如何在Pygame中制作一個循環倒數計時器？

Question

如何在 Pygame 中進行這種倒計時？ （我正在尋找如何使圓的周長減小，這就是問題所在，因為顯示時間並不難）請記住，圓的周長和顯示的時間應該與每個成比例其他。

Answer 1

只需使用pygame.draw.arc並根據計數器指定stop_angle參數：

percentage = counter/100
end_angle = 2 * math.pi * percentage
pygame.draw.arc(window, (255, 0, 0), arc_rect, 0, end_angle, 10)

---

最小的例子：

import pygame
import math

pygame.init()
window = pygame.display.set_mode((200, 200))
clock = pygame.time.Clock()
font = pygame.font.SysFont(None, 100)
counter = 100
text = font.render(str(counter), True, (0, 128, 0))

timer_event = pygame.USEREVENT+1
pygame.time.set_timer(timer_event, 1000)

def drawArc(surf, color, center, radius, width, end_angle):
    arc_rect = pygame.Rect(0, 0, radius*2, radius*2)
    arc_rect.center = center
    pygame.draw.arc(surf, color, arc_rect, 0, end_angle, width)

run = True
while run:
    clock.tick(60)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False
        elif event.type == timer_event:
            counter -= 1
            text = font.render(str(counter), True, (0, 128, 0))
            if counter == 0:
                pygame.time.set_timer(timer_event, 0)                

    window.fill((255, 255, 255))
    text_rect = text.get_rect(center = window.get_rect().center)
    window.blit(text, text_rect)
    drawArc(window, (255, 0, 0), (100, 100), 90, 10, 2*math.pi*counter/100)
    pygame.display.flip()

pygame.quit()
exit()

遺憾的是，寬度> 1 的pygame.draw.arc的質量很差。 然而，這可以改進，使用cv2和cv2.ellipse ：

import pygame
import cv2
import numpy

pygame.init()
window = pygame.display.set_mode((200, 200))
clock = pygame.time.Clock()
font = pygame.font.SysFont(None, 100)
counter = 100
text = font.render(str(counter), True, (0, 128, 0))

timer_event = pygame.USEREVENT+1
pygame.time.set_timer(timer_event, 1000)

def drawArcCv2(surf, color, center, radius, width, end_angle):
    circle_image = numpy.zeros((radius*2+4, radius*2+4, 4), dtype = numpy.uint8)
    circle_image = cv2.ellipse(circle_image, (radius+2, radius+2),
        (radius-width//2, radius-width//2), 0, 0, end_angle, (*color, 255), width, lineType=cv2.LINE_AA) 
    circle_surface = pygame.image.frombuffer(circle_image.flatten(), (radius*2+4, radius*2+4), 'RGBA')
    surf.blit(circle_surface, circle_surface.get_rect(center = center))

run = True
while run:
    clock.tick(60)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False
        elif event.type == timer_event:
            counter -= 1
            text = font.render(str(counter), True, (0, 128, 0))
            if counter == 0:
                pygame.time.set_timer(timer_event, 0)                

    window.fill((255, 255, 255))
    text_rect = text.get_rect(center = window.get_rect().center)
    window.blit(text, text_rect)
    drawArcCv2(window, (255, 0, 0), (100, 100), 90, 10, 360*counter/100)
    pygame.display.flip()

pygame.quit()
exit()