# coding:utf-8
import tkinter as tk

# ウィンドウを描く
root = tk.Tk()
root.geometry('600x400')

# Canvasを置く
canvas = tk.Canvas(root, width=600, height=400, bg='white')
canvas.place(x=0, y=0)

# 円を描く
canvas.create_oval(300 - 20, 200 - 20, 300 + 20, 200 + 20, fill='red', width=0)

root.mainloop()