2
\$\begingroup\$

I made a little application (for windows, but easily compatible with linux by just changing some lines) for displaying a little network graph using Tkinter and Python. I basically draw lines higher and higher while the ping is still running, and when the soft receive the ping response I reset the line height.

My issue is while updating my canvas. Basically the code make a Tk.after call, but I think it might be a little bit too slow/random. I am looking for a way to be sure this function will run exactly every n milliseconds. I saw something like this on PyGame and maybe I am not doing it right.

#!/usr/bin/env python2
# -*- coding:utf-8 -*-

"""
Graphic network graph.

Displays a simple network graph representing how fast your ping is. This tool
is useful for people having some random connection and looking for a tool to
represent the state of their ping.
"""

from Tkinter import *
import socket
import threading
import random
import time
import subprocess

__author__ = "Axel Martin"
__copyright__ = "Copyright 2016, Axel Martin"
__credits__ = ["Axel Martin"]
__licence__ = "GPL"
__version__ = "0.1"
__maintainer__ = "Axel Martin"
__status__ = "Prototype"


class Config:
    """Configuration container."""
    hostname = "foobar.fr"
    updater_rate = 5 # in milliseconds
    ticks = 2
    low_bound, high_bound = 50, 100

class Pingger:
    """Ping tool.

    The purpose of this class is to give abstraction of the ping command line.
    """

    def __init__(self, config):
        self.config = config

        self.reseted = False

        self.alive = True
        self.thread = threading.Thread(target=self.pinger)
        self.thread.start()

    def has_been_reset(self):
        if self.reseted:
            self.reseted = False
            return True
        return False

    def stop(self):
        self.alive = False

    def pinger(self):
        while True:
            subprocess.check_output(["ping", "-n", "1", self.config.hostname])
            self.reseted = True


class App:
    """Tkinter application handler

    Create the window and manage the display on the canvas.
    """

    HEIGHT, WIDTH = 75, 75

    def __init__(self, config):
        self.config = config

        # Interface setup
        self.root = Tk()
        self.canvas = Canvas(self.root, width=self.WIDTH, height=self.HEIGHT)
        self.canvas.pack()
        self.canvas.create_line(0, self.config.low_bound, self.WIDTH - 1, self.config.low_bound, fill="orange", width=2)

        # Drawer helper
        self.pingger = Pingger(self.config)
        self.last_tick_height = 0

        # Updater setup
        self.alive = True
        self.thread = threading.Thread(target=self.update)
        self.thread.start()

    def update(self):
        for offset in range(self.config.ticks + 1, 1, -1):
            self.draw_line(offset)

        # Lines moving
        lines = list(self.canvas.find_withtag("spike"))
        while len(lines) > self.WIDTH:
            self.canvas.delete(lines.pop(0))
        for l in lines:
            x0, y0, x1, y1 = self.canvas.coords(l)
            self.canvas.coords(l, x0 - self.config.ticks, y0, x1 - self.config.ticks, y1)

        # Recall in 10ms
        if self.alive:
            self.root.after(self.config.updater_rate, self.update)

    def draw_line(self, offset):
        if self.pingger.has_been_reset():
            self.last_tick_height = 0
        self.last_tick_height += 1

        if self.last_tick_height * self.config.updater_rate < self.config.low_bound:
            fill = "green"
        elif self.last_tick_height * self.config.updater_rate > self.config.high_bound:
            fill = "red"
        else:
            fill = "orange"

        self.canvas.create_line(self.WIDTH - offset, self.HEIGHT - 1, self.WIDTH - offset,
            self.HEIGHT - self.last_tick_height, tag="spike", fill=fill)

    def stop(self):
        self.alive = False
        self.pingger.stop()

    def start(self):
        self.root.mainloop()

c = Config()
a = App(c)
a.start()

# Passing this point the application closed.
a.stop()
\$\endgroup\$

1 Answer 1

1
\$\begingroup\$

Modyifing the object while getting a value

def has_been_reset(self):
    if self.reseted: 
        self.reseted = False 
        return True
    return False

The method name looks like a question "has the Pinger been reset?" bit it also changes the reset flag going against expactation and single responsability principle.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.