Let TeX handle newlines itself.

anntzer · anntzer · commit bb2924cb87c7 · 2022-02-01T14:05:36.000+01:00
Note that it may be worth passing the baselineskip
(`Text.get_linespacing()`) as argument to texmanager, but that'll wait
for a bigger refactor... for now, let's stick to the old default of
1.25.

test_metrics_cache changes as the cache hit pattern changed for usetex
strings.
diff --git a/lib/matplotlib/tests/test_text.py b/lib/matplotlib/tests/test_text.py
@@ -772,26 +772,11 @@ 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._cachedRenderer
-    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()
-    # 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
+    # Each string gets drawn twice, so the second draw results in a hit.
+    assert info.hits >= info.misses
diff --git a/lib/matplotlib/texmanager.py b/lib/matplotlib/texmanager.py
@@ -217,7 +217,7 @@ def make_tex(self, tex, fontsize):
 %% when using psfrag which gets confused by it.
 \fontsize{%(fontsize)f}{%(baselineskip)f}%%
 \ifdefined\psfrag\else\hbox{}\fi%%
-{%(fontcmd)s %(tex)s}\special{matplotlibbaselinemarker}
+{\obeylines%(fontcmd)s %(tex)s}\special{matplotlibbaselinemarker}
 \end{document}
 """
         Path(texfile).write_text(tex_template % {
diff --git a/lib/matplotlib/text.py b/lib/matplotlib/text.py
@@ -295,7 +295,8 @@ def _get_layout(self, renderer):
         of a rotated text when necessary.
         """
         thisx, thisy = 0.0, 0.0
-        lines = self.get_text().split("\n")  # Ensures lines is not empty.
+        text = self.get_text()
+        lines = [text] if self.get_usetex() else text.split("\n")  # Not empty.
 
         ws = []
         hs = []
