如何更新 tkinter 标签中的图像？

Question

我是 python 的初学者，所以这可能是一个太简单的问题，但我需要帮助。使用此代码，我无法更新 tkinter 标签中的图像。我什至可以根据新加载的图像属性调整窗口大小，但新图像不会显示在 tkinter 标签中。

from Tkinter import Frame, Tk, Label, Text, Menu, END, BOTH, StringVar
from PIL import ImageTk, Image
import numpy
import tkFileDialog

class DIP(Frame):
    def __init__(self, parent):
        Frame.__init__(self, parent) 
        self.parent = parent        
        self.initUI()

def initUI(self):

    self.parent.title("DIP Algorithms- Simple Photo Editor")
    self.pack(fill=BOTH, expand=1)

    menubar = Menu(self.parent)
    self.parent.config(menu=menubar)

    #Open Image Menu
    fileMenu = Menu(menubar)
    fileMenu.add_command(label="Open", command=self.onOpen)
    menubar.add_cascade(label="File", menu=fileMenu)

    #menu for image ngative
    basicMenu=Menu(menubar)
    basicMenu.add_command(label="Negative", command=self.onNeg)
    menubar.add_cascade(label="Basic", menu=basicMenu)

#Image Negative Menu callback
def onNeg(self):
    I2=255-self.I;
    im = Image.fromarray(numpy.uint8(I2))
    photo2=ImageTk.PhotoImage(im)
    self.label2= Label(self.parent,border=25,image=photo2)
    self.label2.image = photo2 # keep a reference!
    self.label2.grid(row=1, column=2)


def setImage(self):

    self.img=Image.open(self.fn)
    self.I = numpy.asarray(self.img)
    l,h = self.img.size
    text=str(2*l+100)+"x"+str(h+50)+"+0+0"
    self.parent.geometry(text)
    photo = ImageTk.PhotoImage(self.img)
    self.label1 = Label(self.parent,border=25,image=photo)
    self.label1.configure(image=photo)
    self.label1.image = photo # keep a reference!
    self.label1.grid(row=1, column=1)

#Open Callback
def onOpen(self):

    ftypes = [('Image Files', '*.tif *.jpg *.png')]
    dlg = tkFileDialog.Open(self, filetypes = ftypes)
    filename = dlg.show()
    self.fn=filename
    #print self.fn #prints filename with path here
    self.setImage()

#def onError(self):
    #box.showerror("Error", "Could not open file")    

def main():

    root = Tk()
    DIP(root)
    root.geometry("320x240")
    root.mainloop()  


if __name__ == '__main__':
    main()

当我运行此代码并打开图像时，它会显示在 label1 中。但是当我再次打开另一个图像时，我希望它会显示在同一个 label1 中，但它没有发生。我知道第二张图片已加载，因为窗口大小相应调整，唯一的问题是它没有被显示，我不知道为什么！

Answer 1

不是每次调用setImage 时都创建一个新的tk.Label，而是在setImage 之外创建一次——例如，在initUI 中。

然后您可以通过调用self.label.configure来更改图像：

---

import Tkinter as tk
import Image
import ImageTk
import numpy as np
import tkFileDialog

class DIP(tk.Frame):
    def __init__(self, parent):
        tk.Frame.__init__(self, parent) 
        self.parent = parent        
        self.initUI()

    def initUI(self):
        self.parent.title("DIP Algorithms- Simple Photo Editor")
        self.pack(fill = tk.BOTH, expand = 1)

        menubar = tk.Menu(self.parent)
        self.parent.config(menu = menubar)

        self.label1 = tk.Label(self, border = 25)
        self.label2 = tk.Label(self, border = 25)
        self.label1.grid(row = 1, column = 1)
        self.label2.grid(row = 1, column = 2)

        #Open Image Menu
        fileMenu = tk.Menu(menubar)
        fileMenu.add_command(label = "Open", command = self.onOpen)
        menubar.add_cascade(label = "File", menu = fileMenu)

        #menu for image ngative
        basicMenu = tk.Menu(menubar)
        basicMenu.add_command(label = "Negative", command = self.onNeg)
        menubar.add_cascade(label = "Basic", menu = basicMenu)

    def onNeg(self):
        #Image Negative Menu callback
        I2 = 255-self.I;
        im = Image.fromarray(np.uint8(I2))
        photo2 = ImageTk.PhotoImage(im)
        self.label2.image = photo2 # keep a reference!

    def setImage(self):
        self.img = Image.open(self.fn)
        self.I = np.asarray(self.img)
        l, h = self.img.size
        text = str(2*l+100)+"x"+str(h+50)+"+0+0"
        self.parent.geometry(text)
        photo = ImageTk.PhotoImage(self.img)
        self.label1.configure(image = photo)
        self.label1.image = photo # keep a reference!

    def onOpen(self):
        #Open Callback
        ftypes = [('Image Files', '*.tif *.jpg *.png')]
        dlg = tkFileDialog.Open(self, filetypes = ftypes)
        filename = dlg.show()
        self.fn = filename
        #print self.fn #prints filename with path here
        self.setImage()

    #def onError(self):
        #box.showerror("Error", "Could not open file")    

def main():

    root = tk.Tk()
    DIP(root)
    root.geometry("320x240")
    root.mainloop()  


if __name__ == '__main__':
    main()