如何在PyGame中旋转对象

Question

Ok. So i have so far found a code for a snake game on python. So far the game is working but now I have started changing the BNP's from squares to circular objects and what I want to know is how to rotate the body and head at the input of lets say the arrow keys making the body parts change. I don't know if this is possible, well it is, but not in the way I want it. Ill post the code below.

import pygame
import sys
from pygame.locals import *
import random
import time

left = -20
right = 20
up = 10
down = -10

size = width, height = 640, 480
block_size = 20

class Food:
    def __init__(self, screen, snake):
        self.snake = snake
        self.screen = screen
        self.image = pygame.image.load('food.bmp').convert()
        self.spawn()

    def spawn(self):
        collision = True

        while collision:
            random_x = random.randrange(0, width, block_size)
            random_y = random.randrange(0, height, block_size)

           collision = False

            for each in snake.parts:
                if each.position.x == random_x and each.position.y == random_y:
                    collision = True
                    break

        self.position = self.image.get_rect().move(random_x, random_y)

        self.blit()

    def blit(self):
        self.screen.blit(self.image, self.position)

class Part:
    def __init__(self, x=0, y=0, direction=right):
        self.direction = direction
    self.image = pygame.image.load('part.bmp').convert()
    self.position = self.image.get_rect().move(x, y)
    self.speed = block_size

def change_direction(self, direction):
    if self.direction + direction == 0:
            return

        self.direction = direction

    def move(self):
        if self.position.x >= width - block_size and self.direction == right:
            return False

        if self.position.y >= height - block_size and self.direction == down:
            return False

        if self.position.x <= 0 and self.direction == left:
            return False

    if self.position.y <= 0 and self.direction == up:
        return False

        if self.direction == up:
            self.position = self.position.move(0, -self.speed)
        elif self.direction == down:
            self.position = self.position.move(0, self.speed)
        elif self.direction == right:
            self.position = self.position.move(self.speed, 0)
        elif self.direction == left:
            self.position = self.position.move(-self.speed, 0)

        return True

class Parthead:
    def __init__(self, x=0, y=0, direction=right):
        self.direction = direction
        self.image = pygame.image.load('parthead.bmp').convert()
        self.position = self.image.get_rect().move(x, y)
        self.speed = block_size

    def change_direction(self, direction):
        if self.direction + direction == 0:
            return

        self.direction = direction

    def move(self):
        if self.position.x >= width - block_size and self.direction == right:
            return False

        if self.position.y >= height - block_size and self.direction == down:
            return False

        if self.position.x <= 0 and self.direction == left:
            return False

        if self.position.y <= 0 and self.direction == up:
            return False

        if self.direction == up:
            self.position = self.position.move(0, -self.speed)
        elif self.direction == down:
            self.position = self.position.move(0, self.speed)
        elif self.direction == right:
        self.position = self.position.move(self.speed, 0)
        elif self.direction == left:
            self.position = self.position.move(-self.speed, 0)

        return True

class Snake:

    def __init__(self, screen, x=0, y=0):
        self.screen = screen
        self.head = Parthead(x, y)
        self.direction = right
        self.length = 1
        self.parts = []
        self.parts.append(self.head)
        self.extend_flag = False

    def change_direction(self, direction):
        self.direction = direction

    def move(self, food):
        new_direction = self.direction
        old_direction = None
        new_part = None

        if self.extend_flag:
            last_part = self.parts[-1]
            new_part = Part(last_part.position.x, last_part.position.y, last_part.direction)

        for each in self.parts:
            old_direction = each.direction
            each.change_direction(new_direction)

            if not each.move():
               return False

            new_direction = old_direction

        if self.extend_flag:
            self.extend(new_part)

        for each in self.parts[1:]:
            if each.position.x == self.head.position.x and each.position.y == self.head.position.y:
                return False

        if food.position.x == self.head.position.x and food.position.y == self.head.position.y:
            food.spawn()
            self.extend_flag = True



        return True



    def extend(self, part):
        self.parts.append(part)
        self.length += 1
        self.extend_flag = False

    def blit(self):
        for each in self.parts:
            self.screen.blit(each.image, each.position)


black = 0, 0, 0

pygame.init()
pygame.display.set_caption('Snake by Jonathan Dring')
screen = pygame.display.set_mode(size)

game = True

while True:
    snake = Snake(screen)
    food = Food(screen, snake)

    while True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT: sys.exit()

            if event.type == KEYDOWN:
                if (event.key == K_RIGHT):
                    snake.change_direction(right)
                elif (event.key == K_LEFT):
                    snake.change_direction(left)
                elif (event.key == K_UP):
                    snake.change_direction(up)
                elif (event.key == K_DOWN):
                    snake.change_direction(down)
                elif (event.key == K_SPACE):
                    snake.extend_flag = True

        if not snake.move(food):
            game = False
            break

        screen.fill(black)
        print ("Snake - The Game")
        snake.blit()
        food.blit()
        pygame.display.update()
        pygame.time.delay(100)

    while not game:
        for event in pygame.event.get():
            if event.type == pygame.QUIT: sys.exit()

            if event.type == KEYDOWN:
                if (event.key == K_SPACE):
                    game = True
                elif (event.key == K_RETURN):
                    game = True
                elif event.key == K_ESCAPE:
                    pygame.quit()






        background = pygame.image.load('gameover.bmp').convert()
        screen.blit(background, (0, 0))
        pygame.display.flip()
        pygame.time.delay(100)

If you know how to do it please reply!

Answer 1

Seeing as there is still no answer, here is how to rotate a sprite. Naturally, you can only rotate the rect of the sprite. This function, when added to a sprite, will make it rotate when you send it an angle to point in:

def rotate(self,angle):
    self.rect = pygame.transform.rotate(self.rect, angle)

This should work.