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.
The idea is to replace code like
return FT_Err_Foo_Bar;
or
return CFF_Err_Foo_Bar;
with
return FT_THROW( Foo_Bar );
The FT_THROW macro has two functions:
. It hides the module specific prefix.
. In debug mode, it calls the empty function `FT_Throw' which can
be thus used to set a breakpoint.
* include/freetype/internal/ftdebug.h (FT_THROW): New macro.
(FT_Throw): New prototype.
* src/base/ftdebug.c (FT_Throw): New function.
The idea is to always have FT_ERR_PREFIX available internally.
* include/freetype/fterrors.h: Use FT2_BUILD_LIBRARY to guard
undefinition of FT_ERR_PREFIX
* src/gxvalid/gxverror.h, src/otvalid/otverror.h,
src/sfnt/sferrors.h: Updated.
* src/base/ftbbox.c (BBox_Cubic_Check): New bisecting algorithm
for extremum search built around simple condition that defines
which half contains the extremum.
* src/tools/test_bbox.c: Add another cubic outline with exact BBox.
(REPEAT): Increase the number of benchmarking cycles.
(profile_outline): Tweak output formatting.
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.
Many compilers such as gcc and clang optimize away pointer overflow
checks `p + n < p', because pointer overflow is undefined behavior.
Use a safe form `n > p_limit - p' instead.
Also avoid possible integer overflow issues, for example, using
`num_glyphs > ( p_limit - p ) / 2' rather than `num_glyphs * 2'
given a large `num_glyphs'.
* src/sfnt/ttsbit0.c (tt_sbit_decoder_load_image): Implement it.
* 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.
It was not taking bit_depth into consideration when blitting!
* src/sfnt/ttsbit0.c (tt_sbit_decoder_load_byte_aligned,
* tt_sbit_decoder_load_bit_aligned): Handle bit
depth.
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 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 recent optimizations of CORDIC iterations drastically reduce
the expansion factor. The vector components with MSB of 29 are now
safe from overflow.
* src/base/fttrigon.c (FT_TRIG_SAFE_MSB): New macro.
(ft_trig_prenorm): Use it and remove dead code.
Werner Lemberg