Add deprecation warnings for 2D classes

lib/matplotlib/transforms.py

@@ -1924,6 +1924,11 @@ def inverted(self):
         return self._inverted
 
 
+@_api.deprecated("3.9", alternative="AffineImmutable")
+class Affine2DBase(AffineImmutable):
+    pass
+
+
 def _affine_factory(mtx, dims, *args, **kwargs):
     if dims == 2:
         return Affine2D(mtx, *args, **kwargs)
@@ -2396,6 +2401,11 @@ def get_matrix(self):
         return self._mtx
 
 
+@_api.deprecated("3.9", alternative="BlendedAffine")
+class BlendedAffine2D(BlendedAffine):
+    pass
+
+
 def blended_transform_factory(*args):
     """
     Create a new "blended" transform using *x_transform* to transform
@@ -2567,6 +2577,11 @@ def get_matrix(self):
         return self._mtx
 
 
+@_api.deprecated("3.9", alternative="CompositeAffine")
+class CompositeAffine2D(CompositeAffine):
+    pass
+
+
 def composite_transform_factory(a, b):
     """
     Create a new composite transform that is the result of applying

lib/matplotlib/transforms.pyi

@@ -231,6 +231,9 @@ class AffineImmutable(AffineBase):
     def frozen(self) -> AffineImmutable: ...
     def to_values(self) -> tuple[float]: ...
 
+class Affine2DBase(AffineImmutable):
+    pass
+
 class Affine2D(AffineImmutable):
     def __init__(self, matrix: ArrayLike | None = ..., **kwargs) -> None: ...
     @staticmethod
@@ -266,9 +269,10 @@ class BlendedGenericTransform(_BlendedMixin, Transform):
     def is_affine(self) -> bool: ...
 
 class BlendedAffine(_BlendedMixin, AffineImmutable):
-    def __init__(
-        self, *args: Transform, **kwargs
-    ) -> None: ...
+    def __init__(self, *args: Transform, **kwargs) -> None: ...
+
+class BlendedAffine2D(BlendedAffine):
+    pass
 
 def blended_transform_factory(
     *args: Transform
@@ -283,6 +287,9 @@ class CompositeAffine(AffineImmutable):
     @property
     def depth(self) -> int: ...
 
+class CompositeAffine2D(CompositeAffine):
+    pass
+
 def composite_transform_factory(a: Transform, b: Transform) -> Transform: ...
 
 class BboxTransform(AffineImmutable):