Flutter text scale animation

text.dart

import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  static const String _title = 'Flutter Code Sample';

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      title: _title,
      home: MyStatefulWidget(),
    );
  }
}

class MyStatefulWidget extends StatefulWidget {
  const MyStatefulWidget({Key? key}) : super(key: key);

  @override
  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
}

/// AnimationControllers can be created with `vsync: this` because of TickerProviderStateMixin.
class _MyStatefulWidgetState extends State<MyStatefulWidget>
    with TickerProviderStateMixin {
  late final AnimationController _controller = AnimationController(
    lowerBound: 0.5,
    upperBound: 1,
    duration: const Duration(seconds: 2),
    vsync: this,
  )..repeat(reverse: true);
  late final Animation<double> _animation = CurvedAnimation(
    parent: _controller,
    curve: Curves.fastOutSlowIn,
  );

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: ScaleTransition(
          scale: _animation,
          child: const Padding(
            padding: EdgeInsets.all(8.0),
            child: Text("""Flutter code compiles to ARM \n"""
            """or Intel machine code as well as JavaScript, \n"""
            """for fast performance on any device."""),
          ),
        ),
      ),
    );
  }
}