pygame-：如何使用input（）值来保持原始形状并在它撞到墙壁时反弹

Question

import pygame
import sys

pygame.init()
screen = pygame.display.set_mode([640,480])
screen.fill([255,255,255])

# A transparent surface with per-pixel alpha.
circle = pygame.Surface((60, 60), pygame.SRCALPHA)
# Draw a circle onto the `circle` surface.
pygame.draw.circle(circle, [255,0,0], [30, 30], 30)

x = 50
y = 50
x_speed = 5
y_speed = 5

done = False
while not done:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            done = True

    pygame.time.delay(20)
    screen.fill((40, 40, 40))
    x = x + x_speed
    y = y + y_speed
    if x > screen.get_width() - 60 or x < 0:
        x_speed = -x_speed
    if y > screen.get_height() - 60 or y < 0:
        y_speed = -y_speed
    # Now blit the surface.
    screen.blit(circle, [x, y]) 
    pygame.display.flip()

pygame.quit()
sys.exit()

我知道[30,30]部分是圆的原点位置坐标。

pygame.draw.circle(circle, [255,0,0], [30, 30], 30)

如果我更改[30,30]的值，则圆圈会被截断而不会改变 原始坐标。

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当我不改变形状并使球飞溅时，它会弹出而不会与窗户壁碰撞。

当我变形并溅起球时，它会与窗户碰撞并弹出。

让我知道如何保持圆圈的形状并使圆圈与窗口碰撞并弹出。