Use a less-invasive approach

skimage/__init__.py

@@ -61,8 +61,6 @@ import imp
 import functools
 import warnings
 from .util.dtype import *
-from .util.colormap import viridis
-from matplotlib.cm import register_cmap
 
 pkg_dir = osp.abspath(osp.dirname(__file__))
 data_dir = osp.join(pkg_dir, 'data')
@@ -101,11 +99,6 @@ else:
             return 1
 
 
-# register the viridis colormap
-register_cmap('viridis', viridis)
-del register_cmap, viridis
-
-
 # do not use `test` as function name as this leads to a recursion problem with
 # the nose test suite
 test = _test

skimage/io/_plugins/matplotlib_plugin.py

@@ -4,11 +4,10 @@ import warnings
 import matplotlib.pyplot as plt
 from ...util import dtype as dtypes
 from ...exposure import is_low_contrast
-from ..._shared._warnings import all_warnings
+from ..util.colormap import viridis
 
-
-_default_colormap = 'viridis'
-_nonstandard_colormap = 'viridis'
+_default_colormap = 'gray'
+_nonstandard_colormap = viridis
 _diverging_colormap = 'RdBu'
 
 

skimage/io/tests/test_mpl_imshow.py

@@ -44,28 +44,28 @@ def n_subplots(ax_im):
 def test_uint8():
     plt.figure()
     ax_im = io.imshow(im8)
-    assert ax_im.cmap.name == 'viridis'
+    assert ax_im.cmap.name == 'gray'
     assert ax_im.get_clim() == (0, 255)
-    assert n_subplots(ax_im) == 2
-    assert ax_im.colorbar is not None
+    assert n_subplots(ax_im) == 1
+    assert ax_im.colorbar is None
 
 
 def test_uint16():
     plt.figure()
     ax_im = io.imshow(im16)
-    assert ax_im.cmap.name == 'viridis'
+    assert ax_im.cmap.name == 'gray'
     assert ax_im.get_clim() == (0, 65535)
-    assert n_subplots(ax_im) == 2
-    assert ax_im.colorbar is not None
+    assert n_subplots(ax_im) == 1
+    assert ax_im.colorbar is None
 
 
 def test_float():
     plt.figure()
     ax_im = io.imshow(imf)
-    assert ax_im.cmap.name == 'viridis'
+    assert ax_im.cmap.name == 'gray'
     assert ax_im.get_clim() == (0, 1)
-    assert n_subplots(ax_im) == 2
-    assert ax_im.colorbar is not None
+    assert n_subplots(ax_im) == 1
+    assert ax_im.colorbar is None
 
 
 def test_low_dynamic_range():