Compose MediumBouncy with StiffnessLow
Both constants come from the Spring object: a damping ratio of 0.5 and the low stiffness, 200. Stiffness 200, damping 14.14 and mass 1 give a damping ratio of 0.5, so the spring is underdamped. It settles to within 0.1% in 0.9 s. It passes the end value by up to 16.3% at 0.256 s and crosses it 3 times.
Demo
Both boxes take 0.9 s. This is real time.
Your system asks for reduced motion, so nothing plays. The chart shows the whole move.
Code
A spring has no fixed duration, so the CSS takes the settle time (900 ms) and a linear() string that follows the spring.
transition: translate 900ms linear(0, 0.0054, 0.0209, 0.0453, 0.0774, 0.1161, 0.1603, 0.2091, 0.2613, 0.3162, 0.3729, 0.4305, 0.4884, 0.546, 0.6026, 0.6577, 0.711, 0.7619, 0.8103, 0.8558, 0.8983, 0.9376, 0.9736, 1.0063, 1.0356, 1.0616, 1.0843, 1.1038, 1.1203, 1.1338, 1.1445, 1.1526, 1.1583, 1.1617, 1.1631, 1.1625, 1.1603, 1.1566, 1.1516, 1.1455, 1.1384, 1.1306, 1.1222, 1.1133, 1.1041, 1.0948, 1.0853, 1.0759, 1.0666, 1.0576, 1.0488, 1.0405, 1.0325, 1.025, 1.0179, 1.0114, 1.0054, 1, 0.9951, 0.9908, 0.9869, 0.9837, 0.9809, 0.9786, 0.9767, 0.9753, 0.9743, 0.9737, 0.9734, 0.9735, 0.9738, 0.9743, 0.9751, 0.9761, 0.9772, 0.9784, 0.9798, 0.9812, 0.9827, 0.9842, 0.9858, 0.9873, 0.9888, 0.9903, 0.9918, 0.9931, 0.9944, 0.9957, 0.9969, 0.9979, 0.9989, 0.9998, 1.0006, 1.0014, 1.002, 1.0026, 1.003, 1.0034, 1.0037, 1.004, 1.0042, 1.0043, 1.0043, 1.0043, 1.0043, 1.0042, 1.0041, 1.0039, 1.0038, 1.0036, 1.0033, 1.0031, 1.0029, 1.0026, 1.0024, 1.0021, 1.0019, 1.0016, 1.0014, 1.0012, 1);el.animate({ translate: ['0 0', '240px 0'] }, { duration: 900, easing: 'linear(0, 0.0054, 0.0209, 0.0453, 0.0774, 0.1161, 0.1603, 0.2091, 0.2613, 0.3162, 0.3729, 0.4305, 0.4884, 0.546, 0.6026, 0.6577, 0.711, 0.7619, 0.8103, 0.8558, 0.8983, 0.9376, 0.9736, 1.0063, 1.0356, 1.0616, 1.0843, 1.1038, 1.1203, 1.1338, 1.1445, 1.1526, 1.1583, 1.1617, 1.1631, 1.1625, 1.1603, 1.1566, 1.1516, 1.1455, 1.1384, 1.1306, 1.1222, 1.1133, 1.1041, 1.0948, 1.0853, 1.0759, 1.0666, 1.0576, 1.0488, 1.0405, 1.0325, 1.025, 1.0179, 1.0114, 1.0054, 1, 0.9951, 0.9908, 0.9869, 0.9837, 0.9809, 0.9786, 0.9767, 0.9753, 0.9743, 0.9737, 0.9734, 0.9735, 0.9738, 0.9743, 0.9751, 0.9761, 0.9772, 0.9784, 0.9798, 0.9812, 0.9827, 0.9842, 0.9858, 0.9873, 0.9888, 0.9903, 0.9918, 0.9931, 0.9944, 0.9957, 0.9969, 0.9979, 0.9989, 0.9998, 1.0006, 1.0014, 1.002, 1.0026, 1.003, 1.0034, 1.0037, 1.004, 1.0042, 1.0043, 1.0043, 1.0043, 1.0043, 1.0042, 1.0041, 1.0039, 1.0038, 1.0036, 1.0033, 1.0031, 1.0029, 1.0026, 1.0024, 1.0021, 1.0019, 1.0016, 1.0014, 1.0012, 1)', fill: 'both' });import { spring, springDuration, springLinear } from '../../core/motion/springs.js';
const k = 200, d = 14.14;
// per-frame code (window.seek, vawe.onFrame): t is seconds since the move starts
const x = 240 * spring(t, k, d);
// CSS and Web Animations: 900 ms, the linear() string above
el.animate(
{ translate: ['0 0', '240px 0'] },
{ duration: springDuration(k, d) * 1000, easing: springLinear(k, d), fill: 'both' },
);Numbers
- Stiffness
- 200k, with mass 1
- Damping
- 14.14d, with mass 1
- Damping ratio
- 0.5underdamped
- Settle time
- 0.9 swithin 0.1% of the end
- Overshoot
- 16.3%peak at 0.256 s
- Crosses the end
- 3times
- 50% of travel
- 0.092 s10% of the settle time
- 90% of travel
- 0.151 s17% of the settle time
- Natural frequency
- 14.14 rad/ssqrt(k)
- Ring period
- 0.513 sone swing of the overshoot
- Peak speed
- 6.94xtimes the average speed
- linear() points
- 121within 0.13% of travel
Computed with spring() and springDuration() from core/motion/springs.js. The settle time is the last moment the spring is more than 0.1% away from the end value; a library stops its own spring by its own rest thresholds, so its clock can run shorter.
Source of the numbers
| Jetpack Compose | androidx main at 9adbcd8 (compose animation-core 1.14.0-alpha01) |
| spring(dampingRatio = Spring.DampingRatioMediumBouncy (0.5), stiffness = Spring.StiffnessLow (200)) | Spring.DampingRatioMediumBouncy, Spring.StiffnessLow |
Conversion: Stiffness is used as it is with mass 1 (SpringSimulation takes the natural frequency as sqrt(stiffness)). damping = 2 x dampingRatio x sqrt(stiffness), the same c = 2 x naturalFreq x dampingRatio that SpringSimulation.getAcceleration uses.
Related springs
The four closest curves in this set, by the average gap between the two springs over their first seconds. A gap of 0.01 is invisible; 0.1 is a different feel.