在 Tkinter canvas 中绘制直线和拖动时出现问题

Question

So, I'm trying to draw vertical lines in canvas on the click of the button "line".

These are the problems and my requirements:

1. When i try click on the line drawn to drag it to a position, it repels away from the mouse cursor but moves in the correct direction. What do i do to prevent this?
2. On subsequent clicks on the "line" button, i want a new line to be drawn (every time i click) while the original lines stays in the canvas unmoved.
3. The latest line is the only one which can be dragged. All other lines should be static.
4. I want coordinates of all these drawn lines. How do i get these?

This is the code i've written:

from tkinter import *   
root = Tk()             

canvas = tkinter.Canvas(root, width = 480,height = 600) 
canvas.pack()

def draw_lines():
    canvas.create_line(300, 35, 300, 200, dash=(4, 2))

def drag(event):
    event.widget.place(x=event.x_root, y=event.y_root,anchor=CENTER)


canvas.bind("<B1-Motion>", drag)

btn1 = Button(root, text = 'line', bd = '5',command = draw_lines)
btn2 = Button(root, text = 'Close', bd = '5',command = root.destroy)

btn1.pack(side = 'top')   
btn2.pack(side = 'top')

canvas.mainloop()

please help!!!!

Answer 1

Using Python 3.11.0rc1.

I added:

• geometry . so it will not resize when dragging.
• Canvas . You have to play around with height set to 800
• I removed bd=5 . You can suit yourself. Don't use quote.
• I removed Quotes for this btn1.pack(side=TOP)
• At last canvas.pack() always next to mainloop()

Here is the code re-worked:

from tkinter import *


root = Tk()             
root.geometry('400x650')

canvas = Canvas(root, width=480, height=600) 
 

def draw_lines():
    canvas.create_line(300, 35, 300, 200, dash=(4, 2))
    

def drag(event):
    event.widget.place(x=event.x_root, y=event.y_root,anchor=CENTER)



canvas.bind("<B1-Motion>", drag)

btn1 = Button(root, text='line',  command=draw_lines)
btn2 = Button(root, text= 'Close', command=root.destroy)

btn1.pack(side=TOP)   
btn2.pack(side=TOP)


canvas.pack()
canvas.mainloop()

Result output: