如何在颤动中使用CustomPainter模糊图片中的特定位置

import 'dart:ui' as ui;
import 'package:flutter/material.dart';
import 'package:flutter_blurhash/flutter_blurhash.dart';

class BlurImagePainter extends CustomPainter {
  final ui.Image image;
  final Offset blurPosition;

  BlurImagePainter(this.image, this.blurPosition);

  @override
  void paint(Canvas canvas, Size size) {
    // 绘制原始图片
    canvas.drawImage(image, Offset.zero, Paint());

    // 获取像素数据
    final imgData = image.toByteData();

    if (imgData != null) {
      // 获取点击位置的像素坐标
      final pixelX = blurPosition.dx.toInt();
      final pixelY = blurPosition.dy.toInt();

      // 获取像素数据
      final pixels = imgData.buffer.asUint8List();

      // 模糊特定位置
      final blurredPixels = blurPixels(pixels, pixelX, pixelY, image.width, image.height);

      // 创建模糊后的图片
      final blurredImage = ui.Image.fromBytes(image.width, image.height, blurredPixels);

      // 绘制模糊后的图片
      canvas.drawImage(blurredImage, Offset.zero, Paint());
    }
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) {
    return true;
  }
}

List<int> blurPixels(List<int> pixels, int x, int y, int width, int height) {
  // TODO: 在这里实现模糊算法，对特定位置的像素及其周围像素进行模糊处理

  return pixels;
}

class BlurImagePage extends StatefulWidget {
  @override
  _BlurImagePageState createState() => _BlurImagePageState();
}

class _BlurImagePageState extends State<BlurImagePage> {
  ui.Image? image;
  Offset? blurPosition;

  @override
  void initState() {
    super.initState();
    loadImage();
  }

  Future<void> loadImage() async {
    final imgProvider = AssetImage('path_to_your_image');
    final img = await imgProvider.obtainKey(ImageConfiguration()).load(imgProvider);
    setState(() {
      image = img.image;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Blur Image'),
      ),
      body: GestureDetector(
        onTapDown: (details) {
          setState(() {
            blurPosition = details.localPosition;
          });
        },
        child: CustomPaint(
          painter: BlurImagePainter(image!, blurPosition!),
          child: Container(),
        ),
      ),
    );
  }
}