from math import sqrt
from tkinter import *
def mdp(E):
    D=[]
    x1=E[0][0]
    x2=E[len(E)-1][0]
    y1=E[0][1]
    y2=E[len(E)-1][1]
    for i in range(1, len(E)-1,1):
        dist=abs((y2-y1)*E[i][0]-(x2-x1)*E[i][1]+x2*y1-y2*x1)/\
             (sqrt((y2-y1)**2+(x2-x1)**2))
        #print(dist)
        D.append((dist,E[i][0],E[i][1],i))
    D.sort(reverse=1)
    return D[0]

def new_line(N):
    for i in range (len(N)-1):
        canvas.create_line(N[i][0], N[i][1], N[i+1][0], N[i+1][1], width=5, fill='red')
def click(click_event):
    global prev
    try:
        canvas.create_line(prev.x, prev.y, click_event.x, click_event.y, width=2, fill='green')
        S.append((click_event.x,click_event.y))
    except:
        prev = click_event
        S.append((click_event.x,click_event.y))
        return
    prev = click_event
def action(K):
    print('iter')
    epsilon = int(eps.get())
    print(N)
    #print(mdp(K)[0])
    if len(K)<=2:
        for i in K:
            if i not in N:
                N.append(i)
                print('add 2 points')
        new_line(N)
    elif mdp(K)[0]<epsilon:
        pass
    else:
        N.append(mdp(K)[1:3])
        action(K[:mdp(K)[3]])
        action(K[mdp(K)[3]:])

master = Tk()
canvas = Canvas(master, width=600, height=300)
canvas.pack(padx=20, pady=20)
canvas.bind('<Button-1>', click)
but1=Button(master,text='show',command=lambda K=S: action(S));but1.pack()
eps=Entry(master,width=5);eps.pack()

S=[]
N=[]

mainloop()