recursive_tree_numworks.py

Created by vnap0v

Created on July 25, 2025

2.38 KB

recursive_tree_numworks.py

This script draws recursively generated trees.

The function

def branch(length, depth, width):

recursively calls itself, when recursion limit is not yet reached

it draws a branch and calls itself twice after changing the heading

when recursion limit is reached it draws a leaf

A lot of the tree’s parameters have random variation.

The code uses Turtle graphics for drawing, the timer function to wait after each tree and random to introduce random variations.

import turtle as tl
from time import *
from random import *

# parameters
title = "Recursive tree"
angle_deg = 25 # angle of a new branch compared to previous branch
length_start = 30 # length of the trunk which is first drawn 
length_factor = 4/5 # factor which shortens branches of each succesive recursion
recursion_depth = 7 # number of recursions
randomness_length = (0.6, 1.4) # the interval of random variation of the length of branches
randomness_angel = (0.7, 1.3) # the interval of random variation of the angle of ea new branch
time_delay_ms = 1000 # time period to drawing of next tree

# set up turtle
def init():
  tl.reset()
  tl.colormode(1.0)
  # set speed
  tl.speed(0) # fastest drawing speed
  tl.hideturtle()

  
# this function recursively calls itself, when recursion limit is not yet reached
# it draws a branch and calls itself twice after changing the heading
# when recursion limit is reached it draws a leaf
def branch(length, depth, width):
  if depth > 0:
    red_value = uniform(0.6,0.8)
    color_value = (red_value, red_value / 2, 0) # random variation of brown colors
    tl.pencolor(color_value)
    if width < 1:
      width = 1 # width is reduced at each recursive function call but may not be smaller then 1
    tl.pensize(width)
    tl.pendown()
    tl.forward(length) # draw new branch
    original_position = tl.pos()
    original_heading = tl.heading()
    tl.right(angle_deg * uniform(*randomness_angel))
    new_length = length * length_factor * uniform(*randomness_length) # length of next branch
    branch(new_length, depth - 1, width - 1) # recursive call of this function
    tl.penup()
    tl.goto(original_position)
    tl.setheading(original_heading)
    tl.left(angle_deg * uniform(*randomness_angel))
    tl.pendown()
    new_length = length * length_factor * uniform(*randomness_length) # length of next branch
    branch(new_length, depth - 1,  width - 1) # recursive call of this function
  else:
    # draw a leaf with random variation in size and color
    color_value = (0, uniform(0.5,1), uniform(0, 0.2))
    tl.color(color_value)
    tl.right(90)
    tl.pensize(2)
    tl.circle(randint(2,4))
  
# clear screen ans starts function branch() to draw new tree 
def draw_tree():
  tl.penup()
  tl.setheading(90)
  tl.goto(0,-100)
  branch(length_start, recursion_depth, recursion_depth) 
    

while True:
  init()
  draw_tree()
  sleep(1)