goBallistic method

@override void goBallistic(double velocity)

Start a physics-driven simulation that settles the pixels position, starting at a particular velocity.

This method defers to ScrollPhysics.createBallisticSimulation, which typically provides a bounce simulation when the current position is out of bounds and a friction simulation when the position is in bounds but has a non-zero velocity.

The velocity should be in logical pixels per second.

Implementation

@override
void goBallistic(double velocity) {
  if (sheetPosition.preventingDrag) {
    goIdle();
    return;
  }

  if (sheetPosition.hasContentDimensions) {
    sheetPosition.goBallistic(velocity);
  }

  if (velocity > 0.0 &&
          sheetPosition.pixels >= sheetPosition.maxScrollExtent ||
      (velocity < 0.0 && pixels > 0)) {
    super.goBallistic(velocity);
    return;
  } else if (outOfRange) {
    beginActivity(
      BallisticScrollActivity(
        this,
        ScrollSpringSimulation(
          SpringDescription.withDampingRatio(
            mass: 0.5,
            stiffness: 100.0,
            ratio: 1.1,
          ),
          pixels,
          0,
          velocity,
        ),
        context.vsync,
        true,
      ),
    );
    return;
  } else {
    goIdle();
    return;
  }
}