BLD: Make ft2font classes final

There appears to be no reason for them to be subtyped, as they are
semi-private, and we don't do that.

Author: QuLogic

doc/api/next_api_changes/behavior/27891-ES.rst

@@ -0,0 +1,5 @@
+ft2font classes are now final
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The ft2font classes `.ft2font.FT2Font`, and `.ft2font.FT2Image` are now final
+and can no longer be subclassed.

lib/matplotlib/ft2font.pyi

@@ -1,4 +1,4 @@
-from typing import BinaryIO, Literal, TypedDict, overload
+from typing import BinaryIO, Literal, TypedDict, final, overload
 
 import numpy as np
 from numpy.typing import NDArray
@@ -158,6 +158,7 @@ class _SfntPcltDict(TypedDict):
     widthType: int
     serifStyle: int
 
+@final
 class FT2Font:
     ascender: int
     bbox: tuple[int, int, int, int]
@@ -233,11 +234,13 @@ class FT2Font:
         self, string: str, angle: float = ..., flags: int = ...
     ) -> NDArray[np.float64]: ...
 
+@final
 class FT2Image:  # TODO: When updating mypy>=1.4, subclass from Buffer.
     def __init__(self, width: float, height: float) -> None: ...
     def draw_rect(self, x0: float, y0: float, x1: float, y1: float) -> None: ...
     def draw_rect_filled(self, x0: float, y0: float, x1: float, y1: float) -> None: ...
 
+@final
 class Glyph:
     width: int
     height: int

src/ft2font_wrapper.cpp

@@ -146,7 +146,7 @@ static PyTypeObject* PyFT2Image_init_type()
     PyFT2ImageType.tp_name = "matplotlib.ft2font.FT2Image";
     PyFT2ImageType.tp_basicsize = sizeof(PyFT2Image);
     PyFT2ImageType.tp_dealloc = (destructor)PyFT2Image_dealloc;
-    PyFT2ImageType.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE;
+    PyFT2ImageType.tp_flags = Py_TPFLAGS_DEFAULT;
     PyFT2ImageType.tp_methods = methods;
     PyFT2ImageType.tp_new = PyFT2Image_new;
     PyFT2ImageType.tp_init = (initproc)PyFT2Image_init;
@@ -236,7 +236,7 @@ static PyTypeObject *PyGlyph_init_type()
     PyGlyphType.tp_name = "matplotlib.ft2font.Glyph";
     PyGlyphType.tp_basicsize = sizeof(PyGlyph);
     PyGlyphType.tp_dealloc = (destructor)PyGlyph_dealloc;
-    PyGlyphType.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE;
+    PyGlyphType.tp_flags = Py_TPFLAGS_DEFAULT;
     PyGlyphType.tp_members = members;
     PyGlyphType.tp_getset = getset;
 
@@ -1495,7 +1495,7 @@ static PyTypeObject *PyFT2Font_init_type()
     PyFT2FontType.tp_doc = PyFT2Font_init__doc__;
     PyFT2FontType.tp_basicsize = sizeof(PyFT2Font);
     PyFT2FontType.tp_dealloc = (destructor)PyFT2Font_dealloc;
-    PyFT2FontType.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE;
+    PyFT2FontType.tp_flags = Py_TPFLAGS_DEFAULT;
     PyFT2FontType.tp_methods = methods;
     PyFT2FontType.tp_getset = getset;
     PyFT2FontType.tp_new = PyFT2Font_new;