CoreText: Fix selection of font file with multi-file variant font

Also prefer semibold and use similar scorer as fontconfig

kitty/fonts/__init__.py

@@ -156,10 +156,9 @@ class FontSpec(NamedTuple):
 
 class Score(NamedTuple):
     variable_score: int
-    style_score: int
+    style_score: Union[int, float]
     monospace_score: int
     width_score: int
-    weight_distance_from_medium: float = 0
 
 
 Descriptor = Union[FontConfigPattern, CoreTextFont]

kitty/fonts/common.py

@@ -26,6 +26,7 @@ if TYPE_CHECKING:
     def is_variable(descriptor: Descriptor) -> bool: ...
     def set_named_style(name: str, font: Descriptor, vd: VariableData) -> bool: ...
     def set_axis_values(tag_map: Dict[str, float], font: Descriptor, vd: VariableData) -> bool: ...
+    def dump_sorted_candidates(bold: bool, italic: bool, candidates: List[Descriptor], scorer: Scorer) -> None: ...
 else:
     FontCollectionMapType = FontMap = None
     if is_macos:
@@ -33,6 +34,7 @@ else:
         from kitty.fonts.core_text import (
             all_fonts_map,
             create_scorer,
+            dump_sorted_candidates,
             find_best_match,
             find_last_resort_text_font,
             is_monospace,
@@ -45,6 +47,7 @@ else:
         from kitty.fonts.fontconfig import (
             all_fonts_map,
             create_scorer,
+            dump_sorted_candidates,
             find_best_match,
             find_last_resort_text_font,
             is_monospace,
@@ -55,6 +58,7 @@ else:
     def face_from_descriptor(descriptor: Descriptor) -> Face: return Face(descriptor=descriptor)
 
 
+dump_sorted_candidates
 cache_for_variable_data_by_path: Dict[str, VariableData] = {}
 attr_map = {(False, False): 'font_family', (True, False): 'bold_font', (False, True): 'italic_font', (True, True): 'bold_italic_font'}
 

kitty/fonts/core_text.py

@@ -79,15 +79,22 @@ def create_scorer(bold: bool = False, italic: bool = False, monospaced: bool = T
     def score(candidate: Descriptor) -> Score:
         assert candidate['descriptor_type'] == 'core_text'
         variable_score = 0 if prefer_variable and candidate['variation'] is not None else 1
-        style_match = 1 if candidate['bold'] == bold and candidate[
-            'italic'
-        ] == italic else 0
-        monospace_match = 1 if candidate['monospace'] else 0
+        bold_score = candidate['weight']  # -1 to 1 with 0 being normal
+        if bold_score < 0:  # thinner than normal, reject
+            bold_score = 2.0
+        else:
+            if bold:
+                # prefer semibold=0.3 to full bold = 0.4
+                bold_score = abs(bold_score - 0.3)
+        italic_score = candidate['slant'] # -1 to 1 with 0 being upright < 0 being backward slant, abs(slant) == 1 implies 30 deg rotation
+        if italic:
+            if italic_score < 0:
+                italic_score = 2.0
+            else:
+                italic_score = abs(1 - italic_score)
+        monospace_match = 0 if candidate['monospace'] else 1
         is_regular_width = not candidate['expanded'] and not candidate['condensed']
-        # prefer semi-bold to bold to heavy, less bold means less chance of
-        # overflow
-        weight_distance_from_medium = abs(candidate['weight'])
-        return Score(variable_score, 1 - style_match, 1 - monospace_match, 1 - is_regular_width, weight_distance_from_medium)
+        return Score(variable_score, bold_score + italic_score, monospace_match, 0 if is_regular_width else 1)
 
     return score
 
@@ -99,6 +106,14 @@ def find_last_resort_text_font(bold: bool = False, italic: bool = False, monospa
     return sorted(candidates, key=scorer)[0]
 
 
+def dump_sorted_candidates(bold: bool, italic: bool, candidates: List[CoreTextFont], scorer: Scorer) -> None:
+    print(f'{bold=} {italic=}')
+    for x in candidates:
+        print(x['postscript_name'], f'bold={x["bold"]}', f'italic={x["italic"]}', f'weight={x["weight"]:.2f}', f'slant={x["slant"]:.2f}')
+        print(scorer(x))
+    print()
+
+
 def find_best_match(
     family: str, bold: bool = False, italic: bool = False, monospaced: bool = True, ignore_face: Optional[CoreTextFont] = None,
     prefer_variable: bool = False
@@ -121,7 +136,8 @@ def find_best_match(
         log_error(f'The font {family} was not found, falling back to Menlo')
         q = 'menlo'
     candidates = font_map['family_map'][q]
-    return sorted(candidates, key=scorer)[0]
+    candidates.sort(key=scorer)
+    return candidates[0]
 
 
 def get_font_from_spec(

kitty/fonts/fontconfig.py

@@ -97,6 +97,14 @@ def create_scorer(bold: bool = False, italic: bool = False, monospaced: bool = T
     return score
 
 
+def dump_sorted_candidates(bold: bool, italic: bool, candidates: List[FontConfigPattern], scorer: Scorer) -> None:
+    print(f'{bold=} {italic=}')
+    for x in candidates:
+        print(x['postscript_name'], f'weight={x["weight"]}', f'slant={x["slant"]}')
+        print(scorer(x))
+    print()
+
+
 def find_last_resort_text_font(bold: bool = False, italic: bool = False, monospaced: bool = True) -> FontConfigPattern:
     # Use fc-match with a generic family
     family = 'monospace' if monospaced else 'sans-serif'