Fix warning when legend is added while using TeX.

Fixes matplotlib#17518.

Co-authored-by: Antony Lee <[email protected]>

Author: 2 people

lib/matplotlib/offsetbox.py

@@ -881,7 +881,8 @@ def get_window_extent(self, renderer):
 
     def get_extent(self, renderer):
         _, h_, d_ = renderer.get_text_width_height_descent(
-            "lp", self._text._fontproperties, ismath=False)
+            "lp", self._text._fontproperties,
+            ismath="TeX" if self._text.get_usetex() else False)
 
         bbox, info, d = self._text._get_layout(renderer)
         w, h = bbox.width, bbox.height