Support text shaping with HarfBuzz

Support text shaping with HarfBuzz

The code to support HarfBuzz was written by these individuals:

  Khaled Hosny <dr.khaled.hosny@gmail.com>
  YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>
  Eli Zaretskii <eliz@gnu.org>

* src/xftfont.c (xftfont_list): Call ftfont_list2.
(xftfont_match): Call ftfont_match2.
(xftfont_open) [HAVE_HARFBUZZ]: Set the font driver to
xfthbfont_driver as required.  Reset xftfont_info->hb_font to
NULL.
(xftfont_close) [HAVE_HARFBUZZ]: Dispose of the hb_font object.
(xftfont_shape): Accept an additional argument DIRECTION and
pass it to ftfont_shape.
(xfthbfont_list, xfthbfont_match, xfthbfont_begin_hb_font)
(xfthbfont_end_hb_font) [HAVE_HARFBUZZ]: New functions.
(syms_of_xftfont): New DEFSYM 'xfthb'.
(syms_of_xftfont_for_pdumper) [HAVE_HARFBUZZ]: Initialize
xfthbfont_driver.

* src/xfns.c (Fx_create_frame, x_create_tip_frame)
[HAVE_HARFBUZZ]: Register the HarfBuzz font driver.

* src/w32uniscribe.c (bswap_32) [HAVE_HARFBUZZ]: Define to use
the builtin for GCC 4.3.9 and newer; else use byteswap.h from
Gnulib.
(struct uniscribe_font_info): New member 'scale'.  The member
'cache' is now used both by Uniscribe and HarfBuzz backends.
(uniscribe_open): Set the font backend as required by the font
entity's font_type field.
(uniscribe_close) [HAVE_HARFBUZZ]: Dispose of the hb_font
object.
(uniscribe_shape): Accept an additional argument DIRECTION.
(w32hb_list, w32hb_match, free_cb, w32hb_get_font_table)
(w32hb_get_font, w32hb_encode_char, w32hb_begin_font)
(w32hb_get_variation_glyphs, load_harfbuzz_funcs)
[HAVE_HARFBUZZ]: New functions.
(syms_of_w32uniscribe_for_pdumper): Initialize
harfbuzz_font_driver if loading the requisite functions from
the HarfBuzz DLL succeeded.

* src/w32font.c (syms_of_w32font): New DEFSYM 'harfbuzz'.

* src/w32fns.c (Fx_create_frame, w32_create_tip_frame):
Determine whether we should register the HarfBuzz backend, or
Uniscribe backend, or both for the new frame.

* src/w32common.h (hbfont_init_w32_funcs) [HAVE_HARFBUZZ]: Add
prototype.

* src/macfont.m (lgstring_direction): New enumeration.
(mac_font_shape_1, mac_screen_font_shape, macfont_shape):
Accept an additional argument DIRECTION; all callers changed.

* src/lisp.h (get_unicode_property): Add prototype.

* src/hbfont.c: New file.

* src/ftxfont.c (ftxfont_list): Call ftfont_list2.
(ftxfont_match): Call ftfont_match2.

* src/ftfont.h [HAVE_HARFBUZZ]: Include hb.h and hb-ft.h.
(struct font_info): New member hb_font.

* src/ftfont.c (ftfont_list2, ftfont_list_family): New functions.
(ftfont_open) [HAVE_HARFBUZZ]: Reset ftfont_info->hb_font to
NULL.  Set the font backend to fthbfont_driver when required.
(ftfont_close) [HAVE_HARFBUZZ]: Dispose of ftfont_info->hb_font.
(ftfont_glyph_metrics): New function.
(ftfont_text_extents): Call ftfont_glyph_metrics instead of
FT_Load_Glyph.
(ftfont_shape): Accept an additional argument DIRECTION.
(ftfont_variation_glyphs) [!HAVE_OTF_GET_VARIATION_GLYPHS]:
Support for variation glyphs without FLT.
(fthbfont_begin_hb_font) [HAVE_HARFBUZZ]: New function.
(syms_of_ftfont): New DEFSYM freetypehb.
(syms_of_ftfont_for_pdumper): Initialize fthbfont_driver.

