65 lines
2.2 KiB
Python
65 lines
2.2 KiB
Python
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import numpy as np
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from skimage.measure import approximate_polygon, subdivide_polygon
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from skimage.measure._polygon import _SUBDIVISION_MASKS
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from skimage._shared import testing
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from skimage._shared.testing import assert_array_equal, assert_equal
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square = np.array([
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[0, 0], [0, 1], [0, 2], [0, 3],
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[1, 3], [2, 3], [3, 3],
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[3, 2], [3, 1], [3, 0],
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[2, 0], [1, 0], [0, 0]
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])
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def test_approximate_polygon():
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out = approximate_polygon(square, 0.1)
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assert_array_equal(out, square[(0, 3, 6, 9, 12), :])
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out = approximate_polygon(square, 2.2)
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assert_array_equal(out, square[(0, 6, 12), :])
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out = approximate_polygon(square[(0, 1, 3, 4, 5, 6, 7, 9, 11, 12), :], 0.1)
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assert_array_equal(out, square[(0, 3, 6, 9, 12), :])
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out = approximate_polygon(square, -1)
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assert_array_equal(out, square)
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out = approximate_polygon(square, 0)
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assert_array_equal(out, square)
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def test_subdivide_polygon():
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new_square1 = square
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new_square2 = square[:-1]
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new_square3 = square[:-1]
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# test iterative subdvision
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for _ in range(10):
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square1, square2, square3 = new_square1, new_square2, new_square3
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# test different B-Spline degrees
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for degree in range(1, 7):
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mask_len = len(_SUBDIVISION_MASKS[degree][0])
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# test circular
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new_square1 = subdivide_polygon(square1, degree)
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assert_array_equal(new_square1[-1], new_square1[0])
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assert_equal(new_square1.shape[0],
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2 * square1.shape[0] - 1)
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# test non-circular
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new_square2 = subdivide_polygon(square2, degree)
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assert_equal(new_square2.shape[0],
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2 * (square2.shape[0] - mask_len + 1))
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# test non-circular, preserve_ends
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new_square3 = subdivide_polygon(square3, degree, True)
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assert_equal(new_square3[0], square3[0])
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assert_equal(new_square3[-1], square3[-1])
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assert_equal(new_square3.shape[0],
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2 * (square3.shape[0] - mask_len + 2))
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# not supported B-Spline degree
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with testing.raises(ValueError):
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subdivide_polygon(square, 0)
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with testing.raises(ValueError):
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subdivide_polygon(square, 8)
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