MNT: support old versions of numpy

tacaswell · tacaswell · commit 1e160aa557d7 · 2017-08-07T15:06:43.000-04:00
Numpy 1.7 does not support `np.nanmin` and `np.nanmax` on masked
arrays (instead of returning a number it returns a MaskedIterator).
diff --git a/lib/matplotlib/image.py b/lib/matplotlib/image.py
@@ -372,8 +372,10 @@ def _make_image(self, A, in_bbox, out_bbox, clip_bbox, magnification=1.0,
                     scaled_dtype = A.dtype
                 else:
                     scaled_dtype = np.float32
-                a_min = np.nanmin(A)
-                a_max = np.nanmax(A)
+                # old versions of numpy do not work with `np.nammin`
+                # and `np.nanmax` as inputs
+                a_min = np.ma.min(A)
+                a_max = np.ma.max(A)
                 # scale the input data to [.1, .9].  The Agg
                 # interpolators clip to [0, 1] internally, use a
                 # smaller input scale to identify which of the
