diff --git a/doc/api/prev_api_changes/api_changes_3.6.0/deprecations.rst b/doc/api/prev_api_changes/api_changes_3.6.0/deprecations.rst
index d59077d2b2d2..3a9e91e12289 100644
--- a/doc/api/prev_api_changes/api_changes_3.6.0/deprecations.rst
+++ b/doc/api/prev_api_changes/api_changes_3.6.0/deprecations.rst
@@ -52,7 +52,12 @@ In Matplotlib 3.6 we have marked those top level functions as pending
deprecation with the intention of deprecation in Matplotlib 3.7. The following
functions have been marked for pending deprecation:
-- ``matplotlib.cm.get_cmap``; use ``matplotlib.colormaps[name]`` instead
+- ``matplotlib.cm.get_cmap``; use ``matplotlib.colormaps[name]`` instead if you
+ have a `str`.
+
+ **Added 3.6.1** Use `matplotlib.cm.ColormapRegistry.get_cmap` if you
+ have a string, `None` or a `matplotlib.colors.Colormap` object that you want
+ to convert to a `matplotlib.colors.Colormap` instance.
- ``matplotlib.cm.register_cmap``; use `matplotlib.colormaps.register
<.ColormapRegistry.register>` instead
- ``matplotlib.cm.unregister_cmap``; use `matplotlib.colormaps.unregister
@@ -305,7 +310,7 @@ Backend-specific deprecations
private functions if you rely on it.
- ``backend_svg.generate_transform`` and ``backend_svg.generate_css``
- ``backend_tk.NavigationToolbar2Tk.lastrect`` and
- ``backend_tk.RubberbandTk.lastrect``
+ ``backend_tk.RubberbandTk.lastrect``
- ``backend_tk.NavigationToolbar2Tk.window``; use ``toolbar.master`` instead.
- ``backend_tools.ToolBase.destroy``; To run code upon tool removal, connect to
the ``tool_removed_event`` event.
diff --git a/lib/matplotlib/cm.py b/lib/matplotlib/cm.py
index f6e5ee8b7156..ec0d472992ef 100644
--- a/lib/matplotlib/cm.py
+++ b/lib/matplotlib/cm.py
@@ -61,12 +61,6 @@ class ColormapRegistry(Mapping):
r"""
Container for colormaps that are known to Matplotlib by name.
- .. admonition:: Experimental
-
- While we expect the API to be final, we formally mark it as
- experimental for 3.5 because we want to keep the option to still adapt
- the API for 3.6 should the need arise.
-
The universal registry instance is `matplotlib.colormaps`. There should be
no need for users to instantiate `.ColormapRegistry` themselves.
@@ -193,6 +187,38 @@ def unregister(self, name):
"colormap.")
self._cmaps.pop(name, None)
+ def get_cmap(self, cmap):
+ """
+ Return a color map specified through *cmap*.
+
+ Parameters
+ ----------
+ cmap : str or `~matplotlib.colors.Colormap` or None
+
+ - if a `.Colormap`, return it
+ - if a string, look it up in ``mpl.colormaps``
+ - if None, return the Colormap defined in :rc:`image.cmap`
+
+ Returns
+ -------
+ Colormap
+ """
+ # get the default color map
+ if cmap is None:
+ return self[mpl.rcParams["image.cmap"]]
+
+ # if the user passed in a Colormap, simply return it
+ if isinstance(cmap, colors.Colormap):
+ return cmap
+ if isinstance(cmap, str):
+ _api.check_in_list(sorted(_colormaps), cmap=cmap)
+ # otherwise, it must be a string so look it up
+ return self[cmap]
+ raise TypeError(
+ 'get_cmap expects None or an instance of a str or Colormap . ' +
+ f'you passed {cmap!r} of type {type(cmap)}'
+ )
+
# public access to the colormaps should be via `matplotlib.colormaps`. For now,
# we still create the registry here, but that should stay an implementation
@@ -281,7 +307,12 @@ def _get_cmap(name=None, lut=None):
# pyplot.
get_cmap = _api.deprecated(
'3.6',
- name='get_cmap', pending=True, alternative="``matplotlib.colormaps[name]``"
+ name='get_cmap',
+ pending=True,
+ alternative=(
+ "``matplotlib.colormaps[name]`` " +
+ "or ``matplotlib.colormaps.get_cmap(obj)``"
+ )
)(_get_cmap)
@@ -687,6 +718,8 @@ def _ensure_cmap(cmap):
"""
Ensure that we have a `.Colormap` object.
+ For internal use to preserve type stability of errors.
+
Parameters
----------
cmap : None, str, Colormap
@@ -698,6 +731,7 @@ def _ensure_cmap(cmap):
Returns
-------
Colormap
+
"""
if isinstance(cmap, colors.Colormap):
return cmap
diff --git a/lib/matplotlib/tests/test_colors.py b/lib/matplotlib/tests/test_colors.py
index f0c23038e11a..86536ab17234 100644
--- a/lib/matplotlib/tests/test_colors.py
+++ b/lib/matplotlib/tests/test_colors.py
@@ -109,6 +109,26 @@ def test_register_cmap():
cm.register_cmap('nome', cmap='not a cmap')
+def test_colormaps_get_cmap():
+ cr = mpl.colormaps
+
+ # check str, and Colormap pass
+ assert cr.get_cmap('plasma') == cr["plasma"]
+ assert cr.get_cmap(cr["magma"]) == cr["magma"]
+
+ # check default
+ assert cr.get_cmap(None) == cr[mpl.rcParams['image.cmap']]
+
+ # check ValueError on bad name
+ bad_cmap = 'AardvarksAreAwkward'
+ with pytest.raises(ValueError, match=bad_cmap):
+ cr.get_cmap(bad_cmap)
+
+ # check TypeError on bad type
+ with pytest.raises(TypeError, match='object'):
+ cr.get_cmap(object())
+
+
def test_double_register_builtin_cmap():
name = "viridis"
match = f"Re-registering the builtin cmap {name!r}."
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