# Tk_plot_polygon.py

# Tk_plot_polygon.py

import math
#change to tkinter for python3
from Tkinter import *
#from PIL import Image, ImageDraw
#import Image, ImageTk

list_of_points=[(20, 20), (20, 120), (100, 60), (40, 280), (120, 280), (140, 60), (160, 80), (140, 280), (200, 280), (200, 180), (220, 280), (300, 280), (220, 160), (280, 100), (220, 100), (200, 140), (220, 40), (180, 60), (200, 20)]

coord=[]
mvPt = 0
mouse_drag = 0
unit = 20

def snapto(event):
    return (event.x+unit/2)/unit*unit, (event.y+unit/2)/unit*unit

def mouse_coords(event):
    x, y = snapto(event)
    if x and y:
        canvas.delete('mouse_pos')
        canvas.create_text(570, 20, text=[x,y], tag='mouse_pos')
        canvas.create_oval(x-6, y-6, x+6, y+6, outline='black', tag='mouse_pos')
        if mvPt:
            list_of_points[mvPt-1] = (x,y)
        func_Draw_polygons()

def draw_polygons(event):
    x, y = snapto(event)
    if x and y:
        list_of_points.append((x, y))
        func_Draw_polygons()

def mouse_release(event):
    global mvPt
    mvPt = 0
    print
    print list_of_points

def move_point(event):
    global mvPt
    x, y = snapto(event)
    if (x,y) in list_of_points:
        mvPt = list_of_points.index((x,y))+1

def delete_last_point(null):
    if list_of_points:
        list_of_points.pop(-1)
        func_Draw_polygons()

def func_Draw_polygons():
    canvas.delete('main')

    for pt in list_of_points:
        x, y =  pt
        x1, y1 = (x - 1), (y - 1)
        x2, y2 = (x + 1), (y + 1)
        canvas.create_oval(x1, y1, x2, y2, fill='green', outline='green', width=5, tag='main')

    numberofPoint=len(list_of_points)
    # Draw polygon
    if numberofPoint>2:
        canvas.create_polygon(list_of_points, fill='', outline='green', width=2, tag='main')
    elif numberofPoint==2 :
        canvas.create_line(list_of_points, tag='main')

    # ImageDraw.ImageDraw.polygon((list_of_points), fill=None, outline=None)

root = Tk()

canvas = Canvas(root,height=600,width=600)
canvas.pack()

root.bind("<Button 1>", draw_polygons)
root.bind("<ButtonRelease-1>", mouse_release)
root.bind("<ButtonRelease-3>", mouse_release)
root.bind("<Button 3>", move_point)
root.bind("<Motion>", mouse_coords)
root.bind("<space>", delete_last_point)

func_Draw_polygons()

root.mainloop()