The previous fix for #46372 misunderstood a composite glyph referring
same component twice as a recursive reference. See the discussion
http://lists.gnu.org/archive/html/freetype/2016-05/msg00000.html
Thanks to Khaled Hosny for finding this issue.
* src/truetype/ttgload.c (ft_list_get_node_at): A function to get
the i-th node from FT_List. (load_truetype_glyph): In the traversal
scan of the reference tree in the composite glyph, we clear the
nodes filled by previous sibling chain.
We never dereference `face_id', and some implementations might use a
running number instead of a pointer. Additionally, disallowing
value zero was undocumented.
* src/cache/ftccmap.c (FTC_CMapCache_Lookup), src/cache/ftcmanag.c
(FTC_Manager_LookupFace, FTC_Manager_RemoveFaceID): Remove test for
`face_id'.
A single decrement counter of segments to draw, instead of an array,
contains all the information necessary to decide when to split and
when to draw a conic segment. The number of splits before each draw is
equal to the number of trailing zeros in the counter.
* src/smooth/ftgrays.c (gray_TWorker): Remove `lev_stack'.
(gray_render_conic): Updated to use decrement counter of segments.
Otherwise some properties could be set to arbitrary values, which is
harmless, but querying could give wrong positive results.
* src/cff/cffdrivr.c (cff_property_set) [hinting-engine],
* src/truetype/ttdriver.c (tt_property_set) [interpreter-version]:
Only allow defined values.
This essentially moves the Gujarati script from the `Indic' hinter to
the `Latin' hinter.
* src/autofit/afblue.dat: Add blue zone data for Gujarati.
* src/autofit/afblue.c, src/autofit/afblue.h: Regenerated.
* src/autofit/afscript.h: Add Gujarati standard characters and move
data out of AF_CONFIG_OPTION_INDIC block.
* src/autofit/afranges.c: Move Gujarati data out of
AF_CONFIG_OPTION_INDIC block.
* src/autofit/afstyles.h: Update Gujarati data; in particular, use
AF_WRITING_SYSTEM_LATIN.
Georgian is problematic, since `uppercase' forms of Mkhedruli
(called Mtavruli) are not yet defined in Unicode, which means that
proper blue zones can't be defined. However, there is already a
proposal submitted to Unicode; see
http://www.unicode.org/L2/L2016/16034-n4707-georgian.pdf
Additionally, due to historical reasons, Unicode treats Khutsuri as
the same script as Mkhedruli, and so does OpenType. However, since
the two scripts have completely different shapes it can happen that
blue zones differ considerably. The tag `geok' used here (derived
from ISO 15924) to differentiate the two scripts is not an OpenType
tag in use. If we now have a font that contains both glyphs for
Mkhedruli and Khutsuri, and it uses OpenType features for both also,
HarfBuzz unavoidably treats all glyphs as `geor'. As a consequence,
blue zones for `geok' are not used for glyphs involved in the
OpenType features.
An issue not yet resolved is which OpenType feature should be used
to access Mtavruli glyph shapes; right now, FreeType doesn't set up
support for them, but it is easy to add them later on as soon as
more information is available.
* src/autofit/afblue.dat: Add blue zone data for Georgian.
* src/autofit/afblue.c, src/autofit/afblue.h: Regenerated.
* src/autofit/afscript.h: Add Georgian standard characters.
* src/autofit/afranges.c: Add Georgian data.
* src/autofit/afstyles.h: Add Georgian data.
Even if the dummy hinter is used as the handler for `none' (which
doesn't use blue zones), it is more consistent than the old value
(which was 0), pointing to Arabic...
* src/autofit/afblue.dat: Add `AF_BLUE_STRINGSET_NONE'.
* src/autofit/afblue.c, src/autofit/afblue.h: Regenerated.
* src/autofit/afstyles.h (none_dflt): Use AF_BLUE_STRINGSET_NONE.
