旋转2D对象的功能？

首先，我们需要一个绕原点旋转点的函数。

当我们绕原点旋转一个点（x，y）theta度时，我们得到的坐标为：

（x cosθ-y sinθ，x sinθ+ y cosθ）

如果要围绕原点以外的其他点旋转它，只需移动它，使中心点成为原点。现在，我们可以编写以下函数：

from math import sin, cos, radiansdef rotate_point(point, angle, center_point=(0, 0)):    """Rotates a point around center_point(origin by default)    Angle is in degrees.    Rotation is counter-clockwise    """    angle_rad = radians(angle % 360)    # Shift the point so that center_point becomes the origin    new_point = (point[0] - center_point[0], point[1] - center_point[1])    new_point = (new_point[0] * cos(angle_rad) - new_point[1] * sin(angle_rad),      new_point[0] * sin(angle_rad) + new_point[1] * cos(angle_rad))    # Reverse the shifting we have done    new_point = (new_point[0] + center_point[0], new_point[1] + center_point[1])    return new_point

一些输出：

print(rotate_point((1, 1), 90, (2, 1)))# This prints (2.0, 0.0)print(rotate_point((1, 1), -90, (2, 1)))# This prints (2.0, 2.0)print(rotate_point((2, 2), 45, (1, 1)))# This prints (1.0, 2.4142) which is equal to (1,1+sqrt(2))

现在，我们只需要使用我们之前的功能旋转多边形的每个角即可：

def rotate_polygon(polygon, angle, center_point=(0, 0)):    """Rotates the given polygon which consists of corners represented as (x,y)    around center_point (origin by default)    Rotation is counter-clockwise    Angle is in degrees    """    rotated_polygon = []    for corner in polygon:        rotated_corner = rotate_point(corner, angle, center_point)        rotated_polygon.append(rotated_corner)    return rotated_polygon

输出示例：

my_polygon = [(0, 0), (1, 0), (0, 1)]print(rotate_polygon(my_polygon, 90))# This gives [(0.0, 0.0), (0.0, 1.0), (-1.0, 0.0)]