i'm trying to print an image and a line on canvas but code does not work

Question

im trying to build a canvas with a line and an image with the following code but it only shows a canvas

    from tkinter import *
    from PIL import Image, ImageTk

    # Create an instance of tkinter frame or window
    win=Tk()

    # Set the size of the tkinter window
    win.geometry("700x350")

    from numpy import asarray
    # load the image
    image = Image.open('image1.jpg')
    # convert image to numpy array
    data = asarray(image)
    print(type(data))
    # summarize shape
    print(data.shape)

    # create Pillow image
    image2 = Image.fromarray(data)
    print(type(image2))

    # summarize image details
    print(image2.mode)
    print(image2.size)

    class Start_Screen:
        def __init__(self, master):
            self.master = master
            # Create a canvas widget
            canvas=tkCanvas(win, width=500, height=300)

        
    # Add a line in canvas widget
        self.canvas.create_line(50,35,500,35, fill="green", width=5)
        self.start_img = Image.open("./image1.jpg")
        image1 = ImageTk.PhotoImage(image)

    # Add the image to the canvas
        self.canvas.create_image(50, 45, anchor='nw', image=image1)

        self.canvas.create_line(50,135,500,135, fill="green", width=5)

        self.canvas.create_line(50,235,500,235, fill="green", width=5)
        
        self.canvas.pack()
        
        self.canvas.pack(expand=YES, fill=BOTH)
    # myvar = canvas.create_line(50,35,500,35, fill="green", width=5)
    #mytuple = (int myvar)
    #myit = iter(mytuple)

    
    win.mainloop()

i tried runnning this in spyder but it only shows canvas

Answer 1

I see mess in your code so it is hard to say what is real problem.

You have wrong indentations - some code is directly in class instead of __init__ - so it may run it in wrong way.

You never create instance of Start_Screen - so it can't run code which puts image on canvas - create_image(). And maybe this is your problem`

Inside class you create canvas but later you use self.canvas - this code should gives you error message.

You may have common problem with bug in PhotoImage - it removes image from memory when it assigned to local variable inside function - and later you see only empty canvas. You may have to use self.image1 instead of image1

You have to clean your code before you put it in question.

---

Minimal working code:

import tkinter as tk  # pep8: `import *` is not preferred
from PIL import Image, ImageTk
import numpy  # pep8: all imports at the beginning

# --- constants --- # pep8: constants before classes
                    # pep8: `UPPER_CASE_NAMES` for constants (with `_`)

# --- classes ---  # pep8: classes before functions and other code
                   # pep8: `CamelCaseNames` for classes (without `_`)

class StartScreen:
    def __init__(self, master):
        self.master = master

        # Create a canvas widget
        self.canvas = tk.Canvas(master, width=500, height=300)  # you can use `master` instead of `win`
        self.canvas.pack(expand=True, fill='both')
    
        # Add the image to the canvas
        self.start_img = Image.open("image1.jpg")
        self.image1 = ImageTk.PhotoImage(self.start_img)
        self.canvas.create_image(50, 45, anchor='nw', image=self.image1)
        
        # Add a line in canvas widget
        self.canvas.create_line(50,35,500,35, fill="green", width=5)
        self.canvas.create_line(50,135,500,135, fill="green", width=5)
        self.canvas.create_line(50,235,500,235, fill="green", width=5)
       
        
# --- functions ---  # pep8: functions after classes and before other code
                     # pep8: `lower_case_names` for functions (with `_`)

def not_used_code():
    """I don't use this code"""
    
    # load the image
    image = Image.open('image1.jpg')

    # convert image to numpy array
    data = numpy.asarray(image)
    print(type(data))

    # summarize shape
    print(data.shape)

    # create Pillow image
    image2 = Image.fromarray(data)
    print(type(image2))

    # summarize image details
    print(image2.mode)
    print(image2.size)

    # myvar = canvas.create_line(50,35,500,35, fill="green", width=5)
    #mytuple = (int myvar)
    #myit = iter(mytuple)
        
# --- main ---        

win = tk.Tk()

# Set the size of the tkinter window
win.geometry("700x350")

screen = StartScreen(win)
screen.canvas.create_line(50, 335, 500, 335, fill="red", width=5)  # access canvas (created in StartScreen) outside class

win.mainloop()

Result:

---

Image source: Wikipedia: Lenna

PEP 8 – Style Guide for Python Code