import tkinter as tk
from tkinter import *
from tkinter import ttk

import matplotlib.pyplot as plt
from matplotlib.figure import Figure
from matplotlib.backends.backend_tkagg import (FigureCanvasTkAgg, NavigationToolbar2Tk)

cnt=1

class Experiment:

    def __init__(self, root):
        self.gui(root)

    def gui(self, root): 

        self.bStart=Button(root,text="START",command=self.hello,font=('Arial','24'))
        self.bStart.pack()

        self.bStop=Button(root,text="STOP",command=exit,font=('Arial','24'))
        self.bStop.pack()

        self.fig=plt.figure()

        self.ax = self.fig.add_subplot(1,1,1)
        self.ax.set_xlim([0,20])
        self.ax.set_ylim([0,20])
        self.ax.plot([i for i in range(10)],[i for i in range(10)])

        self.canvas = FigureCanvasTkAgg(self.fig, master = root)
        self.canvas.draw()

        # placing the canvas on the Tkinter window
        self.canvas.get_tk_widget().pack()
               
        # creating the Matplotlib toolbar
        self.toolbar = NavigationToolbar2Tk(self.canvas, root)
        self.toolbar.update()
                             
        # placing the toolbar on the Tkinter window
        self.canvas.get_tk_widget().pack()

    def hello(self):
        global cnt
        cnt = cnt + 1
        self.ax.plot([i for i in range(20)],[i/cnt for i in range(20)])
        self.canvas.draw()
        print("Hello ")
        print(cnt)

 
if __name__ == '__main__': 
    cnt=1

    root=Tk()

    Experiment(root) 

    root.mainloop()