`FDEF` instructions are specified as allowed only in 'prep' or
'fpgm'. FreeType has attempted to prevent their use in the glyph
program, but they were still allowed in glyph programs if defined in
a function defined in 'prep' or 'fpgm' and called from the glyph
program.
Similarly, `IDEF` instructions are specified not to be able to
modify any existing instruction. FreeType has attempted to prevent
their use in the glyph program, but they can still be used like
`FDEF`.
This change stores the initial bytecode range type and disallows the
use of `FDEF` and `IDEF` while running the glyph program.
Most other state is copied from the `TT_Size` into the execution
context. However, it is possible for a glyph program to use `WS` to
write to the storage area or `WCVTP`, `WCVTF`, and `DELTAC[123]` to
write to the control value table.
Allowing any change to the global state from the glyph program is
problematic as the outlines of any given glyph may change based on
the order the glyphs are loaded or even how many times they are
loaded. There exist fonts that write to the storage area or the
control value table in the glyph program, so their use should not be
an error.
Possible solutions to using these in the glyph program are
* ignore the writes;
* value-level copy on write, discard modified values when finished;
* array-level copy on write, discard the copy when finished;
* array-level copy up-front.
Ignoring the writes may break otherwise good uses. A full copy
up-front was implemented, but was quite heavy as even well behaved
fonts required a full copy and the memory management that goes along
with it. Value-level copy on write could use less memory but
requires a great deal more record keeping and complexity. This
change implements array-level copy on write. If any attempt is made
to write to the control value table or the storage area when the
initial bytecode range was in a glyph program, the relevant array
will be copied to a designated storage area and the copy used for
the rest of the glyph program's execution.
* src/truetype/ttinterp.h (TT_ExecContextRec): New fields
`iniRange`, `glyfCvtSize`, `glyfCvt`, `origCvt`, `glyfStoreSize`,
`glyfStorage`, and `origStorage`.
* src/truetype/ttinterp.c (Modify_CVT_Check): New function to handle
`exc->glyfCvt`.
(Write_CVT, Write_CVT_Stretched, Move_CVT, Move_CVT_Stretched): Use
it.
(Ins_WS): Handle `exc->glyfStorage`.
(Ins_FDEF, Ins_IDEF): Updated.
(TT_RunIns): Updated.
(TT_Done_Context): Free 'glyf' CVT working and storage area.
(TT_Load_Context): Fix/add casts.
* src/truetype/ttgload.c (TT_Load_Simple_Glyph): Fix cast.
* src/truetype/ttinterp.h (TT_Round_Func): Change the last argument.
* src/truetype/ttinterp.c (Ins_ROUND, Ins_NROUND, Ins_MDAP, Ins_MIAP,
Ins_MDRP, Ins_MIRP): Move compensation retrieval from here...
(Round_*): ... to here.
* src/truetype/ttobjs.c (tt_size_init_bytecode): Reserve zero
compensation at color index 3.
This monster commit was created by applying Nikhil's scripts
`docconverter.py' and `markify.py' to all C header and source files,
followed up by minor manual clean-up.
No change in functionality, of course.
I used commit f7419907bc6044b9b7057f9789866426c804ba82 from
https://github.com/nikramakrishnan/freetype-docs.git.
* src/truetype/ttinterp.h (TT_ExecContextRec): Using `FT_ULong' for
loop counter handling.
* src/truetype/ttinterp.c: Updated.
(Ins_SCANTYPE): Use signed constant.
(TT_RunIns): Ensure `num_twilight_points' is 16bit.
This speeds up FreeType's handling of malformed fonts.
* src/truetype/ttinterp.c (TT_RunIns): Set up limits for the number
of twilight points, the total number of negative jumps, and the
total number of loops in LOOPCALL opcodes. The values are based on
the number of points and entries in the CVT table.
(Ins_JMPR): Test negative jump counter.
(Ins_LOOPCALL): Test loopcall counter.
