Backport PR #24259: Move empty hexbin fix to make_norm_from_scale.

QuLogic · meeseeksmachine · commit 0af7ef55af36 · 2022-10-31T22:51:30.000Z
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -4959,9 +4959,7 @@ def reduce_C_function(C: array) -> float
         # autoscale the norm with current accum values if it hasn't been set
         if norm is not None:
             if norm.vmin is None and norm.vmax is None:
-                norm.autoscale_None(accum)
-            norm.vmin = np.ma.masked if norm.vmin is None else norm.vmin
-            norm.vmax = np.ma.masked if norm.vmax is None else norm.vmax
+                norm.autoscale(accum)
 
         if bins is not None:
             if not np.iterable(bins):
diff --git a/lib/matplotlib/colors.py b/lib/matplotlib/colors.py
@@ -1718,10 +1718,14 @@ def inverse(self, value):
         def autoscale(self, A):
             # i.e. A[np.isfinite(...)], but also for non-array A's
             in_trf_domain = np.extract(np.isfinite(self._trf.transform(A)), A)
+            if in_trf_domain.size == 0:
+                in_trf_domain = np.ma.masked
             return super().autoscale(in_trf_domain)
 
         def autoscale_None(self, A):
             in_trf_domain = np.extract(np.isfinite(self._trf.transform(A)), A)
+            if in_trf_domain.size == 0:
+                in_trf_domain = np.ma.masked
             return super().autoscale_None(in_trf_domain)
 
     if base_norm_cls is Normalize:
