introduction of _ColorbarMappable

trygvrad · trygvrad · commit 5f78c20db3d1 · 2026-01-25T01:08:03.000+01:00
diff --git a/lib/matplotlib/colorbar.py b/lib/matplotlib/colorbar.py
@@ -1043,6 +1043,8 @@ def remove(self):
 
         try:
             ax = self.mappable.axes
+            if ax is None:
+                return
         except AttributeError:
             return
         try:
diff --git a/lib/matplotlib/colorizer.py b/lib/matplotlib/colorizer.py
@@ -514,7 +514,51 @@ def _sig_digits_from_norm(norm, data, n):
         return g_sig_digits
 
 
-class _ScalarMappable(_ColorizerInterface):
+class _ColorbarMappable(_ColorizerInterface):
+
+    def __init__(self, colorizer, **kwargs):
+        """
+        Base class for objects that can connect to a colorbar.
+
+        All classes that can act as a mappable for `fig.colorbar(mappable)`
+        will subclass this class.
+        """
+        super().__init__(**kwargs)
+        self._colorizer = colorizer
+        self.colorbar = None
+        self._id_colorizer = self._colorizer.callbacks.connect('changed', self.changed)
+        self.callbacks = cbook.CallbackRegistry(signals=["changed"])
+        self._axes = None
+
+    @property
+    def axes(self):
+        return self._axes
+
+    @axes.setter
+    def axes(self, axes):
+        self._axes = axes
+
+    @property
+    def colorizer(self):
+        return self._colorizer
+
+    @colorizer.setter
+    def colorizer(self, cl):
+        _api.check_isinstance(Colorizer, colorizer=cl)
+        self._colorizer.callbacks.disconnect(self._id_colorizer)
+        self._colorizer = cl
+        self._id_colorizer = cl.callbacks.connect('changed', self.changed)
+
+    def changed(self):
+        """
+        Call this whenever the mappable is changed to notify all the
+        callbackSM listeners to the 'changed' signal.
+        """
+        self.callbacks.process('changed')
+        self.stale = True
+
+
+class _ScalarMappable(_ColorbarMappable):
     """
     A mixin class to map one or multiple sets of scalar data to RGBA.
 
@@ -550,13 +594,9 @@ def __init__(self, norm=None, cmap=None, *, colorizer=None, **kwargs):
         cmap : str or `~matplotlib.colors.Colormap`
             The colormap used to map normalized data values to RGBA colors.
         """
-        super().__init__(**kwargs)
         self._A = None
-        self._colorizer = self._get_colorizer(colorizer=colorizer, norm=norm, cmap=cmap)
-
-        self.colorbar = None
-        self._id_colorizer = self._colorizer.callbacks.connect('changed', self.changed)
-        self.callbacks = cbook.CallbackRegistry(signals=["changed"])
+        colorizer = self._get_colorizer(colorizer=colorizer, norm=norm, cmap=cmap)
+        super().__init__(colorizer, **kwargs)
 
     def set_array(self, A):
         """
@@ -600,14 +640,6 @@ def get_array(self):
         """
         return self._A
 
-    def changed(self):
-        """
-        Call this whenever the mappable is changed to notify all the
-        callbackSM listeners to the 'changed' signal.
-        """
-        self.callbacks.process('changed', self)
-        self.stale = True
-
     @staticmethod
     def _check_exclusionary_keywords(colorizer, **kwargs):
         """
@@ -710,17 +742,6 @@ def __init__(self, colorizer, **kwargs):
         _api.check_isinstance(Colorizer, colorizer=colorizer)
         super().__init__(colorizer=colorizer, **kwargs)
 
-    @property
-    def colorizer(self):
-        return self._colorizer
-
-    @colorizer.setter
-    def colorizer(self, cl):
-        _api.check_isinstance(Colorizer, colorizer=cl)
-        self._colorizer.callbacks.disconnect(self._id_colorizer)
-        self._colorizer = cl
-        self._id_colorizer = cl.callbacks.connect('changed', self.changed)
-
     def _set_colorizer_check_keywords(self, colorizer, **kwargs):
         """
         Raises a ValueError if any kwarg is not None while colorizer is not None.
diff --git a/lib/matplotlib/colorizer.pyi b/lib/matplotlib/colorizer.pyi
@@ -1,4 +1,4 @@
-from matplotlib import cbook, colorbar, colors, artist
+from matplotlib import cbook, colorbar, colors, artist, axes as maxes
 
 import numpy as np
 from numpy.typing import ArrayLike
@@ -71,7 +71,24 @@ class _ColorizerInterface:
     def autoscale_None(self) -> None: ...
 
 
-class _ScalarMappable(_ColorizerInterface):
+class _ColorbarMappable(_ColorizerInterface):
+    def __init__(
+        self,
+        colorizer: Colorizer | None,
+        **kwargs
+    ) -> None: ...
+    @property
+    def colorizer(self) -> Colorizer: ...
+    @colorizer.setter
+    def colorizer(self, cl: Colorizer) -> None: ...
+    def changed(self) -> None: ...
+    @property
+    def axes(self) -> maxes._base._AxesBase | None: ...
+    @axes.setter
+    def axes(self, new_axes: maxes._base._AxesBase | None) -> None: ...
+
+
+class _ScalarMappable(_ColorbarMappable):
     def __init__(
         self,
         norm: colors.Norm | None = ...,
@@ -82,7 +99,6 @@ class _ScalarMappable(_ColorizerInterface):
     ) -> None: ...
     def set_array(self, A: ArrayLike | None) -> None: ...
     def get_array(self) -> np.ndarray | None: ...
-    def changed(self) -> None: ...
 
