Easing

A type of easing function, described from an algorithmic classification and acceleration pattern, providing the sense of motion.

“Nothing in nature moves linearly from one point to another. In reality, things tend to accelerate or decelerate as they move. Our brains are wired to expect this kind of motion, so when animating you should use this to your advantage. Natural motion makes your users feel more comfortable with your apps, which in turn leads to a better overall experience.” - Paul Lewis

The algorithmic classification of an ease.

The acceleration pattern of an ease.

An easing function that determines the path used to get from point A to point B by calculating the position given a specific point in time.

These easing functions are based upon Robert Penner’s Easing Functions. A visualized cheat-sheet of these functions can be found at easings.net.

The aspect of time is crucial to motion — things change over time. Nothing can move in “zero time”, or be in two places at once. In other words, a position needs time to change, and it can have only one value at a specific point in time.

Because position and time have this one-to-one relationship, we can say that position is a function of time. This means that, given a specific point in time, we can find one, and only one, corresponding position.

- Robert Penner