Provide text directionality and language to HarfBuzz shaper

* lisp/language/tv-util.el (tai-viet-composition-function):
* lisp/language/ethio-util.el (ethio-composition-function):
* lisp/language/japanese.el (compose-gstring-for-variation-glyph):
* 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/hebrew.el (hebrew-shape-gstring):
* lisp/composite.el (compose-gstring-for-graphic)
(compose-gstring-for-dotted-circle, auto-compose-chars)
(compose-gstring-for-terminal): Accept 2nd argument DIRECTION; all
callers changed.

* src/composite.c (composition_reseat_it): Call
auto-composition-function with one more argument DIRECTION.
(syms_of_composite) <auto-composition-function>: Update the doc
string.
* src/ftfont.c (ftfont_shape_by_hb): Compute language and
direction, and set buffer properties accordingly.
* src/composite.c (autocmp_chars):
* src/w32uniscribe.c (uniscribe_shape):
* src/xftfont.c (xftfont_shape):
* src/ftfont.c (ftfont_shape, ftfont_shape_by_hb):
* src/font.c (Ffont_shape_gstring): Accept an additional argument
DIRECTION.
* src/macfont.m (lgstring_direction): New enum.
(mac_font_shape_1, mac_screen_font_shape, mac_font_shape):
Accept an additional argument specifying text direction.  All
callers changed.
* src/font.c (syms_of_font): New symbols QL2R and QR2L.
* src/font.h (shape): Accept new argument DIRECTION.  All
implementations changed.  (Bug#33729)
(ftfont_shape): Update prototype.

1 files changed, 6 insertions, 1 deletions

diff --git a/src/w32uniscribe.c b/src/w32uniscribe.c
index 29c9c7a0bd1..3c400f38b13 100644
--- a/src/w32uniscribe.c
+++ b/src/w32uniscribe.c
@@ -198,6 +198,9 @@ uniscribe_otf_capability (struct font *font)
    (N+1)th element of LGSTRING is nil, input of shaping is from the
    1st to (N)th elements.  In each input glyph, FROM, TO, CHAR, and
    CODE are already set.
+   DIRECTION is either L2R or R2L, or nil if unknown.  During
+   redisplay, this comes from applying the UBA, is passed from
+   composition_reseat_it, and is used by the HarfBuzz shaper.
 
    This function updates all fields of the input glyphs.  If the
    output glyphs (M) are more than the input glyphs (N), (N+1)th
@@ -206,7 +209,7 @@ uniscribe_otf_capability (struct font *font)
    than the length of LGSTRING, nil should be returned.  In that case,
    this function is called again with a larger LGSTRING.  */
 static Lisp_Object
-uniscribe_shape (Lisp_Object lgstring)
+uniscribe_shape (Lisp_Object lgstring, Lisp_Object direction)
 {
   struct font *font = CHECK_FONT_GET_OBJECT (LGSTRING_FONT (lgstring));
   struct uniscribe_font_info *uniscribe_font
@@ -394,6 +397,8 @@ uniscribe_shape (Lisp_Object lgstring)
 			 adjustment for the base character, which is
 			 then updated for each successive glyph in the
 			 grapheme cluster.  */
+		      /* FIXME: Should we use DIRECTION here instead
+			 of what ScriptItemize guessed?  */
 		      if (items[i].a.fRTL)
 			{
 			  int j1 = j;