build method

@override Widget build(BuildContext context, Widget child, AnimationController controller, EffectEntry entry,)

Builds the widgets that implement the effect on the target child, based on the provided AnimationController and EffectEntry.

Implementation

@override
Widget build(
  BuildContext context,
  Widget child,
  AnimationController controller,
  EffectEntry entry,
) {
  Animation<double> animation = buildAnimation(controller, entry);
  List<PathMetric> metrics = path.computeMetrics().toList();
  if (metrics.isEmpty) return child;
  PathMetric metric = metrics.first;

  return getOptimizedBuilder<double>(
    animation: animation,
    builder: (_, __) {
      Tangent? tangent =
          metric.getTangentForOffset(metric.length * animation.value);

      Offset position = tangent?.position ?? Offset.zero;
      double rotation = rotate ? -(tangent?.angle ?? 0) + rotationOffset : 0;
      Matrix4 mtx = getMatrix(position.dx, position.dy, rotation);

      return Transform(
        transform: mtx,
        transformHitTests: transformHitTests,
        alignment: Alignment.center,
        child: child,
      );
    },
  );
}