An example that gets better rendered is glyph `uusignTaml' (glyph
index 2286) in font `FreeSerif.ttf' (Version 0412.2263) at 22ppem.
* src/autofit/aflatin.c (af_latin_hints_compute_segments): Properly
handle segments where the last point of the first segment is
identical to the first point in the second one. This can happen for
malformed fonts or spikes. We either merge the new segment with the
previous one (both segments point into the same direction), or we
discard the shorter segment if they point into different directions.
* src/autofit/aflatin.c (af_latin_hints_compute_segments): Change
some local variable names to better differentiate between values
along a segment and values orthogonal to it.
In complex glyph shapes, the original logic was too simple to cater
for situations that would actually need something similar to PS Hint
masks. This fix should alleviate the worst cases.
* src/autofit/aflatin.c (af_latin_hint_edges): Don't allow
complete disappearance of stems.
This improves rendering of scripts like Bengali or Devanagari.
* src/autofit/afhints.c (af_axis_hints_new_edge): Add parameter to
pass top-to-bottom hinting flag. This makes the function sort edges
in descending vertical position.
* src/autofit/afhints.c: Updated.
* src/autofit/aflatin.c (af_latin_hints_compute_edges,
af_latin_hint_edges): Use `top_to_bottom_hinting' flag.
* src/autofit/afcjk.c (af_cjk_hints_compute_edges),
src/autofit/aflatin2.c (af_latin2_hints_compute_edges): Updated.
This was removed while rewriting the HarfBuzz interface.
* src/autofit/afglobal.h (AF_FaceGlobalsRec): Add `hb_buf' field to
hold internal HarfBuzz buffer, needed for feature comparison.
* src/autofit/afglobal.c (af_face_globals_new,
af_face_globals_free): Initialize and destroy `hb_buf'.
* src/autofit/afshaper.c (af_shaper_get_cluster): Compare character
(cluster) with and without applied feature.
* src/autofit/aflatin.c (af_latin_metrics_init_blues): Fix tracing
message.
This feature is mainly for Khmer: The idea is to avoid a clash
between the top of subscript glyphs and the bottom of normal
baseline glyphs.
This only works for character clusters mapped to multiple glyphs.
* src/autofit/afblue.dat: Add subscript top blue zone for Khmer.
* src/autofit/afblue.hin (AF_BLUE_PROPERTY_LATIN_SUB_TOP): New
macro.
* src/autofit/afblue.c, src/autofit/afblue.h: Regenerated.
* src/autofit/aflatin.h (AF_LATIN_IS_SUB_TOP_BLUE,
AF_LATIN_BLUE_SUB_TOP): New macros.
* src/autofit/aflatin.c (af_latin_metrics_init_blues): Handle new
blue zone property.
Update tracing messages.
(af_latin_metrics_scale_dim): Handle new blue zone property.
(af_latin_hints_compute_blue_edges): Updated.
Scripts like Khmer have blue zones that can't be directly
represented by Unicode characters. Instead, it is necessary to let
HarfBuzz convert character clusters into proper glyph representation
forms, then deriving the blue zone information from the resulting
glyphs.
* src/autofit/hbshim.c, src/autofit/hbshim.h: Replaced by...
* src/autofit/afshaper.c, src/autofit/afshaper.h: ... these two new
files, providing a new API to access HarfBuzz.
The new API manages a HarfBuzz buffer with `af_shaper_buf_create'
and `af_shaper_buf_destroy'. The buffer receives a UTF8 encoded
string with function `af_shaper_get_cluster', and the resulting
glyph data (indices, advance widths, vertical offsets) can be
iteratively accessed with function `af_shaper_get_elem'.
* src/autofit/afcjk.c (af_cjk_metrics_init_widths,
af_cjk_metrics_init_blues, af_cjk_metrics_check_digits): Updated.
* src/autofit/aflatin.c (af_latin_metrics_init_widths,
af_latin_metrics_init_blues, af_latin_metrics_check_digits):
Updated.
* include/freetype/internal/fttrace.h: s/afharfbuzz/afshaper/.
* src/autofit/afglobal.c: s/hbshim.h/afshaper.h/.
(af_face_globals_compute_style_coverage): Updated.
* src/autofit/afglocal.h: s/hbshim.h/afshaper.h/.
* src/autofit/autofit.c: s/hbshim.c/afshaper.c/.
* src/autofit/Jamfile, src/autofit/rules.mk (AUTOF_DRV_SRC):
Updated.
This is more flexible; additionally, it would allow character
clusters.
* src/autofit/aftypes.h (SCRIPT, AF_DEFINE_SCRIPT_CLASS): Updated.
(AF_ScriptClassRec): Replace `standard_char[123]' with
`standard_charstring'.
* src/autofit/afscript.h: Replace last three character arguments
of the `SCRIPT' calls with a string parameter, holding the standard
characters (in UTF-8 encoding) separated with spaces.
* src/autofit/afglobal.c, src/autofit/afglobal.h,
src/autofit/afpic.c, src/autofit/afranges.c, src/autofit/hbshim.c
(SCRIPT): Updated.
