P is less
likely to use the costly 64-bit path. We are not changing the type
of F_dot_P to FT_F2Dot14 at this point.
* src/truetype/ttinterp.c (Compute_Funcs): Scale F_dot_P down by 14
bits and modify its use accordingly.
(Direct_Move, Direct_Move_Orig, Compute_Point_Displacement): Modify
the use of F_dot_P field.
* src/truetype/ttobjs.c (tt_size_run_fpgm): Change arbitrary
assignment of F_dot_P to its theoretical maximum in case we decide
to scale back its type later.
* src/truetype/ttinterp.c (TT_DivFix14): New macro.
(Normalize): Use it here.
(Current_Ratio): Use TT_MulFix14 instead of FT_MulDiv.
(Ins_SHPIX): Cancel out two TT_MulFix14 calls.
