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

backInOut detail::backInOutEasing backInOut {} inlineconstexpr Easing function combining anticipation at the start and overshoot at the end. The backInOut easing function creates a dramatic motion curve by pulling back before the start (anticipation), accelerating through the middle, then overshooting past the target before settling (spring-back). This combines the effects of both backIn and backOut for maximum expressiveness. This easing creates highly dynamic animations suitable for: Attention-grabbing transitions that need maximum visual interest Character animations requiring wind-up and follow-through Scene transitions with dramatic flair Emphasizing both the start and end states of an animation The dual overshoot (negative at start, positive at end) makes this one of the most expressive easings, but it should be used judiciously as it can feel exaggerated if overused. It works best for focal animations rather than ambient motion. Note The animation will have values outside the start-to-target range at both ends. During the first half, values will dip below the start; during the second half, values will exceed the target before settling. // Create a dramatic page transition auto position = tweeny::from(-100.0f) .to(100.0f) .via(easing::backInOut) .during(90U) .build(); // Position will go below -100.0f at start and above 100.0f near end See also backIn For only anticipation without overshoot backOut For only overshoot without anticipation elasticInOut For a more extreme oscillating version Visualize at https://easings.net/#easeInOutBack