* src/autofit/afcjk.c (af_cjk_metrics_init_widths),
src/autofit/aflatin.c (af_latin_metrics_init_widths): Updated.
* src/autofit/aflatin.h (AF_LatinBlueRec): Add `ascender' and
`descender' fields.
* src/autofit/aflatin.c (af_latin_metrics_init_blues): Collect
ascender and descender data for blue zones.
(af_latin_metrics_scale_dim): Reject vertical scaling values that
change the result by more than two pixels.
We need the computed standard horizontal and vertical widths for the
emboldening calculation. This method provides a convenient way to
extract it from writing-system-specific metrics structures, which
all script definitions must implement.
* src/autofit/aftypes.h (AF_WritingSystem_GetStdWidthsFunc): New
function type.
(AF_WritingSystemClassRec): New member `style_metrics_getstdw'.
(AF_DEFINE_WRITING_SYSTEM_CLASS): Updated.
* src/autofit/afcjk.c (af_cjk_get_standard_width): New function.
(af_cjk_writing_system_class): Updated.
* src/autofit/afdummy.c (af_dummy_writing_system_class): Updated.
* src/autofit/afindic.c (af_cjk_get_standard_width): New function.
(af_indic_writing_system_class): Updated.
* src/autofit/aflatin.c (af_latin_get_standard_width): New function.
(af_indic_writing_system_class): Updated.
* src/autofit/aflatin.c (af_latin_get_standard_width): New function.
(af_indic_writing_system_class): Updated.
This commit adds two fallback scripts (`latb', `latp') and
implements support for the no-base character ranges introduced in
the previous commit.
* src/autofit/aftypes.h (AF_ScriptClassRec): Add
`script_uni_nobase_ranges' field.
(AF_DEFINE_SCRIPT_CLASS): Updated.
* src/autofit/afscript.h, src/autofit/afstyles.h: Add `latb' and
`latp' fallback scripts.
* src/autofit/afblue.dat: Add blue zones for Latin subscript and
superscript fallback scripts.
* src/autofit/afblue.c, src/autofit/afblue.h: Regenerated.
* src/autofit/afglobal.h (AF_NOBASE): New style flag for no-base
characters.
(AF_STYLE_MASK): Updated.
* src/autofit/afglobal.c (SCRIPT): Updated.
(af_face_globals_compute_style_coverage): Handle new style flag.
* src/autofit/aflatin.c (af_latin_hints_apply): Handle new style
flag.
* src/autofit/afranges.h (SCRIPT): Use it to export no-base ranges.
Lower the flatness threshold from upem/8 to upem/14, making the
auto-hinter accept shorter elements.
Synchronize flat/round stem selection algorithm with blue zone code.
* src/autofit/aflatin.c (FLAT_THRESHOLD): New macro.
(af_latin_metrics_init_blues): Use it.
(af_latin_hints_compute_segments): Collect information on maximum
and minimum coordinates of `on' points; use this to add a constraint
for the flat/round decision similar to
`af_latin_metrics_init_blues'.
This code replaces the debugging hook from the previous commit with
a better, more generic solution.
* include/ftautoh.h: Document it.
* src/autofit/afmodule.h (AF_ModuleRec)
[AF_CONFIG_OPTION_USE_WARPER]: Add `warping' field.
* src/autofit/afmodule.c (_af_debug_disable_warper): Remove.
(af_property_set, af_property_get, af_autofitter_init)
[AF_CONFIG_OPTION_USE_WARPER]: Handle `warping' option.
* src/autofit/afhints.h (AF_HINTS_DO_WARP): Remove use of the no
longer existing `_af_debug_disable_warper'.
* src/autofit/afcjk.c (af_cjk_hints_init), src/autofit/aflatin.c
(af_latin_hints_init), src/autofit/aflatin2.c (af_latin2_hints_init)
[AF_CONFIG_OPTION_USE_WARPER]: Add `AF_SCALER_FLAG_NO_WARPER' to the
scaler flags if warping is off.
* src/autofit/aftypes.h: Updated.
* src/autofit/afmodule.c (_af_debug_disable_warper)
[FT_DEBUG_AUTOFIT]: New global variable.
* src/autofit/aftypes.h: Updated.
(AF_SCALER_FLAG_NO_WARPER): New macro (not actively used yet).
* src/autofit/afhints.h (AF_HINTS_DO_WARP): New macro.
* src/autofi/aflatin.c (af_latin_hints_apply)
[AF_CONFIG_OPTION_USE_WARPER]: Use `AF_HINTS_DO_WARP' to control use
of warper.
* src/autofit/afcjk.c (af_cjk_hints_init, af_cjk_hints_apply)
[AF_CONFIG_OPTION_USE_WARPER]: Synchronize with `aflatin.c'.
* src/autofit/aflatin2.c (af_latin2_hints_apply)
[AF_CONFIG_OPTION_USE_WARPER]: Synchronize with `aflatin.c'.
This harmonizes with other code in FreeType (and reduces the number
of necessary casts to avoid compiler warnings).
