Flutter :如何在图像上创建文本，即可使用手柄4点调整大小

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('Resizable Text on Image')),
        body: Center(child: ImageWithText()),
      ),
    );
  }
}

class ImageWithText extends StatefulWidget {
  @override
  _ImageWithTextState createState() => _ImageWithTextState();
}

class _ImageWithTextState extends State<ImageWithText> {
  double _scale = 1.0;
  Offset _offset = Offset.zero;

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onScaleStart: (details) {
        setState(() {
          _offset = details.focalPoint - Offset(MediaQuery.of(context).size.width / 2, MediaQuery.of(context).size.height / 2);
        });
      },
      onScaleUpdate: (details) {
        setState(() {
          _scale = details.scale;
        });
      },
      child: CustomPaint(
        size: MediaQuery.of(context).size,
        painter: TextPainter(_scale, _offset),
      ),
    );
  }
}

class TextPainter extends CustomPainter {
  final double scale;
  final Offset offset;

  TextPainter(this.scale, this.offset);

  @override
  void paint(Canvas canvas, Size size) {
    final paint = Paint()
      ..color = Colors.red
      ..textSize = 50 * scale
      ..textAlign = TextAlign.center;

    canvas.drawImage(
      NetworkImage('https://via.placeholder.com/350x130'), // 替换为你的图片URL
      Offset.zero,
      Paint(),
    );

    canvas.drawText(
      'Hello World',
      size.width / 2 + offset.dx,
      size.height / 2 + offset.dy,
      paint,
    );
  }

  @override
  bool shouldRepaint(TextPainter oldDelegate) {
    return oldDelegate.scale != scale || oldDelegate.offset != offset;
  }
}