ImageProcess/native_vision/lib/polygon_anim.dart

import 'package:flutter/material.dart';

class PolygonAnimController extends AnimationController {
  late List<Tween<Offset>> _tweens;
  late List<Animation<Offset>> _animations;
  late List<Offset> _currentCoords;
  void Function(List<Offset> coords)? onCoordsChange;

  PolygonAnimController(
      {required int len, required super.vsync, required super.duration}) {
    // _animController = AnimationController(
    // vsync: this, duration: const Duration(milliseconds: 400));
    _tweens = List.generate(len, (index) => Tween<Offset>());
    _animations = List.generate(len, (index) => _tweens[index].animate(this));
    _currentCoords = List.generate(len, (index) => const Offset(0, 0));
    addListener(_listener);
  }

  @override
  void dispose() {
    removeListener(_listener);
    super.dispose();
  }

  void _listener() {
    List<Offset> values =
        List.generate(_animations.length, (index) => _animations[index].value);
    onCoordsChange?.call(values);
  }

  void startAnim(List<Offset> freshCoords) {
    assert(freshCoords.length == _tweens.length, "Their length must be equal!");
    for (int i = 0, len = _tweens.length; i < len; i++) {
      _tweens[i].begin = _currentCoords[i];
      _tweens[i].end = freshCoords[i];
    }
    _currentCoords = freshCoords;
    reset();
    forward();
  }
}