Fix reslicing for non-square in-plane volumes

rtspm/_spm_reslice_rt.py

@@ -100,7 +100,7 @@ def spm_reslice_rt(r, flags):
         temp_x1 = np.transpose(np.array(range(1, r0_dim[0] + 1), ndmin=2))
         x1 = np.tile(temp_x1, (1, r0_dim[1]))
         temp_x2 = np.transpose(np.array(range(1, r0_dim[1] + 1), ndmin=2))
-        x2 = np.transpose(np.tile(temp_x2, (1, r0_dim[1])))
+        x2 = np.transpose(np.tile(temp_x2, (1, r0_dim[0])))
 
         if int(flags['mean']):
             count = np.zeros(r0_dim)

tests/test_rtspm/test_spm.py

@@ -1,9 +1,36 @@
 import numpy as np
+import importlib
 
 from rtspm import spm_realign_rt
 from rtspm import spm_reslice_rt
 
 
+def test_spm_reslice_supports_non_square_in_plane_dimensions(monkeypatch):
+    module = importlib.import_module("rtspm._spm_reslice_rt")
+    monkeypatch.setattr(
+        module.spm,
+        "bsplins",
+        lambda _coefficients, y1, _y2, _y3, _degree: np.ones(y1.shape),
+    )
+    dim = np.array([3, 5, 2])
+    identity = np.eye(4)
+    r = [
+        {"mat": identity, "dim": dim, "C": np.zeros(dim)},
+        {"mat": identity, "dim": dim, "C": np.zeros(dim)},
+    ]
+    flags = {
+        "interp": 1,
+        "wrap": np.zeros(3),
+        "mask": 1,
+        "mean": 0,
+        "which": 2,
+    }
+
+    result = spm_reslice_rt(r, flags)
+
+    assert result.shape == tuple(dim)
+
+
 def img_2d_to_3d(img2d, xdim_img_number, ydim_img_number, dim3d):
     sl = 0
     vol3d = np.zeros(dim3d)