# -*- coding: utf-8 -*-
"""
__author__= 'Du'
__creation_time__= '2018/1/4 17:03'
"""

import sys
import pygame
from pygame.locals import *


def play_ball():
    pygame.init()
    # 視窗大小
    window_size = (width, height) = (1000, 700)
    # 小球執行偏移量[水平，垂直]，值越大，移動越快
    speed = [2, 1]
    # 視窗背景色RGB值
    color_black = (50,205,0)
    # 設定視窗模式
    screen = pygame.display.set_mode(window_size)
    # 設定視窗標題
    pygame.display.set_caption('運動的小球')
    # 載入小球圖片
    ball_image = pygame.image.load("test_circle.png")
    # 獲取小球圖片的區域開狀
    ball_rect = ball_image.get_rect()

    while True:
        # 退出事件處理
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                sys.exit()

        # 使小球移動，速度由speed變數控制
        ball_rect = ball_rect.move(speed)

        # 當小球運動出視窗時，重新設定偏移量
        if (ball_rect.left < 0) or (ball_rect.right > width):
            speed[0] = - speed[0]
        if (ball_rect.top < 0) or (ball_rect.bottom > height):
            speed[1] = - speed[1]

        # 填充視窗背景  # 否則小球的運動軌跡會留下來
        screen.fill(color_black)
        # 在背景Surface上繪製 小球
        screen.blit(ball_image, ball_rect)
        # 更新視窗內容
        pygame.display.update()


if __name__ == '__main__':
    play_ball()