# python实现一个点绕另一个点旋转后的坐标

(x,y)为要转的点，（pointx,pointy)为中心点，如果顺时针角度为angle

srx = (x-pointx)*cos(angle) + (y-pointy)*sin(angle)+pointx

sry = (y-pointy)*cos(angle) - (x-pointx)*sin(angle)+pointy

(x,y)为要转的点，（pointx,pointy)为中心点，如果逆时针角度为angle

nrx = (x-pointx)*cos(angle) - (y-pointy)*sin(angle)+pointx

nry = (x-pointx)*sin(angle) + (y-pointy)*cos(angle)+pointy

```import numpy as np
import math
import matplotlib.pyplot as plt
# 绕pointx,pointy逆时针旋转
def Nrotate(angle,valuex,valuey,pointx,pointy):
valuex = np.array(valuex)
valuey = np.array(valuey)
nRotatex = (valuex-pointx)*math.cos(angle) - (valuey-pointy)*math.sin(angle) + pointx
nRotatey = (valuex-pointx)*math.sin(angle) + (valuey-pointy)*math.cos(angle) + pointy
return nRotatex, nRotatey
# 绕pointx,pointy顺时针旋转
def Srotate(angle,valuex,valuey,pointx,pointy):
valuex = np.array(valuex)
valuey = np.array(valuey)
sRotatex = (valuex-pointx)*math.cos(angle) + (valuey-pointy)*math.sin(angle) + pointx
sRotatey = (valuey-pointy)*math.cos(angle) - (valuex-pointx)*math.sin(angle) + pointy
return sRotatex,sRotatey
pointx = 1
pointy = 1
print(sPointx,sPointy)
plt.plot([0,pointx],[0,pointy])
plt.plot([0,sPointx],[0,sPointy])
plt.xlim(-3.,3.)
plt.ylim(-3.,3.)
plt.xticks(np.arange(-3.,3.,1))
plt.yticks(np.arange(-3.,3.,1))
plt.show()```

```import numpy as np
import math
import matplotlib.pyplot as plt
# 绕pointx,pointy逆时针旋转
def Nrotate(angle,valuex,valuey,pointx,pointy):
valuex = np.array(valuex)
valuey = np.array(valuey)
nRotatex = (valuex-pointx)*math.cos(angle) - (valuey-pointy)*math.sin(angle) + pointx
nRotatey = (valuex-pointx)*math.sin(angle) + (valuey-pointy)*math.cos(angle) + pointy
return nRotatex, nRotatey
# 绕pointx,pointy顺时针旋转
def Srotate(angle,valuex,valuey,pointx,pointy):
valuex = np.array(valuex)
valuey = np.array(valuey)
sRotatex = (valuex-pointx)*math.cos(angle) + (valuey-pointy)*math.sin(angle) + pointx
sRotatey = (valuey-pointy)*math.cos(angle) - (valuex-pointx)*math.sin(angle) + pointy
return sRotatex,sRotatey

x1 = np.array([1,2,3])
y1 = np.array([1,2,3])
x2 = np.array([3,6])
y2 = np.array([2,1])
# x2往x1上拼
disx = x2[0]-x1[0]
disy = y2[0]-y1[0]
removeX2 = x2-disx
removeY2 = y2-disy
tany1 = y1[-1]-y1[0]
tanx1 = x1[-1]-x1[0]
angle1 = math.degrees(np.arctan(tany1/tanx1))
tany2 = y2[-1]-y2[0]
tanx2 = x2[-1]-x2[0]
angle2 = math.degrees(np.arctan(tany2/tanx2))
disAngle = angle2-angle1
print(angle1)
print(angle2)
print(disAngle)
if disAngle<0: