Use the previously changed PS_Driver in type1 module to store
hinting engine configuration.
* include/freetype/ftt1drv.h: New file.
Duplicate and rename config options from CFF.
* include/freetype/config/ftheader.h (FT_TYPE1_DRIVER_H): New macro.
* src/type1/t1driver.c (t1_driver_class): Update declaration.
* src/type1/t1objs.c: Include FT_TYPE1_DRIVER_H.
(T1_Driver_Init): Update code.
Make some fields more generic, so that we can access them the same
way regardless of Type 1 or CFF.
* include/freetype/internal/psaux.h (PS_Builder): Change `TT_Face'
to `FT_Face'.
Remove unused fields.
* src/psaux/psft.c: Update all accesses of `PS_Builder.face'.
Add some asserts to guard against casting `T1_Face' as `TT_Face'.
* src/type1/t1objs.h (T1_GlyphSlot): Reorder fields to follow
`CFF_GlyphSlot', so that we can pretend they are the same in the
interpreter.
* src/psaux/psobjs.c (ps_builder_init, ps_builder_add_point):
Updated with above changes.
We are going to extend this later on.
* include/freetype/internal/ftobjs.h (FT_Size_InternalRec): New
structure with a single field `module_data'.
* src/base/ftobjs.c (FT_New_Size): Allocate `internal' field of
`FT_Size' structure.
* src/cff/cffgload.c (cff_builder_init, cff_decoder_prepare): Use
`size->internal->module_data' instead of `size->internal'.
* src/cff/cffobjs.c (cff_size_done): Deallocate `module_data'.
(cff_size_init, cff_size_select, cff_size_request): Use
`size->internal->module_data' instead of `size->internal'.
* src/cif/cidobjs.c (cid_size_done, cid_size_init,
cid_size_request): Use `size->internal->module_data' instead of
`size->internal'.
* src/psaux/psobjs.c (t1_builder_ini): Use
`size->internal->module_data' instead of `size->internal'.
* src/type1/t1objs.c (T1_Size_Done, T1_Size_Init, T1_Size_Request):
Use `size->internal->module_data' instead of `size->internal'.
For internal use; we want to share code between the forthcoming CFF2
support and TrueType.
* include/freetype/internal/services/svmm.h (FT_Get_Var_Blend_Func):
New typedef.
(MultiMasters): Add `get_var_blend'.
(FT_Service_MultiMasters): Updated.
* src/truetype/ttgxvar.c (tt_get_var_blend): New function.
* src/truetype/ttgxvar.h: Updated.
* src/truetype/ttdriver.c (tt_service_gx_multi_masters): Updated.
* src/type1/t1driver.c (t1_service_multi_masters): Updated.
For internal use; we want to share code between the forthcoming CFF2
support and TrueType.
* include/freetype/internal/services/svmm.h (FT_Done_Blend_Func):
New typedef.
(MultiMasters): Add `done_blend'.
(FT_Service_MultiMasters): Updated.
* src/truetype/ttgxvar.c (tt_done_blend): Use `TT_Face' as argument.
* src/truetype/ttgxvar.h: Updated.
* src/truetype/ttobjs.c (TT_Face_Done): Updated.
* src/truetype/ttdriver.c (tt_service_gx_multi_masters): Updated.
* src/type1/t1driver.c (t1_service_multi_masters): Updated.
Note that the low-level functions aren't implemented yet.
* include/freetype/ftmm.h: Declare.
* include/freetype/internal/services/svmm.h
(FT_Get_Var_Design_Func): New typedef.
(MultiMasters): New MM service function `get_var_design'.
(FT_DEFINE_SERVICE_MULTIMASTERSREC): Updated.
Update all callers.
* src/base/ftmm.c (FT_Get_Var_Design_Coordinates): Implement.
* src/truetype/ttdriver.c: Updated.
* src/truetype/ttgxvar.c (TT_Get_Var_Design): New dummy function to
handle `get_var_design' service.
