matplotlib · timhoffm · Oct 3, 2022 · Oct 2, 2022
diff --git a/lib/matplotlib/dates.py b/lib/matplotlib/dates.py
@@ -173,6 +173,7 @@
 import functools
 import logging
 import math
+import re
 
 from dateutil.rrule import (rrule, MO, TU, WE, TH, FR, SA, SU, YEARLY,
                             MONTHLY, WEEKLY, DAILY, HOURLY, MINUTELY,
@@ -597,7 +598,16 @@ def drange(dstart, dend, delta):
 
 
 def _wrap_in_tex(text):
-    return r"{\fontfamily{\familydefault}\selectfont " + text + "}"
+    p = r'([a-zA-Z]+)'
+    ret_text = re.sub(p, r'}$\1$\\mathdefault{', text)
+
+    # Braces ensure symbols are not spaced like binary operators.
+    ret_text = ret_text.replace('-', '{-}').replace(':', '{:}')
+    # To not concatenate space between numbers.
+    ret_text = ret_text.replace(' ', r'\;')
+    ret_text = '$\\mathdefault{' + ret_text + '}$'
+    ret_text = ret_text.replace('$\\mathdefault{}$', '')
+    return ret_text
 
 
 ## date tickers and formatters ###

diff --git a/lib/matplotlib/dviread.py b/lib/matplotlib/dviread.py
@@ -352,10 +352,40 @@ def _read(self):
         Read one page from the file. Return True if successful,
         False if there were no more pages.
         """
+        # Pages appear to start with the sequence
+        #   bop (begin of page)
+        #   xxx comment
+        #   <push, ..., pop>  # if using chemformula
+        #   down
+        #   push
+        #     down
+        #     <push, push, xxx, right, xxx, pop, pop>  # if using xcolor
+        #     down
+        #     push
+        #       down (possibly multiple)
+        #       push  <=  here, v is the baseline position.
+        #         etc.
+        # (dviasm is useful to explore this structure.)
+        # Thus, we use the vertical position at the first time the stack depth
+        # reaches 3, while at least three "downs" have been executed (excluding
+        # those popped out (corresponding to the chemformula preamble)), as the
+        # baseline (the "down" count is necessary to handle xcolor).
+        down_stack = [0]
         self._baseline_v = None
         while True:
             byte = self.file.read(1)[0]
             self._dtable[byte](self, byte)
+            name = self._dtable[byte].__name__
+            if name == "_push":
+                down_stack.append(down_stack[-1])
+            elif name == "_pop":
+                down_stack.pop()
+            elif name == "_down":
+                down_stack[-1] += 1
+            if (self._baseline_v is None
+                    and len(getattr(self, "stack", [])) == 3
+                    and down_stack[-1] >= 4):
+                self._baseline_v = self.v
             if byte == 140:                         # end of page
                 return True
             if self.state is _dvistate.post_post:   # end of file
@@ -488,8 +518,6 @@ def _fnt_num(self, new_f):
     @_dispatch(min=239, max=242, args=('ulen1',))
     def _xxx(self, datalen):
         special = self.file.read(datalen)
-        if special == b'matplotlibbaselinemarker':
-            self._baseline_v = self.v
         _log.debug(
             'Dvi._xxx: encountered special: %s',
             ''.join([chr(ch) if 32 <= ch < 127 else '<%02x>' % ch

diff --git a/lib/matplotlib/tests/baseline_images/test_usetex/eqnarray.png b/lib/matplotlib/tests/baseline_images/test_usetex/eqnarray.png
diff --git a/lib/matplotlib/tests/test_dates.py b/lib/matplotlib/tests/test_dates.py
@@ -322,13 +322,13 @@ def callable_formatting_function(dates, _):
 
