Question

I’m currently working on sprite sheet tool in python that exports the organization into an xml document but I’ve run into some problems trying to animate a preview. I’m not quite sure how to time the frame rate with python. For example, assuming I have all of my appropriate frame data and drawing functions, how would I go about coding the timing to display it at 30 frames per second (or any other arbitrary rate).

Answer 1

The easiest way to do it is with Pygame:

import pygame
pygame.init()

clock = pygame.time.Clock()
# or whatever loop you're using for the animation
while True:
    # draw animation
    # pause so that the animation runs at 30 fps
    clock.tick(30)

The second easiest way to do it is manually:

import time

FPS = 30
last_time = time.time()
# whatever the loop is...
while True:
    # draw animation
    # pause so that the animation runs at 30 fps
    new_time = time.time()
    # see how many milliseconds we have to sleep for
    # then divide by 1000.0 since time.sleep() uses seconds
    sleep_time = ((1000.0 / FPS) - (new_time - last_time)) / 1000.0
    if sleep_time > 0:
        time.sleep(sleep_time)
    last_time = new_time