FractionallySizedBox example

readme.md

Create by https://gist.github.com/CaiJingLong/a299d15b92edc2d09a8a06cf6dd5a1b0

main.dart

import "package:flutter/material.dart";

void main() {
  runApp(
    MaterialApp(
      home: Container(
        color: Colors.red,
        child: Stack(
          children: [
            Align(
              child: FractionallySizedBox(
                child: Container(
                  color: Colors.blue,
                ),
                widthFactor: 0.3,
                heightFactor: 0.1,
              ),
              alignment: Alignment(-0.5, 0),
            ),
          ],
        ),
      ),
    ),
  );
}