turtle-graphics:我在使用钥匙来缩小和生长海龟时遇到了麻烦

Question

我写了一段代码，让乌龟在盒子里四处走动。我正在尝试编写一个部分，以便在您按下某些键时更改其大小，例如g代表增长，s代表收缩。然而，我觉得我让它变大和变小的方式并不是很好。每当turtle处于默认大小时，我按下shrink，就会得到一个错误消息，指出它的stetch_len/stretch_wid不能是0。

我尝试过使用if使它在大小为1的情况下不能缩小，但我无法让它工作。我想这可能与我缩小它的方法有关，但我不确定。

半相关的是，我设置了一个按钮，当按下时将海龟重置为默认设置。但是，如果我让乌龟长得更大，它就不会缩小那么多。我把它做得越大，它的违约似乎就变得越大。再一次，我认为这与我用来改变大小的方法有关，但我不确定。

import turtle
import os

#Creates the window for the game
wn = turtle.Screen()
wn.bgcolor("cyan")
wn.title("Game Test")

#Creates the background for the game
border_pen = turtle.Turtle()
border_pen.speed(0)
border_pen.color("black")
border_pen.penup()
border_pen.setposition(-250,-250)
border_pen.pendown()
border_pen.pensize(1)
for side in range(4):
    border_pen.fd(500)
    border_pen.lt(90)
border_pen.hideturtle()

#Creates the turtle
player = turtle.Turtle()
player.color("black")
player.shape("square")
player.pensize(2)
#player.penup()
player.setposition(0, 0)
player.setheading(90)
player.shapesize(1)

playerspeed = 10



# This resets the player to its default, beginning state
def reset():
    player.setposition(0, 0)
    player.setheading(90)
    player.shapesize(1)


# Makes the character grow larger
def grow():
    size = player.turtlesize()
    increase = tuple([1 + num for num in size])
    player.turtlesize(*increase)
    return

#Makes the character shrink
def shrink():
    size = player.turtlesize()
    decrease = tuple([-1 + num for num in size])
    if player.turtlesize() == 1:
        return
    else:
        player.turtlesize(*decrease)
    return

# Prints the characters coordinates in a seperate window from the game
def place():
    b, c = player.pos()
    print("\n")
    print(b, ",", c)


# These are the keys you push to activate different things
# The movement uses a number pad, which make programming diagonal keys easier.
turtle.listen()
turtle.onkeypress(reset, "5")
turtle.onkey(grow, "g")
turtle.onkey(shrink, "s")
turtle.onkey(place, "p")


input("Press any key to exit...")

Answer 1

乌里娅·哈彭内斯让我注意到我使用的是turtlesize。我把它切换到shapesize，这样我就可以纠正代码了。

为了解决这个问题，我使用了shapesize，并将变量设置为a、b、c而不是大小。这使得我只需将每个值相加，然后将新值设置为shapesize。

这也意味着对于重置函数，我只需要编写player.shapesize(1, 1, 1)。

#Makes the character shrink
def shrink():
    a, b, c = player.shapesize()
    if a > 1:
        a = a - 1
        b = b - 1
        c = c - 1
        player.shapesize(a, b, c)
        print(a, b, c)
    else:
        print(a, b, c)
        return