MNT: suppress RuntimeWarning for invalid float comparison in images

tacaswell · tacaswell · commit 8ff23db482d6 · 2017-01-10T00:42:10.000-05:00
If do not warn for invalid values when looking for over/under pixels in _ImageBase._make_image. closes #7746
diff --git a/lib/matplotlib/image.py b/lib/matplotlib/image.py
@@ -368,8 +368,9 @@ def _make_image(self, A, in_bbox, out_bbox, clip_bbox, magnification=1.0,
                     # values to carry the over/under/bad information
                     rgba = np.empty((A.shape[0], A.shape[1], 4), dtype=A.dtype)
                     rgba[..., 0] = A  # normalized data
-                    rgba[..., 1] = A < 0  # under data
-                    rgba[..., 2] = A > 1  # over data
+                    with np.errstate(invalid='ignore'):
+                        rgba[..., 1] = A < 0  # under data
+                        rgba[..., 2] = A > 1  # over data
                     rgba[..., 3] = ~A.mask  # bad data
                     A = rgba
                     output = np.zeros((out_height, out_width, 4),
diff --git a/lib/matplotlib/tests/test_image.py b/lib/matplotlib/tests/test_image.py
@@ -4,6 +4,7 @@
 import six
 import io
 import os
+import warnings
 
 from nose.plugins.attrib import attr
 
@@ -753,5 +754,12 @@ def test_imshow_endianess():
     ax2.imshow(Z.astype('>f8'), **kwargs)
 
 
+@cleanup
+def test_imshow_no_warn_invalid():
+    with warnings.catch_warnings(record=True) as warns:
+        plt.imshow([[1, 2], [3, np.nan]])
+    assert len(warns) == 0
+
+
 if __name__ == '__main__':
     nose.runmodule(argv=['-s', '--with-doctest'], exit=False)