* src/truetype/ttgxvar.h: Updated.
* src/type1/t1driver.c: Updated.
* src/type1/t1load.c (T1_Get_Var_Design): New dummp function to
handle `get_var_design' service.
* src/type1/t1load.h: Updated.
* include/freetype/ftmm.h: Declare.
* include/freetype/internal/services/svmm.h (FT_Get_MM_Blend_Func):
New typedef.
(MultiMasters): New MM service function `get_mm_blend'.
(FT_DEFINE_SERVICE_MULTIMASTERSREC): Updated.
Update all callers.
* src/base/ftmm.c (FT_Get_MM_Blend_Coordinates,
FT_Get_Var_Blend_Coordinates): Implement.
* src/truetype/ttdriver.c: Updated.
* src/truetype/ttgxvar.c (TT_Get_MM_Blend): New function to handle
`get_mm_blend' service.
* src/truetype/ttgxvar.h: Updated.
* src/type1/t1driver.c: Updated.
* src/type1/t1load.c (T1_Get_MM_Blend): New function to handle
`get_mm_blend' service.
* src/type1/t1load.h: Updated.
* docs/CHANGES: Document.
We now use a hash to map from subr indices to array elements holding
the subroutines, if necessary.
* include/freetype/internal/t1types.h: Include FT_INTERNAL_HASH_H.
(T1_FontRec): Add `subrs_hash' field.
* include/freetype/internal/psaux.h: Include FT_INTERNAL_HASH_H.
(T1_DecoderRec): Add `subrs_hash' field.
* src/type1/t1load.h (T1_LoaderRec): Add `subrs_hash' field.
* src/type1/t1driver.c: Include FT_INTERNAL_HASH_H.
(t1_ps_get_font_value) [PS_DICT_SUBR]: Look up hash if necessary.
* src/type1/t1load.c: Include FT_INTERNAL_HASH_H.
(parse_subrs): Use hash for subr indices that exceed the allocated
number of subr slots.
(t1_init_loader): Remove unnecessary code.
(t1_done_loader, T1_Open_Face): Updated.
* src/type1/t1gload.c (T1_Compute_Max_Advance, T1_Get_Advances,
T1_Load_Glyph): Updated.
* src/type1/t1objs.c (T1_Face_Done): Updated.
* src/psaux/t1decode.c: Include FT_INTERNAL_HASH_H.
(t1_decoder_parse_charstrings) [op_callsubr]: Look up hash if
necessary.
* src/cid/cidgload.c (cid_load_glyph): Updated.
For functions querying a face, bits 16-30 of the face index can hold
the named instance index if we have a GX font. The indices start
with value 1; value 0 indicates font access without GX variation
data.
* include/freetype/freetype.h (FT_FaceRec): Update documentation.
* include/freetype/internal/sfnt.h: Ditto.
* src/sfnt/sfobjs.c (sfnt_init_face)
[TT_CONFIG_OPTION_GX_VAR_SUPPORT]: Get number of named instances and
do argument checks.
(sfnt_load_face): Updated.
* src/truetype/ttobjs.c (tt_face_init)
[TT_CONFIG_OPTION_GX_VAR_SUPPORT]: Use named instance, overwriting
the style name.
* src/base/ftobjs.c (open_face_from_buffer,
open_face_PS_from_sfnt_stream): Updated.
* src/bdf/bdfdrivr.c (BDF_Face_Init): Updated.
* src/cff/cffload.c (cff_font_load): Updated.
* src/cff/cffobjs.c (cff_face_init): Make function exit early for
pure CFF fonts if `font_index < 0'.
Updated.
* src/cid/cidobjs.c (cid_face_init): Updated.
* src/pcf/pcfdrivr.c (PCF_Face_Init): Updated.
* src/pfr/pfrobjs.c (pfr_face_init): Updated.
* src/type1/t1objs.c (T1_Face_Init): Updated.
