evaluate method

void evaluate(
  1. PointerSample? sample
)

Starts or stops the ticker for the pointer's current edge-zone membership. A null sample means the scrollable is gone: stop.

Implementation

void evaluate(PointerSample? sample) {
  if (sample == null) {
    _stop();
    return;
  }
  final inEdgeZone =
      sample.viewportDy < _edgeZone ||
      sample.viewportDy > sample.viewportHeight - _edgeZone;
  if (inEdgeZone) {
    if (!_ticker.isActive) {
      _lastTick = null;
      _ticker.start();
    }
  } else {
    _stop();
  }
}