Problem reported by Ralf S. Engelschall <rse@engelschall.com>.
* src/autofit/afhints.c (af_glyph_hints_reload): Fix threshold for
finding first non-near point.
Properly initialize non-near point deltas.
This essentially moves the Devanagari script from the `Indic' hinter
to the `Latin' hinter. Thanks to Girish Dalvi
<girish.dalvi@gmail.com> for guidance with blue zone characters!
* src/autofit/afblue.dat: Add blue zone data for Devanagari.
* src/autofit/afblue.c, src/autofit/afblue.h: Regenerated.
* src/autofit/afscript.h: Add Devanagari standard characters and
move data out of AF_CONFIG_OPTION_INDIC block.
* src/autofit/afranges.c: Move Devanagari data out of
AF_CONFIG_OPTION_INDIC block.
Move U+20B9, (new) Rupee sign, from Latin to Devanagari.
* src/autofit/afstyles.h: Update Devanagari data; in particular, use
AF_WRITING_SYSTEM_LATIN.
* 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.
* src/autofit/hbshim.c (af_get_coverage): Merge input glyph coverage
of GSUB lookups into output coverage. Otherwise, ligatures are not
handled properly.
Don't check blue zone characters for default coverage.
In particular, local extrema without horizontal or vertical segments
are better recognized:
+ A + D
\ /
\ /
\ /
\ /
\ + C
\ /
B +/
If the distances AB and CD are large, point B wasn't previously
detected as an extremum since the `ft_corner_is_flat' function
`swallowed' BC regardless of its direction, tagging point B as weak.
The next iteration started at B and made `ft_corner_is_flat' swallow
point C, tagging it as weak also, et voilà.
To improve that, another pass gets now performed before calling
`ft_corner_is_flat' to improve the `topology' of an outline: A
sequence of non-horizontal or non-vertical vectors that point into
the same quadrant are handled as a single, large vector.
Additionally, distances of near points are now accumulated, which
makes the auto-hinter handle them as if they were prepended to the
next non-near vector.
This generally improves the auto-hinter's rendering results.
* src/autofit/afhints.c (af_glyph_hints_reload): Implement it.
* src/autofit/afhints.h (AF_FLAGS): Remove no longer used flag
`AF_FLAG_NEAR'.
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.
This works around a problem with HarfBuzz (<= 0.9.26), which doesn't
validate glyph indices returned by
`hb_ot_layout_lookup_collect_glyphs'.
* src/autofit/hbshim.c (af_get_coverage): Guard `idx'.
* docs/CHANGES: 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.
Split the single, incorrect Indic entry into separate scripts so
that the covered ranges are the same: Bengali, Devanagari, Gujarati,
Gurmukhi, Kannada, Limbu, Malayalam, Oriya, Sinhala, Sundanese,
Syloti Nagri, Tamil, Telugu, and Tibetan. At the same time, remove
entries for Meetai Mayak and Sharada – the Unicode ranges were
incorrect (and nobody has complained about that), fonts are scarce
for those scripts, and the Indic auto-hinter support is rudimentary
anyways.
* src/autofit/afscript.h: Updated, using AF_CONFIG_OPTION_INDIC and
AF_CONFIG_OPTION_CJK.
* src/autofit/afstyles.h (STYLE_DEFAULT_INDIC): New auxiliary macro.
Use it, together with AF_CONFIG_OPTION_INDIC and
AF_CONFIG_OPTION_CJK, to update.
* src/autofit/afranges.c [AF_CONFIG_OPTION_INDIC]: Updated.
[!AF_CONFIG_OPTION_INDIC, !AF_CONFIG_OPTION_CJK]: Removed.
Sort entries by tags.
With this commit, the implementation of coverage handling is
completed.
* src/autofit/hbshim.c (af_get_coverage): Exit early if nothing to
do.
Reject coverages which don't contain appropriate glyphs for blue
zones.
* src/autofit/afglobal.c (af_face_globals_compute_style_coverage):
First handle non-default coverages, then the default coverage of the
default script, and finally the other default coverages.
* src/autofit/afcover.h: Remove coverages for alternative fractions,
denominators, numerators, and fractions.
* src/autofit/afstyles.h (META_STYLE_LATIN): Updated.
* src/autofit/afstyles.h (STYLE_LATIN, META_STYLE_LATIN): New
auxiliary macros; use them to define styles for Cyrillic, Greek, and
Latin.
* src/autofit/afcover.h: Remove coverage for oldstyle figures.
Since those digits are used in combination with ordinary letters, it
makes no sense to handle them separately.
* src/autofit/afglobal.c (af_face_globals_get_metrics): Don't limit
`options' parameter to 4 bits.
* src/autofit/hbshim.c (af_get_coverage)
[FT_CONFIG_OPTION_USE_HARFBUZZ]: Scan GPOS coverage of features also
so that we can skip glyphs that have both GSUB and GPOS data.
* src/autofit/hbshim.c (af_get_char_index): Return error value.
Add argument for y offset (to be used in a yet-to-come patch).
* src/autofit/hbshim.h, src/autofit/afcjk.c,
src/autofit/aflatin.c: Updated.
Combining them, as originally envisioned, would lead to much more
complicated code, as investigations have shown meanwhile. The major
drawback is that we run out of available style slots much earlier.
However, this is only a theoretical issue since we don't support a
large number of scripts currently.
* src/autofit/afcover.h: Replace `COVERAGE_{1,2,3}' macros with
a single-element `COVERAGE' macro, sort the elements by the feature
tags, and add entry for `ruby'.
* src/autofit/aftypes.h: Updated.
* src/autofit/hbshim.c: Updated.
Yet-to-come changes will provide HarfBuzz functionality for the new
function.
* src/autofit/hbshim.c (af_get_char_index): New function.
* src/autofit/hbshim.h: Updated.
* 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.
We now use `hb_font' instead of `hb_face' since yet-to-come changes
need this.
* src/autofit/afglobal.h: Include `hbshim.h'.
(AF_FaceGlobalsRec) [FT_CONFIG_OPTION_USE_HARFBUZZ]: New member
`hb_font'.
* src/autofit/afglobal.c (af_face_globals_new)
[FT_CONFIG_OPTION_USE_HARFBUZZ]: Create `hb_font'.
(af_face_globals_free) [FT_CONFIG_OPTION_USE_HARFBUZZ]: Destroy
`hb_font'.
* src/autofit/hbshim.h: Include HarfBuzz headers.
* src/autofit/hbshim.c: Include `hbshim.h' instead of HarfBuzz
headers.
(af_get_coverage): Updated.
Werner Lemberg