GravitySimulation class Null safety

A simulation that applies a constant accelerating force.

Models a particle that follows Newton's second law of motion. The simulation ends when the position exceeds a defined threshold.

void _startFall() {
  _controller.animateWith(GravitySimulation(
    10.0, // acceleration, pixels per second per second
    0.0, // starting position, pixels
    300.0, // ending position, pixels
    0.0, // starting velocity, pixels per second
  ));
}

This AnimationController could be used with an AnimatedBuilder to animate the position of a child as if it was falling.

The end distance threshold (the constructor's third argument) must be specified as a positive number but can be reached in either the positive or negative direction. For example (assuming negative numbers represent higher physical positions than positive numbers, as is the case with the normal Canvas coordinate system), if the acceleration is positive ("down") the starting velocity is negative ("up"), and the starting distance is zero, the particle will climb from the origin, reach a plateau, then fall back towards and past the origin. If the end distance threshold is less than the height of the plateau, then the simulation will end during the climb; otherwise, it will end during the fall, after the particle travels below the origin by that distance.

See also:

• Curves.bounceOut, a Curve that has a similar aesthetics but includes a bouncing effect.