Python如何生成树形图案

# -*- coding: utf-8 -*- 
 
import Tkinter 
import sys, random, math 
 
class Point(object): 
  def __init__(self, x, y): 
    self.x = x 
    self.y = y 
 
  def __str__(self): 
    return "<Point>: (%f, %f)" % (self.x, self.y) 
 
class Branch(object): 
  def __init__(self, bottom, top, branches, level = 0): 
    self.bottom = bottom 
    self.top = top 
    self.level = level 
    self.branches = branches 
    self.children = [] 
 
  def __str__(self): 
    s = "Top: %s, Bottom: %s, Children Count: %d" % / 
      (self.top, self.bottom, len(self.children)) 
    return s 
 
  def nextGen(self, n = -1, rnd = 1): 
    if n <= 0: n = self.branches 
    if rnd == 1: 
      n = random.randint(n / 2, n * 2) 
      if n <= 0: n = 1 
    dx = self.top.x - self.bottom.x 
    dy = self.top.y - self.bottom.y 
    r = 0.20 + random.random() * 0.2 
    if self.top.x == self.bottom.x: 
      # 如果是一条竖线 
      x = self.top.x 
      y = dy * r + self.bottom.y 
    elif self.top.y == self.bottom.y: 
      # 如果是一条横线 
      x = dx * r + self.bottom.x 
      y = self.top.y 
    else: 
      x = dx * r 
      y = x * dy / dx 
      x += self.bottom.x 
      y += self.bottom.y 
    oldTop = self.top 
    self.top = Point(x, y) 
    a = math.pi / (2 * n) 
    for i in range(n): 
      a2 = -a * (n - 1) / 2 + a * i - math.pi 
      a2 *= 0.9 + random.random() * 0.2 
      self.children.append(self.mkNewBranch(self.top, oldTop, a2)) 
 
  def mkNewBranch(self, bottom, top, a): 
    dx1 = top.x - bottom.x 
    dy1 = top.y - bottom.y 
    r = 0.9 + random.random() * 0.2 
    c = math.sqrt(dx1 ** 2 + dy1 ** 2) * r 
    if dx1 == 0: 
      a2 = math.pi / 2 
    else: 
      a2 = math.atan(dy1 / dx1) 
      if (a2 < 0 and bottom.y > top.y) / 
        or (a2 > 0 and bottom.y < top.y) / 
        : 
        a2 += math.pi 
    b = a2 - a 
    dx2 = c * math.cos(b) 
    dy2 = c * math.sin(b) 
    newTop = Point(dx2 + bottom.x, dy2 + bottom.y) 
    return Branch(bottom, newTop, self.branches, self.level + 1) 
 
class Tree(object): 
  def __init__(self, root, canvas, bottom, top, branches = 3, depth = 3): 
    self.root = root 
    self.canvas = canvas 
    self.bottom = bottom 
    self.top = top 
    self.branches = branches 
    self.depth = depth 
    self.new() 
 
  def gen(self, n = 1): 
    for i in range(n): 
      self.getLeaves() 
      for node in self.leaves: 
        node.nextGen() 
    self.show() 
 
  def new(self): 
    self.leavesCount = 0 
    self.branch = Branch(self.bottom, self.top, self.branches) 
    self.gen(self.depth) 
    print "leaves count: %d" % self.leavesCount 
 
  def chgDepth(self, d): 
    self.depth += d 
    if self.depth < 0: self.depth = 0 
    if self.depth > 10: self.depth = 10 
    self.new() 
 
  def chgBranch(self, d): 
    self.branches += d 
    if self.branches < 1: self.branches = 1 
    if self.branches > 10: self.branches = 10 
    self.new() 
 
  def getLeaves(self): 
    self.leaves = [] 
    self.map(self.findLeaf) 
 
  def findLeaf(self, node): 
    if len(node.children) == 0: 
      self.leaves.append(node) 
 
  def show(self): 
    for i in self.canvas.find_all(): 
      self.canvas.delete(i) 
    self.map(self.drawNode) 
    self.canvas.tag_raise("leaf") 
 
  def exit(self, evt): 
    sys.exit(0) 
 
  def map(self, func = lambda node: node): 
    # 遍历树 
    children = [self.branch] 
    while len(children) != 0: 
      newChildren = [] 
      for node in children: 
        func(node) 
        newChildren.extend(node.children) 
      children = newChildren 
 
  def drawNode(self, node): 
    self.line2( 
#    self.canvas.create_line( 
        node.bottom.x, 
        node.bottom.y, 
        node.top.x, 
        node.top.y, 
        fill = "#100", 
        width = 1.5 ** (self.depth - node.level), 
        tags = "branch level_%d" % node.level, 
      ) 
 
    if len(node.children) == 0: 
      # 画叶子 
      self.leavesCount += 1 
      self.canvas.create_oval( 
          node.top.x - 3, 
          node.top.y - 3, 
          node.top.x + 3, 
          node.top.y + 3, 
          fill = "#090", 
          tag = "leaf", 
        ) 
 
    self.canvas.update() 
 
  def line2(self, x0, y0, x1, y1, width = 1, fill = "#000", minDist = 10, tags = ""): 
    dots = midDots(x0, y0, x1, y1, minDist) 
    dots2 = [] 
    for i in range(len(dots) - 1): 
      dots2.extend([dots[i].x, 
        dots[i].y, 
        dots[i + 1].x, 
        dots[i + 1].y]) 
    self.canvas.create_line( 
        dots2, 
        fill = fill, 
        width = width, 
        smooth = True, 
        tags = tags, 
      ) 
 
def midDots(x0, y0, x1, y1, d): 
  dots = [] 
  dx, dy, r = x1 - x0, y1 - y0, 0 
  if dx != 0: 
    r = float(dy) / dx 
  c = math.sqrt(dx ** 2 + dy ** 2) 
  n = int(c / d) + 1 
  for i in range(n): 
    if dx != 0: 
      x = dx * i / n 
      y = x * r 
    else: 
      x = dx 
      y = dy * i / n 
    if i > 0: 
      x += d * (0.5 - random.random()) * 0.25 
      y += d * (0.5 - random.random()) * 0.25 
    x += x0 
    y += y0 
    dots.append(Point(x, y)) 
  dots.append(Point(x1, y1)) 
  return dots 
 
if __name__ == "__main__": 
  root = Tkinter.Tk() 
  root.title("Tree") 
  gw, gh = 800, 600 
  canvas = Tkinter.Canvas(root, 
      width = gw, 
      height = gh, 
    ) 
  canvas.pack() 
  tree = Tree(root, canvas, Point(gw / 2, gh - 20), Point(gw / 2, gh * 0.2), / 
    branches = 2, depth = 8) 
  root.bind("n", lambda evt: tree.new()) 
  root.bind("=", lambda evt: tree.chgDepth(1)) 
  root.bind("+", lambda evt: tree.chgDepth(1)) 
  root.bind("-", lambda evt: tree.chgDepth(-1)) 
  root.bind("b", lambda evt: tree.chgBranch(1)) 
  root.bind("c", lambda evt: tree.chgBranch(-1)) 
  root.bind("q", tree.exit) 
  root.mainloop()