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

bounceIn detail::bounceInEasing bounceIn {} inlineconstexpr Bounce easing simulating a ball bouncing with increasing height at the start. The bounceIn easing function creates a bouncing effect before the animation begins, like a ball dropped from above that bounces progressively higher before launching into the main motion. This is the reverse of bounceOut's natural physics. Characteristics: Multiple discrete "bounces" at the start Each bounce is higher than the previous Creates anticipation through impact-based motion Less commonly used than bounceOut This easing works well for: Landing preparation: Elements about to drop into place Impact anticipation: Building up to a collision Reverse playback effects: Bounced animations played backward Stylized entrances: Cartoon-style wind-up effects BounceIn is less intuitive than bounceOut because it reverses natural physics (balls don't normally bounce higher each time). Consider backIn for more natural anticipation. // Element that bounces before sliding in auto position = tweeny::from(0.0f) .to(200.0f) .via(easing::bounceIn) .during(50U) .build(); See also bounceOut For natural ball-drop bouncing at the end bounceInOut For bouncing at both start and end backIn For simpler anticipation without discrete impacts Visualize at https://easings.net/#easeInBounce