如何在python中滚动带有图片的画布？

import pygame
from pygame.locals import *

# 初始化pygame
pygame.init()

# 设置画布大小
width, height = 800, 600
screen = pygame.display.set_mode((width, height))

# 加载图片
image = pygame.image.load("image.jpg")

# 设置画布初始位置
x, y = 0, 0

# 设置滚动速度
scroll_speed = 5

# 游戏主循环
running = True
while running:
    # 清空画布
    screen.fill((0, 0, 0))

    # 绘制图片
    screen.blit(image, (x, y))

    # 更新画布
    pygame.display.flip()

    # 处理事件
    for event in pygame.event.get():
        if event.type == QUIT:
            running = False
        elif event.type == KEYDOWN:
            # 按下方向键时滚动画布
            if event.key == K_LEFT:
                x += scroll_speed
            elif event.key == K_RIGHT:
                x -= scroll_speed
            elif event.key == K_UP:
                y += scroll_speed
            elif event.key == K_DOWN:
                y -= scroll_speed

# 退出pygame
pygame.quit()