Text antialiasing for mathtext (matplotlib#26376)

Author: stevezhang1999

doc/users/next_whats_new/antialiasing_text_annotation.rst

@@ -12,8 +12,7 @@ Examples:
     plt.text(0.5, 0.5, '6 inches x 2 inches', antialiased=True)
     ax.annotate('local max', xy=(2, 1), xytext=(3, 1.5), antialiased=False)
 
-If the text contains math expression, then antialiasing will be set by :rc:`text.antialiased`, and *antialiased* will have no effect
-This applies to the whole text.
+If the text contains math expression, *antialiased* applies to the whole text.
 Examples:
 
 .. code-block::

lib/matplotlib/_mathtext.py

@@ -106,7 +106,7 @@ def to_vector(self):
               for x1, y1, x2, y2 in self.rects]
         return VectorParse(w, h + d, d, gs, rs)
 
-    def to_raster(self):
+    def to_raster(self, antialiased=None):
         # Metrics y's and mathtext y's are oriented in opposite directions,
         # hence the switch between ymin and ymax.
         xmin = min([*[ox + info.metrics.xmin for ox, oy, info in self.glyphs],

lib/matplotlib/backends/backend_agg.py

@@ -175,7 +175,8 @@ def draw_path(self, gc, path, transform, rgbFace=None):
     def draw_mathtext(self, gc, x, y, s, prop, angle):
         """Draw mathtext using :mod:`matplotlib.mathtext`."""
         ox, oy, width, height, descent, font_image = \
-            self.mathtext_parser.parse(s, self.dpi, prop)
+            self.mathtext_parser.parse(s, self.dpi, prop,
+                                       antialiased=gc.get_antialiased())
 
         xd = descent * sin(radians(angle))
         yd = descent * cos(radians(angle))

lib/matplotlib/mathtext.py

@@ -18,6 +18,7 @@
 import functools
 import logging
 
+import matplotlib as mpl
 from matplotlib import _api, _mathtext
 from matplotlib.ft2font import LOAD_NO_HINTING
 from matplotlib.font_manager import FontProperties
@@ -58,7 +59,7 @@ def __init__(self, output):
             {"path": "vector", "agg": "raster", "macosx": "raster"},
             output=output.lower())
 
-    def parse(self, s, dpi=72, prop=None):
+    def parse(self, s, dpi=72, prop=None, *, antialiased=None):
         """
         Parse the given math expression *s* at the given *dpi*.  If *prop* is
         provided, it is a `.FontProperties` object specifying the "default"
@@ -74,10 +75,12 @@ def parse(self, s, dpi=72, prop=None):
         # is mutable; key the cache using an internal copy (see
         # text._get_text_metrics_with_cache for a similar case).
         prop = prop.copy() if prop is not None else None
-        return self._parse_cached(s, dpi, prop)
+        if antialiased is None:
+            antialiased = mpl.rcParams['text.antialiased']
+        return self._parse_cached(s, dpi, prop, antialiased)
 
     @functools.lru_cache(50)
-    def _parse_cached(self, s, dpi, prop):
+    def _parse_cached(self, s, dpi, prop, antialiased):
         from matplotlib.backends import backend_agg
 
         if prop is None:
@@ -100,7 +103,7 @@ def _parse_cached(self, s, dpi, prop):
         if self._output_type == "vector":
             return output.to_vector()
         elif self._output_type == "raster":
-            return output.to_raster()
+            return output.to_raster(antialiased=antialiased)
 
 
 def math_to_image(s, filename_or_obj, prop=None, dpi=None, format=None,

lib/matplotlib/mathtext.pyi

@@ -13,7 +13,14 @@ from matplotlib.typing import ColorType
 
 class MathTextParser:
     def __init__(self, output: Literal["path", "agg", "raster", "macosx"]) -> None: ...
-    def parse(self, s: str, dpi: float = ..., prop: FontProperties | None = ...): ...
+    def parse(
+        self,
+        s: str,
+        dpi: float = ...,
+        prop: FontProperties | None = ...,
+        *,
+        antialiased: bool | None = ...
+    ): ...
 
 def math_to_image(
     s: str,

lib/matplotlib/tests/test_text.py

@@ -972,3 +972,19 @@ def test_text_antialiased_on_default_vs_manual(fig_test, fig_ref):
 
     mpl.rcParams['text.antialiased'] = True
     fig_ref.text(0.5, 0.5, '6 inches x 2 inches')
+
+
+@check_figures_equal()
+def test_text_math_antialiased_on_default_vs_manual(fig_test, fig_ref):
+    fig_test.text(0.5, 0.5, r"OutsideMath $I\'m \sqrt{2}$", antialiased=True)
+
+    mpl.rcParams['text.antialiased'] = True
+    fig_ref.text(0.5, 0.5, r"OutsideMath $I\'m \sqrt{2}$")
+
+
+@check_figures_equal()
+def test_text_math_antialiased_off_default_vs_manual(fig_test, fig_ref):
+    fig_test.text(0.5, 0.5, r"OutsideMath $I\'m \sqrt{2}$", antialiased=False)
+
+    mpl.rcParams['text.antialiased'] = False
+    fig_ref.text(0.5, 0.5, r"OutsideMath $I\'m \sqrt{2}$")