调整 tkinter 中内容的大小 canvas

Question

我正在尝试制作一个 canvas，其中包含一个带有标签的 window，当 window 调整大小时，标签将调整大小。这是我的代码。

import tkinter as tk


main_win = tk.Tk()
main_win.test_number = 0

main_canvas = tk.Canvas(master=main_win, borderwidth=2, relief='ridge', highlightthickness=0)
main_canvas.pack(side='top', fill='both', expand=True, padx=30, pady=30)
canvas_frame = tk.Frame(master=main_canvas, borderwidth=2, relief='ridge')
main_canvas.create_window((4,4), window=canvas_frame, anchor='nw')

def _on_config(widget):
    main_win.test_number +=1
    print(main_win.test_number)

    canvas_width = main_canvas.winfo_width()
    widget.config(width=canvas_width)

inner_lbl_frame_1 = tk.Frame(master=canvas_frame, borderwidth=2, relief='ridge')
inner_lbl_frame_1.pack(side='top', fill='x', expand=True)
lbl_test_1 = tk.Label(master=inner_lbl_frame_1, text="Test |")
lbl_test_1.pack(side='left', padx=5, pady=5)
lbl_verify_1 = tk.Label(master=inner_lbl_frame_1, text="To Verify |")
lbl_verify_1.pack(side='left', padx=5, pady=5)
lbl_conclusion_1 = tk.Label(master=inner_lbl_frame_1, text="If Resize Works")
lbl_conclusion_1.pack(side='left', fill='x', expand=True, padx=5, pady=5)

inner_lbl_frame_2 = tk.Frame(master=canvas_frame, borderwidth=2, relief='ridge')
inner_lbl_frame_2.pack(side='top', fill='x', expand=True)
lbl_test_2 = tk.Label(master=inner_lbl_frame_2, text="Test |")
lbl_test_2.pack(side='left', padx=5, pady=5)
lbl_verify_2 = tk.Label(master=inner_lbl_frame_2, text="To Verify |")
lbl_verify_2.pack(side='left', padx=5, pady=5)
lbl_conclusion_2 = tk.Label(master=inner_lbl_frame_2, text="If Resize Works")
lbl_conclusion_2.pack(side='left', fill='x', expand=True, padx=5, pady=5)

main_win.bind("<Configure>", lambda e: _on_config(canvas_frame))

main_win.mainloop()

当我运行这样做时，它陷入了无限循环。我试图自己研究这个问题，但是，由于这是一个有点具体的问题，我还没有看到任何答案。请解释为什么这不起作用以及我如何让它变得更好..

为了解决我使用的帧数，它是为了布局目的。我将添加更多包含标签的标签框以保存大量视觉数据，但这是我能写的最好的最小可重现示例。

我正在使用 Python 3.9.2.

Answer 1

您不应在 main_win 上绑定事件，因为它将继承给其子项，包括 canvas_frame。所以在_on_change()里面改变canvas_frame的宽度会触发事件并再次调用函数，从而导致递归循环。

您应该改为绑定 main_canvas 并使用 main_canvas.itemconfigure() 更改框架的宽度：

...
# save the item ID of the frame
frame_id = main_canvas.create_window((4,4), window=canvas_frame, anchor='nw')

def _on_config(event, widget_id):
    main_win.test_number += 1
    print(main_win.test_number)
    # use itemconfigure(...) on the passed widget_id
    event.widget.itemconfigure(widget_id, width=event.width-8)

...

# bind on main_canvas instead of main_win
main_canvas.bind('<Configure>', lambda e: _on_config(e, frame_id))
...

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