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

exponentialIn detail::exponentialInEasing exponentialIn {} inlineconstexpr Exponential easing with very slow start and explosive acceleration. The exponentialIn easing function starts extremely slowly and builds to a very rapid acceleration toward the end. Based on exponential growth (2^x), this creates one of the most dramatic acceleration curves available, with velocity increasing exponentially over time. Characteristics: Almost no visible motion for the first portion of the animation Sudden, explosive acceleration in the final phase Change rate doubles repeatedly as time progresses Creates extreme contrast between start and end velocity This easing is ideal for: Dramatic reveals: Elements that burst into view Explosive effects: Particle systems, energy blasts, explosions Fade-ins with impact: Starting invisible and suddenly appearing Speed-up effects: Rockets launching, vehicles accelerating Tension building: Slow build-up to sudden release The extreme acceleration curve makes this feel more dramatic than polynomial easings (quadratic, cubic, etc.). The motion appears to "explode" into existence rather than gradually accelerate. Use exponentialIn when you want maximum contrast between the patient start and the explosive finish. For most UI work, cubic or quartic easings provide sufficient acceleration with less extreme behavior. Mathematically: f(t) = 2^(10 * (t - 1)) // Fade in that suddenly snaps to full visibility auto opacity = tweeny::from(0.0f) .to(1.0f) .via(easing::exponentialIn) .during(45U) .build(); // Rocket launch with explosive acceleration auto velocity = tweeny::from(0.0f) .to(1000.0f) .via(easing::exponentialIn) .during(120U) .build(); See also exponentialOut For explosive deceleration at the end exponentialInOut For dramatic acceleration and deceleration quarticIn For strong but less extreme acceleration Visualize at https://easings.net/#easeInExpo