* src/truetype/ttinterp.h (TT_ExecContext): Updated.
* docs/CHANGES: Updated.
This patch prepares data structures and the like.
See added comments in `ttinterp.h' for more information on this and
the following commits in the series.
* devel/ftoption.h, include/freetype/config/ftoption.h
(TT_CONFIG_OPTION_SUBPIXEL_HINTING): Assign values to differentiate
between subpixel versions.
(TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY,
TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL): New macros.
* include/freetype/ftttdrv.h (TT_INTERPRETER_VERSION_40): New macro.
* include/freetype/internal/tttypes.h (TT_FaceRec): Updated.
* src/truetype/ttinterp.h (TT_ExecContextRec): Define new fields
`subpixel_hinting_lean', `vertical_lcd_lean',
`backwards_compatibility', `iupx_called', iupy_called', and
`grayscale_cleartype' for new hinting mode.
* src/truetype/ttdriver.c (tt_property_set): Handle v38 and v40
interpreters conditionally.
* src/truetype/ttgload.c (TT_Hint_Glyph): Save phantom points unless
in v38 backwards compatibility mode.
Updated.
(compute_glyph_metrics): Add v38 backwards compatibility mode
constraint for adjusting advance widths.
Updated.
(tt_loader_init): Handle new flags `subpixel_hinting_lean',
`grayscale_cleartype', and `vertical_lcd_lean'.
Updated.
(tt_get_metrics, TT_Process_Simple_Glyph, TT_LOADER_SET_PP):
Updated.
* src/truetype/ttobjs.c (tt_driver_init): Conditionally set
default interpreter version number.
* src/truetype/ttsubpix.c, src/truetype/ttsubpix.h: Updated.
Previously the code had stipulation for using a per-TT_Size exec
context if `size->debug' was true. But there was no way that
`size->debug' could *ever* be true. As such, the code was always
using the singleton `TT_ExecContext' that was stored in `TT_Driver'.
This was, clearly, not threadsafe.
With this patch, loading glyphs from different faces from different
threads doesn't crash in the bytecode loader code.
* src/truetype/ttobjs.h (TT_SizeRec): Remove `debug' member.
(TT_DriverRec): Remove `context' member.
* src/truetype/ttobjs.c (tt_size_run_fpgm, tt_size_run_prep): Remove
`TT_ExecContext' code related to a global `TT_Driver' object.
(tt_driver_done): Don't remove `TT_ExecContext' object here but ...
(tt_size_done_bytecode): ... here.
(tt_driver_init): Don't create `TT_ExecContext' object here but ...
(tt_size_init_bytecode): ... here, only on demand.
* src/truetype/ttinterp.c (TT_Run_Context): Remove defunct debug
code.
(TT_New_Context): Remove `TT_ExecContext' code related to a global
`TT_Driver' object.
* src/truetype/ttinterp.h: Updated.
* src/truetype/ttgload.c (TT_Hint_Glyph, tt_loader_init): Updated.
This is a follow-up patch.
* src/truetype/ttinterp.c, src/truetype/ttinterp.h
[TT_CONFIG_OPTION_STATIC_INTERPRETER,
TT_CONFIG_OPTION_STATIC_RASTER]: Remove macros and related code.
* src/truetype/ttinterp.h (TT_ExecContextRec): New field
`cur_ppem_func' with a function pointer.
* src/truetype/ttinterp.c (TT_RunIns): Initialize `cur_ppem_func'
depending on the pixel geometry to either...
(Current_Ppem_Stretched): ... this for stretched pixels.
(Current_Ppem): ... or this for square pixels.
(DO_MPPEM, DO_MPS, Ins_DELTAP, Ins_DELTAC): Use `cur_ppem_func'.
This patch unifies the subpixel and non-subpixel cases.
* src/truetype/ttinterp.h (TT_ExecContextRec): Remove
`grayscale_hinting'; all code should refer to `grayscale' instead.
Remove unused `native_hinting' member.
