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How do I change the size of a tkinter canvas through a new window?

So I have one Tkinter screen that has a canvas. I want to change the size of the canvas by creating a new window that has entry widgets. So I created a new screen and added 2 entry widgets. I want to get the value from those widgets and based on that...it should change the size of the canvas. I tried to do this for an hour, but no luck. Please assist me.
Here is my code
from tkinter import *
# create root window
root = Tk()
# Create Canvas
canvas = Canvas(root, width=50, height=50)
# Create an additional window (the one that is used to enter the new geometry)
dialog = Toplevel(root)
# Add entry widgets for width and height to the new window
width_entry = tk.Entry(dialog)
height_entry = tk.Entry(dialog)
# Add a button to the new window that applies the given width and height
apply_button = Button(dialog, text = 'Apply geometry', command = lambda: canvas.geometry(width_entry.get()+'x'+height_entry.get()))
# Its not possible to get the geometry of a canvas in tkinter...so how do I change the size.
# display the entry boxes and button
width_entry.pack()
height_entry.pack()
apply_button.pack()
# start the tk mainloop
root.mainloop()
Please Assist me

The command you are looking for is canvas.config
Here, I have adjusted the given code:
import tkinter as tk
# create root window
root = tk.Tk()
# Create Canvas
canvas = tk.Canvas(root, width=50, height=50)
canvas.pack()
# Create an additional window (the one that is used to enter the new geometry)
dialog = tk.Toplevel(root)
# Add entry widgets for width and height to the new window
width_entry = tk.Entry(dialog)
height_entry = tk.Entry(dialog)
# Add a button to the new window that applies the given width and height
apply_button = tk.Button(dialog, text = 'Apply geometry', command = lambda: canvas.config(width=width_entry.get(), height=height_entry.get()))
# display the entry boxes and button
width_entry.pack()
height_entry.pack()
apply_button.pack()
# start the tk mainloop
root.mainloop()
I also changed a couple other things:
You imported * from tkinter, but for some items you still led with tk.; I changed them all to match that and switched the import to match as well. (You could still use *, but then just don't have the leading tk.s.)
The canvas was never packed so you could never see what was going on there.
One more suggestion, that line where you make the button is really long. Maybe make a function that does what the lambda does and assign its command to that function instead of a lambda. You can probably see that a line that long is even hard to read here much less if someone (maybe a future version of yourself) was to try to read your code, and edit it or make sense of it. Generally, try to keep all lines down to 80 characters.
Let us know if you have any more questions etc.

image not showing on window Tkinter [duplicate]

This question already has answers here:
Why does Tkinter image not show up if created in a function?
(5 answers)
Closed 4 years ago.
I am trying to display an image in a window...seems simple enough right? Well I have a big bug!
I have this exact same code in one file:
import Tkinter
root = Tkinter.Tk()
canvas = Tkinter.Canvas(root)
canvas.grid(row = 0, column = 0)
photo = Tkinter.PhotoImage(file = '/Users/Richy/Desktop/1.gif')
image1 = canvas.create_image(0,0, image=photo)
root.mainloop()
It works.
I have this in part of a bigger file:
def officialPictureWindow(self):
t = Toplevel(self)
t.wm_title("Official Image")
self.__canvas3 = Canvas(t)
self.__canvas3.grid(row = 0, column = 0)
photo = PhotoImage(file = '/Users/Richy/Desktop/1.gif')
image1 = self.__canvas3.create_image(0,0, image=photo)
It doesn't work!
That function is called when someone presses a button on a menubar I have. All the other menubar buttons I have operate properly and show their windows. There's no images in the others though.
This gives no no error. Just a blank screen. Does anyone know why?

You need to keep an additional reference to photo so it doesn't get prematurely garbage collected at the end of the function. An Introduction to Tkinter explains further:
Note: When a PhotoImage object is garbage-collected by Python (e.g. when you return from a function which stored an image in a local variable), the image is cleared even if it’s being displayed by a Tkinter widget.
To avoid this, the program must keep an extra reference to the image object. A simple way to do this is to assign the image to a widget attribute, like this:
label = Label(image=photo)
label.image = photo # keep a reference!
label.pack()
In your case, you could attach the image to your self variable, or maybe the canvas. It doesn't really matter, as long as it is assigned to something.
self.image = photo
#or:
self.__canvas3.image = photo

