#!/usr/bin/python
# .+
#
# .identifier : $Id:$
# .context : Application View Controller
# .title : A counter with count speed control (Tk)
# .kind : python source
# .author : Fabrizio Pollastri
# .site : Torino - Italy
# .creation : 12-May-2008
# .copyright : (c) 2008 Fabrizio Pollastri.
# .license : GNU General Public License (see below)
#
# This file is part of "AVC, Application View Controller".
#
# AVC is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# AVC is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see .
#
# .-
from Tkinter import * # Tk interface
from avc import * # AVC for Tk
from random import randint # random integer generator
TOPLEVEL_NAME = 'countdown' # name of the top level widget
FIRST_COUNT_DELAY = 1000 # let avc_init be called
COUNTDOWN_PERIOD = 500 # count down at 2 unit per second
MAX_CREATION_PERIOD = 4000 # create a new count down at 1/2 this
class Countdown(AVC):
"""
A countdown counter displayed in a Label widget. Count starts at given
value. When count reaches zero the counter and its GUI are destroyed.
"""
def __init__(self,count_start=10):
## create GUI
# main window
self.root = Tk()
self.root.title('AVC Tk countdown example')
self.frame = Frame(self.root,name='countdown',width=350,height=50)
self.frame.pack(expand=1)
# count down label
self.label = Label(self.frame,name='counter')
self.label.place(relx=0.5,rely=0.4,anchor=CENTER)
# terminate program at toplevel window destroy: connect toplevel
# destroy signal to termination handler.
self.root.bind_class('Toplevel','',lambda event: self.root.quit())
# init the counter variable
self.counter = count_start
# connect counter variable with label widget
self.avc_connect(self.root)
# start count down
self.root.after(COUNTDOWN_PERIOD,self.decrementer)
def decrementer(self):
"Counter decrementer. Return False to destroy previous timer."
self.counter -= 1
if self.counter:
# if counter not zero: reschedule count timer
self.root.after(COUNTDOWN_PERIOD,self.decrementer)
else:
# counter reached zero: destroy this countdown and its GUI
self.root.destroy()
class Example(AVC):
"""
Continuously create at random intervals windows with a countdown from 10 to 0.
When a countdown reaches zero, its window is destroyed. Also create a main
window with a "close all" button.
"""
def __init__(self):
## create GUI
# main window
self.root = Tk()
self.root.title('AVC Tk countdown example')
self.frame = Frame(self.root,name='countdown',width=350,height=50)
self.frame.pack(expand=1)
# close all button
self.button = Button(self.frame,name='close_all',text='CLOSE ALL WINDOWS')
self.button.place(relx=0.5,rely=0.5,anchor=CENTER)
# terminate program at toplevel window destroy: connect toplevel
# destroy signal to termination handler.
self.root.bind_class('Toplevel','',lambda event: self.root.quit())
# create the first countdown after avc_init call
self.root.after(FIRST_COUNT_DELAY,self.new_countdown)
# close all button connected variable
self.close_all = False
def new_countdown(self,count_start=10):
"Create a new countdown"
# create a new countdown
Countdown(count_start)
# autocall after a random delay
self.root.after(randint(1,MAX_CREATION_PERIOD),self.new_countdown)
def close_all_changed(self,value):
"Terminate program at 'close all' button pressing"
self.root.quit()
#### MAIN
example = Example() # instantiate the application
example.avc_init() # connect widgets with variables
mainloop() # run Tk event loop until quit
#### END