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.
* src/truetype/ttobjs.c (tt_size_init_bytecode): Don't reset x_ppem
and y_ppem. Otherwise the `*_CVT_Stretched' functions in ttinterp.c
get never called.
An anonymous guy suggested this change on Savannah, and it seems to
be the right solution.
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.
* include/freetype/internal/services/svmm.h add macros to init
instances of FT_Service_MultiMastersRec.
* include/freetype/internal/services/svttglyf.h add macros to init
instances of FT_Service_TTGlyfRec.
* src/truetype/ttdriver.h declare tt_driver_class using macros from
ftdriver.h, when FT_CONFIG_OPTION_PIC is defined create and destroy
functions will be declared.
* src/truetype/ttdriver.c when FT_CONFIG_OPTION_PIC is defined
the following structs:
tt_service_gx_multi_masters, tt_service_truetype_glyf, tt_driver_class
and tt_services array,
will have functions to init or create and destroy them
instead of being allocated in the global scope.
And macros will be used from ttpic.h in order to access them
from the pic_container.
* src/truetype/ttobjs.c change trick_names array to be
PIC-compatible by being a two dimentional array rather than array
of pointers.
New Files:
* src/truetype/ttpic.h declare struct to hold PIC globals for truetype
driver and macros to access them.
* src/truetype/ttpic.c implement functions to allocate, destroy and
initialize PIC globals for truetype driver.
* src/truetype/truetype.c add new file to build: ttpic.c.
* src/truetype/jamfile add new files to FT2_MULTI build: ttpic.c.
extern const FT_Module_Class
(or similar for C++). However, the actual types of the variables
being declared are often different, e.g., FT_Driver_ClassRec or
FT_Renderer_Class. (Some are, indeed, FT_Module_Class.)
This works with most C compilers (since those structs begin with an
FT_Module_Class struct), but technically it's undefined behavior.
To quote the ISO/IEC 9899:TC2 final committee draft, section 6.2.7
paragraph 2:
All declarations that refer to the same object or function shall
have compatible type; otherwise, the behavior is undefined.
(And they are not compatible types.)
Most C compilers don't reject (or even detect!) code which has this
issue, but the GCC LTO development branch compiler does. (It
outputs the types of the objects while generating .o files, along
with a bunch of other information, then compares them when doing the
final link-time code generation pass.)
Patch from Savannah bug #25133.
* src/base/ftinit.c (FT_USE_MODULE): Include variable type.
* builds/amiga/include/freetype/config/ftmodule.h,
include/freetype/config/ftmodule.h, */module.mk: Updated to declare
pass correct types to FT_USE_MODULE.
FT_FACE_FLAG_TRICKY to indicate that the font format's hinting
engine is necessary for correct rendering.
At the same time, slightly modify the behaviour of tricky fonts:
FT_LOAD_NO_HINTING is now ignored. To really force raw loading
of tricky fonts (without hinting), both FT_LOAD_NO_HINTING and
FT_LOAD_NO_AUTOHINT must be used.
Finally, tricky TrueType fonts always use the bytecode interpreter
even if the patented code is used.
* include/freetype/freetype.h (FT_FACE_FLAG_TRICKY, FT_IS_TRICKY):
New macros.
* src/truetype/ttdriver.c (Load_Glyph): Handle new load flags
semantics as described above.
* src/truetype/ttobjs.c (tt_check_trickyness): New function, using
code of ...
(tt_face_init): This function, now simplified and updated to new
semantics.
* src/base/ftobjs.c (FT_Load_Glyph): Don't use autohinter for tricky
fonts.
* docs/CHANGES: Document it.
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.
(cff_face_done), src/pfr/pfrobjs.c (pfr_face_done),
src/pcf/pcfdrivr.c (PCF_Face_Done), src/cid/cidobjs.c
(cid_face_done), src/bdf/bdfdrivr. (BDF_Face_Done),
src/sfnt/sfobjs.c (sfnt_face_done): Protect against face == 0.
Reported by Graham Asher.
include/freetype/config/ftconfig.h, builds/unix/ftconfig.in: Minor
beautifying.
* include/freetype/ftadvanc.h, include/freetype/ftgasp.h,
include/freetype/ftlcdfil.h: Protect against FreeType 1.
Some other minor fixes.
* devel/ftoption.h: Synchronize with
include/freetype/config/ftoption.h.
Formatting, documentation improvements.
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.
* src/raster/ftraster.c (Render_Glyph, Render_Gray_Glyph,
Draw_Sweep): No-dropout mode is value 2, not value 0.
(Draw_Sweep): Really skip dropout handling for no-dropout mode.
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.