Displaying an image in python via Button and Canvas

I am a begginer in python, tkinter. I have written a code that should normally display an image in a canvas.
What happens is that the main frame (gui) is displayed with the menu bar, then when I click on load image, the gui window shrinks (to 100x100 I guess) but nothing is displayed within.
Could you please explain to me why this is happening so I can understand where the error occurs, and how to correct it?
# -*- coding:utf-8 -*-
# Imports
from tkinter import Tk, Menu, Canvas
from PIL import Image, ImageTk
# Function definitions
def deleteImage(canvas):
canvas.delete("all")
return
def loadImage(canvas, img):
filename = ImageTk.PhotoImage(img)
canvas.image = filename
canvas.create_image(0,0,anchor='nw',image=filename)
return
def quitProgram():
gui.destroy()
# Main window
gui = Tk()
# Inside the main gui window
#Creating an object containing an image
# A canvas with borders that adapt to the image within it
img = Image.open("fleur.jpg")
canvas = Canvas(gui,height=img.size[0],width=img.size[0])
canvas.pack()
# Menu bar
menubar = Menu(gui)
# Adding a cascade to the menu bar:
filemenu = Menu(menubar, tearoff=0)
menubar.add_cascade(label="Files", menu=filemenu)
# Adding a load image button to the cascade menu "File"
filemenu.add_command(label="Load an image", command=loadImage)
# Adding a delete image button to the cascade menu "File"
filemenu.add_command(label="Delete image", command=deleteImage)
filemenu.add_separator()
filemenu.add_command(label="Quit", command=quitProgram)
menubar.add_separator()
menubar.add_cascade(label="?")
# Display the menu bar
gui.config(menu=menubar)
gui.mainloop()
EDIT:
The second problem is that I want to create a canvas and the image in the main gui window, and pass them as arguments to the menu buttons (See code above, where img and canvas are created separately from the function loadImage). Seeing as putting parenthesis in the command=loadImage() created a problem on its own.
Another point that rises a question in my head : Regarding the first problem which was solved by keeping a reference to the filename=ImageTk.PhotoImage(img). Wouldn't it normally be pointless to keep a reference inside the function since it's a local variable anyway?

As stated in effbot's PhotoImage page, you have to keep a reference of your image to ensure it's not garbage collected.
You must keep a reference to the image object in your Python program,
either by storing it in a global variable, or by attaching it to
another object.
Note: When a PhotoImage object is garbage-collected by Python (e.g.
when you return from a function which stored an image in a local
variable), the image is cleared even if it’s being displayed by a
Tkinter widget.
To avoid this, the program must keep an extra reference to the image
object. A simple way to do this is to assign the image to a widget
attribute, like this:
Your loadImage() method should look like below.
def loadImage():
img = Image.open("fleur.jpg")
filename = ImageTk.PhotoImage(img)
canvas = Canvas(gui,height=100,width=100)
canvas.image = filename # <--- keep reference of your image
canvas.create_image(0,0,anchor='nw',image=filename)
canvas.pack()

Python Tkinter: How do I apply a new background image when opening a new tk window?

I used the code below (with different variable names for each section) to create a background image for each tkinter window. Each of these is initiated in a function and both work fine independently.
When loading one function from another however, the second fails to display an image. (I have tried importing all relevant in each function aswell). It works in the case that use tk.destruct(), however if If I want to keep it open, or hide it with . withdraw(), the image fails to display, rendering the second window useless.
background_image=tk.PhotoImage(...)
background_label = tk.Label(parent, image=background_image)
background_label.place(x=0, y=0, relwidth=1, relheight=1)

Ok I've made up a solution for you. Basically all you need is to use tk.Toplevel() for the second tkinter window and make sure that the 'parent' is root2 so the image will appear in the second window.
I have used buttons for the images, you had labels so you may wish to change this, but buttons gave me a way to open a new tk window easily, I have also used .pack(), not .place(), as it was faster for me. May also be helpful for you to know that I used python 3.3 with windows so you might need a capital T for tkinter.
import tkinter as tk
root1 = tk.Tk()
def new_window():
root2 = tk.Toplevel()
# click the last button and all tk windows close
def shutdown():
root1.destroy()
root2.destroy()
background_image2 = tk.PhotoImage(file = '...')
background_button2 = tk.Button(root2, image = background_image2, command = shutdown)
background_button2.pack()
root2.mainloop()
background_image1 = tk.PhotoImage(file = '...')
# have used a button not a label for me to make another tk window
background_button1 = tk.Button(root1, image = background_image1, command = new_window)
background_button1.pack()
root1.mainloop()
#user2589273 Next time you should add more code so answers can be easily given, and tailored to you, just a suggestion. Hope this helps.

