用Python代码动态生成一棵树

以下是使用Python代码动态生成一棵树的示例：

import numpy as np
import matplotlib.pyplot as plt

class segment:
    def __init__(self, st, th, L):
        self.st = st
        self.th = th
        self.L = L
        self.setEd()

    def setEd(self):
        x, y = self.st
        th = np.deg2rad(self.th)
        dx = self.L*np.cos(th)
        dy = self.L*np.sin(th)
        self.ed = (x+dx, y+dy)

    def getAxis(self):
        xs = (self.st[0], self.ed[0])
        ys = (self.st[1], self.ed[1])
        return (xs, ys)

    def getChild(self, dTh, L):
        ths = [self.th + dTh, self.th-dTh]
        return [segment(self.ed, th, L) for th in ths]

def drawTree(seg, ax):
    if seg.L < 0.1:
        return
    xs, ys = seg.getAxis()
    ax.plot(xs, ys, color='brown', linewidth=2)
    childSegs = seg.getChild(30, seg.L*0.7)
    for childSeg in childSegs:
        drawTree(childSeg, ax)

fig, ax = plt.subplots()
ax.set_aspect('equal')
ax.axis('off')
rootSeg = segment((0, 0), 90, 1)
drawTree(rootSeg, ax)
plt.show()

这段代码使用了matplotlib库来绘制树的轮廓。首先定义了一个线段类，包含起点、角度和长度等属性，以及计算终点和子线段的方法。然后定义了一个递归函数drawTree，用于绘制树的轮廓。在drawTree函数中，首先绘制当前线段，然后递归绘制子线段，直到线段长度小于0.1为止。最后在主函数中创建根线段并调用drawTree函数进行绘制。