emacs-29 b8d2ec920f: Revert "Improve last change to xfaces.c" (05ece1eb8b)

[Gregory Heytings]

branch: emacs-29
commit b8d2ec920f37f5d77d32440eefc97dd5e8c2c7dc
Author: Gregory Heytings <gregory@heytings.org>
Commit: Gregory Heytings <gregory@heytings.org>

    Revert "Improve last change to xfaces.c" (05ece1eb8b)
    
    * src/xfaces.c: Revert 05ece1eb8b.
    
    See https://debbugs.gnu.org/cgi/bugreport.cgi?bug=59347#331.
---
 src/xfaces.c | 111 ++++++++++++++++++++++++++++-------------------------------
 1 file changed, 52 insertions(+), 59 deletions(-)

diff --git a/src/xfaces.c b/src/xfaces.c
index 7dbcacb35a..643f436589 100644
--- a/src/xfaces.c
+++ b/src/xfaces.c
@@ -6014,21 +6014,6 @@ realize_non_ascii_face (struct frame *f, Lisp_Object 
font_object,
 }
 #endif /* HAVE_WINDOW_SYSTEM */
 
-/* Remove the attribute at INDEX from the font object if SYMBOL
-   appears in `font-fallback-ignored-attributes'.  */
-
-static void
-font_maybe_unset_attribute (Lisp_Object font_object,
-                           enum font_property_index index, Lisp_Object symbol)
-{
-  Lisp_Object tail = Vface_font_lax_matched_attributes;
-
-  FOR_EACH_TAIL_SAFE (tail)
-    {
-      if (EQ (XCAR (tail), symbol))
-       ASET (font_object, index, Qnil);
-    }
-}
 
 /* Realize the fully-specified face with attributes ATTRS in face
    cache CACHE for ASCII characters.  Do it for GUI frame CACHE->f.
@@ -6088,33 +6073,38 @@ realize_gui_face (struct face_cache *cache, Lisp_Object 
attrs[LFACE_VECTOR_SIZE]
       if (! FONT_OBJECT_P (attrs[LFACE_FONT_INDEX]))
        {
          Lisp_Object spec = copy_font_spec (attrs[LFACE_FONT_INDEX]);
-
-         /* Maybe unset several values in SPEC, usually the width,
-            slant, and weight.  The best possible values for these
-            attributes are determined in font_find_for_lface, called
-            by font_load_for_lface, when the list of candidate fonts
-            returned by font_list_entities is sorted by font_select_entity
-            (which calls font_sort_entities, which calls font_score).
-            If these attributes are not unset here, the candidate
-            font list returned by font_list_entities only contains
-            fonts that are exact matches for these weight, slant, and
-            width attributes, which could lead to suboptimal or wrong
-            font selection.  (bug#5934) */
-         font_maybe_unset_attribute (spec, FONT_WEIGHT_INDEX, QCweight);
-         font_maybe_unset_attribute (spec, FONT_SLANT_INDEX, QCslant);
-         font_maybe_unset_attribute (spec, FONT_WIDTH_INDEX, QCwidth);
+#define   MAYBE_UNSET_ATTRIBUTE(ATTR)                  \
+         if (realize_gui_face_ignored_spec_attributes  \
+             & (1 << FONT_##ATTR##_INDEX))             \
+           ASET (spec, FONT_##ATTR##_INDEX, Qnil);
+         /* The default value of
+            realize_gui_face_ignored_spec_attributes unsets the
+            weight, slant and width in spec.  The best possible
+            values for these attributes is determined in
+            font_find_for_lface, called by font_load_for_lface, when
+            the candidate list returned by font_list_entities is
+            sorted by font_select_entity (which calls
+            font_sort_entities, which calls font_score).  If these
+            attributes are not unset here, the candidate font list
+            returned by font_list_entities only contains fonts that
+            are exact matches for these weight, slant and width
+            attributes, which leads to suboptimal or wrong font
+            choices.  See bug#59347.  */
+         MAYBE_UNSET_ATTRIBUTE (WEIGHT);
+         MAYBE_UNSET_ATTRIBUTE (SLANT);
+         MAYBE_UNSET_ATTRIBUTE (WIDTH);
          /* Also allow unsetting other attributes for debugging
-            purposes.  But not FONT_EXTRA_INDEX; that is not safe to
-            touch, at least in the Haiku font backend.  */
-         font_maybe_unset_attribute (spec, FONT_FAMILY_INDEX, QCfamily);
-         font_maybe_unset_attribute (spec, FONT_FOUNDRY_INDEX, QCfoundry);
-         font_maybe_unset_attribute (spec, FONT_REGISTRY_INDEX, QCregistry);
-         font_maybe_unset_attribute (spec, FONT_ADSTYLE_INDEX, QCadstyle);
-         font_maybe_unset_attribute (spec, FONT_SIZE_INDEX, QCsize);
-         font_maybe_unset_attribute (spec, FONT_DPI_INDEX, QCdpi);
-         font_maybe_unset_attribute (spec, FONT_SPACING_INDEX, QCspacing);
-         font_maybe_unset_attribute (spec, FONT_AVGWIDTH_INDEX, QCavgwidth);
-
+            purposes.  */
+         MAYBE_UNSET_ATTRIBUTE (FAMILY);
+         MAYBE_UNSET_ATTRIBUTE (FOUNDRY);
+         MAYBE_UNSET_ATTRIBUTE (REGISTRY);
+         MAYBE_UNSET_ATTRIBUTE (ADSTYLE);
+         MAYBE_UNSET_ATTRIBUTE (SIZE);
+         MAYBE_UNSET_ATTRIBUTE (DPI);
+         MAYBE_UNSET_ATTRIBUTE (SPACING);
+         MAYBE_UNSET_ATTRIBUTE (AVGWIDTH);
+         MAYBE_UNSET_ATTRIBUTE (EXTRA);
+#undef    MAYBE_UNSET_ATTRIBUTE
          attrs[LFACE_FONT_INDEX] = font_load_for_lface (f, attrs, spec);
        }
       if (FONT_OBJECT_P (attrs[LFACE_FONT_INDEX]))
@@ -7404,24 +7394,27 @@ Lisp programs that change the value of this variable 
should also
 clear the face cache, see `clear-face-cache'.  */);
   face_near_same_color_threshold = 30000;
 
