ENH Extend croptobbox for ndim > 2

This is trivial with the slice functionality (which didn't exist when
croptobbox was first written).

ChangeLog

@@ -6,6 +6,7 @@ Version 1.3.0+
 	* Added ``mahotas-features.py`` script
 	* bbox now allows dimensions greater than 2 (including when using the
 	``as_slice`` and ``border`` arguments)
+	* Extended croptobbox for dimensions greater than 2
 
 Version 1.3.0 2014-05-28 by luispedro
 	* Improve memory handling in freeimage.write_multipage

mahotas/bbox.py

@@ -66,6 +66,6 @@ def croptobbox(img, border=None):
 
     This ensures that the result is always a sub-image of the input.
     """
-    min1,max1,min2,max2 = bbox(img, border=border)
-    return img[min1:max1,min2:max2]
+    sl = bbox(img, border=border, as_slice=True)
+    return img[sl]
 

mahotas/tests/test_bbox.py

@@ -19,6 +19,14 @@ def test_croptobbox():
     assert mahotas.croptobbox(ball.T, border=256).sum() == ball.sum()
     assert mahotas.croptobbox(ball.T, border=256).size == ball.size
 
+def test_croptobbox_3d():
+    YXZ = np.indices((32,32,64), float)
+    YXZ -= 8
+    Y,X,Z = YXZ
+    ball = ((X**2+Y**2+Z**2) < 64).astype(np.uint8)
+    assert np.sum(ball) == np.sum(mh.croptobbox(ball))
+
+
 def test_bbox_empty():
     assert mahotas.bbox(np.zeros((), np.bool)).shape == (0,)