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

bounceInOut detail::bounceInOutEasing bounceInOut {} inlineconstexpr Bounce easing with bouncing at both start and end. The bounceInOut easing function combines reverse bouncing at the start with natural bouncing at the end. The motion bounces with increasing height initially, accelerates through the middle, then bounces to rest at the target. Motion profile: First half: Bounces with increasing amplitude (bounceIn) Midpoint: Smooth transition Second half: Bounces with decreasing amplitude (bounceOut) Creates playful, impact-based motion at both ends This easing is appropriate for: Playful transitions: Fun, energetic scene changes Game UI: High-energy, cartoon-style interfaces Children's applications: Whimsical, entertaining motion Attention-grabbing effects: Elements that need maximum personality BounceInOut is quite dramatic and can feel excessive for business applications, productivity tools, and enterprise software where subtlety is preferred. The dual bouncing works best in contexts where playfulness is a design goal. // Playful modal transition auto scale = tweeny::from(0.0f) .to(1.0f) .via(easing::bounceInOut) .during(60U) .build(); See also bounceIn For bouncing only at the start bounceOut For bouncing only at the end (more commonly useful) elasticInOut For spring-like alternative Visualize at https://easings.net/#easeInOutBounce