rotation_blur.dart

import 'dart:math' as math;
import 'dart:ui';

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

// ignore: use_key_in_widget_constructors
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Blurred Edges',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Blurred Edges'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> with TickerProviderStateMixin {
  AnimationController? animator;

  @override
  void initState() {
    super.initState();
    animator = AnimationController(
      vsync: this,
    );
    animator!.repeat(period: const Duration(seconds: 3));
  }

  @override
  Widget build(BuildContext context) {
    print('device pixel ratio = ${window.devicePixelRatio}');
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Stack(
        children: <Widget>[
          Container(width: 360, height: 400),
          Positioned(
            left: 50,
            top: 50,
            child: Container(width: 50, height: 50, color: Colors.grey),
          ),
          Positioned(
            left: 50,
            top: 50,
            child: ImageFiltered(
              imageFilter: ImageFilter.blur(sigmaX: 20.0, sigmaY: 20.0),
              child: Container(width: 50, height: 50, color: Colors.red),
            ),
          ),
          Positioned(
            left: 250.2,
            top: 50.2,
            child: Container(width: 50.2, height: 50.2, color: Colors.grey),
          ),
          Positioned(
            left: 250.2,
            top: 50.2,
            child: ImageFiltered(
              imageFilter: ImageFilter.blur(sigmaX: 20.0, sigmaY: 20.0),
              child: Container(width: 50.2, height: 50.2, color: Colors.red),
            ),
          ),
          Positioned(
            left: 50,
            top: 250,
            child: Container(width: 50, height: 50, color: Colors.grey),
          ),
          Positioned(
            left: 50,
            top: 250,
            child: ImageFiltered(
              imageFilter: ImageFilter.blur(sigmaX: 20.0, sigmaY: 20.0),
              child: Transform.rotate(
                angle: math.pi / 4.0,
                child: Container(width: 50, height: 50, color: Colors.red),
              ),
            ),
          ),
          Positioned(
            left: 250,
            top: 250,
            child: Container(width: 50, height: 50, color: Colors.grey),
          ),
          Positioned(
            left: 250,
            top: 250,
            child: ImageFiltered(
              imageFilter: ImageFilter.blur(sigmaX: 10.0, sigmaY: 10.0),
              child: RotationTransition(
                turns: animator!,
                child: Container(width: 50, height: 50, color: Colors.red),
              ),
            ),
          ),
        ],
      ),
    );
  }
}