Merge pull request #1214 from blink1073/remove-null-plugin

Remove null_plugin in Favor of  the pil_plugin

skimage/io/_plugins/null_plugin.ini

@@ -1,3 +0,0 @@
-[null]
-description = Default plugin that does nothing
-provides = imshow, imread, imsave, _app_show

skimage/io/_plugins/null_plugin.py

@@ -1,25 +0,0 @@
-__all__ = ['imshow', 'imread', 'imsave', '_app_show']
-
-import warnings
-
-message = '''\
-No plugin has been loaded.  Please refer to the docstring for ``skimage.io``
-for a list of available plugins.  You may specify a plugin explicitly as
-an argument to ``imread``, e.g. ``imread("image.jpg", plugin='pil')``.
-
-'''
-
-
-def imshow(*args, **kwargs):
-    warnings.warn(RuntimeWarning(message))
-
-
-def imread(*args, **kwargs):
-    warnings.warn(RuntimeWarning(message))
-
-
-def imsave(*args, **kwargs):
-    warnings.warn(RuntimeWarning(message))
-
-
-_app_show = imshow

skimage/io/_plugins/pil_plugin.py

@@ -1,20 +1,12 @@
 __all__ = ['imread', 'imsave']
 
 import numpy as np
-
-try:
-    from PIL import Image
-except ImportError:
-    raise ImportError("The Python Image Library could not be found. "
-                      "Please refer to "
-                      "https://pypi.python.org/pypi/Pillow/ (or "
-                      "http://pypi.python.org/pypi/PIL/) "
-                      "for further instructions.")
+from six import string_types
+from PIL import Image
 
 from skimage.util import img_as_ubyte, img_as_uint
-
-from six import string_types
-from skimage.external.tifffile import imread as tif_imread, imsave as tif_imsave
+from skimage.external.tifffile import (
+    imread as tif_imread, imsave as tif_imsave)
 
 
 def imread(fname, dtype=None):

skimage/io/manage_plugins.py

@@ -44,7 +44,8 @@ plugin_meta_data = {}
 # the following preferences.
 preferred_plugins = {
     # Default plugins for all types (overridden by specific types below).
-    'all': ['pil', 'matplotlib', 'qt', 'freeimage', 'null']
+    'all': ['pil', 'matplotlib', 'qt', 'freeimage'],
+    'imshow': ['matplotlib']
 }
 
 

skimage/io/tests/test_null.py

@@ -1,50 +0,0 @@
-import os
-import warnings
-from contextlib import contextmanager
-
-import numpy as np
-from numpy.testing import raises
-
-from skimage import io
-from skimage import data_dir
-
-
-@contextmanager
-def warnings_as_errors():
-    # Temporarily set warnings as errors so we can test the warning is raised.
-    with warnings.catch_warnings():
-        warnings.filterwarnings('error')
-        yield
-
-@raises(Warning)
-def test_null_imread():
-    path = os.path.join(data_dir, 'color.png')
-    with warnings_as_errors():
-        io.imread(path, plugin='null')
-
-
-@raises(Warning)
-def test_null_imsave():
-    with warnings_as_errors():
-        io.imsave('dummy.png', np.zeros((3, 3)), plugin='null')
-
-
-@raises(Warning)
-def test_null_imshow():
-    with warnings_as_errors():
-        io.imshow(np.zeros((3, 3)), plugin='null')
-
-
-@raises(Warning)
-def test_null_imread_collection():
-    # Note that the null plugin doesn't define an `imread_collection` plugin
-    # but this function is dynamically added by the plugin manager.
-    path = os.path.join(data_dir, '*.png')
-    with warnings_as_errors():
-        collection = io.imread_collection(path, plugin='null')
-        collection[0]
-
-
-if __name__ == '__main__':
-    from numpy.testing import run_module_suite
-    run_module_suite()

skimage/io/tests/test_plugin.py

@@ -4,21 +4,10 @@ from numpy.testing import assert_equal, raises
 
 from skimage import io
 from skimage.io import manage_plugins
-from numpy.testing.decorators import skipif
 
-try:
-    io.use_plugin('pil')
-    PIL_available = True
-    priority_plugin = 'pil'
-except ImportError:
-    PIL_available = False
 
-try:
-    io.use_plugin('freeimage')
-    FI_available = True
-    priority_plugin = 'freeimage'
-except RuntimeError:
-    FI_available = False
+io.use_plugin('pil')
+priority_plugin = 'pil'
 
 
 def setup_module():
@@ -65,7 +54,6 @@ def test_failed_use():
     manage_plugins.use_plugin('asd')
 
 
-@skipif(not PIL_available and not FI_available)
 def test_use_priority():
     manage_plugins.use_plugin(priority_plugin)
     plug, func = manage_plugins.plugin_store['imread'][0]
@@ -76,7 +64,6 @@ def test_use_priority():
     assert_equal(plug, 'test')
 
 
-@skipif(not PIL_available)
 def test_use_priority_with_func():
     manage_plugins.use_plugin('pil')
     plug, func = manage_plugins.plugin_store['imread'][0]
@@ -106,28 +93,28 @@ def test_available():
 
 
 def test_load_preferred_plugins_all():
-    from skimage.io._plugins import null_plugin
+    from skimage.io._plugins import pil_plugin
 
     with protect_preferred_plugins():
-        manage_plugins.preferred_plugins = {'all': ['null']}
+        manage_plugins.preferred_plugins = {'all': ['pil']}
         manage_plugins.reset_plugins()
 
         for plugin_type in ('imread', 'imsave', 'imshow'):
             plug, func = manage_plugins.plugin_store[plugin_type][0]
-            assert func == getattr(null_plugin, plugin_type)
+            assert func == getattr(pil_plugin, plugin_type)
 
 
 def test_load_preferred_plugins_imread():
-    from skimage.io._plugins import null_plugin
+    from skimage.io._plugins import pil_plugin, matplotlib_plugin
 
     with protect_preferred_plugins():
-        manage_plugins.preferred_plugins['imread'] = ['null']
+        manage_plugins.preferred_plugins['imread'] = ['pil']
         manage_plugins.reset_plugins()
 
         plug, func = manage_plugins.plugin_store['imread'][0]
-        assert func == null_plugin.imread
+        assert func == pil_plugin.imread
         plug, func = manage_plugins.plugin_store['imshow'][0]
-        assert func != null_plugin.imshow
+        assert func == matplotlib_plugin.imshow, func.__module__
 
 
 if __name__ == "__main__":