如何添加边框

Question

我想添加一个边框，以便每当蛇碰到边框时，游戏都会停止。

我尝试使用pygame.draw.rect制作一个矩形，然后以某种方式制作一个边框，但实际上并没有用。游戏只是无法运行。

import random
import pygame


class cube(object):
    rows = 20
    w = 500
    def __init__(self,start,dirnx=1,dirny=0,color=(0,0,0)):
        self.pos = start
        self.dirnx = 1
        self.dirny = 0
        self.color = color


    def move(self, dirnx, dirny):
        self.dirnx = dirnx
        self.dirny = dirny
        self.pos = (self.pos[0] + self.dirnx, self.pos[1] + self.dirny)

    def draw(self, surface, eyes=False):
        dis = self.w // self.rows
        i = self.pos[0]
        j = self.pos[1]

        pygame.draw.rect(surface, self.color, (i*dis+1,j*dis+1, dis-2, dis-2))








class snake(object):
    body = []
    turns = {}
    def __init__(self, color, pos):
        self.color = color
        self.head = cube(pos)
        self.body.append(self.head)

    def move(self):
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()

            keys = pygame.key.get_pressed()

            for key in keys:
                if keys[pygame.K_LEFT]:
                    self.dirnx = -1
                    self.dirny = 0
                    self.turns[self.head.pos[:]] = [self.dirnx, self.dirny]

                elif keys[pygame.K_RIGHT]:
                    self.dirnx = 1
                    self.dirny = 0
                    self.turns[self.head.pos[:]] = [self.dirnx, self.dirny]

                elif keys[pygame.K_UP]:
                    self.dirnx = 0
                    self.dirny = -1
                    self.turns[self.head.pos[:]] = [self.dirnx, self.dirny]

                elif keys[pygame.K_DOWN]:
                    self.dirnx = 0
                    self.dirny = 1
                    self.turns[self.head.pos[:]] = [self.dirnx, self.dirny]

        for i, c in enumerate(self.body):
            p = c.pos[:]
            if p in self.turns:
                turn = self.turns[p]
                c.move(turn[0],turn[1])
                if i == len(self.body)-1:
                    self.turns.pop(p)
            else:
                if c.dirnx == -1 and c.pos[0] <= 0: c.pos = (c.rows-1, c.pos[1])
                elif c.dirnx == 1 and c.pos[0] >= c.rows-1: c.pos = (0,c.pos[1])
                elif c.dirny == 1 and c.pos[1] >= c.rows-1: c.pos = (c.pos[0], 0)
                elif c.dirny == -1 and c.pos[1] <= 0: c.pos = (c.pos[0],c.rows-1)
                else: c.move(c.dirnx,c.dirny)







    def addCube(self):
        tail = self.body[-1]
        dx, dy = tail.dirnx, tail.dirny

        if dx == 1 and dy == 0:
            self.body.append(cube((tail.pos[0]-1,tail.pos[1])))
        elif dx == -1 and dy == 0:
            self.body.append(cube((tail.pos[0]+1,tail.pos[1])))
        elif dx == 0 and dy == 1:
            self.body.append(cube((tail.pos[0],tail.pos[1]-1)))
        elif dx == 0 and dy == -1:
            self.body.append(cube((tail.pos[0],tail.pos[1]+1)))

        self.body[-1].dirnx = dx
        self.body[-1].dirny = dy


    def draw(self, surface):
        for i, c in enumerate(self.body):
            if i ==0:
                c.draw(surface, True)
            else:
                c.draw(surface)

def drawGrid(w, rows, surface):
    sizein = w // rows

    x = 0
    y = 0

    for l in range(rows):
        x = x + sizein
        y = y + sizein






def redrawWindow(surface):
    global rows, width, s, snack
    surface.fill((255,255,255))
    s.draw(surface)
    snack.draw(surface)
    drawGrid(width,rows, surface)
    pygame.display.update()



def randomSnack(rows, item):

    positions = item.body

    while True:
        x = random.randrange(rows)
        y = random.randrange(rows)
        if len(list(filter(lambda z:z.pos == (x,y), positions))) > 0:
            continue
        else:
            break

    return (x,y)



def main():
    global width, rows, s, snack
    width = 500
    rows = 20
    win = pygame.display.set_mode((width, width))
    s = snake((255,0,0), (10,10))
    snack = cube(randomSnack(rows, s), color=(0,0,0))
    flag = True

    clock = pygame.time.Clock()

    while flag:
        pygame.time.delay(50)
        clock.tick(7)
        s.move()
        if s.body[0].pos == snack.pos:
            s.addCube()
            snack = cube(randomSnack(rows, s), color=(0,0,0))

        for x in range(len(s.body)):
            if s.body[x].pos in list(map(lambda z:z.pos,s.body[x+1:])):
                print('Score: ', len(s.body))
                message_box('You Lost!', 'Play again...')
                s.reset((10,10))
                break


        redrawWindow(win)

main()

我想要一个与现在相同尺寸的边框，而我要做的就是每当蛇碰到它时，游戏停止，没什么。