# Tk_ui_font_size.py

# Tk_ui_font_size.py

import Tkinter as tk
import tkFont

UI_SIZES = ["Tiny", "Small", "Normal", "Large", "Huge"]

TINY_FONT_SIZE = 8
SMALL_FONT_SIZE = 12
NORMAL_FONT_SIZE = 16
LARGE_FONT_SIZE = 18
HUGE_FONT_SIZE = 24

root = tk.Tk()

ui_size = tk.StringVar(root, "Normal")
entry_text = tk.StringVar(root, "Entry Text")


def text_size_callback(*_args):
    """change the program font size when the font_size variable changes"""
    font = tkFont.nametofont("TkDefaultFont")
    selected_size = ui_size.get()
    if selected_size == "Tiny":
        font.configure(size=TINY_FONT_SIZE)
    elif selected_size == "Small":
        font.configure(size=SMALL_FONT_SIZE)
    elif selected_size == "Normal":
        font.configure(size=NORMAL_FONT_SIZE)
    elif selected_size == "Large":
        font.configure(size=LARGE_FONT_SIZE)
    elif selected_size == "Huge":
        font.configure(size=HUGE_FONT_SIZE)
    root.option_add("*Font", font)


ui_size.trace('w', text_size_callback)
ui_size.set("Normal")

ui_radio_group = tk.Frame(root)
ui_size_radios = []
for sizeval in UI_SIZES:
    ui_size_radios.append(tk.Radiobutton(
        ui_radio_group,
        text=sizeval,
        variable=ui_size,
        value=sizeval
    ))
text_entry = tk.Entry(ui_radio_group, textvariable=entry_text)

i = 0
for sizeradio in ui_size_radios:
    sizeradio.grid(row=i, column=0, sticky=tk.W)
    i += 1
text_entry.grid(row=2, column=1)
ui_radio_group.pack()

root.mainloop()