 @pytest.mark.parametrize('delta, expected', [
     (datetime.timedelta(weeks=52 * 200),
-     range(1990, 2171, 20)),
+     [r'$\mathdefault{%d}$' % year for year in range(1990, 2171, 20)]),
     (datetime.timedelta(days=30),
-     ['1990-01-%02d' % day for day in range(1, 32, 3)]),
+     [r'$\mathdefault{1990{-}01{-}%02d}$' % day for day in range(1, 32, 3)]),
     (datetime.timedelta(hours=20),
-     ['01-01 %02d' % hour for hour in range(0, 21, 2)]),
+     [r'$\mathdefault{01{-}01\;%02d}$' % hour for hour in range(0, 21, 2)]),
     (datetime.timedelta(minutes=10),
-     ['01 00:%02d' % minu for minu in range(0, 11)]),
+     [r'$\mathdefault{01\;00{:}%02d}$' % minu for minu in range(0, 11)]),
 ])
 def test_date_formatter_usetex(delta, expected):
     style.use("default")
@@ -341,8 +341,7 @@ def test_date_formatter_usetex(delta, expected):
     locator.axis.set_view_interval(mdates.date2num(d1), mdates.date2num(d2))
 
     formatter = mdates.AutoDateFormatter(locator, usetex=True)
-    assert [formatter(loc) for loc in locator()] == [
-        r'{\fontfamily{\familydefault}\selectfont %s}' % s for s in expected]
+    assert [formatter(loc) for loc in locator()] == expected
 
 
 def test_drange():
@@ -645,14 +644,24 @@ def test_offset_changes():
 
 @pytest.mark.parametrize('t_delta, expected', [
     (datetime.timedelta(weeks=52 * 200),
-     range(1980, 2201, 20)),
+     ['$\\mathdefault{%d}$' % (t, ) for t in range(1980, 2201, 20)]),
     (datetime.timedelta(days=40),
-     ['Jan', '05', '09', '13', '17', '21', '25', '29', 'Feb', '05', '09']),
+     ['Jan', '$\\mathdefault{05}$', '$\\mathdefault{09}$',
+      '$\\mathdefault{13}$', '$\\mathdefault{17}$', '$\\mathdefault{21}$',
+      '$\\mathdefault{25}$', '$\\mathdefault{29}$', 'Feb',
+      '$\\mathdefault{05}$', '$\\mathdefault{09}$']),
     (datetime.timedelta(hours=40),
-     ['Jan-01', '04:00', '08:00', '12:00', '16:00', '20:00',
-      'Jan-02', '04:00', '08:00', '12:00', '16:00']),
+     ['Jan$\\mathdefault{{-}01}$', '$\\mathdefault{04{:}00}$',
+      '$\\mathdefault{08{:}00}$', '$\\mathdefault{12{:}00}$',
+      '$\\mathdefault{16{:}00}$', '$\\mathdefault{20{:}00}$',
+      'Jan$\\mathdefault{{-}02}$', '$\\mathdefault{04{:}00}$',
+      '$\\mathdefault{08{:}00}$', '$\\mathdefault{12{:}00}$',
+      '$\\mathdefault{16{:}00}$']),
     (datetime.timedelta(seconds=2),
-     ['59.5', '00:00', '00.5', '01.0', '01.5', '02.0', '02.5']),
+     ['$\\mathdefault{59.5}$', '$\\mathdefault{00{:}00}$',
+      '$\\mathdefault{00.5}$', '$\\mathdefault{01.0}$',
+      '$\\mathdefault{01.5}$', '$\\mathdefault{02.0}$',
+      '$\\mathdefault{02.5}$']),
 ])
 def test_concise_formatter_usetex(t_delta, expected):
     d1 = datetime.datetime(1997, 1, 1)
@@ -663,8 +672,7 @@ def test_concise_formatter_usetex(t_delta, expected):
     locator.axis.set_view_interval(mdates.date2num(d1), mdates.date2num(d2))
 
     formatter = mdates.ConciseDateFormatter(locator, usetex=True)
-    assert formatter.format_ticks(locator()) == [
-        r'{\fontfamily{\familydefault}\selectfont %s}' % s for s in expected]
+    assert formatter.format_ticks(locator()) == expected
 
 
 def test_concise_formatter_formats():
@@ -1347,12 +1355,6 @@ def test_date_ticker_factory(span, expected_locator):
         assert isinstance(locator, expected_locator)
 