* src/type42/t42objs.c (T42_Face_Init): Updated.
* src/winfonts/winfnt.c (fnt_face_get_dll_font, FNT_Face_Init):
Updated.
* docs/CHANGES: Updated.
* src/type1/t1gload.c (T1_Load_Glyph): Directly modify advances only
if font matrix is not trivial.
* src/cff/cffgload.c (cff_slot_load): Ditto.
* sff/cid/cidgload.c (cid_slot_load_glyph): Ditto for advances and the
entire outline.
* src/type1/t1load.c (t1_parse_font_matrix): Scale units per EM only
when necessary. Refresh comments.
* src/cid/cidload.c (cid_parse_font_matrix): Ditto.
* src/type42/t42parse.c (t42_parse_font_matrix): Refresh comments.
This is just very basic stuff and just a little bit tested on
GNU/Linux only. I won't delve into this since I'm not a Jam user.
* Jamfile: Call `HDRMACRO' for `ftserv.h' also.
(DEFINES): Replace with...
(CCFLAGS): ... this.
* src/Jamfile: Don't call `HDRMACRO' for `internal.h'; this is
already handled in the top-level Jamfile.
* src/autofit/Jamfile (DEFINES): Replace with...
(CCFLAGS): ... this.
(_sources): Add missing files.
* src/cache/Jamfile: Don't call `HDRMACRO' for `ftcache.h'; it no
longer contains macro header definitions.
* src/base/Jamfile, src/cff/Jamfile, src/sfnt/Jamfile,
src/truetype/Jamfile (_sources): Add missing files.
This commit allows `num_coords' to be larger or smaller than the
number of available axes while selecting a design instance, either
ignoring excess data or using defaults if data is missing.
* src/truetype/ttgxvar.c (TT_Set_MM_Blend, TT_Set_Var_Design):
Implement it.
* src/type1/t1load.c (T1_Set_MM_Blend, T1_Set_MM_Design,
T1_Set_Var_Design): Ditto.
* include/internal/t1types.h (AFM_KernPairRec): Make indices
unsigned.
Update users.
(AFM_FontInfoRec): Make element counters unsigned.
Update users.
* src/psaux/afmparse.h (AFM_ValueRec): Add union member for unsigned
int.
* src/psaux/afmparse.c (afm_parse_track_kern, afm_parse_kern_pairs):
Reject negative values for number of kerning elements.
* src/type1/t1afm.c, src/tools/test_afm.c: Updated.
Assure that FreeType's internal include directories are found before
`CPPFLAGS' (which might be set by the user in the environment), and
`CPPFLAGS' before `CFLAGS'.
* builds/freetype.mk (FT_CFLAGS): Don't add `INCLUDE_FLAGS'.
(FT_COMPILE): Make this a special variable for compiling only the
files handled in `freetype.mk'.
(.c.$O): Removed, unused.
* src/*/rules.mk (*_COMPILE): Fix order of include directories.
We use a cast to indicate that we intentionally ignore a function's
return value. However, this doesn't apply to API functions where
errors can only happen for trivially invalid input.
* src/base/ftstroke.c (FT_Glyph_Stroke, FT_Glyph_StrokeBorder),
src/base/ftsynth.c (FT_GlyphSlot_Embolden), src/cff/cffgload.c
(cff_slot_load), src/pfr/pfrdrivr.c (pfr_get_kerning),
src/type1/t1load.c (parse_encoding), src/type42/t42parse.c
(t42_parse_encoding): Do it.
* src/type1/t1load.c (t1_parse_font_matrix): Properly handle result
of `T1_ToFixedArray'.
* src/cid/cidload.c (cid_parse_font_matrix): Synchronize with
`t1_parse_font_matrix'.
* src/type42/t42parse.c (t42_parse_font_matrix): Synchronize with
`t1_parse_font_matrix'.
(t42_parse_encoding): Synchronize with `t1_parse_encoding'.
