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import 'package:flutter/material.dart';
class CullOpacityPage extends StatefulWidget {
@override
State<StatefulWidget> createState() => _CullOpacityPageState();
}
class _CullOpacityPageState extends State<CullOpacityPage> with SingleTickerProviderStateMixin {
Animation<double> _offsetY;
AnimationController _controller;
@override
void initState() {
super.initState();
_controller = AnimationController(vsync: this, duration: const Duration(seconds: 2));
_offsetY = Tween<double>(begin: 0, end: -1000.0).animate(_controller)..addListener((){
setState(() {});
});
_controller.repeat();
}
@override
Widget build(BuildContext context) {
return Stack(children: List<Widget>.generate(50, (int i) => Positioned(
left: 0,
top: (200 * i).toDouble() + _offsetY.value,
child: Opacity(
opacity: 0.5,
child: RepaintBoundary(
child: Container(
// Slightly change width to invalidate raster cache.
width: 1000 - (_offsetY.value / 100),
height: 100, color: Colors.red,
),
),
),
)));
}
}