Fix bugs in scatter with invalid points and with integer arrays.

Author: efiring

lib/matplotlib/axes/_axes.py

@@ -4347,7 +4347,7 @@ def scatter(self, x, y, s=None, c=None, marker=None, cmap=None, norm=None,
             edgecolors = 'face'
             linewidths = rcParams['lines.linewidth']
 
-        offsets = np.column_stack([x, y])
+        offsets = np.ma.column_stack([x, y])
 
         collection = mcoll.PathCollection(
                 (path,), scales,

lib/matplotlib/cbook/__init__.py

@@ -1123,8 +1123,8 @@ def _combine_masks(*args):
                 if x.ndim > 1:
                     raise ValueError("Masked arrays must be 1-D")
             x = np.asanyarray(x)
-            if x.ndim == 1 and x.dtype.kind == 'f':
-                x = np.ma.masked_invalid(x)
+            if x.ndim == 1:
+                x = safe_masked_invalid(x)
                 seqlist[i] = True
         margs.append(x)
     masks = []    # list of masks that are True where bad