master 89d7a71: Fix font selection via :family on MS-Windows

[Eli Zaretskii]

branch: master
commit 89d7a71ce6a7338e4650409f16e419a53fff9723
Author: Eli Zaretskii <eliz@gnu.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    Fix font selection via :family on MS-Windows
    
    * src/font.c (font_delete_unmatched) [HAVE_NTGUI]: Allow non-exact
    matches of :weight when looking for a suitable font.  (Bug#51768)
---
 src/font.c | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/src/font.c b/src/font.c
index f70054e..420a4f8 100644
--- a/src/font.c
+++ b/src/font.c
@@ -2759,10 +2759,31 @@ font_delete_unmatched (Lisp_Object vec, Lisp_Object 
spec, int size)
          continue;
        }
       for (prop = FONT_WEIGHT_INDEX; prop < FONT_SIZE_INDEX; prop++)
-       if (FIXNUMP (AREF (spec, prop))
-           && ((XFIXNUM (AREF (spec, prop)) >> 8)
-               != (XFIXNUM (AREF (entity, prop)) >> 8)))
-         prop = FONT_SPEC_MAX;
+       {
+         if (FIXNUMP (AREF (spec, prop)))
+           {
+             int required = XFIXNUM (AREF (spec, prop)) >> 8;
+             int candidate = XFIXNUM (AREF (entity, prop)) >> 8;
+
+             if (candidate != required
+#ifdef HAVE_NTGUI
+                 /* A kludge for w32 font search, where listing a
+                    family returns only 4 standard weights: regular,
+                    italic, bold, bold-italic.  For other values one
+                    must specify the font, not just the family in the
+                    :family attribute of the face.  But specifying
+                    :family in the face attributes looks for regular
+                    weight, so if we require exact match, the
+                    non-regular font will be rejected.  So we relax
+                    the accuracy of the match here, and let
+                    font_sort_entities find the best match.  */
+                 && (prop != FONT_WEIGHT_INDEX
+                     || eabs (candidate - required) > 100)
+#endif
+                 )
+               prop = FONT_SPEC_MAX;
+           }
+       }
       if (prop < FONT_SPEC_MAX
          && size
          && XFIXNUM (AREF (entity, FONT_SIZE_INDEX)) > 0)