Make pickles work again.

efiring · efiring · commit 94f04a956eb6 · 2020-04-29T14:30:22.000-10:00
diff --git a/lib/matplotlib/axis.py b/lib/matplotlib/axis.py
@@ -1599,6 +1599,11 @@ def set_pickradius(self, pickradius):
         """
         self.pickradius = pickradius
 
+    # Helper for set_ticklabels. Defining it here makes it pickleable.
+    @staticmethod
+    def _format_with_dict(x, pos, tickd):
+        return tickd.get(x, "")
+
     def set_ticklabels(self, ticklabels, *, minor=False, **kwargs):
         r"""
         Set the text values of the tick labels.
@@ -1630,7 +1635,7 @@ def set_ticklabels(self, ticklabels, *, minor=False, **kwargs):
                    else self.get_major_locator())
         if isinstance(locator, mticker.FixedLocator):
             tickd = {loc: lab for loc, lab in zip(locator.locs, ticklabels)}
-            formatter = mticker.FuncFormatter(lambda x, pos: tickd.get(x, ""))
+            formatter = mticker.FuncFormatter(self._format_with_dict, tickd)
         else:
             formatter = mticker.FixedFormatter(ticklabels)
         if minor:
diff --git a/lib/matplotlib/ticker.py b/lib/matplotlib/ticker.py
@@ -379,11 +379,13 @@ class FuncFormatter(Formatter):
 
     The function should take in two inputs (a tick value ``x`` and a
     position ``pos``), and return a string containing the corresponding
-    tick label.
+    tick label.  The function may take additional arguments that are
+    supplied upon instantiation.
     """
 
-    def __init__(self, func):
+    def __init__(self, func, *args):
         self.func = func
+        self.args = args
         self.offset_string = ""
 
     def __call__(self, x, pos=None):
@@ -392,7 +394,7 @@ def __call__(self, x, pos=None):
 
         *x* and *pos* are passed through as-is.
         """
-        return self.func(x, pos)
+        return self.func(x, pos, *self.args)
 
     def get_offset(self):
         return self.offset_string
