Reported by Jeremy Manson <jeremy.manson@gmail.com>.
src/truetype/ttgload.c (load_truetype_glyph): Add parameter to
quickly load the glyph header only.
Update all callers.
(tt_loader_init): Add parameter to quickly load the `glyf' table
only.
Update all callers.
(TT_Load_Glyph): Compute linear advance values for embedded bitmap
glyphs too.
The calculation of `vertBearingX' is not defined in the OTF font
spec so FreeType does a `best effort' attempt. However, this value
is defined in the PDF and PostScript specs, and that algorithm is
better than the one FreeType currently uses:
FreeType: Use the middle of the bounding box as the X coordinate
of the vertical origin.
Adobe PDF spec: Use the middle of the horizontal advance vector as
the X coordinate of the vertical origin.
FreeType's algorithm goes wrong if you have a really small glyph
(like the full-width, circle-like dot at the end of the sentence, as
used in CJK scripts) with large bearings. With the FreeType
algorithm this dot gets centered on the baseline; with the PDF
algorithm it gets the correct location (in the top right). Note
that this is a serious issue, it's like printing the dot at the end
of a Roman sentence at the center of the textline instead of on the
baseline like it should. So i believe the PDF spec's algorithm
should be used in FreeType as well.
The `vertBearingY' value for such small glyphs is also very strange
if no `vmtx' information is present, since the height of the bbox is
not representable for the height of the glyph visually (the
whitespace up to the baseline is part of the glyph). The fix also
includes some code for a better estimate of `vertBearingY'.
* src/base/ftobjs.c (ft_synthesize_vertical_metrics): `vertBearingX'
is now calculated as described by the Adobe PDF Spec. Estimate for
`vertBearingY' now works better for small glyphs completely above or
below the baseline into account.
* src/cff/cffgload.c (cff_slot_load): `vertBearingX' is now
calculated as described by the Adobe PDF Spec. Vertical metrics
information was always ignored when FT_CONFIG_OPTION_OLD_INTERNALS
was not defined.
* src/truetype/ttgload.c (compute_glyph_metrics): `vertBearingX' is
now calculated as described by the Adobe PDF Spec.
Normally, the SCANMODE instruction (if present) to set the drop-out
mode in a TrueType font is located in the `prep' table only and thus
valid for all glyphs. However, there are fonts like `pala.ttf'
which additionally contain this instruction in the hinting code of
some glyphs (but not all). As a result it can happen that a
composite glyph needs multiple drop-out modes for its subglyphs
since the rendering state gets reset for each subglyph.
FreeType collects the hinted outlines from all subglyphs, then it
sends the data to the rasterizer. It also sends the drop-out mode
-- after hinting has been applied -- and here is the error: It sends
the drop-out mode of the last subglyph only; drop-out modes of all
other subglyphs are lost.
This patch fixes the problem; it adds a second, alternative
mechanism to pass the drop-out mode: For each contour, the
rasterizer now checks the first `tags' array element. If bit 2 is
set, bits 5-7 contain the contour's drop-out mode, overriding the
global drop-out mode.
* include/freetype/ftimage.h (FT_CURVE_TAG_HAS_SCANMODE): New macro.
* src/truetype/ttgload.c (TT_Hint_Glyph): Store drop-out mode in
`tags[0]'.
* src/raster/ftraster.c (Flow_Up, Overshoot_Top, Overshoot_Bottom):
Use bits 3-5 instead of 0-2.
(New_Profile): Set the drop-out mode in the profile's `flags' field.
(Decompose_Curve): Check `tags[0]' and set `dropOutControl' if
necessary.
(Vertical_Sweep_Drop, Horizontal_Sweep_Drop,
Horizontal_Gray_Sweep_Drop, Draw_Sweep): Use the profile's drop-out
mode.
nor bitmaps can be considered as containing space `glyphs' only.
* src/truetype/ttpload.c (tt_face_load_loca): Handle the case where
a `glyf' table is missing.
* src/truetype/ttgload.c (load_truetype_glyph): Abort if we have no
`glyf' table but a non-zero `loca' entry.
