refactor: Refactor classes to match with native API

packages/example/lib/vision_detector_views/painters/subject_segmentation_painter.dart

@@ -4,7 +4,7 @@ import 'package:google_mlkit_subject_segmentation/google_mlkit_subject_segmentat
 import 'coordinates_translator.dart';
 
 class SubjectSegmentationPainter extends CustomPainter {
-  final SubjectSegmenterMask mask;
+  final SubjectSegmentationResult mask;
   final Size imageSize;
   final Color color = Colors.red;
   final InputImageRotation rotation;
@@ -19,18 +19,16 @@ class SubjectSegmentationPainter extends CustomPainter {
 
   @override
   void paint(Canvas canvas, Size size) {
-    final int width = mask.width;
-    final int height = mask.height;
-    final List<Subject> subjects = mask.subjects ?? [];
+    final List<Subject> subjects = mask.subjects;
 
     final paint = Paint()..style = PaintingStyle.fill;
 
     for (final Subject subject in subjects) {
       final int startX = subject.startX;
       final int startY = subject.startY;
-      final int subjectWidth = subject.subjectWidth;
-      final int subjectHeight = subject.subjectHeight;
-      final List<double> confidences = subject.confidences ?? [];
+      final int subjectWidth = subject.width;
+      final int subjectHeight = subject.height;
+      final List<double> confidences = subject.confidenceMask ?? [];
 
       for (int y = 0; y < subjectHeight; y++) {
         for (int x = 0; y < subjectWidth; x++) {
@@ -40,15 +38,15 @@ class SubjectSegmentationPainter extends CustomPainter {
           final int tx = translateX(
                   absoluteX.toDouble(),
                   size,
-                  Size(width.toDouble(), height.toDouble()),
+                  Size(imageSize.width.toDouble(), imageSize.height.toDouble()),
                   rotation,
                   cameraLensDirection)
               .round();
 
           final int ty = translateY(
                   absoluteY.toDouble(),
                   size,
-                  Size(width.toDouble(), height.toDouble()),
+                  Size(imageSize.width.toDouble(), imageSize.height.toDouble()),
                   rotation,
                   cameraLensDirection)
               .round();

packages/example/lib/vision_detector_views/subject_segmenter_view.dart

@@ -12,7 +12,15 @@ class SubjectSegmenterView extends StatefulWidget {
 
 class _SubjectSegmenterViewState extends State<SubjectSegmenterView> {
   final SubjectSegmenter _segmenter = SubjectSegmenter(
-      options: SubjectSegmenterOptions(enableForegroundConfidenceMask: true));
+    options: SubjectSegmenterOptions(
+      enableForegroundConfidenceMask: false,
+      enableForegroundBitmap: false,
+      enableMultipleSubjects: SubjectResultOptions(
+        enableConfidenceMask: true,
+        enableSubjectBitmap: true,
+      ),
+    ),
+  );
   bool _canProcess = true;
   bool _isBusy = false;
   CustomPaint? _customPaint;
@@ -45,7 +53,8 @@ class _SubjectSegmenterViewState extends State<SubjectSegmenterView> {
     setState(() {
       _text = '';
     });
-    final SubjectSegmenterMask mask = await _segmenter.processImage(inputImage);
+    final SubjectSegmentationResult mask =
+        await _segmenter.processImage(inputImage);
     if (inputImage.metadata?.size != null &&
         inputImage.metadata?.rotation != null) {
       final painter = SubjectSegmentationPainter(
@@ -57,7 +66,7 @@ class _SubjectSegmenterViewState extends State<SubjectSegmenterView> {
       _customPaint = CustomPaint(painter: painter);
     } else {
       // TODO: set _customPaint to draw on top of image
-      _text = 'There is a mask with ${mask.subjects?.length} subjects';
+      _text = 'There is a mask with ${mask.subjects.length} subjects';
       _customPaint = null;
     }
     _isBusy = false;

packages/google_mlkit_subject_segmentation/README.md

@@ -88,7 +88,7 @@ final segmenter = SubjectSegmenter(options: options);
 #### Process image
 
 ```dart
-final mask = await segmenter.processImage(inputImage);
+final result = await segmenter.processImage(inputImage);
 ```
 
