CompositeTransformUtil, new ANTs interface

Author: TheChymera

nipype/interfaces/ants/__init__.py

@@ -5,7 +5,7 @@
 
 # Registraiton programs
 from .registration import (ANTS, Registration, RegistrationSynQuick,
-                           MeasureImageSimilarity)
+                           CompositeTransformUtil, MeasureImageSimilarity)
 
 # Resampling Programs
 from .resampling import (ApplyTransforms, ApplyTransformsToPoints,

nipype/interfaces/ants/registration.py

@@ -1596,3 +1596,69 @@ def _list_outputs(self):
             outputs['forward_warp_field'] = out_base + '1Warp.nii.gz'
             outputs['inverse_warp_field'] = out_base + '1InverseWarp.nii.gz'
         return outputs
+
+class CompositeTransformUtilInputSpec(ANTSCommandInputSpec):
+    process = traits.Enum('assemble', 'disassemble', argstr='--%s',
+        position=1, usedefault=True,
+        desc='What to do with the transform inputs (assemble or disassemble)',
+        )
+    in_file = InputMultiPath(File(exists=True), mandatory=True, argstr='%s...',
+        position=2, desc='Input transform file(s)')
+    output_prefix = Str("transform", usedefault=True, argstr='%s',
+        position=3, desc="A prefix that is prepended to all output files")
+
+class CompositeTransformUtilOutputSpec(TraitedSpec):
+    affine_transform = File(exists=True, desc="Affine transform component",
+            mandatory=True, position=2)
+    displacement_field = File(desc="Displacement field component")
+
+class CompositeTransformUtil(ANTSCommand):
+    """
+    ANTs utility which can combine or break apart transform files into their individual
+    constituent components.
+
+    Examples
+    --------
+
+    >>> from nipype.interfaces.ants import CompositeTransformUtil
+    >>> tran = CompositeTransformUtil()
+    >>> tran.inputs.process = 'disassemble'
+    >>> tran.inputs.in_file = 'output_Composite.h5'
+    >>> tran.cmdline
+    'CompositeTransformUtil --disassemble output_Composite.h5 transform'
+    >>> tran.run()  # doctest: +SKIP
+
+    example for assembling transformation files
+
+    >>> from nipype.interfaces.ants import CompositeTransformUtil
+    >>> tran = CompositeTransformUtil()
+    >>> tran.inputs.process = 'assemble'
+    >>> tran.inputs.in_file = ['output_Composite.h5', 'transform1', 'transform2']
+    >>> tran.cmdline
+    'CompositeTransformUtil --assemble output_Composite.h5 transform1 transform2 '
+    >>> tran.run()  # doctest: +SKIP
+    """
+
+    _cmd = 'CompositeTransformUtil'
+    input_spec = CompositeTransformUtilInputSpec
+    output_spec = CompositeTransformUtilOutputSpec
+
+    def _num_threads_update(self):
+        """
+        CompositeTransformUtil ignores environment variables,
+        so override environment update from ANTSCommand class
+        """
+        pass
+
+    def _format_arg(self, name, spec, value):
+        if name == 'output_prefix' and self.inputs.process == 'assemble':
+            value = ''
+        return super(CompositeTransformUtil, self)._format_arg(name, spec, value)
+
+    def _list_outputs(self):
+        outputs = self.output_spec().get()
+        outputs['affine_transform'] = os.path.abspath(
+            '00_{}_AffineTransform.mat'.format(self.inputs.output_prefix))
+        outputs['displacement_field'] = os.path.abspath(
+            '01_{}_DisplacementFieldTransform.nii.gz'.format(self.inputs.output_prefix))
+        return outputs