今天是植树节，你“植树”了吗？

今天是植树节，不要忘记植树嗷！

一、代码

# -*- coding: UTF-8 -*-
"""
@Author  ：远方的星
@Time   : 2021/3/2 14:28
@CSDN    ：https://blog.csdn.net/qq_44921056
@腾讯云   ： https://cloud.tencent.com/developer/column/91164
"""

from turtle import Turtle


def tree(plist, l, a, f):
    # 宽度优先绘制法
    """ plist is list of pens
    l is length of branch
    a is half of the angle between 2 branches
    f is factor by which branch is shortened
    from level to level."""
    if l > 5:
        lst = []
        for p in plist:
            p.forward(l)  # Move the turtle forward by the specified distance, in the direction the turtle is headed.
            q = p.clone()  # Create and return a clone of the turtle with same position, heading and turtle properties.
            p.left(a)  # Turn turtle left by angle units
            q.right(
                a)  # turn turtle right by angle units, nits are by default degrees, but can be set via the degrees() and radians() functions.
            lst.append(p)
            lst.append(q)
        tree(lst, l * f, a, f)


def tree2(p, l, a, f):
    # 深度优先绘制法
    if l > 5:
        p.forward(l)
        q = p.clone()
        p.left(a)
        q.right(a)
        tree2(p, l * f, a, f)
        tree2(q, l * f, a, f)


def maketree(x, y):
    p = Turtle()
    p.color("blue")
    p.pensize(5)
    p.setundobuffer(None)
    p.hideturtle()
    # Make the turtle invisible. It’s a good idea to do this while you’re in the middle of doing some complex drawing,
    # because hiding the turtle speeds up the drawing observably.
    # p.speed(9)
    p.getscreen().tracer(1, 0)  # Return the TurtleScreen object the turtle is drawing on.
    # TurtleScreen methods can then be called for that object.
    p.left(90)  # Turn turtle left by angle units. direction

    p.penup()  # Pull the pen up – no drawing when moving.
    p.goto(x,
           y)  # Move turtle to an absolute position. If the pen is down, draw line. Do not change the turtle’s orientation.
    p.pendown()  # Pull the pen down – drawing when moving.
    # 这三条语句是一个组合相当于先把笔收起来再移动到指定位置，再把笔放下开始画.否则turtle一移动就会自动的把线画出来

    tree([p], 100, 65, 0.6375)

    p.penup()
    p.setheading(90)  # Set the orientation of the turtle to to_angle.
    p.goto(x, y)
    p.down()
    p.color("green")

    tree2(p, 100, 65, 0.6375)


def main():
    maketree(-200, -200)
    maketree(0, 0)
    maketree(200, -200)


main()

二、运算结果