Tweener

Helper functions for easing and tweening

Installation

  pip install tweener

Reference

Tween object

Tween(begin, end, duration, easing, easing_mode, boomerang, loop, reps)

Parameter	Type	Description
begin	float	The beginning value of a property (default: 0.0)
end	float	The end value of a property (default: 1.0)
duration	int	The length of time that an animation takes to complete (default: 600 ms)
easing	Easing	The type of easing to apply. (default: Easing.LINEAR)
easing_mode	EasingMode	The mode of easing IN, OUT, IN_OUT, (default: IN)
boomerang	bool	Returns the animation back to its starting point and vice versa. (default: False)
loop	bool	Loops the animation. When used with boomerang, it does the back and forth animation. (default: False)
reps	int	Number of times the animation will be repeated. Zero means infinite. (default: 0)

Starts the animation

Tween().start()

Updates the animation state

Tween().update()

Pauses the animation

Tween().pause()

Resumes the animation

Tween().resume()

Easing types

LINEAR
SINE
QUAD
CUBIC
QUART
QUINT
EXPO
CIRC
BACK
ELASTIC
BOUNCE

Easing modes (except linear)

IN
OUT
IN_OUT

Example

I used Python version 3.10.5 and pygame 2.1.2

import pygame
from tweener import *

WIDTH = 600
HEIGHT = 600
TITLE = "Motion Demo"
FPS = 60

pygame.init()
canvas = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption(TITLE)

running = True
clock = pygame.time.Clock()

rect = pg.Rect(0, 100, 100, 100)
anim_y = Tween(begin=0, 
               end=WIDTH-100,
               duration=1000,
               easing=Easing.BOUNCE,
               easing_mode=EasingMode.OUT,
               boomerang=True, 
               loop=True)

while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        elif event.type == pygame.KEYUP:
            match event.key:
                case pygame.K_SPACE:
                    anim_y.start()
                case pygame.K_p:
                    anim_y.pause()
                case pygame.K_r:
                    anim_y.resume()

    canvas.fill(pygame.Color(255, 255, 255))

    # Update
    anim_y.update()
    rect.x = anim_y.value

    # Render
    pygame.draw.rect(canvas, (255, 0, 0), rect)
    pygame.display.flip()
    clock.tick(FPS)

pygame.quit()

Demo

demo.mp4

Contributing

Contributions are always welcome!

References

• https://easings.net/
• http://robertpenner.com/easing/