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

circularInOut detail::circularInOutEasing circularInOut {} inlineconstexpr Circular easing with smooth acceleration and deceleration. The circularInOut easing function uses circular curves for both acceleration and deceleration, creating balanced motion suitable for general UI work. This is a popular all-purpose easing. Motion profile: First half: Circular acceleration Midpoint: Maximum velocity Second half: Circular deceleration Creates smooth S-curve This easing is appropriate for: All-purpose UI animations: Buttons, dialogs, drawers Material Design: Recommended in Google's motion guidelines Business applications: Productivity tools, enterprise apps Default animation choice: Safe, versatile motion curve CircularInOut is often recommended as a starting point for animations because it provides polish without being too subtle or too dramatic. // Modal dialog appearance auto opacity = tweeny::from(0.0f) .to(1.0f) .via(easing::circularInOut) .during(25U) .build(); See also circularIn For only acceleration circularOut For only deceleration quadraticInOut For gentler motion cubicInOut For more dramatic motion Visualize at https://easings.net/#easeInOutCirc