用pygame画一个圆

import sys, random, math, pygame
from pygame.locals import *
from datetime import datetime, date, time

pygame.init()

screen = pygame.display.set_mode((600, 500))
pygame.display.set_caption("Analog Clock Demo")
#screen.fill((0, 0, 100))

pos_x = 300
pos_y = 250
radius = 250
angle = 360

while True:
for event in pygame.event.get():
if event.type in (QUIT, KEYDOWN):
sys.exit()
screen.fill((0, 0, 200))
color = 255, 255, 0
position = 300, 250
radius = 100
width = 10

pygame.draw.circle(screen, color, position, radius, width)
pygame.display.update()