Make imageio dependency optional

Author: christianbrodbeck

.travis.yml

@@ -29,8 +29,7 @@ install:
         travis_retry sudo apt-get install mencoder;
       fi;
     - pip install -q coverage coveralls nose-timer nibabel flake8
-    - python setup.py build
-    - python setup.py install
+    - pip install .[save_movie]
     - SRC_DIR=$(pwd)
 
 before_script:

doc/install.rst

@@ -11,6 +11,11 @@ If you already have PySurfer installed, you can also use pip to update it::
 
     pip install -U pysurfer
 
+If you would like to save movies of time course data, also include the
+optional dependency `imageio` with::
+
+    pip install -U pysurfer[save_movie]
+
 If you'd like to install the development version, you have two options. You can
 use pip::
 

setup.py

@@ -92,6 +92,6 @@ def check_dependencies():
           platforms='any',
           packages=['surfer', 'surfer.tests'],
           scripts=['bin/pysurfer'],
-          install_requires=['nibabel >= 1.2',
-                            'imageio >= 1.5'],
+          install_requires=['nibabel >= 1.2'],
+          extras_require={'save_movie': ['imageio >= 1.5']},
           )

surfer/tests/test_viz.py

@@ -4,15 +4,14 @@
 import shutil
 from tempfile import mkdtemp, mktemp
 
-import imageio
 from nose.tools import assert_equal
 from mayavi import mlab
 import nibabel as nib
 import numpy as np
 from numpy.testing import assert_raises, assert_array_equal
 
 from surfer import Brain, io, utils
-from surfer.utils import requires_fsaverage
+from surfer.utils import requires_fsaverage, requires_imageio
 
 subj_dir = utils._get_subjects_dir()
 subject_id = 'fsaverage'
@@ -214,10 +213,13 @@ def test_morphometry():
     brain.close()
 
 
+@requires_imageio
 @requires_fsaverage
 def test_movie():
     """Test saving a movie of an MEG inverse solution
     """
+    import imageio
+
     # create and setup the Brain instance
     mlab.options.backend = 'auto'
     brain = Brain(*std_args)

surfer/utils.py

@@ -623,5 +623,18 @@ def has_fsaverage(subjects_dir=None):
         return False
     return True
 
+
+def has_imageio():
+    try:
+        import imageio
+    except ImportError:
+        return False
+    else:
+        return True
+
+
 requires_fsaverage = np.testing.dec.skipif(not has_fsaverage(),
                                            'Requires fsaverage subject data')
+
+requires_imageio = np.testing.dec.skipif(not has_imageio(),
+                                         "Requires imageio package")

surfer/viz.py

@@ -3,7 +3,6 @@
 from os.path import join as pjoin
 from warnings import warn
 
-import imageio
 import numpy as np
 from scipy import stats, ndimage, misc
 from scipy.interpolate import interp1d
@@ -2194,7 +2193,22 @@ def save_movie(self, fname, time_dilation=4., tmin=None, tmax=None,
         bitrate : str | float
             Bitrate to use to encode movie. Can be specified as number (e.g.
             64000) or string (e.g. '64k'). Default value is 1M
+
+        Notes
+        -----
+        Requires imageio package, which can be installed together with
+        PySurfer with::
+
+            $ pip install -U pysurfer[save_movie]
         """
+        try:
+            import imageio
+        except ImportError:
+            raise ImportError("Saving movies from PySurfer requires the "
+                              "imageio library. To install imageio with "
+                              "PySurfer, run\n\n    $ pip install -U "
+                              "pysurfer[save_movie]\n")
+
         if tmin is None:
             tmin = self._times[0]
         elif tmin < self._times[0]: