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# -*- coding: utf-8 -*-
import math
def rotate_point(point, centre, angle):
""" Rotates a point around another point by a number of degrees (anticlockwise)
:param point: point coordinates - 2 element list
:param centre: centre of rotation coordinates - 2 element list
:param angle: rotate by the given angle
:return: a rotated point - 2 element list
"""
# convert angle to radians
angle = math.radians(angle)
pt = [0, 0]
# translate the rotation point to the origin
pt[0] = point[0] - centre[0]
pt[1] = point[1] - centre[1]
# calculate the new coordinates after rotation
res = [int(round(pt[0] * math.cos(angle) - pt[1] * math.sin(angle))),
int(round(pt[1] * math.cos(angle) + pt[0] * math.sin(angle)))]
# cancel translation
res[0] += centre[0]
res[1] += centre[1]
return res
def rotate_points(points, centre, angle):
""" Rotates a list of points around another point by a number of degrees (anticlockwise)
:param points: a list of 2 element lists containing initial coordinates of individual points
:param centre: a list of 2 elements containing a coordinates of the centre of rotation
:param angle: the angle by which the points are to be rotated in degrees
:return: a list of rotated points about a centre point
"""
rotated_points = []
for point in points:
rotated_points.append(rotate_point(point, centre, angle))
print(rotated_points)
return rotated_points
def test_rotate_points():
assert rotate_points([[1, 0], [0, 1]], [0, 0], 90) == [[0, 1], [-1, 0]]
assert rotate_points([[1, 0], [0, 1]], [1, 1], 90) == [[2, 1], [1, 0]]
assert rotate_points([[1, 1], [-2, -2]], [-1, -1], 90) == [[-3, 1], [0, -2]]
test_rotate_points()
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