colors: ensure masked array data is an ndarray

Nathan Goldbaum · Nathan Goldbaum · commit 1fcf591156ce · 2016-06-21T10:20:29.000-04:00
This fixes compatibility for imshow plots with array data that is a unit-aware
ndarray subclass, for example data frmo yt.units or astropy.units.
diff --git a/lib/matplotlib/colors.py b/lib/matplotlib/colors.py
@@ -925,7 +925,7 @@ def __call__(self, value, clip=None):
                 result = np.ma.array(np.clip(result.filled(vmax), vmin, vmax),
                                      mask=mask)
             # ma division is very slow; we can take a shortcut
-            resdat = result.data
+            resdat = np.asarray(result.data)
             resdat -= vmin
             resdat /= (vmax - vmin)
             result = np.ma.array(resdat, mask=result.mask, copy=False)
