Python Tkinter Canvas，无法将PS转为PNG文件

如何解决Python Tkinter Canvas，无法将PS转为PNG文件

我在将 Postscript 转换为 PNG 时遇到问题

the_canvas.update()
the_canvas.postscript(file="filename.ps",colormode='color')
psimage=Image.open('filename.ps')
psimage.save('filename.png')

完整代码：

from tkinter import *
from PIL import ImageTk,Image
from PIL import ImageGrab
from datetime import date

root = Tk()



width_i= root.winfo_screenwidth()
height_i= root.winfo_screenheight()

today = date.today()

root.geometry("%dx%d" % (width_i,height_i))
root.title("Fullscreen")

the_canvas = Canvas(root,width= 1280,height = 720,bg= "white",highlightthickness=0)


the_image = ImageTk.PhotoImage(Image.open("GUI/GUI materials/MAT.PNG"))
the_canvas.create_image(0,image=the_image,anchor=NW)

the_label = Label(root,text= " "+str(today.day) +"-"+ str(today.month) +"-"+ str(today.year)+" ",fg= "white",bg= "black",font = ("Helvetica",36))
the_labelw = the_canvas.create_window(645,650,window=the_label)

the_canvas.pack(expand=True,fill=BOTH)

the_canvas.update()
the_canvas.postscript(file="filename.ps",colormode='color')
psimage=Image.open('filename.ps')
psimage.save('filename.png')

root.mainloop()

请帮忙！