Fixed mask check problem by adding ma.nomask to Numeric and Numarray numerix versions.

svn path=/trunk/matplotlib/; revision=1976

Author: teoliphant

lib/matplotlib/lines.py

@@ -276,7 +276,7 @@ def set_data(self, *args):
         mx = ma.getmask(x)
         my = ma.getmask(y)
         mask = ma.mask_or(mx, my)
-        if mask is not None:
+        if mask is not ma.nomask:
             x = ma.masked_array(x, mask=mask).compressed()
             y = ma.masked_array(y, mask=mask).compressed()
             self._segments = unmasked_index_ranges(mask)

lib/matplotlib/numerix/ma/__init__.py

@@ -2,8 +2,10 @@
 
 if which[0] == "numarray":
     from numarray.ma import *
+    nomask = None
 elif which[0] == "numeric":
     from MA import *
+    nomask = None
 elif which[0] == "numpy":
     from numpy.core.ma import *
 else: