Variable Horizontal Size Field...

main.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter EveryDaySoft',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(
        title: "Example",
      ),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});
  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  Size size = Size.zero;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: SizedBox(
          height: 50,
          width: 100 < size.width ? size.width * 1.2 : 120,
          child: TextFormField(
            decoration: const InputDecoration(hintText: 'TextFormField'),
            onChanged: (value) {
              setState(() {
                size = _sizeWith(value);
              });
            },
          ),
        ),
      ),
    );
  }

  Size _sizeWith(String text) {
    return (TextPainter(
            text: TextSpan(
              text: text,
            ),
            maxLines: 1,
            textScaleFactor: MediaQuery.of(context).textScaleFactor,
            textDirection: TextDirection.ltr)
          ..layout())
        .size;
  }
}

default.mov