python - python turtle奇怪的光标跳

我正在尝试用鼠标绘制乌龟图，我得到了下面的演示代码，但鼠标移动时有时会跳光标：

#!/usr/bin/env python
import turtle
import sys

width = 600
height = 300
def gothere(event):
    turtle.penup()
    x = event.x
    y = event.y
    print "gothere (%d,%d)"%(x,y)
    turtle.goto(x,y)
    turtle.pendown()

def movearound(event):
    x = event.x
    y = event.y
    print "movearound (%d,%d)"%(x,y)
    turtle.goto(x,y)

def release(event):
    print "release"
    turtle.penup()

def circle(x,y,r):
    turtle.pendown()
    turtle.goto(x,y)
    turtle.circle(r)
    turtle.penup()
    return

def reset(event):
    print "reset"
    turtle.clear()

#------------------------------------------------#
sys.setrecursionlimit(90000)
turtle.screensize(canvwidth=width, canvheight=height, bg=None)
turtle.reset()
turtle.speed(0)
turtle.setup(width, height)

canvas = turtle.getcanvas()

canvas.bind("<Button-1>", gothere)
canvas.bind("<B1-Motion>", movearound)
canvas.bind("<ButtonRelease-1>", release)
canvas.bind("<Escape>",reset)

screen = turtle.Screen()
screen.setworldcoordinates(0,height,width,0)
screen.listen()

turtle.mainloop()
#------------------------------------------------#

实际行为见以下GIF：

不确定是否有任何API调用错误！

最佳答案

我看到您的代码有几个问题：
将面向对象的接口与Turtle
该模块的功能接口。我推荐一个还是那个
其他，但不是两者。请参见myimportchange to force oop only。
您使用的是低级别的tkinter鼠标和关键事件，而不是
乌龟自己的事件。我建议你试着在乌龟级工作
（尽管与您的实现相比，这引入了一个小故障，请参见
下面。）
不关闭事件会引入意外的递归
在事件处理程序中。在这些处理程序中禁用事件
这需要花费大量的时间来清理图形。
这是我对以上代码的重做。其中一个问题是，与您的原始版本不同，“移动乌龟到这里”和“开始拖动”将需要两次单击，一次屏幕单击将乌龟移动到当前位置，一次乌龟单击开始拖动。这是由于Turtle提供给tkinter事件的接口不同造成的。（在这方面，python 3稍微好一点，但不适合这种情况。）
为了缓解这个问题，我使用了一个更大的海龟光标。我还添加了标题逻辑：

from turtle import Turtle, Screen, mainloop

WIDTH = 600
HEIGHT = 300

def gothere(x, y):
    screen.onscreenclick(gothere)  # disable events inside handler

    turtle.penup()
    print("gothere (%d,%d)" % (x, y))
    turtle.goto(x, y)
    turtle.pendown()

    screen.onscreenclick(gothere)

def movearound(x, y):
    turtle.ondrag(None)  # disable events inside handler

    turtle.setheading(turtle.towards(x, y))
    print("movearound (%d,%d)" % (x, y))
    turtle.goto(x, y)

    turtle.ondrag(movearound)

def release(x, y):
    print("release (%d,%d)" % (x, y))
    turtle.penup()

def reset():
    print("reset")
    turtle.clear()

screen = Screen()
screen.setup(WIDTH, HEIGHT)
# screen.setworldcoordinates(0, HEIGHT, WIDTH, 0)  # should work fine either way

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

turtle.ondrag(movearound)
turtle.onrelease(release)

screen.onscreenclick(gothere)
screen.onkey(reset, "Escape")

screen.listen()

mainloop()  # normally screen.mainloop() but not in Python 2

但也请参见this answer我在哪里演示如何使tkinter的onmove事件对Turtle可用。
…“移动到这里”然后“开始拖动”限制非常不
对用户来说舒适吗？我们该如何改进？
将我上面的代码与我链接到的备选答案结合起来，我们得到的解决方案与您开始时的解决方案类似，但没有出现问题，而且更像乌龟风格：

from turtle import Turtle, Screen, mainloop
from functools import partial

WIDTH = 600
HEIGHT = 300

VERBOSE = False

def onscreenmove(self, fun, btn=1, add=None):  # method missing from turtle.py

    if fun is None:
        self.cv.unbind('<Button%s-Motion>' % btn)
    else:
        def eventfun(event):
            fun(self.cv.canvasx(event.x) / self.xscale, -self.cv.canvasy(event.y) / self.yscale)

        self.cv.bind('<Button%s-Motion>' % btn, eventfun, add)

def onscreenrelease(self, fun, btn=1, add=None):  # method missing from turtle.py

    if fun is None:
        self.cv.unbind("<Button%s-ButtonRelease>" % btn)
    else:
        def eventfun(event):
            fun(self.cv.canvasx(event.x) / self.xscale, -self.cv.canvasy(event.y) / self.yscale)

        self.cv.bind("<Button%s-ButtonRelease>" % btn, eventfun, add)

def gothere(x, y):

    if VERBOSE:
        print("gothere (%d,%d)" % (x, y))

    turtle.penup()
    turtle.goto(x, y)
    turtle.pendown()

def movearound(x, y):

    screen.onscreenmove(None)  # disable events inside handler

    if VERBOSE:
        print("movearound (%d,%d)" % (x, y))


    turtle.setheading(turtle.towards(x, y))
    turtle.goto(x, y)

    screen.onscreenmove(movearound)  # reenable events

def release(x, y):

    if VERBOSE:
        print("release (%d,%d)" % (x, y))

    turtle.penup()

def reset():

    if VERBOSE:
        print("reset")

    turtle.clear()

screen = Screen()
screen.setup(WIDTH, HEIGHT)
screen.onscreenrelease = partial(onscreenrelease, screen)  # install missing methods
screen.onscreenmove = partial(onscreenmove, screen)

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

screen.onscreenclick(gothere)
screen.onscreenrelease(release)
screen.onscreenmove(movearound)

screen.onkey(reset, "Escape")
screen.listen()

mainloop()  # normally screen.mainloop() but not in Python 2

关于python - python turtle奇怪的光标跳，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/50105860/