How to display an image from a numpy array in tkinter?

Question

The following short code is meant to create an array with numpy, convert it into an image object with PIL and then insert into a canvas on a tkinter window.

from tkinter import *
from PIL import Image

root = Tk()
array = np.ones((40,40))*150
img = Image.fromarray(array)
canvas = Canvas(root,width=300,height=300)
canvas.pack()
canvas.create_image(20,20,anchor=NW,image=img)

root.mainloop()

This throws the error:

TclError: image "<PIL.Image.Image image mode=F size=40x40 at 0x7F42D3BC3290>" doesn't exist

Answer 1

You need to use PhotoImage from ImageTk.

Do this instead:

import tkinter as tk
import numpy as np
from PIL import Image, ImageTk

root = tk.Tk()

array = np.ones((40,40))*150
img =  ImageTk.PhotoImage(image=Image.fromarray(array))

canvas = tk.Canvas(root,width=300,height=300)
canvas.pack()
canvas.create_image(20,20, anchor="nw", image=img)

root.mainloop()