用鼠标指针移动 python 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画布上乌龟的坐标（在笔向上位置），并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现。我已经将它从 Tk 中移出并直接移入海龟中。但是，我引入了低级别的 Tk 调用来实现丢失的海龟 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。确保首先单击窗口的标题栏以使其处于活动状态：

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 的回答，当您访问时，请随时给它点赞。 （正如您的 drag_handler() 来自我对 Turtle freehand drawing 的回答一样，如果您还没有投票，请随时给那个人投票。）