 #### Release resources with `close()`

packages/google_mlkit_subject_segmentation/android/src/main/java/com/google_mlkit_subject_segmentation/GoogleMlKitSubjectSegmentationPlugin.java

@@ -6,17 +6,17 @@
 import io.flutter.plugin.common.MethodChannel;
 
 public class GoogleMlKitSubjectSegmentationPlugin implements FlutterPlugin {
-  private MethodChannel channel;
-  private static final String channelName = "google_mlkit_subject_segmentation";
+    private MethodChannel channel;
+    private static final String channelName = "google_mlkit_subject_segmentation";
 
-  @Override
-  public void onAttachedToEngine(@NonNull FlutterPluginBinding flutterPluginBinding) {
-      channel = new MethodChannel(flutterPluginBinding.getBinaryMessenger(), channelName);
-      channel.setMethodCallHandler(new SubjectSegmenterProcess(flutterPluginBinding.getApplicationContext()));
-  }
+    @Override
+    public void onAttachedToEngine(@NonNull FlutterPluginBinding flutterPluginBinding) {
+        channel = new MethodChannel(flutterPluginBinding.getBinaryMessenger(), channelName);
+        channel.setMethodCallHandler(new SubjectSegmenter(flutterPluginBinding.getApplicationContext()));
+    }
 
-  @Override
-  public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {
-      channel.setMethodCallHandler(null);
-  }
+    @Override
+    public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {
+        channel.setMethodCallHandler(null);
+    }
 }

packages/google_mlkit_subject_segmentation/android/src/main/java/com/google_mlkit_subject_segmentation/SubjectSegmenter.java