(tt_loader_init): Handle missing `glyf' table.
* src/base/ftobjs.c (FT_Load_Glyph): Undo change 2008-12-05.
* src/sfnt/sfobjs.c (sfnt_load_face): A font with neither outlines
nor bitmaps is scalable.
include/freetype/config/ftheader.h, include/freetype/freetype.h,
src/base/Jamfile, src/base/rules.mk, src/cff/cffdrivr.c,
src/cff/cffgload.c, src/cff/cffgload.h, src/truetype/ttdriver.c,
src/truetype/ttgload.h, src/truetype/ttgload.c, src/type1/t1driver.c,
src/type1/t1gload.h, src/type1/t1gload.c:
Add a new header named FT_ADVANCES_H declaring some new APIs
to extract the advances of one or more glyphs without necessarily
loading their outlines. Also provide 'fast loaders' for the
TrueType, Type1 and CFF font drivers (more to come later)
* autogen.sh: add checks for minimum version of the 'autotools'
stuff.
Pass dropout rules from the TT bytecode interpreter to the
rasterizer; temporarily this is enabled only if
`USE_SCAN_CONVERSION_RULES' is defined.
* include/freetype/ftimage.h (FT_OUTLINE_SMART_DROPOUTS,
FT_OUTLINE_EXCLUDE_STUBS): New flags for for FT_Outline.
* src/raster/ftraster.c (Vertical_Sweep_Drop, Horizontal_Sweep_Drop,
Horizontal_Gray_Sweep_Drop): Use same mode numbers as given in the
OpenType specification.
Fix mode 4 computation.
(Render_Glyph, Render_Gray_Glyph): Handle new outline flags.
* src/truetype/ttgload.c (TT_Load_Glyph)
[USE_SCAN_CONVERSION_RULES]: Convert scan conversion mode to
FT_OUTLINE_XXX flags.
* src/truetype/ttinterp.c (Ins_SCANCTRL): Enable ppem check.
of the graphics state for subglyphs to...
(TT_Hint_Glyph): This function.
Hinting instructions for a composite glyph apparently refer to the
just hinted subglyphs, not the unhinted, unscaled outline. This
seems to fix Savannah bugs #20973 and (at least partially) #23310.
expanded). This is needed for options like
--includedir='${prefix}/include'.
* builds/unix/detect.mk, configure: Prevent argument expansion in
call to the (real) `configure' script.
* src/truetype/ttgload.c (load_truetype_glyph): Fix compilation if
TT_USE_BYTECODE_INTERPRETER isn't defined.
There exist CFFs which contain opcodes for the Type 1 operators
`hsbw' and `closepath' which are both invalid in Type 2 charstrings.
However, it doesn't harm to support them.
* src/cff/cffgload.c (CFF_Operator): Add `cff_op_hsbw' and
`cff_op_closepath.'
(cff_argument_counts): Ditto.
(cff_decoder_parse_charstrings): Handle Type 1 opcodes 9 (closepath)
and 13 (hsbw) which are invalid in Type 2 charstrings.
recursion depth of 1. This was the maximum value in TrueType 1.0,
and some older fonts don't set this field correctly.
* src/gxvalid/gxvmort1.c
(gxv_mort_subtable_type1_substTable_validate): Fix tracing message.
number of points in contours. Problem reported by Victor Stinner
<victor.stinner@haypocalc.com>.
(TT_Process_Simple_Glyph): Synchronize variable types.
* src/truetype/ttgload.c (tt_loader_init): Re-execute the CVT
program after a change from mono to grayscaling (and vice versa).
Use correct constant for comparison to get `exec->grayscale'.
include/freetype/internal/tttypes.h, src/base/ftgloadr.c,
src/base/ftobjs.c, src/truetype/ttgload.c, src/truetype/ttinterp.c,
src/truetype/ttobjs.c: improvements to native TrueType hinting,
this is a first try, controlled by the FIX_BYTECODE macro in
src/truetype/ttinterp.c
Werner Lemberg