Merge pull request #5081 from Harry-Kwon/remove-private-imports

Alexandre de Siqueira · web-flow · commit 663e9e4b0f2b · 2020-11-26T16:22:31.000-08:00
removed usage of numpy's private functions from util.arraycrop
diff --git a/skimage/util/arraycrop.py b/skimage/util/arraycrop.py
@@ -4,7 +4,6 @@
 """
 
 import numpy as np
-from numpy.lib.arraypad import _as_pairs
 
 __all__ = ['crop']
 
@@ -20,8 +19,8 @@ def crop(ar, crop_width, copy=False, order='K'):
         Number of values to remove from the edges of each axis.
         ``((before_1, after_1),`` ... ``(before_N, after_N))`` specifies
         unique crop widths at the start and end of each axis.
-        ``((before, after),)`` specifies a fixed start and end crop
-        for every axis.
+        ``((before, after),) or (before, after)`` specifies
+        a fixed start and end crop for every axis.
         ``(n,)`` or ``n`` for integer ``n`` is a shortcut for
         before = after = ``n`` for all axes.
     copy : bool, optional
@@ -39,7 +38,30 @@ def crop(ar, crop_width, copy=False, order='K'):
         view of the input array.
     """
     ar = np.array(ar, copy=False)
-    crops = _as_pairs(crop_width, ar.ndim, as_index=True)
+
+    if isinstance(crop_width, int):
+        crops = [[crop_width, crop_width]] * ar.ndim
+    elif isinstance(crop_width[0], int):
+        if len(crop_width) == 1:
+            crops = [[crop_width[0], crop_width[0]]] * ar.ndim
+        elif len(crop_width) == 2:
+            crops = [crop_width] * ar.ndim
+        else:
+            raise ValueError(
+                f"crop_width has an invalid length: {len(crop_width)}\n"
+                "crop_width should be a sequence of N pairs, "
+                "a single pair, or a single integer"
+            )
+    elif len(crop_width) == 1:
+        crops = [crop_width[0]] * ar.ndim
+    elif len(crop_width) == ar.ndim:
+        crops = crop_width
+    else:
+        raise ValueError(
+            f"crop_width has an invalid length: {len(crop_width)}\n"
+            "crop_width should be a sequence of N pairs, "
+            "a single pair, or a single integer"
+        )
 
     slices = tuple(slice(a, ar.shape[i] - b)
                    for i, (a, b) in enumerate(crops))
diff --git a/skimage/util/tests/test_arraycrop.py b/skimage/util/tests/test_arraycrop.py
@@ -20,6 +20,14 @@ def test_pair_crop():
     assert_equal(out.shape, (6, 2))
 
 
+def test_pair_tuple_crop():
+    arr = np.arange(45).reshape(9, 5)
+    out = crop(arr, ((1, 2),))
+    assert_array_equal(out[0], [6, 7])
+    assert_array_equal(out[-1], [31, 32])
+    assert_equal(out.shape, (6, 2))
+
+
 def test_int_crop():
     arr = np.arange(45).reshape(9, 5)
     out = crop(arr, 1)
@@ -28,6 +36,14 @@ def test_int_crop():
     assert_equal(out.shape, (7, 3))
 
 
+def test_int_tuple_crop():
+    arr = np.arange(45).reshape(9, 5)
+    out = crop(arr, (1,))
+    assert_array_equal(out[0], [6, 7, 8])
+    assert_array_equal(out[-1], [36, 37, 38])
+    assert_equal(out.shape, (7, 3))
+
+
 def test_copy_crop():
     arr = np.arange(45).reshape(9, 5)
     out0 = crop(arr, 1, copy=True)
