easing-functions

1.0.4 verified Sat May 09 auth: no python

A collection of basic easing functions for Python, implementing Robert Penner's easing equations. Current version 1.0.4, with infrequent releases and no active maintenance.

pip install easing-functions

Common errors

error ModuleNotFoundError: No module named 'easing' ↓

cause Trying to import from 'easing' instead of 'easing_functions'.

fix

Use 'from easing_functions import QuadEaseIn'.

error AttributeError: module 'easing_functions' has no attribute 'QuadEaseIn' ↓

cause Trying to access easing class incorrectly, perhaps via 'easing_functions.QuadEaseIn' without importing.

fix

Import explicitly: 'from easing_functions import QuadEaseIn'.

error TypeError: 'QuadEaseIn' object is not callable ↓

cause Forgetting to instantiate the class (e.g., QuadEaseIn instead of QuadEaseIn(...)).

fix

Instantiate: ease = QuadEaseIn(start=0.0, end=1.0, duration=1.0), then call ease(t).

Warnings

gotcha The instance is callable: ease_instance(t) returns the eased value at time t. t must be between 0 and duration, inclusive. ↓

fix Ensure t in [0, duration].

gotcha All easing classes require start, end, and duration parameters at instantiation. ↓

fix Instantiate as QuadEaseIn(start=0.0, end=10.0, duration=2.0).

gotcha The library provides no easing functions as plain functions; all are callable class instances. ↓

fix Use class instantiation and call the object.

Imports

easing_functions
wrong
```
from easing import ...
```
correct
```
from easing_functions import QuadEaseIn, QuadEaseOut, ...
```
Wrong module name: must be 'easing_functions', not 'easing'.

QuadEaseIn

wrong

from easing_functions.easing import QuadEaseIn

correct

from easing_functions import QuadEaseIn

Easing classes are directly under easing_functions, not a submodule.

Quickstart

Import an easing class (e.g., QuadEaseIn), instantiate with start, end, and duration, then call the instance with a time value (0 <= t <= duration) to get the eased value.

from easing_functions import QuadEaseIn
ease = QuadEaseIn(start=0.0, end=1.0, duration=1.0)
result = ease(0.5)
print(result)  # Output: 0.25