Rename `subpixel_hinting' member to `subpixel.
* src/truetype/ttgload.c (TT_LOADER_SET_PP): Updated.
(tt_loader_init): Updated.
* src/truetype/ttinterp.c (Ins_GETINFO): Simplify.
Updated.
Two benefits: The allocated FDEF (and IDEF) array gets slightly
smaller, and the `ttdebug' demo program has access to function
numbers without additional costs.
Fortunately, no changes to FontForge are necessary – this is the
only external TrueType debugger I know of, but others may exist and
should check the code accordingly.
* src/truetype/ttinterp.h (TT_CallRec): Replace `Cur_Restart' and
`Cur_End' with a pointer to the corresponding `TT_DefRecord'
structure.
* src/truetype/ttinterp.c (DO_JROT, DO_JMPR, DO_JROF, Ins_ENDF,
Ins_CALL, Ins_LOOPCALL, Ins_UNKNOWN, TT_RunIns <Invalid_Opcode>):
Updated.
This patches fixes many issues with the ttsubpix implementation.
1. Data tables are defined, instead of declared, in the header, and
thus copied into each source file that includes it.
2. These tables were defined as global, mutable, visible variables,
and thus costing private RAM to every process that loads the
library (> 50 KB / process, this is huge!).
Additionally, this also made the library export the symbols
completely needlessly.
3. Missing `sph_' and `SPH_' prefixes to some of the definitions.
Note that this doesn't try to fix the incredibly inefficient storage
format for the data tables used by the code. This one will require
another pass in the future.
* src/truetype/ttinterp.h (MAX_NAME_SIZE, MAX_CLASS_MEMBERS):
Renamed to...
(SPH_MAX_NAME_SIZE, SPH_MAX_CLASS_MEMBERS): This.
Update all users.
(SPH_TweakRule, SPH_ScaleRule): Decorate with `const' where
appropriate.
(Font_Class): Rename to...
(SPH_Font_Class): This. Decorate with `const' where appropriate.
* src/truetype/ttsubpix.h (scale_test_tweak, sph_test_tweak):
Decorate arguments with `const' where appropriate.
Move font tweaking tables to...
* src/truetype/ttsubpic.c: This file and decorate them with `static'
and `const' where appropriate.
(X_SCALING_Rules, X_SCALING_RULES_SIZE): Renamed to...
(spu_X_SCALING_Rules, SPH_X_SCALING_RULES_SIZE): This.
Update all users.
* include/freetype/internal/ftcalc.h (FT_MulDiv_No_Round): Don't
enclose with `TT_USE_BYTECODE_INTERPRETER'; we now need the function
elsewhere also.
* src/autofit/afcjk.h: Use AF_CONFIG_OPTION_CJK.
* src/truetype/ttgload.c (tt_loader_init): Fix compiler warning.
* src/truetype/ttinterp.c (Ins_MSIRP): Fix compiler warning.
* src/truetype/ttinterp.h: Use
TT_CONFIG_OPTION_BYTECODE_INTERPRETER.
This is the large, famous `Infinality' patch to support ClearType
bytecode which has been available from
http://www.infinality.net/blog/ for some time, and which has been
refined over the last years. While still experimental, it is now
mature enough to be included directly into FreeType.
Most of the code is based on the ClearType whitepaper written by
Greg Hitchcock
http://www.microsoft.com/typography/cleartype/truetypecleartype.aspx
which gives a detailed overview of the necessary changes to the
Microsoft rasterizer so that older fonts are supported. However, a
lot of details are still missing, and this patches provides a
framework to easily handle rendering issues down to the glyph level
of certain fonts.
Note that ClearType support is not completely implemented! In
particular, full support for the options `compatible_widths',
`symmetrical_smoothing, and `bgr' (via the GETINFO bytecode
instruction) is missing.
* src/truetype/ttsubpix.c: New file, providing code to handle
`tweaks', this is, rules for certain glyphs in certain fonts
(including wildcards) which need a special treatment.