* src/autofit/afblue.hin: Make flag macros unsigned.
* src/autofit/afblue.h: Regenerated.
* src/autofit/afcjk.h: Replace flag enumeration with macros.
* src/autofit/afcjk.c: Updated.
* src/autofit/afhints.h (AF_Flags, AF_Edge_Flags): Replace with
macros.
* src/autofit/afhints.c: Updated.
* src/autofit/aflatin.h: Replace flag enumerations with macros.
* src/autofit/aflatin.c, src/autofit/aflatin2.c: Updated.
* src/autofit/aftypes.h (AF_ScalerFlags): Replace with macros.
* src/autofit/afhints.h (AF_Edge_Flags): New value
`AF_EDGE_NEUTRAL'.
* src/autofit/aflatin.c (af_latin_hints_compute_blue_edges): Trace
neutral blue zones with AF_EDGE_NEUTRAL.
(af_latin_hint_edges): Skip neutral blue zones if necessary.
Such blue zones match either the top or the bottom of a contour. We
need them for scripts where accent-like elements directly touch the
base character (for example, some vowel signs in Devanagari, cf.
U+0913 or U+0914).
* src/autofit/afblue.hin (AF_BLUE_PROPERTY_LATIN_NEUTRAL): New
property.
* src/autofit/afblue.h: Regenerated.
* src/autofit/aflatin.h (AF_LATIN_IS_NEUTRAL_BLUE): New macro.
(AF_LATIN_BLUE_NEUTRAL): New enumeration value.
* src/autofit/aflatin.c (af_latin_metrics_init_blues,
af_latin_hints_compute_blue_edges): Handle neutral blue zones.
The adaptation of the cjk auto-hinter module to blue stringsets in
2013-08-25 had three severe bugs. Mea culpa.
1. Contrary to the latin auto-hinter, characters for reference and
overshoot values of a blue zone are specified separately. Due to
the screwed-up change it didn't work at all.
2. A boolean comparison was erroneously replaced with a cast,
causing invalid results with the `^' operator later on. The
visual artifact caused by this problem is the topic of the bug
report.
3. Two flag values were inverted, causing incorrect assignment of
reference and overshoot values.
* src/autofit/afblue.dat: Fix CJK bluestrings, introducing a new
syntax to have both reference and overshoot characters in a single
string. This is error #1.
Add extensive comments.
* src/autofit/afblue.hin (AF_BLUE_PROPERTY_CJK_FILL): Removed, no
longer used.
(AF_BLUE_PROPERTY_CJK_TOP, AF_BLUE_PROPERTY_CJK_HORIZ): Fix values.
This is error #3.
* src/autofit/afblue.c, src/autofit/afblue.h: Regenerated.
* src/autofit/afcjk.c (af_cjk_metrics_init_blues): Correct error #1.
Use character `|' to separate characters for reference and overshoot
values.
Improve tracing messages, synchronizing them with the latin
auto-hinter.
(af_cjk_hints_compute_blue_edges): Fix value of `is_top_right_blue'.
This is error #2.
(af_cjk_align_linked_edge): Add tracing message.
* src/autofit/afcjk.h (AF_CJK_IS_FILLED_BLUE): Removed, no longer
used.
Problem reported by Karsten Lücke <karsten.luecke@kltf.de>.
The new algorithm takes care of the width of stems: If the distance
between two segments is larger than the largest stem width, the
demerits quickly increase for larger distances. This improves
hinting of slanted fonts (especially if the inner parts of serifs
have non-horizontal `shoulders'), avoiding false stem links.
* src/autofit/aflatin.c (af_latin_hints_link_segments): Use largest
stem width (if available) to compute better demerits for distances
between stems.
(af_latin_hints_detect_features): Pass stem width array and array
size.
(af_latin_metrics_init_widths): Updated to use original algorithm.
(af_latin_hints_apply): Updated to use new algorithm.
* src/autofit/aflatin.h: Updated.
* src/autofit/afcjk.c: Updated.
* src/autofit/afcjk.c (af_cjk_metrics_init_widths),
src/autofit/aflatin.c (af_latin_metrics_init_widths): Fix handling
of alternative standard characters.
This also fixes a compilation warning in non-debug mode.
This is useful for OpenType features like `c2sc' (caps to small
caps) that don't have lowercase letters by definition, or other
features that mainly operate on numerals.
* src/autofit/afscript.h: Add more standard characters.
* src/autofit/aftypes.h: Update use of `SCRIPT' macro.
(AF_ScriptClassRec): Add members to hold two more standard
characters.
(AF_DEFINE_SCRIPT_CLASS): Updated.
* src/autofit/afglobal.c, src/autofit/afglobal.h,
* src/autofit/afpic.c, src/autofit/afranges.h, src/autofit/hbshim.c:
Update use of `SCRIPT' macro.
* src/autofit/afcjk.c (af_cjk_metrics_init_widths),
src/autofit/aflatin.c (af_latin_metrics_init_widths): Scan two more
standard characters.
Werner Lemberg