TriangleMesh/GiftiSurface classes have method to load vertex data. I/O will be

kept in these classes, instead of in FSLeyes.

fsl/data/gifti.py

@@ -23,6 +23,8 @@ are available:
 
 import os.path as op
 
+import nibabel as nib
+
 import fsl.utils.path as fslpath
 from . import            mesh
 
@@ -50,7 +52,6 @@ class GiftiSurface(mesh.TriangleMesh):
         :arg infile: A GIFTI surface file
         """
 
-        import nibabel as nib
 
         surfimg           = nib.load(infile)
         vertices, indices = extractGiftiSurface(surfimg)
@@ -65,6 +66,16 @@ class GiftiSurface(mesh.TriangleMesh):
         self.surfImg    = surfimg
 
 
+    def loadVertexData(self, dataSource):
+        """Attempts to load scalar data associated with each vertex of this
+        ``GiftiSurface`` from the given ``dataSource``. 
+        """
+
+        # TODO make this more robust
+        norms = nib.load(dataSource)
+        return norms.darrays[0].data 
+
+
 ALLOWED_EXTENSIONS = ['.surf.gii', '.gii']
 """List of file extensions that a file containing Gifti surface data
 is expected to have.

fsl/data/mesh.py

@@ -55,6 +55,14 @@ class TriangleMesh(object):
                    the vertex indices for :math:`M` triangles
     ============== ====================================================
 
+
+    And the following methods:
+
+    .. autosummary::
+       :nosignatures:
+
+       getBounds
+       loadVertexData
     """
 
     
@@ -117,6 +125,15 @@ class TriangleMesh(object):
         return (self.__loBounds, self.__hiBounds)
 
 
+    def loadVertexData(self, dataSource):
+        """Attempts to load scalar data associated with each vertex of this
+        ``TriangleMesh`` from the given ``dataSource``.
+
+        This method may be overridden by sub-classes.
+        """
+        raise NotImplementedError('Not implemented yet')
+
+
 ALLOWED_EXTENSIONS     = ['.vtk']
 """A list of file extensions which could contain :class:`TriangleMesh` data.
 """