Python tkinter 的 .grid() 方法设置的部件之间的 padding，即使我没有设置

您的代码没有问题，这里的问题是 colored颜色 Canvas和Eyedropper单选框在同一列(column=2)，这意味着这两个元素的列宽是相同的.

现在有一些方法可以让你随心所欲地打开windows

对于这种类型的设计

您可以将单选按钮的跨度从Eyedropper改为2，这意味着单选按钮现在将分成两列.

ttk.Radiobutton(self, text='Eyedropper', value=2, variable=self.root.tool).grid(row=1, column=2, columnspan=2)

完整代码

import tkinter as tk
from string import hexdigits
from tkinter import ttk
from random import choices

color_hex = '#C91212'

class MainWindow(tk.Tk):
    def __init__(self):
        super().__init__()
        self.title('Main window')
        self.tool = tk.IntVar(value=0)
        self.topmenu = TopMenu(self)
        self.topmenu.pack()

class TopMenu(tk.Frame):
    def __init__(self, master: MainWindow):
        tk.Frame.__init__(self, master)
        self.root = master
        ttk.Label(self, text="Hex color:").grid(row=0, column=0, padx=10)

        self.symbol_entry_text = tk.StringVar(value=color_hex)
        self.symbol_entry = ttk.Entry(self, textvariable=self.symbol_entry_text)
        self.symbol_entry.grid(row=0, column=1)

        ttk.Button(self, text='Random').grid(column=3, row=0, padx=10)
        ttk.Button(self, text='Load').grid(column=4, row=0)
        ttk.Button(self, text='Save').grid(column=5, row=0, padx=10)

        self.c = tk.Canvas(self, width=21, height=21, highlightthickness=0, bg=color_hex)
        self.c.grid(column=2, row=0)
        
        ttk.Radiobutton(self, text='Pencil', value=0, variable=self.root.tool).grid(row=1, column=0)
        ttk.Radiobutton(self, text='Floodfill', value=1, variable=self.root.tool).grid(row=1, column=1)
        ttk.Radiobutton(self, text='Eyedropper', value=2, variable=self.root.tool).grid(row=1, column=2, columnspan=2) # see here

if __name__ == "__main__":
    app = MainWindow()
    app.mainloop()

Or for this

您可以在画布网格中添加sticky="w"(w表示西方

self.c.grid(column=2, row=0, sticky="w")

完整代码

import tkinter as tk
from string import hexdigits
from tkinter import ttk
from random import choices

color_hex = '#C91212'

class MainWindow(tk.Tk):
    def __init__(self):
        super().__init__()
        self.title('Main window')
        self.tool = tk.IntVar(value=0)
        self.topmenu = TopMenu(self)
        self.topmenu.pack()

class TopMenu(tk.Frame):
    def __init__(self, master: MainWindow):
        tk.Frame.__init__(self, master)
        self.root = master
        ttk.Label(self, text="Hex color:").grid(row=0, column=0, padx=10)

        self.symbol_entry_text = tk.StringVar(value=color_hex)
        self.symbol_entry = ttk.Entry(self, textvariable=self.symbol_entry_text)
        self.symbol_entry.grid(row=0, column=1)

        ttk.Button(self, text='Random').grid(column=3, row=0, padx=10)
        ttk.Button(self, text='Load').grid(column=4, row=0)
        ttk.Button(self, text='Save').grid(column=5, row=0, padx=10)

        self.c = tk.Canvas(self, width=21, height=21, highlightthickness=0, bg=color_hex)
        self.c.grid(column=2, row=0, sticky="w")
        
        ttk.Radiobutton(self, text='Pencil', value=0, variable=self.root.tool).grid(row=1, column=0)
        ttk.Radiobutton(self, text='Floodfill', value=1, variable=self.root.tool).grid(row=1, column=1)
        ttk.Radiobutton(self, text='Eyedropper', value=2, variable=self.root.tool).grid(row=1, column=2)

if __name__ == "__main__":
    app = MainWindow()
    app.mainloop()