Update OrthoSlicer3D._set_position in viewers.py

wrong indices to original data leading to weird selection of voxels for weird affine transforms and weird volumes

this bug is also related to strange behavior with special acquisition, for example with small animal settings such as rodents leading to wrong location of origin (0,0,0) with image.orthoview()

Author: gjpcbecq

nibabel/viewers.py

@@ -399,7 +399,8 @@ def _set_position(self, x, y, z, notify=True):
         # deal with slicing appropriately
         self._position[:3] = [x, y, z]
         idxs = np.dot(self._inv_affine, self._position)[:3]
-        for ii, (size, idx) in enumerate(zip(self._sizes, idxs)):
+        idxs_new_order = idxs[self._order]
+        for ii, (size, idx) in enumerate(zip(self._sizes, idxs_new_order)):
             self._data_idx[ii] = max(min(int(round(idx)), size - 1), 0)
         for ii in range(3):
             # sagittal: get to S/A