hodopy

Python package for Hodograph Control Curve

Demo

Basic usage

Install hodopy from PyPi via

pip install hodopy

import hodopy as hp
import numpy as np
import matplotlib.pyplot as plt

xylist = np.array([68,343,96,100,214,317,334,200,365,333])
ctlptlist = np.reshape(xylist, (-1,2))

ndiv = 200
t = np.linspace(-1,1,ndiv+1)

ptlist = hp.getHCCPt(ctlptlist, t, 'all')    

print(ptlist.shape)

(201, 3, 2)

polygonlen = hp.computePolygonLength(ctlptlist)
curvelen = hp.getHCCLength(ctlptlist, ndiv=200, curve="all")
labs = ['Gauss-Legendre','Gauss-Lobatto', 'Bézier', 'Control Polygon']
lengths = np.hstack((curvelen, [polygonlen]) )
lab2 = [labs[i] + f"({lengths[i]:0.3f})" for i in range(4)]
print(lab2)

['Gauss-Legendre(697.953)', 'Gauss-Lobatto(651.357)', 'Bézier(418.043)', 'Control Polygon(795.779)']

px, py = ptlist[:,:,0], ptlist[:,:,1]
res = plt.plot(px, py)
[res[i].set_color(c) for i, c in enumerate(['b','r','k'])]

cx, cy = ctlptlist[:,0], ctlptlist[:,1]
plt.plot(cx, cy, '--k')
plt.plot(cx, cy, 'ro', markersize=10)
plt.gca().invert_yaxis()

plt.legend(lab2)
plt.show()