backIn backInOut backOut bounceIn bounceInOut bounceOut byName circularIn circularInOut circularOut cubicIn cubicInOut cubicOut def elasticIn elasticInOut elasticOut exponentialIn exponentialInOut exponentialOut linear quadraticIn quadraticInOut quadraticOut quarticIn quarticInOut quarticOut quinticIn quinticInOut quinticOut sinusoidalIn sinusoidalInOut sinusoidalOut stepped

quarticInOut detail::quarticInOutEasing quarticInOut {} inlineconstexpr Quartic polynomial easing with strong acceleration and deceleration. The quarticInOut easing function combines strong acceleration and deceleration for confident, purposeful motion. More dramatic than cubic, less extreme than quintic. Motion profile: First half: Strong acceleration (t⁴) Midpoint: Maximum velocity Second half: Strong deceleration Creates pronounced S-curve This easing is appropriate for: Emphasized transitions: Strong acceleration and deceleration Current design patterns: Strong deceleration curves Important animations: Focal transitions Medium durations: 300-600ms range Mathematically: Combines quarticIn for t < 0.5 and quarticOut for t >= 0.5 // Page transition with impact auto x = tweeny::from(0.0f) .to(1920.0f) .via(easing::quarticInOut) .during(45U) .build(); See also quarticIn For only strong acceleration quarticOut For only strong deceleration cubicInOut For gentler motion quinticInOut For more dramatic motion Visualize at https://easings.net/#easeInOutQuart