Make Text.update_from copy usetex state.

anntzer · anntzer · commit 6c76bbd9ef3b · 2020-01-28T22:46:51.000+01:00
This is used in particular by tick handling code to propagate text
properties across ticks, so this change avoids having some ticks using
usetex and others not using usetex if the rcParam value changes after
axes creation.
diff --git a/doc/api/next_api_changes/behaviour.rst b/doc/api/next_api_changes/behaviour.rst
@@ -70,3 +70,6 @@ shape ``(n, 2)`` would plot the first column of *x* against the first column
 of *y*, the second column of *x* against the second column of *y*, **and** the
 first column of *x* against the third column of *y*.  This now raises an error
 instead.
+
+`.Text.update_from` now copies usetex state from the source Text 
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/lib/matplotlib/tests/test_text.py b/lib/matplotlib/tests/test_text.py
@@ -532,6 +532,21 @@ def test_hinting_factor_backends():
                                rtol=0.1)
 
 
+@needs_usetex
+def test_usetex_is_copied():
+    # Indirectly tests that update_from (which is used to copy tick label
+    # properties) copies usetex state.
+    fig = plt.figure()
+    plt.rcParams["text.usetex"] = False
+    ax1 = fig.add_subplot(121)
+    plt.rcParams["text.usetex"] = True
+    ax2 = fig.add_subplot(122)
+    fig.canvas.draw()
+    for ax, usetex in [(ax1, False), (ax2, True)]:
+        for t in ax.xaxis.majorTicks:
+            assert t.label1.get_usetex() == usetex
+
+
 @needs_usetex
 def test_single_artist_usetex():
     # Check that a single artist marked with usetex does not get passed through
diff --git a/lib/matplotlib/text.py b/lib/matplotlib/text.py
@@ -262,6 +262,7 @@ def update_from(self, other):
         self._verticalalignment = other._verticalalignment
         self._horizontalalignment = other._horizontalalignment
         self._fontproperties = other._fontproperties.copy()
+        self._usetex = other._usetex
         self._rotation = other._rotation
         self._picker = other._picker
         self._linespacing = other._linespacing
