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, 23 insertions, 8 deletions

diff --git a/src/macfont.m b/src/macfont.m
index d137648937c..ee6c1737269 100644
--- a/src/macfont.m
+++ b/src/macfont.m
@@ -38,6 +38,12 @@ Original author: YAMAMOTO Mitsuharu
 
 #include <libkern/OSByteOrder.h>
 
+/* Values for `dir' argument to shaper functions.  */
+enum lgstring_direction
+  {
+    DIR_R2L = -1, DIR_UNKNOWN = 0, DIR_L2R = 1,
+  };
+
 static double mac_font_get_advance_width_for_glyph (CTFontRef, CGGlyph);
 static CGRect mac_font_get_bounding_rect_for_glyph (CTFontRef, CGGlyph);
 static CFArrayRef mac_font_create_available_families (void);
@@ -48,7 +54,8 @@ static Boolean mac_font_descriptor_supports_languages (CTFontDescriptorRef,
                                                        CFArrayRef);
 static CFStringRef mac_font_create_preferred_family_for_attributes (CFDictionaryRef);
 static CFIndex mac_font_shape (CTFontRef, CFStringRef,
-                               struct mac_glyph_layout *, CFIndex);
+                               struct mac_glyph_layout *, CFIndex,
+                               enum lgstring_direction);
 static CFArrayRef mac_font_copy_default_descriptors_for_language (CFStringRef);
 static CFStringRef mac_font_copy_default_name_for_charset_and_languages (CFCharacterSetRef, CFArrayRef);
 #if USE_CT_GLYPH_INFO
@@ -317,7 +324,8 @@ mac_screen_font_get_metrics (ScreenFontRef font, CGFloat *ascent,
 
 static CFIndex
 mac_font_shape_1 (NSFont *font, NSString *string,
-                  struct mac_glyph_layout *glyph_layouts, CFIndex glyph_len)
+                  struct mac_glyph_layout *glyph_layouts, CFIndex glyph_len,
+                  enum lgstring_direction dir)
 {
   NSUInteger i;
   CFIndex result = 0;
@@ -581,11 +589,11 @@ mac_font_shape_1 (NSFont *font, NSString *string,
 static CFIndex
 mac_screen_font_shape (ScreenFontRef font, CFStringRef string,
                        struct mac_glyph_layout *glyph_layouts,
-                       CFIndex glyph_len)
+                       CFIndex glyph_len, enum lgstring_direction dir)
 {
   return mac_font_shape_1 ([(NSFont *)font printerFont],
                            (NSString *) string,
-                           glyph_layouts, glyph_len);
+                           glyph_layouts, glyph_len, dir);
 }
 
 static CGColorRef
@@ -2916,7 +2924,7 @@ macfont_draw (struct glyph_string *s, int from, int to, int x, int y,
 }
 
 static Lisp_Object
-macfont_shape (Lisp_Object lgstring)
+macfont_shape (Lisp_Object lgstring, Lisp_Object direction)
 {
   struct font *font = CHECK_FONT_GET_OBJECT (LGSTRING_FONT (lgstring));
   struct macfont_info *macfont_info = (struct macfont_info *) font;
@@ -2966,12 +2974,18 @@ macfont_shape (Lisp_Object lgstring)
                                                kCFAllocatorNull);
   if (string)
     {
+      enum lgstring_direction dir = DIR_UNKNOWN;
+
+      if (EQ (direction, QL2R))
+        dir = DIR_L2R;
+      else if (EQ (direction, QR2L))
+        dir = DIR_R2L;
       glyph_layouts = alloca (sizeof (struct mac_glyph_layout) * glyph_len);
       if (macfont_info->screen_font)
         used = mac_screen_font_shape (macfont_info->screen_font, string,
-                                      glyph_layouts, glyph_len);
+                                      glyph_layouts, glyph_len, dir);
       else
-        used = mac_font_shape (macfont, string, glyph_layouts, glyph_len);
+        used = mac_font_shape (macfont, string, glyph_layouts, glyph_len, dir);
       CFRelease (string);
     }
 
@@ -3652,7 +3666,8 @@ mac_font_create_line_with_string_and_font (CFStringRef string,
 
 static CFIndex
 mac_font_shape (CTFontRef font, CFStringRef string,
-                struct mac_glyph_layout *glyph_layouts, CFIndex glyph_len)
+                struct mac_glyph_layout *glyph_layouts, CFIndex glyph_len,
+                lgstring_direction dir)
 {
   CFIndex used, result = 0;
   CTLineRef ctline = mac_font_create_line_with_string_and_font (string, font);