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Cannot Display an Image in Tkinter [duplicate]

This question already has answers here: 开发者_高级运维 Why does Tkinter image not show up if created in a function? (5 answers) Closed 4 years ago.

When I run the program the canvas shows up but the Image does not.

canvas = Canvas(frame, width = 128, height = 128, bg= 'white')
    image_data = Image.open('NoArt.gif')
    ppm_f = ImageTk.PhotoImage(image_data)
    canvas.create_image(0, 0, image = ppm_f, anchor = NW)
    canvas.pack(side=BOTTOM)

any Ideas??

PS.

I have PIL ver 1.6, python 2.6, and The Version of Tkinter that comes with python 2.6


Ok, I figured It out. Apparently due to the way that python deals with garbage disposal the pictures just get erased. A reference to the image in the global scope is required. This is the working code I eventually ended up using:

self.photo = PhotoImage(file="noart.ppm")
    self.Artwork = Label(self.frame, image=self.photo)
    self.Artwork.photo = self.photo
    self.Artwork.pack()

that self.Artwork.photo = self.photo is the important part. It ensures that the Image will be shown.


As mentioned in this very answer and this more popular question & answer and also in effbot.page

When you add a PhotoImage or other Image object to a Tkinter widget, you must keep your own reference to the image object. If you don’t, the image won’t always show up.

The problem is that the Tkinter/Tk interface doesn’t handle references to Image objects properly; the Tk widget will hold a reference to the internal object, but Tkinter does not. When Python’s garbage collector discards the Tkinter object, Tkinter tells Tk to release the image. But since the image is in use by a widget, Tk doesn’t destroy it. Not completely. It just blanks the image, making it completely transparent…

The solution is to make sure to keep a reference to the Tkinter object,

For example the image in below code

Cannot Display an Image in Tkinter [duplicate]

, if at all as it isn't declared in global scope:

import tkinter as tk

root = tk.Tk()

def show_image():
    img_label = tk.Label(root)
    image = tk.PhotoImage(file="test.png")
    img_label['image'] = image

    img_label.pack()


show_image()
root.mainloop()

Cannot Display an Image in Tkinter [duplicate]

whereas in the example below img_label.image is declared globally, as an attribute attached to our very img_label in this example, and

Cannot Display an Image in Tkinter [duplicate]

:

import tkinter as tk

root = tk.Tk()

def show_image():
    img_label = tk.Label(root)
    img_label.image = tk.PhotoImage(file="test.png")
    img_label['image'] = img_label.image

    img_label.pack()


show_image()
root.mainloop()

Cannot Display an Image in Tkinter [duplicate]

It is though still strange as img_label isn't globally declared either. A less confusing way would be adding global image as the first line to the show_image.


If anyone else ever has a similar problem, you can try this hardcoded solution:

import Image
import Tkinter as tk

def cleanhex(x):
    return str(hex(x))[-2:]

def renderimage(target,data,w,h):
    canvas = tk.Canvas(target,width=w,height=h)
    canvas.pack()
    for x in range(w):
        for y in range(h):
            c = "#" + cleanhex(data[x,y][0]) + cleanhex(data[x,y][1]) + cleanhex(data[x,y][2])
            canvas.create_line(x,y,x+1,y+1,fill=c)

im = Image.open("whatever.whatever")
renderimage(root,im.load(),im.size[0],im.size[1])
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