Revert "Revert "Improve last change to xfaces.c" (05ece1eb8b)"

This reverts commit b8d2ec920f37f5d77d32440eefc97dd5e8c2c7dc.

Not only does it make debugging Emacs harder for users, that change is
unsafe for the Haiku port.

diff --git a/src/xfaces.c b/src/xfaces.c
index 643f436589627b711cb1294aa3fe31ab1e30ce23..7dbcacb35ace9193230ad500bf94d56a2c37833f 100644 (file)
--- a/src/xfaces.c
+++ b/src/xfaces.c
@@ -6014,6 +6014,21 @@ 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.
@@ -6073,38 +6088,33 @@ 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]);
-#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);
+
+         /* 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);
          /* Also allow unsetting other attributes for debugging
-            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
+            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);
+
          attrs[LFACE_FONT_INDEX] = font_load_for_lface (f, attrs, spec);
        }
       if (FONT_OBJECT_P (attrs[LFACE_FONT_INDEX]))
@@ -7394,27 +7404,24 @@ 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_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);
+  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);
 
 #ifdef HAVE_WINDOW_SYSTEM
   defsubr (&Sbitmap_spec_p);