def test_decompose_pentagon(self):
# Make sure decompose returns correct thing for a pentagon.
result = decompose_to_triangles(self.pentagon)
benchmark = array([[[0, 0], [2, 0], [2, 1]],
[[0, 0], [2, 1], [1, 2]],
[[0, 0], [1, 2], [0, 2]]], dtype='float')
assert_equal(result, benchmark)
def find_area_of_polygon(vertices):
"""
Return area of polygon.
Parameters
----------
vertices : N x 2 np.ndarray
Returns
-------
area : real number
"""
decomposition = decompose_to_triangles(vertices)
area = 0.0
for triangle in decomposition:
area += find_area_of_triangle(triangle)
return area
def center_of_mass(vertices):
"""
Return center of mass of polygon spanned by vertex list.
Parameters
----------
vertices : N x 2 np.ndarray
Returns
-------
center : 1 x 2 np.ndarray
"""
center = np.array([0, 0], dtype='float')
area = find_area_of_polygon(vertices)
decomposition = decompose_to_triangles(vertices)
for triangle in decomposition:
area_of_triangle = find_area_of_polygon(triangle)
center_of_triangle = find_center_of_mass_triangle(triangle)
center += area_of_triangle*center_of_triangle
center = (1/area)*center
return center
def test_decompose_trapezoid(self):
# Make sure decompose returns correct thing for a trapezoid.
result = decompose_to_triangles(self.trapezoid)
benchmark = array([[[0, 0], [2, 0], [1, 1]],
[[0, 0], [1, 1], [0, 1]]], dtype='float')
assert_equal(result, benchmark)
def test_decompose_triangle2(self):
# Make sure decompose returns same thing if given another triangle.
result = decompose_to_triangles(self.triangle2)
benchmark = array([[[0, 0], [2, 0], [0, 1]]], dtype='float')
assert_equal(result, benchmark)
