Flutter人脸检测插件google_mediapipe_face_detection_platform_interface的使用

Flutter人脸检测插件google_mediapipe_face_detection_platform_interface的使用

google_mediapipe_face_detection_platform_interface 是一个用于 google_mediapipe_face_detection 插件的通用平台接口。这个接口允许实现特定平台的 google_mediapipe_face_detection 插件，并确保它们支持相同的接口。

使用方法

要实现一个新的平台特定的 google_mediapipe_face_detection 实现，需要扩展 [GoogleMediapipeFaceDetectionPlatform][2] 类，并在其中实现特定平台的行为。当你注册你的插件时，可以通过调用 GoogleMediapipeFaceDetectionPlatformPlatform.instance = MyPlatformGoogleMediapipeFaceDetection() 来设置默认的 GoogleMediapipeFaceDetectionPlatformPlatform。

完整示例Demo

下面是一个完整的示例，展示如何使用 google_mediapipe_face_detection 插件来实现人脸检测功能。

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: FaceDetectionScreen(),
    );
  }
}

class FaceDetectionScreen extends StatefulWidget {
  @override
  _FaceDetectionScreenState createState() => _FaceDetectionScreenState();
}

class _FaceDetectionScreenState extends State<FaceDetectionScreen> {
  late GoogleMediapipeFaceDetection faceDetection;

  @override
  void initState() {
    super.initState();
    faceDetection = GoogleMediapipeFaceDetection();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('人脸检测'),
      ),
      body: Center(
        child: Container(
          width: 300,
          height: 300,
          color: Colors.grey,
          child: FutureBuilder<List<Face>>(
            future: faceDetection.detectFacesFromImageFile('path/to/your/image.jpg'),
            builder: (context, snapshot) {
              if (snapshot.connectionState == ConnectionState.done) {
                if (snapshot.hasError) {
                  return Text('错误: ${snapshot.error}');
                } else if (!snapshot.hasData) {
                  return Text('未检测到人脸');
                } else {
                  List<Face> faces = snapshot.data!;
                  return CustomPaint(
                    painter: FacePainter(faces),
                  );
                }
              } else {
                return CircularProgressIndicator();
              }
            },
          ),
        ),
      ),
    );
  }
}

class FacePainter extends CustomPainter {
  final List<Face> faces;

  FacePainter(this.faces);

  @override
  void paint(Canvas canvas, Size size) {
    Paint paint = Paint()
      ..color = Colors.red
      ..strokeWidth = 5.0
      ..style = PaintingStyle.stroke;

    for (var face in faces) {
      canvas.drawRect(face.boundingBox, paint);
    }
  }

  @override
  bool shouldRepaint(covariant FacePainter oldDelegate) {
    return oldDelegate.faces != faces;
  }
}

代码解释

1. 导入必要的库:

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

2. 主应用类:

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

3. 创建主界面:

   class MyApp extends StatelessWidget {
     @override
     Widget build(BuildContext context) {
       return MaterialApp(
         home: FaceDetectionScreen(),
       );
     }
   }
   

4. 人脸检测屏幕类:

   class FaceDetectionScreen extends StatefulWidget {
     @override
     _FaceDetectionScreenState createState() => _FaceDetectionScreenState();
   }
   

5. 状态管理类:

   class _FaceDetectionScreenState extends State<FaceDetectionScreen> {
     late GoogleMediapipeFaceDetection faceDetection;
   
     @override
     void initState() {
       super.initState();
       faceDetection = GoogleMediapipeFaceDetection();
     }
   
     @override
     Widget build(BuildContext context) {
       return Scaffold(
         appBar: AppBar(
           title: Text('人脸检测'),
         ),
         body: Center(
           child: Container(
             width: 300,
             height: 300,
             color: Colors.grey,
             child: FutureBuilder<List<Face>>(
               future: faceDetection.detectFacesFromImageFile('path/to/your/image.jpg'),
               builder: (context, snapshot) {
                 if (snapshot.connectionState == ConnectionState.done) {
                   if (snapshot.hasError) {
                     return Text('错误: ${snapshot.error}');
                   } else if (!snapshot.hasData) {
                     return Text('未检测到人脸');
                   } else {
                     List<Face> faces = snapshot.data!;
                     return CustomPaint(
                       painter: FacePainter(faces),
                     );
                   }
                 } else {
                   return CircularProgressIndicator();
                 }
               },
             ),
           ),
         ),
       );
     }
   }
   

6. 绘制人脸框的自定义画布:

   class FacePainter extends CustomPainter {
     final List<Face> faces;
   
     FacePainter(this.faces);
   
     @override
     void paint(Canvas canvas, Size size) {
       Paint paint = Paint()
         ..color = Colors.red
         ..strokeWidth = 5.0
         ..style = PaintingStyle.stroke;
   
       for (var face in faces) {
         canvas.drawRect(face.boundingBox, paint);
       }
     }
   
     @override
     bool shouldRepaint(covariant FacePainter oldDelegate) {
       return oldDelegate.faces != faces;
     }
   }