Flutter - Radial Hero Animation

import 'dart:math' as math;

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter/scheduler.dart' show timeDilation;

void main() {
  runApp(MaterialApp(home: RadialExpansionDemo()));
}

class Photo extends StatelessWidget {
  Photo({super.key, required this.photo, required this.color, required this.onTap});

  final String photo;
  final Color color;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    return Material(
      color: Theme.of(context).primaryColor.withOpacity(0.25),
      child: InkWell(
        onTap: onTap,
        child: LayoutBuilder(
          builder: (BuildContext context, BoxConstraints size) {
            return Image.asset(
              photo,
              fit: BoxFit.contain,
            );
          },
        ),
      ),
    );
  }
}

class RadialExpansion extends StatelessWidget {
  RadialExpansion({
    super.key,
    required this.maxRadius,
    required this.child,
  }) : clipRectSize = 2.0 * (maxRadius / math.sqrt2);

  final double maxRadius;
  final double clipRectSize;
  final Widget child;

  @override
  Widget build(BuildContext context) {
    return ClipOval(
      child: Center(
        child: SizedBox(
          width: clipRectSize,
          height: clipRectSize,
          child: ClipRect(
            child: child,
          ),
        ),
      ),
    );
  }
}

class RadialExpansionDemo extends StatelessWidget {
  static const double kMinRadius = 32.0;
  static const double kMaxRadius = 128.0;
  static const opacityCurve = Interval(0.0, 0.75, curve: Curves.fastOutSlowIn);

  static Tween<Rect?> _createRectTween(Rect? begin, Rect? end) {
    return MaterialRectCenterArcTween(begin: begin, end: end);
  }

  static Widget _buildPage(BuildContext context, String imageName, String description) {
    return Container(
      color: Theme.of(context).canvasColor,
      child: Center(
        child: Card(
          elevation: 8.0,
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              SizedBox(
                width: kMaxRadius * 2.0,
                height: kMaxRadius * 2.0,
                child: Hero(
                  createRectTween: _createRectTween,
                  tag: imageName,
                  child: RadialExpansion(
                    maxRadius: kMaxRadius,
                    child: Photo(
                      photo: imageName,
                      onTap: () {
                        Navigator.of(context).pop();
                      },
                      color: Colors.white,
                    ),
                  ),
                ),
              ),
              Text(
                description,
                style: TextStyle(fontWeight: FontWeight.bold),
                textScaleFactor: 3.0,
              ),
              const SizedBox(height: 20.0),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildHero(BuildContext context, String imageName, String description) {
    return Container(
      width: kMinRadius * 3.0,
      height: kMinRadius * 3.0,
      child: Hero(
        createRectTween: _createRectTween,
        tag: imageName,
        child: RadialExpansion(
          maxRadius: kMaxRadius,
          child: Photo(
            photo: imageName,
            color: Colors.white,
            onTap: () {
              Navigator.of(context).push(
                PageRouteBuilder<void>(
                  pageBuilder: (BuildContext context, Animation<double> animation,
                      Animation<double> secondaryAnimation) {
                    return AnimatedBuilder(
                      animation: animation,
                      builder: (BuildContext context, Widget? child) {
                        return Opacity(
                          opacity: opacityCurve.transform(animation.value),
                          child: _buildPage(context, imageName, description),
                        );
                      },
                    );
                  },
                ),
              );
            },
          ),
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    // animation speed.
    timeDilation = 4.0;

    return Scaffold(
      appBar: AppBar(
        title: const Text('GeeksForGeeks'),
        backgroundColor: Colors.green,
      ),
      body: Container(
        padding: const EdgeInsets.all(33.0),
        alignment: FractionalOffset.bottomLeft,
        child: Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: [
            _buildHero(context, 'assets/images/aquaman.png', 'Aquaman'),
            _buildHero(context, 'assets/images/superman.jpg', 'Superman'),
            _buildHero(context, 'assets/images/wonderwomen.jpg', 'Wonderwomen'),
          ],
        ),
      ),
    );
  }
}