* src/psaux/psobjs.c (ps_parser_load_field) <T1_FIELD_TYPE_BBOX>,
<T1_FIELD_TYPE_MMOX>: Properly handle result of `ps_tofixedarray'.
Previously, the loading of a glyph was traced at level 4, if at all.
With this change, all font loading routines emit a tracing message
at level 1, making it easier to select tracing output (for example
using F2_DEBUG="any:1 afhints:7 aflatin:7").
* src/bdf/bdfdrivr.c (BDF_Glyph_Load): Add tracing message.
* src/cff/cffdrivr.c (cff_glyph_load): Ditto.
* src/cff/cffgload.c (cff_decoder_prepare): Improve tracing
messages.
* src/cid/cidgload.c (cid_load_glyph): Use level 1 for tracing
message.
* src/pcf/pcfdrivr.c (PCF_Glyph_Load): Ditto.
* src/pfr/pfrobjs.c (pfr_slot_load): Add tracing message.
* src/truetype/ttgload.c (TT_Load_Glyph): Ditto.
* src/type1/t1gload.c (T1_Load_Glyph): Ditto.
* src/type42/t42objs.c (T42_GlyphSlot_Load): Ditto.
* src/winfonts/winfnt.c (FNT_Load_Glyph): Ditto.
The call was (from the top-level of the FreeType tree):
cppcheck --force \
--enable=all \
-I /usr/include \
-I /usr/local/include \
-I /usr/lib/gcc/i586-suse-linux/4.7/include \
-I include \
-I include/freetype \
-I include/freetype/config \
-I include/freetype/internal \
-DFT2_BUILD_LIBRARY \
. &> cppcheck.log
using cppcheck git commit f7e93f99.
Note that cppcheck still can't handle `#include FOO' (with `FOO' a
macro).
*/* Improve variable scopes.
*/* Remove redundant initializations which get overwritten.
* src/gxvalid/*: Comment out redundant code or guard it with
FT_DEBUG_LEVEL_TRACE.
http://cppcheck.sourceforge.net/
Note that the current version heavily chokes on FreeType, delivering
even wrong results. I will report those issues to the cppcheck team
so that a newer version gives improved results hopefully.
*/* Improve variable scopes.
*/* Remove redundant initializations which get overwritten.
* src/base/ftmac.c ,builds/mac/ftmac.c (count_faces_scalable):
Remove unused variable.
* src/base/ftdbgmem.c (ft_mem_table_destroy): `table' can't be zero.
* src/gxvalid/gxvkern.c (gxv_kern_subtable_fmt1_entry_validate):
Remove functionless code.
* src/tools/ftrandom.c (main): Fix memory leak.
This is essentially a mechanical conversion, adding inclusion of
`FT_INTERNAL_DEBUG_H' where necessary, and providing the macros for
stand-alone compiling modes of the rasterizer modules.
To convert the remaining occurrences of FT_Err_XXX and friends it is
necessary to rewrite the code. Note, however, that it doesn't harm
if some cases are not handled since FT_THROW is a no-op.
* include/freetype/internal/ftserv.h (FT_SERVICE_UNAVAILABLE): Use
`logical not' operator instead of negation. The idea is that `~'
returns exactly the data type enforced by the cast to a pointer (be
it 32bit or 64bit or whatever), while a negative integer has not
this flexibility.
* src/cache/ftccmap.c (FTC_CMAP_UNKNOWN): Ditto.
* src/truetype/ttgxvar.c (ALL_POINTS, TT_Get_MM_Var): Ditto.
* src/type/t1load.c (T1_Get_MM_Var): Ditto.
(parse_blend_axis_types): Use cast.
* src/bdf/bdflib.c (_bdf_readstream): Use cast.
Based on the patch given in the bug report.
* src/type1/t1load.c (IS_INCREMENTAL): New macro.
(read_binary_data): Add parameter `incremental'.
Update all callers using `IS_INCREMENTAL'.
