This patch provides slightly optimized versions for ARM, x86, and
x86_64 CPUs if built with GCC.
Also remove some dead code.
* src/truetype/ttinterp.c (TT_MulFix14_arm, TT_MulFix14_long_long,
TT_DotFix14_long_long): New functions.
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/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.
* 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.
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 b7ef2b0968]. 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.
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.
* src/truetype/ttinterp.c (Ins_ISECT): Use angle between vectors to
avoid grazing intersections. The previous threshold was too coarse,
incorrectly rejecting short but valid vectors.
* include/freetype/internal/ftcalc.h (FT_MulDiv_No_Round): Don't
enclose with `TT_USE_BYTECODE_INTERPRETER'; we now need the function
elsewhere also.
* src/autofit/afcjk.h: Use AF_CONFIG_OPTION_CJK.
* src/truetype/ttgload.c (tt_loader_init): Fix compiler warning.
* src/truetype/ttinterp.c (Ins_MSIRP): Fix compiler warning.
* src/truetype/ttinterp.h: Use
TT_CONFIG_OPTION_BYTECODE_INTERPRETER.
This is the large, famous `Infinality' patch to support ClearType
bytecode which has been available from
http://www.infinality.net/blog/ for some time, and which has been
refined over the last years. While still experimental, it is now
mature enough to be included directly into FreeType.
Most of the code is based on the ClearType whitepaper written by
Greg Hitchcock
http://www.microsoft.com/typography/cleartype/truetypecleartype.aspx
which gives a detailed overview of the necessary changes to the
Microsoft rasterizer so that older fonts are supported. However, a
lot of details are still missing, and this patches provides a
framework to easily handle rendering issues down to the glyph level
of certain fonts.
Note that ClearType support is not completely implemented! In
particular, full support for the options `compatible_widths',
`symmetrical_smoothing, and `bgr' (via the GETINFO bytecode
instruction) is missing.
* src/truetype/ttsubpix.c: New file, providing code to handle
`tweaks', this is, rules for certain glyphs in certain fonts
(including wildcards) which need a special treatment.
* src/truetype/ttsubpix.h: New file, holding the tweaking rules.
* include/freetype/config/ftoption.h, src/devel/ftoption.h
(TT_CONFIG_OPTION_SUBPIXEL_HINTING): New macro.
* include/freetype/internal/ftobjs.h (FT_PIX_FLOOR_GRID,
FT_PIX_ROUND_GRID, FT_PIX_CEIL_GRID): New macros.
* src/truetype/truetype.c [TT_USE_BYTECODE_INTERPRETER]: Include
`ttsubpix.c'.
* src/truetype/ttgload.c: Include `ttsubpix.h'.
[All changes below are guarded by TT_CONFIG_OPTION_SUBPIXEL_HINTING.]
(tt_get_metrics): Set tweak flags.
(TT_Hint_Glyph): Call `FT_Outline_EmboldenXY' if necessary.
(TT_Process_Simple_Glyph): Compensate emboldening if necessary.
(compute_glyph_metrics): Handle `compatible widths' option.
(tt_loader_init): Handle ClearType GETINFO information bits.
* src/truetype/rules.mk (TT_DRC_SRC): Updated.
* src/truetype/ttinterp.c: Include `ttsubpix.h'.
[Where necessary, changes below are guarded by
TT_CONFIG_OPTION_SUBPIXEL_HINTING.]
(Direct_Move, Direct_Move_X): Extended.
(Round_None, Round_To_Grid, Round_To_Half_Grid, Round_Down_To_Grid,
Round_Up_To_Grid, Round_To_Double_Grid, Round_Super, Round_Super_45,
SetSuperRound): Add parameter to handle the number of grid lines per
pixel.
(SET_SuperRound, ROUND_None, CUR_Func_round): Updated.
(DO_SROUND, DOS45ROUND, DO_ODD, DO_EVEN): Updated.
(DO_ROUND, DO_NROUND): Updated.
(DO_RS): Take care of `Typeman' bytecode patterns.
(Ins_FDEF): Add some debugging code. Commented out.
(Ins_ENDF): Restore state.
(Ins_CALL, Ins_LOOPCALL): Handle inline delta functions.
(Ins_MD): Handle `Vacuform' rounds.
(Move_Zp2_Point, Ins_SHPIX, Ins_MSIRP, Ins_MDAP, Ins_MIAP,
Ins_MDRP, Ins_MIRP): Handle tweaks.
(Ins_ALIGNRP): Add tweak guard.
(Ins_IUP, Ins_DELTAP): Handle tweaks.
(Ins_GETINFO): Handle new ClearType bits.
(TT_RunIns): Handle tweaks.
* src/truetype/ttinterp.h: Updated.
(SPH_TweakRule, SPH_ScaleRule): New structures for tweaks.
(TT_ExecContextRec): Add members for subpixel hinting support.
* src/truetype/ttobjs.h (TT_DefRecord): Add `inline_delta' member.
* src/truetype/ttinterp.c (DO_SSW): SSW *does* use font units. For
verification, it took some time to find a font which actually uses
this instruction.
* src/truetype/ttinterp.c (Ins_MIRP): Typo, present since ages. The
code is now in sync with the other operators (e.g. MSIRP) which
modify twilight points.
Jump instructions are now bound to the current function. The MS
Windows rasterizer behaves the same, as confirmed by Greg Hitchcock.
* src/truetype/ttinterp.h (TT_CallRec): Add `Cur_End' element.
* src/truetype/ttobjs.h (TT_DefRecord): Add `end' element.
* src/truetype/ttinterp.c (DO_JROT, DO_JMPR, DO_JROF): Check upper
bound of jump address.
(Ins_FDEF, Ins_CALL, Ins_LOOPCALL, Ins_UNKNOWN, TT_RunIns): Updated.
Werner Lemberg