* src/truetype/ttsubpix.h: New file, holding the tweaking rules.
* include/freetype/config/ftoption.h, src/devel/ftoption.h
(TT_CONFIG_OPTION_SUBPIXEL_HINTING): New macro.
* include/freetype/internal/ftobjs.h (FT_PIX_FLOOR_GRID,
FT_PIX_ROUND_GRID, FT_PIX_CEIL_GRID): New macros.
* src/truetype/truetype.c [TT_USE_BYTECODE_INTERPRETER]: Include
`ttsubpix.c'.
* src/truetype/ttgload.c: Include `ttsubpix.h'.
[All changes below are guarded by TT_CONFIG_OPTION_SUBPIXEL_HINTING.]
(tt_get_metrics): Set tweak flags.
(TT_Hint_Glyph): Call `FT_Outline_EmboldenXY' if necessary.
(TT_Process_Simple_Glyph): Compensate emboldening if necessary.
(compute_glyph_metrics): Handle `compatible widths' option.
(tt_loader_init): Handle ClearType GETINFO information bits.
* src/truetype/rules.mk (TT_DRC_SRC): Updated.
* src/truetype/ttinterp.c: Include `ttsubpix.h'.
[Where necessary, changes below are guarded by
TT_CONFIG_OPTION_SUBPIXEL_HINTING.]
(Direct_Move, Direct_Move_X): Extended.
(Round_None, Round_To_Grid, Round_To_Half_Grid, Round_Down_To_Grid,
Round_Up_To_Grid, Round_To_Double_Grid, Round_Super, Round_Super_45,
SetSuperRound): Add parameter to handle the number of grid lines per
pixel.
(SET_SuperRound, ROUND_None, CUR_Func_round): Updated.
(DO_SROUND, DOS45ROUND, DO_ODD, DO_EVEN): Updated.
(DO_ROUND, DO_NROUND): Updated.
(DO_RS): Take care of `Typeman' bytecode patterns.
(Ins_FDEF): Add some debugging code. Commented out.
(Ins_ENDF): Restore state.
(Ins_CALL, Ins_LOOPCALL): Handle inline delta functions.
(Ins_MD): Handle `Vacuform' rounds.
(Move_Zp2_Point, Ins_SHPIX, Ins_MSIRP, Ins_MDAP, Ins_MIAP,
Ins_MDRP, Ins_MIRP): Handle tweaks.
(Ins_ALIGNRP): Add tweak guard.
(Ins_IUP, Ins_DELTAP): Handle tweaks.
(Ins_GETINFO): Handle new ClearType bits.
(TT_RunIns): Handle tweaks.
* src/truetype/ttinterp.h: Updated.
(SPH_TweakRule, SPH_ScaleRule): New structures for tweaks.
(TT_ExecContextRec): Add members for subpixel hinting support.
* src/truetype/ttobjs.h (TT_DefRecord): Add `inline_delta' member.
Jump instructions are now bound to the current function. The MS
Windows rasterizer behaves the same, as confirmed by Greg Hitchcock.
* src/truetype/ttinterp.h (TT_CallRec): Add `Cur_End' element.
* src/truetype/ttobjs.h (TT_DefRecord): Add `end' element.
* src/truetype/ttinterp.c (DO_JROT, DO_JMPR, DO_JROF): Check upper
bound of jump address.
(Ins_FDEF, Ins_CALL, Ins_LOOPCALL, Ins_UNKNOWN, TT_RunIns): Updated.
* src/truetype/ttinterp.c (BOUNDSL): New macro.
Change `BOUNDS' to `BOUNDSL' where appropriate.
* src/truetype/ttinterp.h (TT_ExecContextRec): Fix type of
`cvtSize'.
Acroread does the same.
* src/truetype/ttgload.c (TT_Process_Composite_Glyph): Call
`Update_Max' to adjust size of instructions array if necessary and
add a rough safety check.