* src/type1/t1load.c (parse_subrs): Add proper guards for `strncmp'.
* src/psaux/psobjs.c (ps_parser_skip_PS_token): Emit error message
only if cur < limit.
Previously, FreeType misleadingly returned
FT_Err_Unknown_File_Format if a module was missing (or a test was
missing completely).
* include/freetype/fterrdef.h (FT_Err_Missing_Module): Define.
* src/cff/cffobjs.c (cff_face_init), src/cid/cidobjs.c
(cid_face_init), src/sfnt/sfobjs.c (sfnt_init_face),
src/truetype/ttobjs.c (tt_face_init), src/type1/t1objs.c
(T1_Face_Init), src/type42/t42objs.c (T42_Face_Init,
T42_Driver_Init): Updated.
* src/type1/t1afm.c (T1_Read_Metrics), src/type/t1objs.c
(T1_Face_Init), src/type42/t42objs.c (T42_Face_Init): Remove now
redundant test for `psaux'.
This allows a Type 1 font face to be interrogated to retrieve most
of the dictionary keys (keys not relevant to FreeType's Type 1
interpreter are not available).
* include/freetype/internal/services/svpsinfo.h
(PS_GetFontValueFunc): New typedef.
(PSInfo): Add `ps_get_font_value'.
(FT_DEFINE_SERVICE_PSINFOREC): Updated.
* include/freetype/internal/t1types.h (T1_EncodingType): Moved to...
* include/freetype/t1tables.h: Here.
(PS_Dict_Keys): New enumeration.
(FT_Get_PS_Font_Value): New declaration.
* src/base/fttype1.c (FT_Get_PS_Font_Value): New function.
* src/type1/t1driver.c (t1_ps_get_font_value): This new function
does the real job.
(t1_service_ps_info): Add it.
* src/cff/cffdrivr.c (cff_service_ps_info), src/cid/cidriver.c
(cid_service_ps_info), src/type42/t42drivr.c (t42_service_ps_info):
Updated.
Found with font fuzzying.
* src/psaux/t1decode.c (t1_decoder_parse_charstrings): Check
`decoder->buildchar'.
* src/type1/t1load.c (t1_load_keyword): Check `blend->num_designs'.
Permit a face for Type1, Type42 and CFF without charmap,
patch by Tor Andersson.
* src/type1/t1objs.c (T1_Face_Init): Reset the error if it
is FT_Err_No_Unicode_Glyph_Name.
* src/type42/t42objs.c (T42_Face_Init): Ditto.
* src/cff/cffobjs.c (cff_face_init): Ditto.
Too serious check of errors by `FT_CMap_New' since 2010-07-04
is fixed. Reported by Tor Andersson.
* include/freetype/fterrdef.h
(PSnames_Err_No_Unicode_Glyph_Name): New error code to
indicate the Unicode charmap synthesis failed because
no Unicode glyph name is found.
* src/psnames/psmodule.c (ps_unicodes_init): Return
PSnames_Err_No_Unicode_Glyph_Name when no Unicode glyph name
is found in the font.
* src/cff/cffcmap.c (cff_cmap_unicode_init): Return
CFF_Err_No_Unicode_Glyph_Name when no SID is available.
* src/type1/t1objs.c (T1_Face_Init): Proceed if `FT_CMap_New'
is failed by the lack of Unicode glyph name.
* src/type42/t42objs.c (T42_Face_Init): Ditto.
* src/cff/cffobjs.c (cff_face_init): Ditto.
Since we consider `sbw' for the horizontal direction only, we still have
to synthesize vertical metrics if the user wants to use the vertical
writing direction.
* src/cff/cffgload.c (cff_slot_load), src/cid/cidgload.c
(cid_slot_load_glyph), src/type1/t1gload.c (T1_Load_Glyph):
Synthesize vertical metrics (only) if FT_LOAD_VERTICAL_LAYOUT is
set.
