Expire BoxStyle._Base deprecation.

anntzer · anntzer · commit 866e03bca294 · 2022-06-10T18:47:56.000+02:00
diff --git a/doc/api/next_api_changes/removals/XXXXX-AL.rst b/doc/api/next_api_changes/removals/XXXXX-AL.rst
@@ -0,0 +1,4 @@
+``BoxStyle._Base`` and ``transmute`` method of boxstyles
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+... have been removed.  Boxstyles implemented as classes no longer need to
+inherit from a base class.
diff --git a/lib/matplotlib/patches.py b/lib/matplotlib/patches.py
@@ -2268,94 +2268,19 @@ class BoxStyle(_Style):
 
     %(AvailableBoxstyles)s
 
-    An instance of any boxstyle class is an callable object,
-    whose call signature is::
+    An instance of any boxstyle class is an callable object, whose call
+    signature is::
 
-       __call__(self, x0, y0, width, height, mutation_size)
+       __call__(self, x0, y0, width, height, mutation_size) -> Path
 
-    and returns a `.Path` instance. *x0*, *y0*, *width* and
-    *height* specify the location and size of the box to be
-    drawn. *mutation_scale* determines the overall size of the
-    mutation (by which I mean the transformation of the rectangle to
-    the fancy box).
+    *x0*, *y0*, *width* and *height* specify the location and size of the box
+    to be drawn; *mutation_size* scales the outline properties such as padding.
     """
 
     _style_list = {}
 
-    @_api.deprecated("3.4")
-    class _Base:
-        """
-        Abstract base class for styling of `.FancyBboxPatch`.
-
-        This class is not an artist itself.  The `__call__` method returns the
-        `~matplotlib.path.Path` for outlining the fancy box. The actual drawing
-        is handled in `.FancyBboxPatch`.
-
-        Subclasses may only use parameters with default values in their
-        ``__init__`` method because they must be able to be initialized
-        without arguments.
-
-        Subclasses must implement the `__call__` method. It receives the
-        enclosing rectangle *x0, y0, width, height* as well as the
-        *mutation_size*, which scales the outline properties such as padding.
-        It returns the outline of the fancy box as `.path.Path`.
-        """
-
-        @_api.deprecated("3.4")
-        def transmute(self, x0, y0, width, height, mutation_size):
-            """Return the `~.path.Path` outlining the given rectangle."""
-            return self(self, x0, y0, width, height, mutation_size, 1)
-
-        # This can go away once the deprecation period elapses, leaving _Base
-        # as a fully abstract base class just providing docstrings, no logic.
-        def __init_subclass__(cls):
-            transmute = _api.deprecate_method_override(
-                __class__.transmute, cls, since="3.4")
-            if transmute:
-                cls.__call__ = transmute
-                return
-
-            __call__ = cls.__call__
-
-            @_api.delete_parameter("3.4", "mutation_aspect")
-            def call_wrapper(
-                    self, x0, y0, width, height, mutation_size,
-                    mutation_aspect=_api.deprecation._deprecated_parameter):
-                if mutation_aspect is _api.deprecation._deprecated_parameter:
-                    # Don't trigger deprecation warning internally.
-                    return __call__(self, x0, y0, width, height, mutation_size)
-                else:
-                    # Squeeze the given height by the aspect_ratio.
-                    y0, height = y0 / mutation_aspect, height / mutation_aspect
-                    path = self(x0, y0, width, height, mutation_size,
-                                mutation_aspect)
-                    vertices, codes = path.vertices, path.codes
-                    # Restore the height.
-                    vertices[:, 1] = vertices[:, 1] * mutation_aspect
-                    return Path(vertices, codes)
-
-            cls.__call__ = call_wrapper
-
-        def __call__(self, x0, y0, width, height, mutation_size):
-            """
-            Given the location and size of the box, return the path of
-            the box around it.
-
-            Parameters
-            ----------
-            x0, y0, width, height : float
-                Location and size of the box.
-            mutation_size : float
-                A reference scale for the mutation.
-
-            Returns
-            -------
-            `~matplotlib.path.Path`
-            """
-            raise NotImplementedError('Derived must override')
-
     @_register_style(_style_list)
-    class Square(_Base):
+    class Square:
         """A square box."""
 
         def __init__(self, pad=0.3):
@@ -2378,7 +2303,7 @@ def __call__(self, x0, y0, width, height, mutation_size):
                         closed=True)
 
     @_register_style(_style_list)
-    class Circle(_Base):
+    class Circle:
         """A circular box."""
 
         def __init__(self, pad=0.3):
@@ -2399,7 +2324,7 @@ def __call__(self, x0, y0, width, height, mutation_size):
                                max(width, height) / 2)
 
     @_register_style(_style_list)
-    class LArrow(_Base):
+    class LArrow:
         """A box in the shape of a left-pointing arrow."""
 
         def __init__(self, pad=0.3):
@@ -2441,7 +2366,7 @@ def __call__(self, x0, y0, width, height, mutation_size):
             return p
 
     @_register_style(_style_list)
-    class DArrow(_Base):
+    class DArrow:
         """A box in the shape of a two-way arrow."""
         # Modified from LArrow to add a right arrow to the bbox.
 
@@ -2478,7 +2403,7 @@ def __call__(self, x0, y0, width, height, mutation_size):
                         closed=True)
 
     @_register_style(_style_list)
-    class Round(_Base):
+    class Round:
         """A box with round corners."""
 
         def __init__(self, pad=0.3, rounding_size=None):
@@ -2538,7 +2463,7 @@ def __call__(self, x0, y0, width, height, mutation_size):
             return path
 
     @_register_style(_style_list)
-    class Round4(_Base):
+    class Round4:
         """A box with rounded edges."""
 
         def __init__(self, pad=0.3, rounding_size=None):
@@ -2589,7 +2514,7 @@ def __call__(self, x0, y0, width, height, mutation_size):
             return path
 
     @_register_style(_style_list)
-    class Sawtooth(_Base):
+    class Sawtooth:
         """A box with a sawtooth outline."""
 
         def __init__(self, pad=0.3, tooth_size=None):
@@ -4025,11 +3950,9 @@ def set_boxstyle(self, boxstyle=None, **kwargs):
         """
         if boxstyle is None:
             return BoxStyle.pprint_styles()
-
-        if isinstance(boxstyle, BoxStyle._Base) or callable(boxstyle):
-            self._bbox_transmuter = boxstyle
-        else:
-            self._bbox_transmuter = BoxStyle(boxstyle, **kwargs)
+        self._bbox_transmuter = (
+            BoxStyle(boxstyle, **kwargs) if isinstance(boxstyle, str)
+            else boxstyle)
         self.stale = True
 
     def set_mutation_scale(self, scale):
