GUI application using Tkinter - Drag and Drop

Question

I have recently been using WxPython to create a GUI Network simulator like Cisco packet tracer but if I am honest it has been extremely difficult trying to find examples of what I need etc etc. Iv resorted back to the old faithful Tk.

My program thus far has a menu bar which consists of a File > Exit. It also has an Exit button at the bottom Right hand side of the application. As well as this it has a canvas of a set size and a variety of buttons which when clicked produce a small image of the hardware on the canvas. This was done using PIL

What I need next is to be able to drag these images around the canvas and this is proving a little difficult. I have looked at the following example of how it has been broken down and I kind of understand how you need an on click definition, motion (going from a to b) and on release definition, but how do I apply it to my code that I already have?

Here is the link to what I referenced above: http://www.python-forum.org/pythonforum/viewtopic.php?f=4&p=75789

Finally Here is the code I have already. I can appreciate that the layout and structure of my code isn't great as I am fairly new to programming but any guidance / examples / visual representations would be amazing.

  from Tkinter import*
from PIL import Image, ImageTk
class AllTkinterWidgets:
    def __init__(self, master):
        frame= Frame(master, width=900, height=600)
        frame.pack()

        iframe5 = Frame (frame, bd=2, relief=RAISED)
        iframe5.pack(expand=1, fill=X, pady=10, padx=5)

        c = Canvas(iframe5, bg='white', width=600, height=500)
        c.pack()

    # definitions to print hardware images to the canvas
    # -----------------------------------------------------------------------
        def show_imageRouter():
            c.create_image(30,30, image=image1)

        def show_imageSwitch():
            c.create_image(30,60, image=image2)

        def show_imageServer():
            c.create_image(30,100, image=image3)

        def show_imageIpPhone():
            c.create_image(30,140, image=image4)

        def show_imageWirelessRouter():
            c.create_image(30,180, image=image5)

        def show_imageHost():
            c.create_image(30, 220, image=image6)

    # Network hardware buttons created
    # ----------------------------------------------------
        self.button = Button(frame, text = "Router", height= 1, width= 8, padx=2, pady=2,command=show_imageRouter)
        self.button.pack(side = LEFT)

        self.button = Button(frame, text = "Switch",height= 1, width= 8, padx=2, pady=2, command=show_imageSwitch)
        self.button.pack(side = LEFT)

        self.button = Button(frame, text = "Server",height= 1, width= 8, padx=2, pady=2, command=show_imageServer)
        self.button.pack(side = LEFT)

        self.button = Button(frame, text = "IP Phone",height= 1, width= 8, padx=2, pady=2, command=show_imageIpPhone)
        self.button.pack(side = LEFT)

        self.button = Button(frame, text = "Wireless Router",height= 1, width= 12, padx=2, pady=2, command=show_imageWirelessRouter)
        self.button.pack(side = LEFT)

        self.button = Button(frame, text = "Host",height= 1, width= 8, padx=2, pady=2, command=show_imageHost)
        self.button.pack(side = LEFT)

        self.button = Button(frame, text = "Cabling",height= 1, width= 8, padx=2, pady=2)
        self.button.pack(side = LEFT)

        self.button = Button(frame, text = "Square",height= 1, width= 8, padx=2, pady=2)
        self.button.pack(side = LEFT)

    # Create the image objects for the hardware Images
    # ----------------------------------------------------------------------
        imageFile = "router.png"
        image1 = ImageTk.PhotoImage(Image.open(imageFile))

        imageFile = "switch.png"
        image2 = ImageTk.PhotoImage(Image.open(imageFile))

        imageFile = "Server.png"
        image3 = ImageTk.PhotoImage(Image.open(imageFile))

        imageFile = "ipPhone.png"
        image4 = ImageTk.PhotoImage(Image.open(imageFile))

        imageFile = "WirelessRouter.png"
        image5 = ImageTk.PhotoImage(Image.open(imageFile))

        imageFile = "Host.png"
        image6 = ImageTk.PhotoImage(Image.open(imageFile))

root = Tk()
all = AllTkinterWidgets(root)

def Exit():
    print "Exit"

# Create an Exit Button
toolbar = Frame(root)
b = Button(toolbar, text="Exit", width=6, height=3, command=Exit)
b.pack(side=RIGHT, padx=2, pady=2)
toolbar.pack(side=BOTTOM, fill=X)

# Press Esc to quit
root.bind("<Escape>", exit)

# Creation of a menu File > Exit
menu = Menu(root)
root.config(menu=menu)

filemenu = Menu(menu)
menu.add_cascade(label="File", menu=filemenu)
filemenu.add_command(label="Exit", command=Exit)

root.mainloop()

Sorry if the indentation is a bit strange. I've adjusted it to make it block together here.

Solution

This answer to the question "board drawing code to move an oval" shows how to drag an object on a canvas.