Merge pull request matplotlib#26335 from eendebakpt/imshow

Optimize imshow

Author: greglucas

lib/matplotlib/cbook.py

@@ -731,8 +731,7 @@ def safe_masked_invalid(x, copy=False):
         # copy with the byte order swapped.
         x = x.byteswap(inplace=copy).newbyteorder('N')  # Swap to native order.
     try:
-        xm = np.ma.masked_invalid(x, copy=False)
-        xm.shrink_mask()
+        xm = np.ma.masked_where(~(np.isfinite(x)), x, copy=False)
     except TypeError:
         return x
     return xm

lib/matplotlib/cm.py

@@ -735,5 +735,6 @@ def _ensure_cmap(cmap):
     cmap_name = cmap if cmap is not None else mpl.rcParams["image.cmap"]
     # use check_in_list to ensure type stability of the exception raised by
     # the internal usage of this (ValueError vs KeyError)
-    _api.check_in_list(sorted(_colormaps), cmap=cmap_name)
+    if cmap_name not in _colormaps:
+        _api.check_in_list(sorted(_colormaps), cmap=cmap_name)
     return mpl.colormaps[cmap_name]

lib/matplotlib/colors.py

@@ -1390,6 +1390,12 @@ def autoscale(self, A):
     def autoscale_None(self, A):
         """If vmin or vmax are not set, use the min/max of *A* to set them."""
         A = np.asanyarray(A)
+
+        if isinstance(A, np.ma.MaskedArray):
+            # we need to make the distinction between an array, False, np.bool_(False)
+            if A.mask is False or not A.mask.shape:
+                A = A.data
+
         if self.vmin is None and A.size:
             self.vmin = A.min()
         if self.vmax is None and A.size: