用鼠标指针移动 python 只乌龟

Question

我一直在尝试为我的手写文本识别项目保存捕获手写文本的图像。为此，我使用了 python 乌龟。我想通过移动鼠标来更改 canvas 上乌龟的坐标（在笔向上位置），并通过在按住鼠标左键的同时移动鼠标使其写入（在笔向下位置）。我无法实现这一点。这是我的代码。

import tkinter
import turtle

sc = tkinter.Tk()
sc.geometry("1000x1000+100+100")

fr4 = tkinter.Frame(sc, height=500, width=600, bd=4, bg="light green", takefocus="", relief=tkinter.SUNKEN)

fr4.grid(row=2, column=2, sticky=(tkinter.N, tkinter.E, tkinter.W, tkinter.S))

# Canvas
canvas = tkinter.Canvas(fr4, width=1920, height=1080)
canvas.pack()

# Turtle
turtle1 = turtle.RawTurtle(canvas)
turtle1.color("black")
turtle1.shape("turtle")
turtle1.speed(100000)

def drag_handler(x, y):
    turtle1.ondrag(None)  # disable event inside event handler
    turtle1.goto(x, y)
    turtle1.ondrag(drag_handler)  # reenable event on event handler exit

turtle1.ondrag(drag_handler)

sc.mainloop()

Answer 1

以下是我对您所描述内容的实施。我已经将它从 Tk 中移出并直接放入 turtle 中。但是，我引入了低级 Tk 调用来实现缺少的 turtle onmove() 事件处理程序。一旦到位，它就变成了管理运动、点击、释放和拖动的问题。请务必先单击 window 的标题栏以将其激活：

from turtle import Turtle, Screen

MOVING, DRAGGING = range(2)  # states

def move_handler(x, y):
    if state != MOVING:  # ignore stray events
        return

    onmove(screen, None)  # avoid overlapping events
    yertle.penup()
    yertle.setheading(yertle.towards(x, y))
    yertle.goto(x, y)
    onmove(screen, move_handler)

def click_handler(x, y):
    global state

    yertle.onclick(None)  # disable until release
    onmove(screen, None)  # disable competing handler

    yertle.onrelease(release_handler)  # watch for release event
    yertle.ondrag(drag_handler)  # motion is now dragging until release

    state = DRAGGING

def release_handler(x, y):
    global state

    yertle.onrelease(None)  # disable until click
    yertle.ondrag(None)  # disable competing handler

    yertle.onclick(click_handler)  # watch for click event
    onmove(screen, move_handler)  # dragging is now motion until click

    state = MOVING

def drag_handler(x, y):
    if state != DRAGGING:  # ignore stray events
        return

    yertle.ondrag(None)  # disable event inside event handler
    yertle.pendown()
    yertle.setheading(yertle.towards(x, y))
    yertle.goto(x, y)
    yertle.ondrag(drag_handler)  # reenable event on event handler exit

def onmove(self, fun, add=None):
    """
    Bind fun to mouse-motion event on screen.

    Arguments:
    self -- the singular screen instance
    fun  -- a function with two arguments, the coordinates
        of the mouse cursor on the canvas.

    Example:

    >>> onmove(turtle.Screen(), lambda x, y: print(x, y))
    >>> # Subsequently moving the cursor on the screen will
    >>> # print the cursor position to the console
    >>> screen.onmove(None)
    """

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

screen = Screen()
screen.setup(500, 600)
screen.screensize(1920, 1080)

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

state = MOVING

# Initially we track the turtle's motion and left button clicks
onmove(screen, move_handler)  # a la screen.onmove(move_handler)
yertle.onclick(click_handler)  # a click will turn motion into drag

screen.mainloop()

onmove() 事件的实现来自我对 Find the cursor's current position in Python turtle, feel free to give it an upvote when you visit. (Just as your drag_handler() is from my answer to Turtle freehand drawing 的回答，如果您还没有，请随时给它一个赞。）

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