 
-def test_usetex_newline():
-    fig, ax = plt.subplots()
-    ax.xaxis.set_major_formatter(mdates.DateFormatter('%d/%m\n%Y'))
-    fig.canvas.draw()
-
-
 def test_datetime_masked():
     # make sure that all-masked data falls back to the viewlim
     # set in convert.axisinfo....

diff --git a/lib/matplotlib/tests/test_text.py b/lib/matplotlib/tests/test_text.py
@@ -806,11 +806,26 @@ def test_metrics_cache():
 
     fig = plt.figure()
     fig.text(.3, .5, "foo\nbar")
-    fig.text(.5, .5, "foo\nbar")
     fig.text(.3, .5, "foo\nbar", usetex=True)
     fig.text(.5, .5, "foo\nbar", usetex=True)
     fig.canvas.draw()
+    renderer = fig._get_renderer()
+    ys = {}  # mapping of strings to where they were drawn in y with draw_tex.
+
+    def call(*args, **kwargs):
+        renderer, x, y, s, *_ = args
+        ys.setdefault(s, set()).add(y)
+
+    renderer.draw_tex = call
+    fig.canvas.draw()
+    assert [*ys] == ["foo", "bar"]
+    # Check that both TeX strings were drawn with the same y-position for both
+    # single-line substrings.  Previously, there used to be an incorrect cache
+    # collision with the non-TeX string (drawn first here) whose metrics would
+    # get incorrectly reused by the first TeX string.
+    assert len(ys["foo"]) == len(ys["bar"]) == 1
 
     info = mpl.text._get_text_metrics_with_cache_impl.cache_info()
-    # Each string gets drawn twice, so the second draw results in a hit.
-    assert info.hits == info.misses
+    # Every string gets a miss for the first layouting (extents), then a hit
+    # when drawing, but "foo\nbar" gets two hits as it's drawn twice.
+    assert info.hits > info.misses
diff --git a/lib/matplotlib/tests/test_usetex.py b/lib/matplotlib/tests/test_usetex.py
@@ -64,6 +64,21 @@ def test_mathdefault():
     fig.canvas.draw()
 
 
+@image_comparison(['eqnarray.png'])
+def test_multiline_eqnarray():
+    text = (
+        r'\begin{eqnarray*}'
+        r'foo\\'
+        r'bar\\'
+        r'baz\\'
+        r'\end{eqnarray*}'
+    )
+
+    fig = plt.figure(figsize=(1, 1))
+    fig.text(0.5, 0.5, text, usetex=True,
+             horizontalalignment='center', verticalalignment='center')
+
+
 @pytest.mark.parametrize("fontsize", [8, 10, 12])
 def test_minus_no_descent(fontsize):
     # Test special-casing of minus descent in DviFont._height_depth_of, by

diff --git a/lib/matplotlib/texmanager.py b/lib/matplotlib/texmanager.py
@@ -230,8 +230,7 @@ def _get_tex_source(cls, tex, fontsize):
             r"% last line's baseline.",
             rf"\fontsize{{{fontsize}}}{{{baselineskip}}}%",
             r"\ifdefined\psfrag\else\hbox{}\fi%",
-            rf"{{\obeylines{fontcmd} {tex}}}%",
-            r"\special{matplotlibbaselinemarker}%",
+            rf"{{{fontcmd} {tex}}}%",
             r"\end{document}",
         ])
 

diff --git a/lib/matplotlib/text.py b/lib/matplotlib/text.py
@@ -302,8 +302,7 @@ def _get_layout(self, renderer):
         of a rotated text when necessary.
         """
         thisx, thisy = 0.0, 0.0
-        text = self.get_text()
-        lines = [text] if self.get_usetex() else text.split("\n")  # Not empty.
+        lines = self.get_text().split("\n")  # Ensures lines is not empty.
 
         ws = []
         hs = []