easeInOutQuart

easeInOutQuart is a timing function used in animation to control the rate of change of a property over time. It is characterized by a smooth acceleration at the beginning of the animation and a smooth deceleration at the end. The "quart" in its name refers to the fact that the function is based on a quartic polynomial (a polynomial of degree four).

The mathematical formula for easeInOutQuart is typically expressed as follows: if t is the time elapsed from 0 to 1, then the output value is 3t^4 - 2t^3 for the first half of the animation (0 <= t < 0.5) and 1 - ((-2t + 2)^4) / 2 for the second half (0.5 <= t <= 1). This formula results in a curve that starts slowly, speeds up in the middle, and then slows down again towards the end.

This type of easing is often preferred for visual appeal as it mimics natural motion more closely than a linear transition. It avoids the abrupt start and stop of a linear ease and the sometimes jarring acceleration and deceleration of simpler easing functions like easeInQuad or easeOutQuad. Animations using easeInOutQuart appear more fluid and organic.

Implementations of easeInOutQuart are common in various animation libraries and frameworks across different programming languages, including JavaScript (e.g., in libraries like GreenSock Animation Platform - GSAP, or built-in browser APIs), CSS, and others. Developers use it to create engaging user interfaces, smooth transitions, and visually pleasing effects in web development and application design.