如何在Flutter中删除图像的选定部分？

import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';

class ImagePickerExample extends StatefulWidget {
  @override
  _ImagePickerExampleState createState() => _ImagePickerExampleState();
}

class _ImagePickerExampleState extends State<ImagePickerExample> {
  File _image;

  Future getImage() async {
    var image = await ImagePicker.pickImage(source: ImageSource.gallery);

    setState(() {
      _image = image;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Image Picker Example'),
      ),
      body: Center(
        child: _image == null ? Text('No image selected.') : Image.file(_image),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: getImage,
        tooltip: 'Pick Image',
        child: Icon(Icons.add_a_photo),
      ),
    );
  }
}

import 'package:flutter/material.dart';
import 'package:image_crop/image_crop.dart';

class ImageCropExample extends StatefulWidget {
  final File imageFile;

  ImageCropExample({Key key, this.imageFile}) : super(key: key);

  @override
  _ImageCropExampleState createState() => _ImageCropExampleState();
}

class _ImageCropExampleState extends State<ImageCropExample> {
  final cropKey = GlobalKey<CropState>();
  File croppedFile;

  Future<void> _cropImage() async {
    final scale = cropKey.currentState.scale;
    final area = cropKey.currentState.area;
    final croppedFile = await ImageCrop.cropImage(
      file: widget.imageFile,
      area: area,
      scale: scale,
    );

    setState(() {
      this.croppedFile = croppedFile;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Image Crop Example'),
      ),
      body: Crop(
        key: cropKey,
        image: FileImage(widget.imageFile),
        aspectRatio: 1.0,
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _cropImage,
        tooltip: 'Crop Image',
        child: Icon(Icons.crop),
      ),
    );
  }
}

import 'package:flutter/material.dart';
import 'package:path_provider/path_provider.dart';

class ImageSaveExample extends StatefulWidget {
  final File croppedFile;

  ImageSaveExample({Key key, this.croppedFile}) : super(key: key);

  @override
  _ImageSaveExampleState createState() => _ImageSaveExampleState();
}

class _ImageSaveExampleState extends State<ImageSaveExample> {
  String savedImagePath;

  Future<void> _saveImage() async {
    final directory = await getApplicationDocumentsDirectory();
    final imagePath = '${directory.path}/cropped_image.jpg';
    await widget.croppedFile.copy(imagePath);

    setState(() {
      savedImagePath = imagePath;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Image Save Example'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            widget.croppedFile != null
                ? Image.file(widget.croppedFile)
                : Text('No image selected.'),
            SizedBox(height: 16),
            RaisedButton(
              onPressed: _saveImage,
              child: Text('Save Image'),
            ),
            savedImagePath != null
                ? Text('Image saved to: $savedImagePath')
                : Container(),
          ],
        ),
      ),
    );
  }
}