查看“Ellipse”的源代码

 python code
 
	import numpy as np
	from matplotlib import pyplot as plt
	from math import pi, cos, sin
        ###
	u=1.       #x-position of the center
	v=0.5      #y-position of the center
	a=2.       #radius on the x-axis
	b=1.5      #radius on the y-axis
	t_rot=pi/4 #rotation angle
        ###
	t = np.linspace(0, 2*pi, 100)
	Ell = np.array([a*np.cos(t) , b*np.sin(t)])  
		 #u,v removed to keep the same center location
	R_rot = np.array([[cos(t_rot) , -sin(t_rot)],[sin(t_rot) , cos(t_rot)]])  
		 #2-D rotation matrix
        ###
	Ell_rot = np.zeros((2,Ell.shape[1]))
	for i in range(Ell.shape[1]):
		Ell_rot[:,i] = np.dot(R_rot,Ell[:,i])
        ###
	plt.plot( u+Ell[0,:] , v+Ell[1,:] )     #initial ellipse
	plt.plot( u+Ell_rot[0,:] , v+Ell_rot[1,:],'darkorange' )    #rotated ellipse
	plt.grid(color='lightgray',linestyle='--')
	plt.show()