该程序通过绘制树干（最初是树；后来是树枝）并递归地添加树来绘制“树”。 使用Pillow。
利用递归函数绘制分形树（fractal tree)，分形几何学的基本思想：客观事物具有自相似的层次结构，局部与整体在形态、功能、信息、时间、空间等方面具有统计意义上的相似性，成为自相似性。自相似性是指局部是整体成比例缩小的性质。
版本：Python 3
# Adapted from #Python # to parameterise, and add colour. # # Author: Alan Richmond, Python3.codes, and others (Rosettacode) import math, colorsys from PIL import Image, ImageDraw spread = 17 # how much branches spread apart width, height = 1000, 800 # window size maxd = 12 # maximum recursion depth len = 9.0 # branch length factor # img = Image.new('RGB', (width, height)) # d = ImageDraw.Draw(img) # This function calls itself to add sub-trees def drawTree(x1, y1, angle, depth): if depth > 0: # compute this branch's next endpoint x2 = x1 + int(math.cos(math.radians(angle)) * depth * len) y2 = y1 + int(math.sin(math.radians(angle)) * depth * len) # https://docs.python.org/2/library/colorsys.html (r, g, b) = colorsys.hsv_to_rgb(float(depth) / maxd, 1.0, 1.0) R, G, B = int(255 * r), int(255 * g), int(255 * b) # draw the branch d.line([x1, y1, x2, y2], (R, G, B), depth) # and append 2 trees by recursion drawTree(x2, y2, angle - spread, depth - 1) drawTree(x2, y2, angle + spread, depth - 1) # Start drawing! drawTree(width / 2, height * 0.9, -90, maxd) img.show() img.save("www.linuxidc.com.png", "PNG")
效果图如下：
关注Linux公社微信公众号（linuxidc_com），（见https://www.linuxidc.com/Linux/2013-12/93755.htm）发送“分形树”即可获得本文Python代码。