From Andras:

Nice catch!

Functionally all those methods are correct, however the argument names in SetIJKToRASDirections are indeed incorrect (or at least misleading).

v_ras = T_ijk_to_ras*v_ijk

[v_r] [ Tir Tjr Tkr ] [ v_i ]
[v_a] = [ Tia Tja Tka ] * [ v_j ]
[v_s] [ Tis Tjs Tks ] [ v_k ]

Therefore, the correct SetIJKToRASDirections should be written as:

void vtkMRMLVolumeNode::SetIJKToRASDirections(double ir, double jr, double kr,
double ia, double ja, double ka,
double is, double js, double ks)
{
IJKToRASDirections[0][0] = ir;
IJKToRASDirections[0][1] = jr;
IJKToRASDirections[0][2] = kr;
IJKToRASDirections[1][0] = ia;
IJKToRASDirections[1][1] = ja;
IJKToRASDirections[1][2] = ka;
IJKToRASDirections[2][0] = is;
IJKToRASDirections[2][1] = js;
IJKToRASDirections[2][2] = ks;
}

Agreed - good catch!

Yes, the {I,J,K}IToRASDirection vectors should be the direction in patient space when of stepping by one unit in {row, column, slice} pixel space.

Andras's fix looks right to me.

-Steve

Fix is pushed here: https://github.com/yuzhengZ/Slicer/commit/a90f9de56ea1a4cafd0bb7410c6a406e760e68ec

Fixed in r22298
See http://viewvc.slicer.org/viewvc.cgi/Slicer4?view=revision&revision=22298

Closing resolved issues that have not been updated in more than 3 months

Fix committed to 2145-support-for-installing-extension-from-file branch.