* src/ftcrfont.c (ftcrfont_list): Call ftfont_list2.
(ftcrfont_match): Call ftfont_match2.
(ftcrfont_open) [HAVE_HARFBUZZ]: Set the font backend to
ftcrhbfont_driver as required.  Reset ftcrfont_info->hb_font
to NULL.
(ftcrfont_close) [HAVE_HARFBUZZ]: Discard of
ftcrfont_info->hb_font.
(ftcrfont_shape): Pass DIRECTION to ftfont_shape.
(ftcrhbfont_list, ftcrhbfont_match)
(ftcrhbfont_begin_hb_font, ftcrhbfont_end_hb_font)
[HAVE_HARFBUZZ]: New functions.
(syms_of_ftcrfont): New DEFSYM ftcrhb.
(syms_of_ftcrfont_for_pdumper): Initialize ftcrhbfont_driver.

* src/font.h [HAVE_HARFBUZZ]: Include hb.h.
(struct font_driver): Update comments and function signatures
to reflect the new argument DIRECTION accepted by the 'shape'
method.  New methods 'begin_hb_font' and 'end_hb_font'.
(hbfont_shape, hbfont_combining_capability)
(fthbfont_begin_hb_font) [HAVE_HARFBUZZ]: Add prototypes.

* src/font.c (Ffont_shape_gstring): Accept an additional
argument DIRECTION, and pass it to the font driver's 'shape'
method.
(Ffont_variation_glyphs): Doc fix.
(syms_of_font): New DEFSYMS L2R and R2L.

* src/composite.h (composition_reseat_it): Adjust prototype.

* src/composite.c (autocmp_chars): Accept additional argument
DIRECTION, and pass it to auto-composition-function.  All
callers changed.
(composition_reseat_it): Accept additional argument
BIDI_LEVEL, and use it to determine the DIRECTION argument to
be passed to autocmp_chars.  All callers changed.
(syms_of_composite) <auto-composition-function>: Improve the
doc string; document the meaning of the new argument
DIRECTION.

* src/chartab.c (get_unicode_property): New function,
refactored from the body of get-unicode-property-internal.
(Fget_unicode_property_internal): Call get_unicode_property
after validating the input arguments.

* src/Makefile.in (HARFBUZZ_CFLAGS, HARFBUZZ_LIBS): New macros.
(EMACS_CFLAGS): Use HARFBUZZ_CFLAGS.
(SOME_MACHINE_OBJECTS): Add hbfont.o
(LIBES): Add HARFBUZZ_LIBS.

* lisp/language/tv-util.el (tai-viet-composition-function):
* lisp/language/thai-util.el (thai-composition-function):
* lisp/language/misc-lang.el (arabic-shape-gstring):
* lisp/language/lao-util.el (lao-composition-function):
* lisp/language/japanese.el (compose-gstring-for-variation-glyph):
* lisp/language/hebrew.el (hebrew-shape-gstring):
* lisp/language/ethio-util.el (ethio-composition-function):
* lisp/composite.el (compose-chars-after)
(compose-gstring-for-graphic)
(compose-gstring-for-dotted-circle)
(compose-gstring-for-terminal, auto-compose-chars): All
composition functions that call shapers now accept an
additional argument DIRECTION, either L2R or R2L.

* etc/NEWS: Document the HarfBuzz support.

* etc/HELLO: Add diacritics to Hebrew greetings.

* doc/lispref/frames.texi (Font and Color Parameters):
* doc/emacs/msdos.texi (Windows Fonts): Describe the
'harfbuzz' font backend on MS-Windows and how it is preferred
to 'uniscribe'.

* configure.ac (--wthout-harfbuzz): New option.
(HAVE_HARFBUZZ): New tests.
(FONT_OBJ) [HAVE_HARFBUZZ]: Add hbfont.o
(emacs_config_features): Add HARFBUZZ.

* admin/nt/dist-build/build-dep-zips.py: Add HarfBuzz dependency.