Flutter文本识别插件learning_text_recognition的使用

Flutter文本识别插件learning_text_recognition的使用

ML Text Recognition

ML Kit的文本识别可以识别拉丁、中文、印地文、日文和韩文等语言的文本，并且可以用于自动化数据录入任务，如处理信用卡、收据和名片。

Getting Started

在你的Flutter项目中添加依赖：

$ pub add learning_text_recognition

Usage

import 'package:learning_text_recognition/learning_text_recognition.dart';

Input Image

输入图像作为InputImage实例，这是learning_input_image包的一部分。

你可以使用InputCameraView从learning_input_image包作为默认实现来处理相机/存储中的图像（或图像流）到InputImage格式。但如果你愿意，也可以学习InputCameraView代码以创建自己的自定义实现。

以下是如何使用InputCameraView获取InputImage进行文本识别的示例：

import 'package:learning_input_image/learning_input_image.dart';

InputCameraView(
  canSwitchMode: false,
  mode: InputCameraMode.gallery,
  title: 'Text Recognition',
  onImage: (InputImage image) {
    // 现在我们可以将输入图像馈入文本识别过程
  },
)

Text Recognition

获取InputImage后，可以通过调用TextRecognition实例的方法process开始进行文本识别。

// 当使用拉丁文字母时
TextRecognition textRecognition = TextRecognition();
// 或像这样：
TextRecognition textRecognition = TextRecognition(
  options: TextRecognitionOptions.Default
);

// 当使用中文时
TextRecognition textRecognition = TextRecognition(
  options: TextRecognitionOptions.Chinese
);

// 当使用印地文时
TextRecognition textRecognition = TextRecognition(
  options: TextRecognitionOptions.Devanagari
);

// 当使用日文时
TextRecognition textRecognition = TextRecognition(
  options: TextRecognitionOptions.Japanese
);

// 当使用韩文时
TextRecognition textRecognition = TextRecognition(
  options: TextRecognitionOptions.Korean
);

// 进行文本识别...
RecognizedText result = await textRecognition.process(image);

Output

文本识别的结果是一个RecognizededText对象，它包含描述输入图像中识别文本细节的嵌套元素。以下是RecognizededText结构的数据的示例：

• RecognizededText

  • Text: Wege der parlamentarischen Demokratie
  • Blocks: (1 block)

• TextBlock

  • Text: Wege der parlamentarischen Demokratie
  • Frame: (117.0, 258.0, 190.0, 83.0)
  • Corner Points: (117, 227), (301.64, 228.49), (306.05, 329.36), (121.41, 340.86)
  • Recognized Language Code: de
  • Lines: (3 lines)

• TextLine

  • Text: Wege der
  • Frame: (167.0, 221.0, 91.0, 28.0)
  • Corner Points: (167, 227), (255.82, 221.46), (257.19, 283.42), (168.36, 288.95)
  • Recognizeded Language Code: de
  • Elements: (2 elements)

• TextElement

  • Text: Wege
  • Frame: (167.0, 223.0, 59.0, 22.0)
  • Corner Points: (167, 227), (223.88, 223.45), (225.25, 285.41), (168.36, 288.95)

Dispose

textRecognition.dispose();

Example Project

你可以从示例项目了解更多：example

import 'package:flutter/material.dart';
import 'package:learning_input_image/learning_input_image.dart';
import 'package:learning_text_recognition/learning_text_recognition.dart';
import 'package:provider/provider.dart';

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

class MyApp extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.lightBlue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
        primaryTextTheme: TextTheme(
          headline6: TextStyle(color: Colors.white),
        ),
      ),
      home: ChangeNotifierProvider(
        create: (_) => TextRecognitionState(),
        child: TextRecognitionPage(),
      ),
    );
  }
}

class TextRecognitionPage extends StatefulWidget {
  [@override](/user/override)
  _TextRecognitionPageState createState() => _TextRecognitionPageState();
}

class _TextRecognitionPageState extends State<TextRecognitionPage> {
  TextRecognition? _textRecognition = TextRecognition();

  /* TextRecognition? _textRecognition = TextRecognition(
    options: TextRecognitionOptions.Japanese
  ); */

  [@override](/user/override)
  void dispose() {
    _textRecognition?.dispose();
    super.dispose();
  }

  Future<void> _startRecognition(InputImage image) async {
    TextRecognitionState state = Provider.of(context, listen: false);

    if (state.isNotProcessing) {
      state.startProcessing();
      state.image = image;
      state.data = await _textRecognition?.process(image);
      state.stopProcessing();
    }
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return InputCameraView(
      mode: InputCameraMode.gallery,
      // resolutionPreset: ResolutionPreset.high,
      title: 'Text Recognition',
      onImage: _startRecognition,
      overlay: Consumer<TextRecognitionState>(
        builder: (_, state, __) {
          if (state.isNotEmpty) {
            return Center(
              child: Container(
                padding: EdgeInsets.symmetric(vertical: 10, horizontal: 16),
                decoration: BoxDecoration(
                  color: Colors.white.withOpacity(0.8),
                  borderRadius: BorderRadius.all(Radius.circular(4.0)),
                ),
                child: Text(
                  state.text,
                  style: TextStyle(
                    fontWeight: FontWeight.w500,
                  ),
                ),
              ),
            );
          }

          return Container();
        },
      ),
    );
  }
}

class TextRecognitionState extends ChangeNotifier {
  InputImage? _image;
  RecognizededText? _data;
  bool _isProcessing = false;

  InputImage? get image => _image;
  Recogn RecognedText? get data => _data;
  String get text => _data!.text;
  bool get isNotProcessing => !_isProcessing;
  bool get isNotEmpty => _data != null && text.isNotEmpty;

  void startProcessing() {
    _isProcessing = true;
    notifyListeners();
  }

  void stopProcessing() {
    _isProcessing = false;
    notifyListeners();
  }

  set image(InputImage? image) {
    _image = image;
    notifyListeners();
  }

  set data(Recogn RecognedText? data) {
    _data = data;
    notifyListeners();
  }
}