How do I use a PyGame timer event? How to add a clock to a pygame screen using a timer?

Solution 1:

The number of milliseconds since pygame.init() can be retrieved by pygame.time.get_ticks(). See pygame.time module.

Furthermore in pygame exists a timer event. Use pygame.time.set_timer() to repeatedly create an USEREVENT. e.g.:

time_delay = 500 # 0.5 seconds
timer_event = pygame.USEREVENT + 1
pygame.time.set_timer(timer_event , time_delay )

Note, in pygame customer events can be defined. Each event needs a unique id. The ids for the user events have to start at pygame.USEREVENT. In this case pygame.USEREVENT+1 is the event id for the timer event.

Receive the event in the event loop:

running = True
while running:

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

         elif event.type == timer_event:
             # [...]

The timer event can be stopped by passing 0 to the time parameter.

See the example:

import pygame

pygame.init()
window = pygame.display.set_mode((200, 200))
clock = pygame.time.Clock()
font = pygame.font.SysFont(None, 100)

counter = 0
text = font.render(str(counter), True, (0, 128, 0))

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

# main application loop
run = True
while run:
    clock.tick(60)

    # event loop
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False
        elif event.type == timer_event:
            # recreate text
            counter += 1
            text = font.render(str(counter), True, (0, 128, 0))

    # clear the display
    window.fill((255, 255, 255))

    # draw the scene
    text_rect = text.get_rect(center = window.get_rect().center)   
    window.blit(text, text_rect)

    # update the display
    pygame.display.flip()