awesome-uiwidgets/AwesomeUIWidgets/Assets/Scripts/heroSample/radial_expansion.cs

using System;
using Unity.UIWidgets.animation;
using Unity.UIWidgets.foundation;
using Unity.UIWidgets.material;
using Unity.UIWidgets.painting;
using Unity.UIWidgets.widgets;
using UnityEngine;

namespace UIWidgetsGallery.gallery
{
    public class Photo : StatelessWidget
    {
        public Photo(Key key = null, string photo = null, Action onTap = null) : base(key: key)
        {
            D.assert(photo != null);
            this.photo = photo;
            this.onTap = onTap;
        }

        public readonly string photo;
        public readonly Action onTap;

        public override Widget build(BuildContext context)
        {
            return new GestureDetector(
                onTap: () => onTap?.Invoke(),
                child: new LayoutBuilder(
                    builder: ((buildContext, constraints) =>
                    {
                        return Image.file(photo, fit: BoxFit.contain);
                    })                )
                );

        }
    }

    public class RadialExpansion : StatelessWidget
    {
        public RadialExpansion(Key key = null, float maxRadius = 0.0f, Widget child = null)
        : base(key: key)
        {
            this.maxRadius = maxRadius;
            this.child = child;
        }
        
        public readonly float maxRadius;
        public readonly Widget child;

        public override Widget build(BuildContext context)
        {
            return new ClipOval(
                        child: new Center(
                            child: new SizedBox(
                                width: 2.0f * (maxRadius / Mathf.Sqrt(2)),
                                height: 2.0f * (maxRadius / Mathf.Sqrt(2)),
                                child: new ClipRect(
                                    child: child
                                )
                            )
                        )
                    );
        }
    }
}