Deprecate auto-removal of grid by pcolor/pcolormesh.

anntzer · anntzer · commit 968b96e88ef4 · 2020-01-14T01:36:46.000+01:00
diff --git a/doc/api/next_api_changes/deprecations.rst b/doc/api/next_api_changes/deprecations.rst
@@ -169,3 +169,9 @@ The ``TTFPATH`` and ``AFMPATH`` environment variables
 Support for the (undocumented) ``TTFPATH`` and ``AFMPATH`` environment
 variables is deprecated.  Additional fonts may be registered using
 ``matplotlib.font_manager.fontManager.addfont()``.
+
+Auto-removal of grids by `~.Axes.pcolor` and `~.Axes.pcolormesh`
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+`~.Axes.pcolor` and `~.Axes.pcolormesh` currently remove any visible axes major
+grid.  This behavior is deprecated; please explicitly call ``ax.grid(False)``
+to remove the grid.
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -5652,6 +5652,14 @@ def _pcolorargs(funcname, *args, allmatch=False):
         C = cbook.safe_masked_invalid(C)
         return X, Y, C
 
+    def _pcolor_grid_deprecation_helper(self):
+        if any(axis._gridOnMajor for axis in self._get_axis_list()):
+            cbook.warn_deprecated(
+                "3.3", message="Auto-removal of grids by pcolor() and "
+                "pcolormesh() is deprecated since %(since)s and will be "
+                "removed %(removal)s; please call grid(False) first.")
+        self.grid(False)
+
     @_preprocess_data()
     @docstring.dedent_interpd
     def pcolor(self, *args, alpha=None, norm=None, cmap=None, vmin=None,
@@ -5852,7 +5860,7 @@ def pcolor(self, *args, alpha=None, norm=None, cmap=None, vmin=None,
         collection.set_cmap(cmap)
         collection.set_norm(norm)
         collection._scale_norm(norm, vmin, vmax)
-        self.grid(False)
+        self._pcolor_grid_deprecation_helper()
 
         x = X.compressed()
         y = Y.compressed()
@@ -6066,8 +6074,7 @@ def pcolormesh(self, *args, alpha=None, norm=None, cmap=None, vmin=None,
         collection.set_cmap(cmap)
         collection.set_norm(norm)
         collection._scale_norm(norm, vmin, vmax)
-
-        self.grid(False)
+        self._pcolor_grid_deprecation_helper()
 
         # Transform from native to data coordinates?
         t = collection._transform
