[Tkinter] integrating plot to box

[zapad]

Good morning
I am meeting a problem in integrating a matplotlib graph into a tkinter gui:
The program works ok ,but it only appears in the shell console.
I tried to skim the docs on 'plots': there are a lot of sources, but the examples provided are complex and
I cannot identify simple principles adapted to my case.. hence my call:
This is a script that retrieves a .txt file and reproduces it into histograms representing
the frequency of letters... aka Cesar
I would like it to be displayed in my 'frame2'
in my source below I deactivated the ''plot' part
Thanks for helping

import tkinter 
from tkinter import*
import tkinter as tk
import re, string
from PIL import Image, ImageTk
from tkinter import filedialog
from unidecode import unidecode
from tkinter.scrolledtext import ScrolledText
import numpy as np
import matplotlib.pyplot as plt
#--------------------  Main Window
#----------------------------------------------------

root = tk.Tk()
root.title("            Python Crypto    esssai     GUI-005") # nom du script(((((((
root.geometry('1230x850+80+80') # taille box
#------------------------------------- creation------View gui -----------avec scroll   BOX1 
txt1 = ScrolledText(root, border=3,  bg="tan1",)
txt1.config(borderwidth=2, relief="raised", 
            height=10 , width=45, font=('Arial',12,'bold',))
txt1.place(x=30,y=90)
#-------------------------------------------  FRAME2 
frame2=Frame(root,bg = "grey25",width=500,  
             height=310,border=3, cursor = "target",highlightbackground='gray60',highlightthicknes=2)
frame2.place(x=600,y=80)
 
##def openFile():
##    tf = filedialog.askopenfilename(
##    initialdir="C:/Users/MainFrame/Desktop/",
##    title="Ouvrir fichier",
##    filetypes=(("Text Files", "*.txt"),))
####    pathh.insert(tk.END, tf)
##    tf = open(tf,mode="r", encoding="utf-8")
##    file_cont = tf.read()
##    komp = len(file_cont)
##    txt1.delete("1.0", "end-1c")
##    txt1.insert(tk.END, file_cont) 
##    tf.close()
#---------------------
#  Portion  PLOT
text_file = 'fr-txt.txt'
#text_file = txt1.get("1.0","end-1c") 
 
letters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
# Initialize the dictionary of letter counts: {'A': 0, 'B': 0, ...}
lcount = dict([(l, 0) for l in letters])
 
# Lecture du txt & compteles  occurences
for l in open(text_file).read():
    try:
        lcount[l.upper()] += 1
    except KeyError:
        # Ignore characters that are not letters
        pass
# The total number of letters
norm = sum(lcount.values())
text_file
#---------------------
fig = plt.figure()
ax = fig.add_subplot(111)
# The bar chart, with letters along the horizontal axis and the calculated
# letter frequencies as percentages as the bar height
x = range(26)
ax.bar(x, [lcount[l]/norm * 100 for l in letters], width=0.8,
       color='g', alpha=0.5, align='center')
ax.set_xticks(x)
ax.set_xticklabels(letters)
ax.tick_params(axis='x', direction='out')
ax.set_xlim(-0.5, 25.5)
# ------------------------------------Bouton actif
btnDec=Button(root,text=" go",bg='violetred', fg='goldenrod1',     )
btnDec.config(borderwidth=2, relief="raised",  width=12,
            height=1, font=('Arial',12,'bold',))
btnDec.place(x=840,y=480)
# ----------------------------------FINEX    ------------ 
tk.mainloop()

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