FIX DateFormatter for month names when usetex=True

Author: smartlixx

lib/matplotlib/dates.py

@@ -592,7 +592,21 @@ def drange(dstart, dend, delta):
 
 def _wrap_in_tex(text):
     # Braces ensure dashes are not spaced like binary operators.
-    return '$\\mathdefault{' + text.replace('-', '{-}') + '}$'
+    p = re.compile("[a-zA-Z]+")
+    m = p.finditer(text)
+    cursor = 0
+    ret_text = ''
+
+    for i in m:
+        start = i.start()
+        end = i.end()
+
+        ret_text += '$\\mathdefault{'+text[cursor:start].replace('-', '{-}')
+        ret_text += '}$'+text[start:end]
+        cursor = end
+
+    ret_text += '$\\mathdefault{'+text[cursor:].replace('-', '{-}')+'}$'
+    return ret_text
 
 
 ## date tickers and formatters ###

lib/matplotlib/tests/test_dates.py

@@ -271,7 +271,8 @@ def callable_formatting_function(dates, _):
     (datetime.timedelta(weeks=52 * 200),
      [r'$\mathdefault{%d}$' % (year,) for year in range(1990, 2171, 20)]),
     (datetime.timedelta(days=30),
-     [r'$\mathdefault{Jan %02d 1990}$' % (day,) for day in range(1, 32, 3)]),
+     [r'$\mathdefault{}$Jan$\mathdefault{ %02d 1990}$' % (day,)
+      for day in range(1, 32, 3)]),
     (datetime.timedelta(hours=20),
      [r'$\mathdefault{%02d:00:00}$' % (hour,) for hour in range(0, 21, 2)]),
 ])
@@ -284,6 +285,7 @@ def test_date_formatter_usetex(delta, expected):
     locator.axis.set_view_interval(mdates.date2num(d1), mdates.date2num(d2))
 
     formatter = mdates.AutoDateFormatter(locator, usetex=True)
+    print([formatter(loc) for loc in locator()])
     assert [formatter(loc) for loc in locator()] == expected
 
 
@@ -550,15 +552,16 @@ def test_concise_formatter_show_offset(t_delta, expected):
     (datetime.timedelta(weeks=52 * 200),
      ['$\\mathdefault{%d}$' % (t, ) for t in range(1980, 2201, 20)]),
     (datetime.timedelta(days=40),
-     ['$\\mathdefault{Jan}$', '$\\mathdefault{05}$', '$\\mathdefault{09}$',
-      '$\\mathdefault{13}$', '$\\mathdefault{17}$', '$\\mathdefault{21}$',
-      '$\\mathdefault{25}$', '$\\mathdefault{29}$', '$\\mathdefault{Feb}$',
-      '$\\mathdefault{05}$', '$\\mathdefault{09}$']),
+     ['$\\mathdefault{}$Jan$\\mathdefault{}$', '$\\mathdefault{05}$',
+      '$\\mathdefault{09}$', '$\\mathdefault{13}$', '$\\mathdefault{17}$',
+      '$\\mathdefault{21}$', '$\\mathdefault{25}$', '$\\mathdefault{29}$',
+      '$\\mathdefault{}$Feb$\\mathdefault{}$', '$\\mathdefault{05}$',
+      '$\\mathdefault{09}$']),
     (datetime.timedelta(hours=40),
-     ['$\\mathdefault{Jan{-}01}$', '$\\mathdefault{04:00}$',
+     ['$\\mathdefault{}$Jan$\\mathdefault{{-}01}$', '$\\mathdefault{04:00}$',
       '$\\mathdefault{08:00}$', '$\\mathdefault{12:00}$',
       '$\\mathdefault{16:00}$', '$\\mathdefault{20:00}$',
-      '$\\mathdefault{Jan{-}02}$', '$\\mathdefault{04:00}$',
+      '$\\mathdefault{}$Jan$\\mathdefault{{-}02}$', '$\\mathdefault{04:00}$',
       '$\\mathdefault{08:00}$', '$\\mathdefault{12:00}$',
       '$\\mathdefault{16:00}$']),
     (datetime.timedelta(seconds=2),