flutter - 如何在Flutter中裁剪图像？

Question

我使用tflite进行图像识别

对于此图像:

我有以下结果:

{rect:{w:0.9337246417999268，x:0.03002336621284485，h:0.669991135597229，y:0.31182175874710083}，confidenceInClass:0.609375，DetectedClass:人}

通过使用上面的结果，我可以在对象周围创建一个矩形

如何自动裁剪已识别的矩形并将其保存到内存中。

Answer 1

通过使用 image_cropper .

也许这个包有帮助 - Flutter Image cropper
您只需将此权限添加到 AndroidManifest.xml 中即可。

<activity
    android:name="com.yalantis.ucrop.UCropActivity"
    android:screenOrientation="portrait"
    android:theme="@style/Theme.AppCompat.Light.NoActionBar"/>

这是使用 image_cropper 的官方示例

import 'package:flutter/material.dart';
import 'dart:async';
import 'dart:io';

import 'package:image_cropper/image_cropper.dart';
import 'package:image_picker/image_picker.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'ImageCropper',
      theme: ThemeData.light().copyWith(primaryColor: Colors.deepOrange),
      home: MyHomePage(
        title: 'ImageCropper',
      ),
    );
  }
}

class MyHomePage extends StatefulWidget {
  final String title;

  MyHomePage({required this.title});

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

enum AppState {
  free,
  picked,
  cropped,
}

class _MyHomePageState extends State<MyHomePage> {
  late AppState state;
  File? imageFile;

  @override
  void initState() {
    super.initState();
    state = AppState.free;
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: imageFile != null ? Image.file(imageFile!) : Container(),
      ),
      floatingActionButton: FloatingActionButton(
        backgroundColor: Colors.deepOrange,
        onPressed: () {
          if (state == AppState.free)
            _pickImage();
          else if (state == AppState.picked)
            _cropImage();
          else if (state == AppState.cropped) _clearImage();
        },
        child: _buildButtonIcon(),
      ),
    );
  }

  Widget _buildButtonIcon() {
    if (state == AppState.free)
      return Icon(Icons.add);
    else if (state == AppState.picked)
      return Icon(Icons.crop);
    else if (state == AppState.cropped)
      return Icon(Icons.clear);
    else
      return Container();
  }

  Future<Null> _pickImage() async {
    final pickedImage =
        await ImagePicker().getImage(source: ImageSource.gallery);
    imageFile = pickedImage != null ? File(pickedImage.path) : null;
    if (imageFile != null) {
      setState(() {
        state = AppState.picked;
      });
    }
  }

  Future<Null> _cropImage() async {
    File? croppedFile = await ImageCropper.cropImage(
        sourcePath: imageFile!.path,
        aspectRatioPresets: Platform.isAndroid
            ? [
                CropAspectRatioPreset.square,
                CropAspectRatioPreset.ratio3x2,
                CropAspectRatioPreset.original,
                CropAspectRatioPreset.ratio4x3,
                CropAspectRatioPreset.ratio16x9
              ]
            : [
                CropAspectRatioPreset.original,
                CropAspectRatioPreset.square,
                CropAspectRatioPreset.ratio3x2,
                CropAspectRatioPreset.ratio4x3,
                CropAspectRatioPreset.ratio5x3,
                CropAspectRatioPreset.ratio5x4,
                CropAspectRatioPreset.ratio7x5,
                CropAspectRatioPreset.ratio16x9
              ],
        androidUiSettings: AndroidUiSettings(
            toolbarTitle: 'Cropper',
            toolbarColor: Colors.deepOrange,
            toolbarWidgetColor: Colors.white,
            initAspectRatio: CropAspectRatioPreset.original,
            lockAspectRatio: false),
        iosUiSettings: IOSUiSettings(
          title: 'Cropper',
        ));
    if (croppedFile != null) {
      imageFile = croppedFile;
      setState(() {
        state = AppState.cropped;
      });
    }
  }

  void _clearImage() {
    imageFile = null;
    setState(() {
      state = AppState.free;
    });
  }
}

或者您可以观看如下教程:

• How to crop image in Flutter, by: Retro Portal Studio