* src/pfr/pfrsbit.c (pfr_lookup_bitmap_data): Replace `left',
`right', and `middle' with `min', `max', and `mid' as used in other
FreeType binary search code.
(pfr_load_bitmap_metrics): Fix invalid left shift.
We did a binary search for a charcode without ensuring that the
searched data is ordered. Validating the order is now done lazily,
this is, the first access to a bitmap glyph triggers the order check
in the corresponding bitmap strike.
* src/pfr/pfrtypes.h (PFR_BitmapFlags): New values
`PFR_BITMAP_VALID_CHARCODES' and `PFR_BITMAP_CHARCODES_VALIDATED'.
* src/pfr/pfrsbit.c (pfr_lookup_bitmap_data): Make `flags' argument
a pointer. Handle new PFR_BITMAP_XXX flags.
(pfr_slot_load_bitmap): Updated.
Extra items are indicated with different bit positions.
* src/pfr/pfrtypes.h (PFR_GlyphFlags): Replace
`PFR_GLYPH_EXTRA_ITEMS' with `PFR_GLYPH_SIMPLE_EXTRA_ITEMS' and
`PFR_GLYPH_COMPOUND_EXTRA_ITEMS'.
* src/pfr/pfrgload.c (pfr_glyph_load_simple,
pfr_glyph_load_compound): Use them.
* src/pfr/pfrsbit.c (pfr_load_bitmap_metrics): Correctly handle
signed nibbles.
(pfr_slot_load_bitmap): Correctly exit frame in case of error.
Fix invalid left shifts.
* src/smooth/ftgrays.c (gray_render_conic, gray_render_cubic): Move
band clipping from here.
(gray_conic_to, gray_cubic_to): ... to here.
(gray_rander_line, gray_render_scanline): Initialize variables closer
to their use.
We probably did not notice this as all fonts we tested had only
tuple_coords[i] be +1 or -1 for non-intermediate tuples.
* src/truetype/ttgxvar.c (ft_var_apply_tuple): Implement it.
The goal is to avoid integer overflows in the rendering algorithms.
The limit is chosen arbitrarily at some 2^18 pixels, which should be
enough for modern devices including printers.
* src/base/ftoutln.c (FT_Outline_Render): Check CBox and reject
enormous outlines.
* src/autofit/aflatin.c (af_latin_compute_stem_width): Add argument
to pass difference between hinted and unhinted position of base
point; use this to adjust the stem width depending on the PPEM so
that it doesn't become too large under certain circumstances.
Update all callers using value 0 for this argument except...
(af_latin_align_linked_edge): Pass position delta of base point to
`af_latin_compute_stem_width'.
This essentially moves the Sinhala script from the `Indic' hinter to
the `Latin' hinter.
* src/autofit/afblue.dat: Add blue zone data for Sinhala.
* src/autofit/afblue.c, src/autofit/afblue.h: Regenerated.
* src/autofit/afscript.h: Add Sinhala standard character and move data
out of AF_CONFIG_OPTION_INDIC block.
* src/autofit/afranges.c: Move Sinhala data out of
AF_CONFIG_OPTION_INDIC block.
* src/autofit/afstyles.h: Update Sinhala data; in particular, use
AF_WRITING_SYSTEM_LATIN.
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 essentially moves the Tamil script from the `Indic' hinter to
the `Latin' hinter.
* src/autofit/afblue.dat: Add blue zone data for Tamil.
* src/autofit/afblue.c, src/autofit/afblue.h: Regenerated.
* src/autofit/afscript.h: Add Tamli standard character and move data
out of AF_CONFIG_OPTION_INDIC block.
* src/autofit/afranges.c: Move Tamil data out of
AF_CONFIG_OPTION_INDIC block.
* src/autofit/afstyles.h: Update Tamil data; in particular, use
AF_WRITING_SYSTEM_LATIN.
Werner Lemberg