text: 
  import numpy as np
  
  
  def coor_trans(point, theta):
  	"""
  		coordinate transformation (坐标转换)
  
  		theta方向：以顺时针旋转为正
  	"""
  	point = np.transpose(point)
  	k = np.array([[np.cos(theta), np.sin(theta)],
  				  [-np.sin(theta), np.cos(theta)]])
  	print(point)
  	# return np.dot(k, point)
  	return np.round(np.dot(k, point),6)
  
  
  if __name__ == "__main__":
  	point = np.array([[1,0],[1,2],[2,0],[1,0]])
  	print(point)
  	point_trans = coor_trans(point, np.pi / 2)
  	print(point_trans)
  