After long discussion, we now consider the character width vector
(wx,wy) returned by the `sbw' Type 1 operator as being part of *one*
direction only. For example, if you are using the horizontal
writing direction, you get the horizontal and vertical components of
the advance width for this direction. Note that OpenType and CFF fonts
don't have such a vertical component; instead, the GPOS table can be
used to generate two-dimensional advance widths (but this isn't
handled by FreeType).
* include/freetype/ftincrem.h (FT_Incremental_MetricsRec): Add
`advance_v' field to hold the vertical component of the advance
value.
* src/truetype/ttgload.c (tt_get_metrics), src/cff/cffgload.c
(cff_slot_load), src/type1/t1gload.c
(T1_Parse_Glyph_And_Get_Char_String), src/cid/cidgload.c
(cid_load_glyph): Use it.
* src/cff/cffobjs.c (cff_face_init), src/cid/cidobjs.c
(cid_face_init), src/type1/t1afm.c (T1_Read_Metrics),
src/type1/t1objs.c (T1_Face_Init): Don't use unsigned constant
values for rounding if the argument can be negative.
* include/freetype/internal/t1types.h (T1_EncodingRecRec_): Update
comment to reflect revised code_last meaning.
* src/type1/t1load.c (T1_Open_Face), src/type42/t42objs.c
(T42_Open_Face): Assign max_char as highest character code + 1 and
use this for T1_EncodingRecRec_::code_last.
* src/psaux/t1cmap.c (t1_cmap_custom_init): Follow revised
T1_EncodingRecRec_::code_last meaning.
This fixes Savannah bug #26867.
Previously, only integers have been used which can lead to serious
rounding errors.
However, fractional values are only used internally; after the
charstrings (of either Type 1 or 2) have been processed, the
resulting coordinates get rounded to integers currently -- before
applying scaling. This should be fixed; at the same time a new load
flag should be introduced, to be used in combination with
FT_LOAD_NO_SCALE, which indicates that font units are returned in
16.16 format. Similarly, the incremental interface should be
extended to allow fractional values for metrics.
* include/freetype/internal/psaux.h (T1_BuilderRec): Remove `shift'
field.
* include/freetype/internal/pshints.h (T1_Hints_SetStemFunc,
T1_Hints_SetStem3Func): Use FT_Fixed for coordinates.
* src/psaux/psobjs.c: Include FT_INTERNAL_CALC_H.
(t1_build_add_point): Always convert fixed to integer.
* src/psaux/t1decode.c (t1_decoder_parse_charstrings):
Use 16.16 format everywhere (except for large integers followed by a
`div').
[CAN_HANDLE_NON_INTEGRAL_T1_OPERANDS]: Remove #ifdef and activate
code uncoditionally.
Add support for random numbers and update remaining code
accordingly; this should work now.
(t1_operator_seac): Updated.
* src/psaux/pshrec.c: Include FT_INTERNAL_CALC_H.
(ps_hints_t1stem3, t1_hints_stem): Updated.
* src/cid/cidgload.c: Include FT_INTERNAL_CALC_H.
(cid_load_glyph) [FT_CONFIG_OPTION_INCREMENTAL],
(cid_face_compute_max_advance, cid_slot_load_glyph): Updated.
* src/type1/t1gload.c (T1_Parse_Glyph_And_Get_Char_String)
[FT_CONFIG_OPTION_INCREMENTAL], (T1_Get_Advances, T1_Load_Glyph):
Updated.
* src/type1/t1load.c: Include FT_INTERNAL_CALC_H.
* src/type1/t1objs.c (T1_Face_Init): Updated.
Instead, we define a new internal PS_FontExtraRec structure to
hold the additionnal field, then place it in various internal
positions of the corresponding FT_Face derived objects.
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.
fonts (like HELVI.PFB version 003.001, used on OS/2) which define
some `subrs' elements more than once. Problem reported by Peter
Weilbacher <mozilla@weilbacher.org>.
(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.