ENH: expose font_file in Brain.add_text

doc/changes/dev/13778.newfeature.rst

@@ -0,0 +1 @@
+Added a ``font_file`` parameter to :meth:`mne.viz.Brain.add_text` to allow custom ``.ttf``/``.ttc`` fonts for improved Unicode glyph rendering, by `Pragnya Khandelwal`_.

mne/viz/_brain/_brain.py

@@ -2796,6 +2796,7 @@ def add_text(
         col=0,
         font_size=None,
         justification=None,
+        font_file=None,
     ):
         """Add a text to the visualization.
 
@@ -2824,6 +2825,9 @@ def add_text(
             The font size to use.
         justification : str | None
             The text justification.
+        font_file : path-like | None
+            Path to a ``.ttf`` or ``.ttc`` font file to use for rendering
+            the text. This can be helpful for Unicode glyph coverage.
         """
         _validate_type(name, (str, None), "name")
         name = text if name is None else name
@@ -2840,6 +2844,7 @@ def add_text(
                     color=color,
                     size=font_size,
                     justification=justification,
+                    font_file=font_file,
                 )
                 if "text" not in self._actors:
                     self._actors["text"] = dict()

mne/viz/_brain/tests/test_brain.py

@@ -538,7 +538,7 @@ def __init__(self):
     with pytest.raises(ValueError, match="already exists"):
         brain.add_text(x=0, y=0, text="foo")
     brain.remove_text("foo")
-    brain.add_text(x=0, y=0, text="foo")
+    brain.add_text(x=0, y=0, text="foo", font_file=None)
     brain.remove_text()
 
     brain.close()

mne/viz/backends/_abstract.py

@@ -474,7 +474,16 @@ def quiver3d(
         pass
 
     @abstractclassmethod
-    def text2d(self, x_window, y_window, text, size=14, color="white"):
+    def text2d(
+        self,
+        x_window,
+        y_window,
+        text,
+        size=14,
+        color="white",
+        justification=None,
+        font_file=None,
+    ):
         """Add 2d text in the scene.
 
         Parameters
@@ -493,6 +502,10 @@ def text2d(self, x_window, y_window, text, size=14, color="white"):
             The color of the text as a tuple (red, green, blue) of float
             values between 0 and 1 or a valid color name (i.e. 'white'
             or 'w').
+        justification : str | None
+            The text justification.
+        font_file : path-like | None
+            Path to a ``.ttf`` or ``.ttc`` font file for rendering text.
         """
         pass
 

mne/viz/backends/_pyvista.py

@@ -720,13 +720,26 @@ def quiver3d(
         return actor, mesh
 
     def text2d(
-        self, x_window, y_window, text, size=14, color="white", justification=None
+        self,
+        x_window,
+        y_window,
+        text,
+        size=14,
+        color="white",
+        justification=None,
+        font_file=None,
     ):
         size = 14 if size is None else size
         position = (x_window, y_window)
-        actor = self.plotter.add_text(
-            text, position=position, font_size=size, color=color, viewport=True
+        kwargs = dict(
+            text=text,
+            position=position,
+            font_size=size,
+            color=color,
+            viewport=True,
+            font_file=font_file,
         )
+        actor = self.plotter.add_text(**kwargs)
         if isinstance(justification, str):
             if justification == "left":
                 actor.GetTextProperty().SetJustificationToLeft()

mne/viz/backends/tests/test_renderer.py

@@ -167,6 +167,7 @@ def test_3d_backend(renderer):
         text=txt_text,
         size=txt_size,
         justification="right",
+        font_file=None,
     )
     rend.text3d(x=0, y=0, z=0, text=txt_text, scale=1.0)
     rend.set_camera(
@@ -175,6 +176,36 @@ def test_3d_backend(renderer):
     rend.show()
 
 
+def test_text2d_font_file_passthrough(renderer, monkeypatch):
+    """Test that text2d forwards font_file values to the backend."""
+    rend = renderer.create_3d_figure(
+        size=(300, 300),
+        bgcolor="black",
+        smooth_shading=True,
+        scene=False,
+    )
+    seen = []
+
+    class _DummyActor:
+        def GetTextProperty(self):
+            return None
+
+        def SetVisibility(self, value):
+            return None
+
+    def _add_text(**kwargs):
+        seen.append(kwargs)
+        return _DummyActor()
+
+    monkeypatch.setattr(rend.plotter, "add_text", _add_text)
+    rend.text2d(x_window=0.0, y_window=0.0, text="label", font_file="dummy.ttf")
+    rend.text2d(x_window=0.0, y_window=0.0, text="label", font_file=None)
+
+    assert seen[0]["font_file"] == "dummy.ttf"
+    assert "font_file" in seen[1]
+    assert seen[1]["font_file"] is None
+
+
 def test_get_3d_backend(renderer):
     """Test get_3d_backend function call for side-effects."""
     # Test twice to ensure the first call had no side-effect