'''
20210923
R. Dawes
'''

import tkinter as tk

window = tk.Tk()       # create an object that can be displayed on the screen
window.title("My First GUI")  # give it a title
window.geometry("1200x800")   # width x height in pixels


#add a label - a box with text on it
label_1 = tk.Label(window,text="This is a label")   
# the "window" in this attaches the new label to the displayable object created above


#add an entry box to accept input
entry_1 = tk.Entry(window, width = 10)   # width in characters, not pixels

#add a text box to show output
text_1 = tk.Text(window,height = 5, width = 30)

# add a button - a clickable object

# add a function to react to button_1
# This function must be defined BEFORE the button is defined
def button_1_clicked():
   x = entry_1.get()
   text_1.insert(tk.END,"You entered\n\n"+x)
   
# the first parameter of the insert function indicates where in the Text box
# the new string is to be placed.  "tk.END" is a special indicator that means
# "after all the current content of the Text box".


button_1 = tk.Button(window, text = "Click Me!", command = button_1_clicked)
# note that when we specify the function to be run when the button is clicked, we
# do NOT include parentheses () after the function name

# The objects we have just created will not be displayed unless we tell tkinter where
# to place them in the displayable object called "window"

#~ # place widgets using pack - quick and simple, basically useless
#~ label_1.pack()
#~ entry_1.pack()
#~ text_1.pack()
#~ button_1.pack()

# place widgets using pack - semi-useful
#~ label_1.pack(side = tk.TOP)
#~ entry_1.pack(side = tk.LEFT)
#~ text_1.pack(side = tk.LEFT)
#~ button_1.pack(side = tk.BOTTOM)

# place widgets in a flexible grid
label_1.grid(row = 0, column = 0)
entry_1.grid(row = 1, column = 0)
text_1.grid(row = 1, column = 1)
button_1.grid(row = 2, column = 2)

window.mainloop()       
# this command displays the object and all the widgets we have
# positioned on it.  It will now loop forever, waiting patiently for
# our actions.