matplotlib · QuLogic · Mar 23, 2021 · Feb 20, 2021
diff --git a/doc/api/next_api_changes/removals/19552-GL.rst b/doc/api/next_api_changes/removals/19552-GL.rst
@@ -0,0 +1,5 @@
+ScalarMappable update checkers
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+``ScalarMappable.update_dict``, ``ScalarMappable.add_checker()``, and
+``ScalarMappable.check_update()`` have been removed. A callback can
+be registered in ``ScalarMappable.callbacksSM`` to be notified of updates.
diff --git a/lib/matplotlib/cm.py b/lib/matplotlib/cm.py
@@ -264,7 +264,6 @@ def __init__(self, norm=None, cmap=None):
         #: The last colorbar associated with this ScalarMappable. May be None.
         self.colorbar = None
         self.callbacksSM = cbook.CallbackRegistry()
-        self._update_dict = {'array': False}
 
     def _scale_norm(self, norm, vmin, vmax):
         """
@@ -369,7 +368,6 @@ def set_array(self, A):
         A : ndarray or None
         """
         self._A = A
-        self._update_dict['array'] = True
 
     def get_array(self):
         """Return the data array."""
@@ -476,30 +474,10 @@ def autoscale_None(self):
         self.norm.autoscale_None(self._A)
         self.changed()
 
-    def _add_checker(self, checker):
-        """
-        Add an entry to a dictionary of boolean flags
-        that are set to True when the mappable is changed.
-        """
-        self._update_dict[checker] = False
-
-    def _check_update(self, checker):
-        """Return whether mappable has changed since the last check."""
-        if self._update_dict[checker]:
-            self._update_dict[checker] = False
-            return True
-        return False
-
     def changed(self):
         """
         Call this whenever the mappable is changed to notify all the
         callbackSM listeners to the 'changed' signal.
         """
         self.callbacksSM.process('changed', self)
-        for key in self._update_dict:
-            self._update_dict[key] = True
         self.stale = True
-
-    update_dict = _api.deprecate_privatize_attribute("3.3")
-    add_checker = _api.deprecate_privatize_attribute("3.3")
-    check_update = _api.deprecate_privatize_attribute("3.3")
diff --git a/lib/matplotlib/collections.py b/lib/matplotlib/collections.py
@@ -851,7 +851,6 @@ def set_alpha(self, alpha):
             supported.
         """
         artist.Artist._set_alpha_for_array(self, alpha)
-        self._update_dict['array'] = True
         self._set_facecolor(self._original_facecolor)
         self._set_edgecolor(self._original_edgecolor)
 
@@ -907,7 +906,7 @@ def update_scalarmappable(self):
         if not self._set_mappable_flags():
             return
         # Allow possibility to call 'self.set_array(None)'.
-        if self._check_update("array") and self._A is not None:
+        if self._A is not None:
             # QuadMesh can map 2d arrays (but pcolormesh supplies 1d array)
             if self._A.ndim > 1 and not isinstance(self, QuadMesh):
                 raise ValueError('Collections can only map rank 1 arrays')
@@ -958,7 +957,6 @@ def update_from(self, other):
         self._A = other._A
         self.norm = other.norm
         self.cmap = other.cmap
-        # do we need to copy self._update_dict? -JJL
         self.stale = True
 
 

diff --git a/lib/matplotlib/tests/test_collections.py b/lib/matplotlib/tests/test_collections.py
@@ -715,6 +715,22 @@ def test_quadmesh_set_array():
     assert np.array_equal(coll.get_array(), np.ones(9))
 
 
+def test_quadmesh_vmin_vmax():
+    # test when vmin/vmax on the norm changes, the quadmesh gets updated
+    fig, ax = plt.subplots()
+    cmap = mpl.cm.get_cmap('plasma')
+    norm = mpl.colors.Normalize(vmin=0, vmax=1)
+    coll = ax.pcolormesh([[1]], cmap=cmap, norm=norm)
+    fig.canvas.draw()
+    assert np.array_equal(coll.get_facecolors()[0, :], cmap(norm(1)))
+
+    # Change the vmin/vmax of the norm so that the color is from
+    # the bottom of the colormap now
+    norm.vmin, norm.vmax = 1, 2
+    fig.canvas.draw()
+    assert np.array_equal(coll.get_facecolors()[0, :], cmap(norm(1)))
+
+
 def test_quadmesh_alpha_array():
     x = np.arange(4)
     y = np.arange(4)

diff --git a/lib/mpl_toolkits/mplot3d/art3d.py b/lib/mpl_toolkits/mplot3d/art3d.py
@@ -695,13 +695,11 @@ def _update_scalarmappable(sm):
     """
     if sm._A is None:
         return
-    copy_state = sm._update_dict['array']
-    ret = sm.update_scalarmappable()
-    if copy_state:
-        if sm._face_is_mapped:
-            sm._facecolor3d = sm._facecolors
-        elif sm._edge_is_mapped:  # Should this be plain "if"?
-            sm._edgecolor3d = sm._edgecolors
+    sm.update_scalarmappable()
+    if sm._face_is_mapped:
+        sm._facecolor3d = sm._facecolors
+    elif sm._edge_is_mapped:  # Should this be plain "if"?
+        sm._edgecolor3d = sm._edgecolors
 
 
 def patch_collection_2d_to_3d(col, zs=0, zdir='z', depthshade=True):