Python code problem, application has been destroyed Tcl error

I am making a Tkinter GUI to do nothing except call images - and of course, I have struggled to find decent tkinter documentation all along.
There is a line of my code which cannot seem to do as asked - I want to call up all the values in a dictionary and individually print and pull an image by the same name for each one before the next value is called up. I have tried dict.itervalues() and dict.values() and can't seem to figure anything out altogether...
Anyway, here is the snippet:
for key in ansDict.iterkeys(): #using the iterkeys function... kind of
x=key
root = tk.Tk() # root window created (is this in the right place?)
root.title('C H E M I S T R Y A B C\'s')
frameAns=tk.Frame(root)
frameAns.grid(row=0, column=0, sticky=tk.NW)
for i in range(len(ansDict[x])):
print '-->' + ansDict[x][i]
for value in ansDict.itervalues(): #This is the most important part
for i in range(len(value)): #pulls value list from dictionary named ansDict
picRef1 = Image.open(value[i] + '.jpg') #calls image file by the same name using PIL
photo1 = ImageTk.PhotoImage(picRef1, master=root)
button1 = tk.Button(frameAns, compound=tk.TOP, image=photo1, text=str(value[i]) + '\nClose me!', bg='white') #pulls up button onto which the image is pasted
button1.grid(sticky=tk.NW, padx=2, pady=2) #places button on grid
button1.image=photo1
root.mainloop()
Finally, at the end, it pulls up one or two images and then I get the following error:
TclError: can't invoke "image" command: application has been destroyed
and I can't figure out what is wrong. I can't move the image command, and somehow I need to "save" it so it isn't destroyed. I know there are other code errors here, but I think that if I figure out the TclError that I am getting that I can set everything else straight.
If there is an easier way to do all this please do tell!

I have looked around for a good solution to this but have yet to find the proper solution. Looking at the Tkinter.py class it looks like the Image del value is:
def __del__(self):
if self.name:
try:
self.tk.call('image', 'delete', self.name)
except TclError:
# May happen if the root was destroyed
pass
This means if you wanted to do a BRUTAL hack you could setup a PhotoImage as described in jtp's link.
photo = tk.PhotoImage(file="C:/myimage.gif")
widget["image"] = photo
widget.image = photo
Then you could just before the program exited do the following hack:
photo.name = None
This would prevent it from trying to clean itself up in the PhotoImage delete and prevent the exception from being called in the del method. I do not really recommend you do this unless your back is up against the wall, and you have no alternative.
I will continue to look into this and if I find a better solution will edit this post with a better one (hopefully someone will give the correct solution before then).

Here is one possibility, although it is structured differently than your example. It stacks the four 100 pixel square images on top of one another. I believe you need to keep a separate reference to each Image object, so I tucked them away in the images dictionary.
from Tkinter import *
import os
from PIL import Image, ImageTk
image_names = { '1':'one','2':'two','3':'three','4':'four' }
images = {}
root = Tk()
root.title("HELLO")
frm = Frame(root)
for v in image_names.itervalues():
images[v] = {}
images[v]['i'] = Image.open("%s%s.jpg" % (os.path.dirname(__file__), v))
images[v]['pi'] = ImageTk.PhotoImage(images[v]['i'])
images[v]['b'] = Button(frm, image=images[v]['pi'])
images[v]['b'].pack()
frm.pack()
mainloop()
Here is a good link discussing the PhotoImage class.
http://effbot.org/tkinterbook/photoimage.htm

It seems that you did not get the idea of Event-driven programming. You should create whole GUI once, fill it with widgets, setup the events and then enter infinite loop. The GUI should call callback functions based on your event to function binding. So those parts of your program should definitely be called just once: root = tk.Tk(), root.mainloop().
Edit: Added Event-driven programming "idea example".
from Tkinter import *
master = Tk()
def callback():
print "click!"
b = Button(master, text="OK", command=callback)
b.pack()
mainloop()