Colorbar cleanup.

anntzer · anntzer · commit 5a0b306429ed · 2020-01-11T11:40:47.000+01:00
Deprecate on_mappable_changed in favor of update_normal (they're the
same now (except for a logging call) now that colorbars just use the
norm of the mappable).

Deprecate update_bruteforce in favor of update_normal -- it's not used
anywhere except in axes_grid, but that's just because whoever introduced
update_normal forgot to update axes_grid at the same time.

axes_grid.colorbar is already deprecated but until its complete removal,
we need to backport update_normal to it...
diff --git a/doc/api/next_api_changes/deprecations.rst b/doc/api/next_api_changes/deprecations.rst
@@ -144,3 +144,9 @@ and containment checks) via `.Line2D.set_picker` is deprecated.  Use
 
 `.Line2D.set_picker` no longer sets the artist's custom-contain() check.  Use
 ``Line2D.set_contains`` instead.
+
+`~matplotlib.colorbar.Colorbar` methods
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The ``on_mappable_changed`` and ``update_bruteforce`` methods of
+`~matplotlib.colorbar.Colorbar` are deprecated; both can be replaced by calls
+to `~matplotlib.colorbar.Colorbar.update_normal`.
diff --git a/lib/matplotlib/colorbar.py b/lib/matplotlib/colorbar.py
@@ -1209,6 +1209,7 @@ def __init__(self, ax, mappable, **kwargs):
                 _add_disjoint_kwargs(kwargs, alpha=mappable.get_alpha())
             ColorbarBase.__init__(self, ax, **kwargs)
 
+    @cbook.deprecated("3.3", alternative="update_normal")
     def on_mappable_changed(self, mappable):
         """
         Update this colorbar to match the mappable's properties.
@@ -1249,9 +1250,8 @@ def update_normal(self, mappable):
         """
         Update solid patches, lines, etc.
 
-        Unlike `.update_bruteforce`, this does not clear the axes.  This is
-        meant to be called when the norm of the image or contour plot to which
-        this colorbar belongs changes.
+        This is meant to be called when the norm of the image or contour plot
+        to which this colorbar belongs changes.
 
         If the norm on the mappable is different than before, this resets the
         locator and formatter for the axis, so if these have been customized,
@@ -1274,6 +1274,7 @@ def update_normal(self, mappable):
                 self.add_lines(CS)
         self.stale = True
 
+    @cbook.deprecated("3.3", alternative="update_normal")
     def update_bruteforce(self, mappable):
         """
         Destroy and rebuild the colorbar.  This is
@@ -1684,7 +1685,7 @@ def colorbar_factory(cax, mappable, **kwargs):
     else:
         cb = Colorbar(cax, mappable, **kwargs)
 
-    cid = mappable.callbacksSM.connect('changed', cb.on_mappable_changed)
+    cid = mappable.callbacksSM.connect('changed', cb.update_normal)
     mappable.colorbar = cb
     mappable.colorbar_cid = cid
 
diff --git a/lib/mpl_toolkits/axes_grid1/axes_grid.py b/lib/mpl_toolkits/axes_grid1/axes_grid.py
@@ -44,12 +44,7 @@ def colorbar(self, mappable, *, ticks=None, **kwargs):
             self, mappable, orientation=orientation, ticks=ticks, **kwargs)
         self._config_axes()
 
-        def on_changed(m):
-            cb.set_cmap(m.get_cmap())
-            cb.set_clim(m.get_clim())
-            cb.update_bruteforce(m)
-
-        self.cbid = mappable.callbacksSM.connect('changed', on_changed)
+        self.cbid = mappable.callbacksSM.connect('changed', cb.update_normal)
         mappable.colorbar = cb
 
         if mpl.rcParams["mpl_toolkits.legacy_colorbar"]:
diff --git a/lib/mpl_toolkits/axes_grid1/colorbar.py b/lib/mpl_toolkits/axes_grid1/colorbar.py
@@ -703,6 +703,33 @@ def add_lines(self, CS):
         #tlinewidths = [col.get_linewidth()[0] for lw in CS.collections]
         ColorbarBase.add_lines(self, CS.levels, tcolors, tlinewidths)
 
+    def update_normal(self, mappable):
+        """
+        Update solid patches, lines, etc.
+
+        This is meant to be called when the norm of the image or contour plot
+        to which this colorbar belongs changes.
+
+        If the norm on the mappable is different than before, this resets the
+        locator and formatter for the axis, so if these have been customized,
+        they will need to be customized again.  However, if the norm only
+        changes values of *vmin*, *vmax* or *cmap* then the old formatter
+        and locator will be preserved.
+        """
+        self.mappable = mappable
+        self.set_alpha(mappable.get_alpha())
+        self.cmap = mappable.cmap
+        if mappable.norm != self.norm:
+            self.norm = mappable.norm
+            self._reset_locator_formatter_scale()
+
+        self.draw_all()
+        if isinstance(self.mappable, contour.ContourSet):
+            CS = self.mappable
+            if not CS.filled:
+                self.add_lines(CS)
+        self.stale = True
+
     def update_bruteforce(self, mappable):
         """
         Update the colorbar artists to reflect the change of the
