如何使用 Python 乌龟画一朵花

Question

我正在练习我的 Python 技能。我很好奇如何使用海龟和函数绘制这朵花，而不使用turtle.circle(radius)。

https://i.stack.imgur.com/ZYUsz.png

此外，我做了一个这样的多边形螺旋：

import turtle
import math


def draw_polygons():
    """"Make t draws a polygon of side sd and length l"""
    sd = 20
    area = 50000
    while sd >= 3:
        side_length = math.sqrt(area / sd * 4 * math.atan(math.pi / sd))
        for i in range(sd):
            for a_color in ["red", "yellow", "blue", "brown", "pink", "green", "black", "orange", "purple"]:
                rest.fillcolor(a_color)
            rest.begin_fill()
            rest.forward(side_length)
            rest.left(360/sd)
            print("side length =", side_length)
        rest.penup()
        rest.forward(side_length / 2)
        rest.pendown()
        rest.right(30)
        sd -= 1

rest = turtle.Turtle()
wn = turtle.Screen()


draw_polygons()

wn.exitonclick()

我想用不同的颜色填充每个多边形，我做错了什么步骤？或者我接下来应该做什么？

示例多边形螺旋如下所示：

https://i.stack.imgur.com/4U9uD.png

Answer 1

您询问两个不同的程序，让我们先解决第二个。除了您的颜色问题之外，您的循环逻辑在 begin_fill() 内部而不是内部循环之外是不正确的。因此，让我们重新编写该程序：

from turtle import Turtle, Screen
import math

COLORS = ["red", "yellow", "blue", "brown", "pink", "green", "black", "orange", "purple"]

def draw_polygons(sides, area):
    """ Draws a polygon with 'sides' sides and area 'area' """

    for i, sd in enumerate(range(sides, 2, -1)):
        side_length = math.sqrt(area / sd * 4 * math.atan(math.pi / sd))
        # print("side length =", side_length)

        a_color = COLORS[i % len(COLORS)]
        rest.fillcolor(a_color)

        rest.pendown()
        rest.begin_fill()

        for _ in range(sd):
            rest.forward(side_length)
            rest.left(360 / sd)

        rest.end_fill()
        rest.penup()

        rest.forward(side_length / 2)
        rest.right(30)

wn = Screen()

rest = Turtle()
rest.speed('fastest')

draw_polygons(20, 40_000)

rest.hideturtle()

wn.exitonclick()

要回到你原来的问题，一种方法是在矩形的下一种颜色之前放下矩形的每种颜色。这是您的代码的返工，仅绘制图像的花瓣部分，因为我认为这就是您要问的。我只是观察了下面的一些距离和角度，您需要进行数学运算才能使它们正确：

from turtle import Turtle, Screen
import math

COLORS = ["green", "orange", "red", "yellow"]

def draw_polygons(area):
    """ Draws a circle using rectangles with area 'area' """

    side_length = math.sqrt(area * math.atan(math.pi / 4))

    for a_color in COLORS:

        for _ in range(12):

            rest.fillcolor(a_color)

            rest.forward(3 * side_length / 10)
            rest.right(15)

            rest.left(112)  # I eyeballed this angle, need to do math
            rest.pendown()
            rest.begin_fill()

            for _ in range(2):
                rest.forward(side_length * 2)
                rest.left(90)
                rest.forward(side_length / 2)
                rest.left(90)
            rest.end_fill()
            rest.penup()
            rest.right(112)  # undo rotation

            rest.forward(3 * side_length / 10)
            rest.right(15)

        # I eyeballed these opposing parameters -- need to do the math
        rest.forward(2 * side_length / 13)
        rest.right(7.5)

wn = Screen()

rest = Turtle()
rest.speed('fastest')
rest.penup()
rest.sety(120)

draw_polygons(20_000)

rest.hideturtle()

wn.exitonclick()

Answer 2

乍一看我会说你的缩进是错误的。

 for a_color in ["red", "yellow", "blue", "brown", "pink", "green", "black", "orange", "purple"]:
     rest.fillcolor(a_color)
  rest.begin_fill()

在这里循环所有颜色，然后填充形状。 颜色将始终为紫色，因为这是您在 rest.fillcolor 中设置的最后一种颜色

作为解决问题的一种方法，您可以创建一个颜色列表并通过调用rest.fillcolor(colors[(i % len(colors))) 来获取您需要的颜色。