DOC: Add docstring w/ doctest

Author: effigies

nipype/interfaces/image.py

@@ -30,7 +30,53 @@ class ReorientOutputSpec(TraitedSpec):
 
 
 class Reorient(SimpleInterface):
-    """Reorient an image
+    """Conform an image to a given orientation
+
+    Flips and reorder the image data array so that the axes match the
+    directions indicated in ``orientation``.
+    The default ``RAS`` orientation corresponds to the first axis being ordered
+    from left to right, the second axis from posterior to anterior, and the
+    third axis from inferior to superior.
+
+    For oblique images, the original orientation is considered to be the
+    closest plumb orientation.
+
+    No resampling is performed, and thus the output image is not de-obliqued
+    or registered to any other image or template.
+
+    The effective transform is calculated from the original affine matrix to
+    the reoriented affine matrix.
+
+    Examples
+    --------
+
+    If an image is not reoriented, the original file is not modified
+
+    >>> import numpy as np
+    >>> from nipype.interfaces.image import Reorient
+    >>> reorient = Reorient(orientation='LPS')
+    >>> reorient.inputs.in_file = 'segmentation0.nii.gz'
+    >>> res = reorient.run()
+    >>> res.outputs.out_file
+    'segmentation0.nii.gz'
+
+    >>> print(np.loadtxt(res.outputs.transform))
+    [[1. 0. 0. 0.]
+     [0. 1. 0. 0.]
+     [0. 0. 1. 0.]
+     [0. 0. 0. 1.]]
+
+    >>> reorient.inputs.orientation = 'RAS'
+    >>> res = reorient.run()
+    >>> res.outputs.out_file  # doctest: +ELLIPSIS
+    '.../segmentation0_ras.nii.gz'
+
+    >>> print(np.loadtxt(res.outputs.transform))
+    [[-1.  0.  0. 60.]
+     [ 0. -1.  0. 72.]
+     [ 0.  0.  1.  0.]
+     [ 0.  0.  0.  1.]]
+
     """
     input_spec = ReorientInputSpec
     output_spec = ReorientOutputSpec