import pygame
from pygame.sprite import Sprite

class Man(Sprite):

    def __init__(self, ai_settings, screen):
        """初始化人，并设置其起始位置"""
        super(Man, self).__init__()
        self.screen = screen
        self.ai_settings = ai_settings

        # 加载人的图像，并获取其rect
        self.image = pygame.image.load('images/man.png')
        self.rect = self.image.get_rect()
        self.screen_rect = screen.get_rect()

        # 在屏幕底部中央启动
        self.rect.centerx = self.screen_rect.centerx
        self.rect.bottom = self.screen_rect.bottom
        
        # 存储人中心的十进制值
        self.center = float(self.rect.centerx)
        
        # 运动
        self.moving_right = False
        self.moving_left = False
        
    def center_man(self):
        """在窗口上使人居中"""
        self.center = self.screen_rect.centerx
        
    def update(self):
        """根据移动标志更新人位置"""
        # 更新人的中心值，而不是rect
        if self.moving_right and self.rect.right < self.screen_rect.right:
            self.center += self.ai_settings.man_speed_factor
        if self.moving_left and self.rect.left > 0:
            self.center -= self.ai_settings.man_speed_factor
            
        # 从self.center更新rect对象
        self.rect.centerx = self.center

    def blitme(self):
        """在当前位置绘制人"""
        self.screen.blit(self.image, self.rect)