snake.py

import sys 
import random 
from PIL import Image, ImageTk 
from tkinter import Tk, Frame, Canvas, ALL, NW 

WIDTH = 300 
HEIGHT = 300 
DOT_SIZE = 10 
RAND_POS = 27 
DELAY = 100 

class Board(Canvas):
    
    def __init__(self,parent):
        super().__init__(width=WIDTH, height=HEIGHT,background='black',highlightthickness=0) 

        self.parent = parent
        self.ini_game()
        self.pack() 

    def ini_game(self):
        self.left = False 
        self.right = True 
        self.up = False 
        self.down = False 
        self.in_game = True 

        self.dot_x = 100 
        self.dot_y = 190 

        try: 
            self.ibody = Image.open('dot.png') 
            self.body = ImageTk.PhotoImage(self.ibody)
            self.ihead = Image.open('head.png') 
            self.head = ImageTk.PhotoImage(self.ihead)
            self.idot = Image.open('dot.png') 
            self.dot = ImageTk.PhotoImage(self.idot)

        except IOError as e:
            print(str(e))
            sys.exit(1) 

        self.focus_get() 
        self.create_objects()
        self.bind_all('<Key>',self.on_key_pressed)
        self.after(DELAY,self.on_time)

    def create_objects(self):

        self.create_image(self.dot_x, self.dot_y, image=self.dot, anchor=NW, tag='dot')
        self.create_image(50, 50, image=self.head, anchor=NW, tag='head')
        self.create_image(40, 50, image=self.body, anchor=NW, tag='body')
        self.create_image(30, 50, image=self.body, anchor=NW, tag='body') 
    
    def check_dot(self):
        dot = self.find_withtag('dot')
        head = self.find_withtag('head') 

        x1, y1, x2 , y2 = self.bbox(head) 
        overlap = self.find_overlapping(x1, y1 , x2, y2) 

        for ovr in overlap:
            if dot[0] == ovr:
                x , y = self.coords(dot)
                self.create_image(x, y, image = self.body, anchor=NW, tag ='body') 
                self.locate_dot() 

    def locate_dot(self):
        dot = self.find_withtag('dot') 
        self.delete(dot[0]) 
        r = random.randint(0, RAND_POS) 
        self.dot_x = r * DOT_SIZE 
        r = random.randint(0, RAND_POS)
        self.dot_y = r * DOT_SIZE

        self.create_image(self.dot_x, self.dot_y, image = self.body, anchor=NW, tag ='dot')  

    def do_move(self):
        bodys = self.find_withtag('body') 
        head = self.find_withtag('head') 

        items = bodys + head 

        k=0
        while(k < len(items) - 1):
            c1 = self.coords(items[k]) 
            c2 = self.coords(items[k + 1]) 
            self.move(items[k], c2[0] -c1[0], c2[1] - c1[1]) 
            k += 1 

        if self.left: 
            self.move(head, -DOT_SIZE,0)

        if self.right: 
            self.move(head, DOT_SIZE,0)

        if self.up: 
            self.move(head, 0, -DOT_SIZE) 

        if self.down: 
            self.move(head, 0, DOT_SIZE) 

    def check_collisions(self):
        bodys = self.find_withtag('body')
        head = self.find_withtag('head')

        x1, y1, x2, y2 = self.bbox(head)
        overlap = self.find_overlapping(x1, y1, x2, y2)

        for body in bodys:
            for ovr in overlap:
                if body == ovr:
                    self.in_game = False

        if x1 < 0:
            self.in_game = False

        if x1 > WIDTH - DOT_SIZE:
            self.in_game = False

        if y1 < 0:
            self.in_game = False

        if y1 > HEIGHT - DOT_SIZE:
            self.in_game = False 

    def on_key_pressed(self, e):
        key = e.keysym 
        if key == 'Left' and not self.right:
            self.left = True 
            self.up = False 
            self.down = False
        
        if key == 'Right' and not self.left:
            self.right = True 
            self.up = False 
            self.down = False

        if key == 'Up' and not self.down:
            self.left = False 
            self.up = True 
            self.right = False

        if key == 'Down' and not self.up:
            self.down = True 
            self.left = False 
            self.right = False 

    def on_time(self):
        if self.in_game:
            self.check_collisions() 
            self.check_dot() 
            self.do_move() 
            self.after(DELAY,self.on_time)
        else:
            self.game_over()

    def game_over(self):
        self.delete(ALL) 
        self.create_text(self.winfo_width()/2, self.winfo_height()/2, text='Game Over',fill='White') 

class Snake(Frame):

    def __init__(self,parent):
        super().__init__(parent) 
        parent.title('Snake') 
        self.board = Board(parent) 
        self.pack() 

def main():
    root = Tk() 
    snake = Snake(root) 
    root.mainloop() 

if __name__ == "__main__":
    main()