(load_truetype_glyph): Save `loader->byte_len' before recursive
call.
* src/truetype/ttinterp.h, src/truetype/ttinterp.c (Update_Max):
Declare it as FT_LOCAL.
unused `max_points' and `max_contours'.
* src/cid/cidobjs.c (cid_face_init), src/type1/t1objs.c
(T1_Face_Init), src/type42/t42objs.c (T42_Face_Init): Update.
* include/freetype/internal/tttypes.h (TT_FaceRec): Remove unused
`max_components'.
* src/truetype/ttinterp.h (TT_ExecContextRec): Remove unused
`loadSize' and `loadStack'.
* src/truetype/ttinterp.c (TT_Done_Context, TT_Load_Context),
src/sfnt/ttload.c (tt_face_load_maxp): Update.
* src/cff/cffobjs.h (cff_size_select), src/sfnt/sfdriver.c
(sfnt_interface), src/truetype/ttdriver.c (tt_size_request): Fix
compiler errors/warnings when TT_CONFIG_OPTION_EMBEDDED_BITMAPS is not
defined.
* src/sfnt/ttmtx.c (tt_face_load_hmtx, tt_face_get_metrics): Fix
possible segment faults for the non-FT_OPTIMIZE_MEMORY'ed versions.
(finally!)
For most OpenType tables, `tt_face_load_xxxx' simply loads the table
and `face->root' is set later in `sfnt_load_face'. Here, we try to
make this work for _all_ tables.
* src/sfnt/ttsbit.c, src/sfnt/ttsbit0.c, src/sfnt/ttload.c,
src/sfnt/ttmtx.c: all `tt_face_load_xxxx' should load the table and
then exit. Error handling or setting face->root is done later in
`sfnt_load_face'.
Pretty trace messages.
* src/sfnt/sfobjs.c (sfnt_load_face): Work harder.
Mac bitmap-only fonts are not scalable.
Check that `face->header.Units_Per_EM' is not zero.
(LOAD_, LOADM_): Pretty trace messages.
* src/sfnt/ttsbit0.c (tt_face_load_strike_metrics): Read metrics from
`eblc'.
* src/sfnt/ttcmap.c (tt_face_build_cmaps), src/sfnt/ttpost.c
(load_format_20, load_format_25, tt_face_get_ps_name): Use
face->max_profile.numGlyphs, instead of face->root.num_glyphs.
TT_Done_Context and rename TT_Destroy_Context to TT_Done_Context with
slight changes.
* src/truetype/ttobjs.h (tt_slot_init): New function.
* src/truetype/ttobjs.c (tt_driver_init): Initialize execution context
here.
(tt_slot_init): New function to create extra points for the internal
glyph loader. We then use it directly, instead of face's glyph loader,
when loading glyph.
* src/truetype/ttdriver.c: Use tt_slot_init for glyph slot
initialization.
(TT_Load_Glyph): Load flag dependencies are handled here.
Return error if size is NULL.
* src/truetype/ttgload.c: Heavy cleanup and refactor.
(TT_Hint_Glyph): New funcion to hint a zone, prepared by caller.
(TT_Process_Simple_Glyph): Use loader->pp's instead of recalculating.
Use TT_Hint_Glyph.
No need to save/restore loader->stream before/after
TT_Vary_Get_Glyph_Deltas now.
(TT_LOADER_SET_PP): New macro to calculate and set the four phantom points.
(TT_Process_Composite_Component, TT_Process_Composite_Glyph,
load_truetype_glyph): Refactor load_truetype_glyph into these three functions.
Never set exec->glyphSize to 0. (close#13107)
Forget glyph frame before calling TT_Process_Simple_Glyph.
(TT_Load_Glyph, load_sbit_image, tt_loader_init): Refactor TT_Load_Glyph into
these three functions.
Set various fields of `glyph' here, instead of in load_truetype_glyph
and compute_glyph_metrics.
Ben Wagner