Add support for more accents in mathtext

oscargus · oscargus · commit df3add6eab6a · 2022-06-06T14:32:00.000+02:00
diff --git a/lib/matplotlib/_mathtext.py b/lib/matplotlib/_mathtext.py
@@ -2031,6 +2031,9 @@ def unknown_symbol(self, s, loc, toks):
         r'overrightarrow': r'\rightarrow',
         r'overleftarrow':  r'\leftarrow',
         r'mathring':       r'\circ',
+        r'=':              r'\combiningoverline',
+        r'H':              r'\combiningdoubleacuteaccent',
+        r'check':          r'\combiningcaron',
     }
 
     _wide_accents = set(r"widehat widetilde widebar".split())
@@ -2050,8 +2053,18 @@ def accent(self, s, loc, toks):
             accent_box = AutoWidthChar(
                 '\\' + accent, sym.width, state, char_class=Accent)
         else:
+            # Check if accent and character can be combined
+            a = get_unicode_index(self._accent_map[accent])
+            if isinstance(sym, Char):
+                c = sym.c
+            else:
+                c = sym.children[0].c
+            comb = unicodedata.normalize('NFC', c + chr(a))
+            if len(comb) == 1:
+                return Char(comb, state)
+            # Cannot be combined
             accent_box = Accent(self._accent_map[accent], state)
-        if accent == 'mathring':
+        if accent in ('mathring', 'r'):
             accent_box.shrink()
             accent_box.shrink()
         centered = HCentered([Hbox(sym.width / 4.0), accent_box])
@@ -2137,9 +2150,6 @@ def is_slanted(self, nucleus):
             return nucleus.is_slanted()
         return False
 
-    def is_between_brackets(self, s, loc):
-        return False
-
     def subsuper(self, s, loc, toks):
         nucleus = toks.get("nucleus", Hbox(0))
         subsuper = toks.get("subsuper", [])
diff --git a/lib/matplotlib/_mathtext_data.py b/lib/matplotlib/_mathtext_data.py
@@ -1002,6 +1002,8 @@
     'combiningdotabove'        : 775,
     'combiningthreedotsabove'  : 8411,
     'combiningfourdotsabove'   : 8412,
+    'combiningdoubleacuteaccent' : 779,
+    'combiningcaron'           : 780,
     'to'                       : 8594,
     'succeq'                   : 8829,
     'emptyset'                 : 8709,
diff --git a/tutorials/text/mathtext.py b/tutorials/text/mathtext.py
@@ -306,7 +306,7 @@
     Command                        Result
     ============================== =================================
     ``\acute a`` or ``\'a``        :mathmpl:`\acute a`
-    ``\bar a``                     :mathmpl:`\bar a`
+    ``\bar a`` or ``\= a``         :mathmpl:`\bar a`
     ``\breve a``                   :mathmpl:`\breve a`
     ``\dot a`` or ``\.a``          :mathmpl:`\dot a`
     ``\ddot a`` or ``\''a``        :mathmpl:`\ddot a`
@@ -316,6 +316,8 @@
     ``\hat a`` or ``\^a``          :mathmpl:`\hat a`
     ``\tilde a`` or ``\~a``        :mathmpl:`\tilde a`
     ``\vec a``                     :mathmpl:`\vec a`
+    ``\check a``                   :mathmpl:`\check a`
+    ``\H a``                       :mathmpl:`\H a`
     ``\overline{abc}``             :mathmpl:`\overline{abc}`
     ============================== =================================
 
