Python中Tkinter画布上.jpg图像的滚动条

Question

我试图使一个画布上的jpeg可滚动，但我似乎无法使我的滚动条工作。下面是一些示例代码：

from Tkinter import *
import Image, ImageTk

root = Tk()

frame = Frame(root, bd=2, relief=SUNKEN)

frame.grid_rowconfigure(0, weight=1)
frame.grid_columnconfigure(0, weight=1)

xscrollbar = Scrollbar(frame, orient=HORIZONTAL)
xscrollbar.grid(row=1, column=0, sticky=E+W)

yscrollbar = Scrollbar(frame)
yscrollbar.grid(row=0, column=1, sticky=N+S)

canvas = Canvas(frame, bd=0, xscrollcommand=xscrollbar.set, yscrollcommand=yscrollbar.set)
canvas.grid(row=0, column=0, sticky=N+S+E+W)

File = "jpg filepath here"
img = ImageTk.PhotoImage(Image.open(File))
canvas.create_image(0,0,image=img, anchor="nw")

xscrollbar.config(command=canvas.xview)
yscrollbar.config(command=canvas.yview)

frame.pack()
root.mainloop()