 
 class ColorizingArtist(_ScalarMappable, artist.Artist):
diff --git a/lib/mpl_toolkits/mplot3d/art3d.py b/lib/mpl_toolkits/mplot3d/art3d.py
@@ -15,11 +15,12 @@
 
 from matplotlib import (
     _api, artist, cbook, colors as mcolors, lines, text as mtext,
-    path as mpath, rcParams)
+    path as mpath, rcParams, colorizer as mcolorizer)
 from matplotlib.collections import (
     Collection, LineCollection, PolyCollection, PatchCollection, PathCollection)
 from matplotlib.patches import Patch
 from . import proj3d
+import collections
 
 
 def _norm_angle(a):
@@ -1712,9 +1713,10 @@ def norm(x):
     return colors
 
 
-class VoxelDict(dict):
+class VoxelDict(mcolorizer._ColorbarMappable,
+                collections.abc.MutableMapping):
     """
-    A dictionary subclass indexed by coordinate, where ``faces[i, j, k]``
+    A mapping indexed by coordinate, where ``faces[i, j, k]``
     is a `.Poly3DCollection` of the faces drawn for the voxel
     ``filled[i, j, k]``. If no faces were drawn for a given voxel,
     either because it was not asked to be drawn, or it is fully
@@ -1724,33 +1726,37 @@ class VoxelDict(dict):
     for a colorbar.
     """
 
-    def __init__(self, axes, colorizer):
+    def __init__(self, colorizer, axes):
         """
         Parameters
         ----------
+        colorizer : `mpl.colorizer.Colorizer`
+            The colorizer uset to convert data to color.
+
         axes : `mplot3d.axes3d.Axes3D`
             The axes the voxels are contained in.
 
-        colorizer : `mpl.colorizer.Colorizer`
-            The colorizer uset to convert data to color.
         """
-        super().__init__(self)
+
+        super().__init__(colorizer)
         self.axes = axes
-        self.colorizer = colorizer
-        self._callbacks = cbook.CallbackRegistry(signals=["changed"])
         self._A = None
+        self._mapping = dict()
+
+    def __getitem__(self, key):
+        return self._mapping[key]
 
-    @property
-    def cmap(self):
-        return self.colorizer.cmap
+    def __setitem__(self, key, val):
+        self._mapping[key] = val
 
-    @property
-    def norm(self):
-        return self.colorizer.norm
+    def __delitem__(self, key):
+        del self._mapping[key]
 
-    @property
-    def callbacks(self):
-        return self._callbacks
+    def __len__(self):
+        return len(self._mapping)
+
+    def __iter__(self):
+        return reversed(self._mapping)
 
     def get_array(self):
         """
@@ -1772,72 +1778,3 @@ def set_array(self, A):
         self._A = A
         for a, k in zip(A, self.keys()):
             self[k].set_array(a)
-
-    def add_callback(self, func):
-        """
-        Add a callback function that will be called whenever one of the
-        `.Artist`'s properties changes.
-
-        Parameters
-        ----------
-        func : callable
-            The callback function. It must have the signature::
-
-                def func(artist: Artist) -> Any
-
-            where *artist* is the calling `.Artist`. Return values may exist
-            but are ignored.
-
-        Returns
-        -------
-        int
-            The observer id associated with the callback. This id can be
-            used for removing the callback with `.remove_callback` later.
-
-        See Also
-        --------
-        remove_callback
-        """
-        # Wrapping func in a lambda ensures it can be connected multiple times
-        # and never gets weakref-gc'ed.
-        return self._callbacks.connect("changed", lambda: func(self))
-
-    def remove_callback(self, oid):
-        """
-        Remove a callback based on its observer id.
-
-        See Also
-        --------
-        add_callback
-        """
-        self._callbacks.disconnect(oid)
-
-    def changed(self, *args):
-        """
-        Call all of the registered callbacks.
-
-        This function is triggered internally when a property is changed.
-
-        See Also
-        --------
-        add_callback
-        remove_callback
-        """
-        self._callbacks.process("changed")
-
-    def get_alpha(self):
-        return 1.0
-
-    def autoscale(self, A):
-        """
-        Autoscale the scalar limits on the norm instance using the
-        current array
-        """
-        self.colorizer.autoscale(A)
-
-    def autoscale_None(self):
-        """
-        Autoscale the scalar limits on the norm instance using the
-        current array, changing only limits that are None
-        """
-        self.colorizer.autoscale_None(self._A)
diff --git a/lib/mpl_toolkits/mplot3d/axes3d.py b/lib/mpl_toolkits/mplot3d/axes3d.py
@@ -3592,7 +3592,7 @@ def permutation_matrices(n):
 
         # iterate over the faces, and generate a Poly3DCollection for each
         # voxel
-        polygons = art3d.VoxelDict(self, colorizer)
+        polygons = art3d.VoxelDict(colorizer, self)
         for coord, faces_inds in voxel_faces.items():
             # convert indices into 3D positions
             if xyz is None:
diff --git a/lib/mpl_toolkits/mplot3d/tests/test_axes3d.py b/lib/mpl_toolkits/mplot3d/tests/test_axes3d.py
@@ -2,6 +2,7 @@
 import itertools
 import platform
 import sys
+import collections.abc
 
 from packaging.version import parse as parse_version
 import pytest
@@ -1496,7 +1497,7 @@ def test_alpha(self):
         colors[v1] = [0, 1, 0, 0.5]
         v = ax.voxels(voxels, facecolors=colors)
 
-        assert type(v) is dict
+        assert issubclass(type(v), collections.abc.MutableMapping)
         for coord, poly in v.items():
             assert voxels[coord], "faces returned for absent voxel"
             assert isinstance(poly, art3d.Poly3DCollection)
