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

sinusoidalIn detail::sinusoidalInEasing sinusoidalIn {} inlineconstexpr Sinusoidal easing based on sine wave for smooth acceleration. The sinusoidalIn easing function uses a sine curve for acceleration, creating extremely smooth, natural motion. Based on trigonometric functions rather than polynomials. Characteristics: Very smooth acceleration Natural, organic feel No abrupt velocity changes Gentle but noticeable This easing is ideal for: Natural motion: Organic, flowing animations Smooth camera moves: Pans, zooms, orbits Elegant transitions: Refined, sophisticated feel Accessible animations: Gentle on motion sensitivity Mathematically: f(t) = 1 - cos(t * π/2) // Smooth camera pan auto x = tweeny::from(0.0f) .to(1000.0f) .via(easing::sinusoidalIn) .during(60U) .build(); See also sinusoidalOut For smooth deceleration sinusoidalInOut For smooth motion at both ends quadraticIn For similar gentleness Visualize at https://easings.net/#easeInSine