-  DEFVAR_LISP ("face-font-lax-matched-attributes",
-              Vface_font_lax_matched_attributes,
-              doc: /* Font-related face attributes to match in lax manner when 
realizing faces.
-
-The value should be a list of font-related face attribute symbols;
-see `set-face-attribute' for the full list of attributes.  The
-corresponding face attributes will be treated as "soft" constraints
-when looking for suitable fonts: if an exact match is not possible,
-a font can be selected that is a close, but not an exact, match.  For
-example, looking for a semi-bold font might select a bold or a medium
-font if no semi-bold font matching other attributes is found.  Emacs
-still tries to find a font that is the closest possible match; in
-particular, if a font is available that matches the face attributes
-exactly, it will be selected.
-
-Note that if the `:extra' attribute is present in the value, it
-will be ignored.  */);
-  Vface_font_lax_matched_attributes = list3 (QCweight, QCslant, QCwidth);
+  DEFVAR_INT ("realize-gui-face-ignored-spec-attributes",
+             realize_gui_face_ignored_spec_attributes,
+             doc: /* Ignored font-spec attributes in realize_gui_face.
+
+The value is an integer number and represents a bit mask.
+The attribute corresponding to each bit that is set is cleared in
+realize_gui_face.  The bits are: 1 = :foundry, 2 = :family,
+3 = :adstyle, 4 = :registry, 5 = :weight, 6 = :slant, 7 = :width,
+8 = :size, 9 = :dpi, 10 = :spacing, 11 = :avgwidth, 12 = extra
+attributes (:name, :script, :lang and :otf).
+
+Bits 5 to 7 are set in the default value.  When these bits are not
+set, and when the font chosen for the default face has a weight, slant
+or width that is not supported by other available fonts on the system,
+such as 'medium', Emacs may select suboptimal fonts for other faces.
+
+There is no reason to change that value except for debugging purposes.  */);
+  realize_gui_face_ignored_spec_attributes =
+    (1 << FONT_WEIGHT_INDEX) |
+    (1 << FONT_SLANT_INDEX) |
+    (1 << FONT_WIDTH_INDEX);
 
 #ifdef HAVE_WINDOW_SYSTEM
   defsubr (&Sbitmap_spec_p);