mathtext: fix normal/italic usage in STIXFonts

llohse · llohse · commit 82f1cc6a8b83 · 2026-02-18T14:58:16.000+01:00
diff --git a/lib/matplotlib/_mathtext.py b/lib/matplotlib/_mathtext.py
@@ -493,7 +493,6 @@ def _get_glyph(self, fontname: str, font_class: str,
                 # same as LaTeX does.
                 # This was previously mapped via `latex_to_bakoma`.
                 fontname = "rm"
-
             slanted = (fontname == "it")
             font = self._get_font(fontname)
             if font is not None:
@@ -846,7 +845,7 @@ def _map_virtual_font(self, fontname: str, font_class: str,
                 fontname = mpl.rcParams['mathtext.default']
 
         # Fix some incorrect glyphs.
-        if fontname in ('rm', 'it'):
+        if fontname in ('rm', 'it', 'normal'):
             uniindex = stix_glyph_fixes.get(uniindex, uniindex)
 
         # Handle private use area glyphs
@@ -1852,6 +1851,10 @@ def font(self) -> str:
     def font(self, name: str) -> None:
         if name in ('rm', 'it', 'bf', 'bfit'):
             self.font_class = name
+        if name == 'normal':
+            # workaround to keep hardcoded maps in _mathtext_data.py
+            # font_class is exclusively used by STIXFonts
+            self.font_class = 'it'
         self._font = name
 
     def get_current_underline_thickness(self) -> float:
diff --git a/lib/matplotlib/_mathtext_data.py b/lib/matplotlib/_mathtext_data.py
@@ -1340,7 +1340,7 @@
              "\N{DOUBLE-STRUCK CAPITAL PI}"),
             ("\N{GREEK CAPITAL LETTER SIGMA}",
              "\N{GREEK CAPITAL LETTER SIGMA}",
-             "it",
+             "rm",
              "\N{DOUBLE-STRUCK N-ARY SUMMATION}"),  # \Sigma (not in beta STIX fonts)
             ("\N{GREEK SMALL LETTER GAMMA}",
              "\N{GREEK SMALL LETTER GAMMA}",