@@ -0,0 +1,154 @@
+package com.google_mlkit_subject_segmentation;
+
+import android.content.Context;
+import android.graphics.Bitmap;
+
+import androidx.annotation.NonNull;
+
+import com.google.mlkit.vision.common.InputImage;
+import com.google.mlkit.vision.segmentation.subject.Subject;
+import com.google.mlkit.vision.segmentation.subject.SubjectSegmentation;
+import com.google.mlkit.vision.segmentation.subject.SubjectSegmentationResult;
+
+import java.io.ByteArrayOutputStream;
+import java.util.ArrayList;
+import java.util.List;
+import java.nio.FloatBuffer;
+import java.util.HashMap;
+import java.util.Map;
+
+import io.flutter.plugin.common.MethodCall;
+import io.flutter.plugin.common.MethodChannel;
+
+import com.google.mlkit.vision.segmentation.subject.SubjectSegmenterOptions;
+import com.google_mlkit_commons.InputImageConverter;
+
+public class SubjectSegmenter implements MethodChannel.MethodCallHandler {
+    private static final String START = "vision#startSubjectSegmenter";
+    private static final String CLOSE = "vision#closeSubjectSegmenter";
+
+    private final Context context;
+
+    private final Map<String, com.google.mlkit.vision.segmentation.subject.SubjectSegmenter> instances = new HashMap<>();
+
+    public SubjectSegmenter(Context context) {
+        this.context = context;
+    }
+
+    @Override
+    public void onMethodCall(@NonNull MethodCall call, @NonNull MethodChannel.Result result) {
+        String method = call.method;
+        switch (method) {
+            case START:
+                handleDetection(call, result);
+                break;
+            case CLOSE:
+                closeDetector(call);
+                result.success(null);
+                break;
+            default:
+                result.notImplemented();
+                break;
+        }
+    }
+
+    private void handleDetection(MethodCall call, MethodChannel.Result result) {
+        Map<String, Object> imageData = (Map<String, Object>) call.argument("imageData");
+        InputImage inputImage = InputImageConverter.getInputImageFromData(imageData, context, result);
+        if (inputImage == null) return;
+
+        String id = call.argument("id");
+        com.google.mlkit.vision.segmentation.subject.SubjectSegmenter subjectSegmenter = getOrCreateSegmenter(id, call);
+        subjectSegmenter.process(inputImage).addOnSuccessListener(subjectSegmentationResult -> processResult(subjectSegmentationResult, result)).addOnFailureListener(e -> result.error("Subject segmentation failure!", e.getMessage(), e));
+    }
+
+    private com.google.mlkit.vision.segmentation.subject.SubjectSegmenter getOrCreateSegmenter(String id, MethodCall call) {
+        return instances.computeIfAbsent(id, k -> initialize(call));
+    }
+
+    private com.google.mlkit.vision.segmentation.subject.SubjectSegmenter initialize(MethodCall call) {
+        Map<String, Object> options = call.argument("options");
+        SubjectSegmenterOptions.Builder builder = new SubjectSegmenterOptions.Builder();
+        assert options != null;
+        configureBuilder(builder, options);
+        return SubjectSegmentation.getClient(builder.build());
+    }
+
+    private void configureBuilder(SubjectSegmenterOptions.Builder builder, Map<String, Object> options) {
+        if (Boolean.TRUE.equals(options.get("enableForegroundBitmap"))) {
+            builder.enableForegroundBitmap();
+        }
+        if (Boolean.TRUE.equals(options.get("enableForegroundConfidenceMask"))) {
+            builder.enableForegroundConfidenceMask();
+        }
+        configureMultipleSubjects(builder, (Map<String, Object>) options.get("enableMultiSubjectBitmap"));
+    }
+
+    private void configureMultipleSubjects(SubjectSegmenterOptions.Builder builder, Map<String, Object> options) {
+        boolean enableConfidenceMask = Boolean.TRUE.equals(options.get("enableConfidenceMask"));
+        boolean enableSubjectBitmap = Boolean.TRUE.equals(options.get("enableSubjectBitmap"));
+        SubjectSegmenterOptions.SubjectResultOptions.Builder subjectResultOptionsBuilder = new SubjectSegmenterOptions.SubjectResultOptions.Builder();
+        if (enableConfidenceMask) subjectResultOptionsBuilder.enableConfidenceMask();
+        if (enableSubjectBitmap) subjectResultOptionsBuilder.enableSubjectBitmap();
+        if (enableConfidenceMask || enableSubjectBitmap) {
+            builder.enableMultipleSubjects(subjectResultOptionsBuilder.build());
+        }
+    }
+
+    private void processResult(SubjectSegmentationResult subjectSegmentationResult, MethodChannel.Result result) {
+        Map<String, Object> resultMap = new HashMap<>();
+        FloatBuffer foregroundConfidenceMask = subjectSegmentationResult.getForegroundConfidenceMask();
+        if (foregroundConfidenceMask != null) {
+            resultMap.put("foregroundConfidenceMask", getConfidenceMask(foregroundConfidenceMask));
+        }
+        Bitmap foregroundBitmap = subjectSegmentationResult.getForegroundBitmap();
+        if (foregroundBitmap != null) {
+            resultMap.put("foregroundBitmap", getBitmapBytes(foregroundBitmap));
+        }
+        List<Map<String, Object>> subjectsData = new ArrayList<>();
+        for (Subject subject : subjectSegmentationResult.getSubjects()) {
+            Map<String, Object> subjectData = getStringObjectMap(subject);
+            subjectsData.add(subjectData);
+        }
+        resultMap.put("subjects", subjectsData);
+        result.success(resultMap);
+    }
+
+    private static float[] getConfidenceMask(FloatBuffer floatBuffer) {
+        float[] mask = new float[floatBuffer.remaining()];
+        floatBuffer.get(mask);
+        return mask;
+    }
+
+    private static byte[] getBitmapBytes(Bitmap bitmap) {
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        bitmap.compress(Bitmap.CompressFormat.PNG, 100, outputStream);
+        return outputStream.toByteArray();
+    }
+
+    @NonNull
+    private static Map<String, Object> getStringObjectMap(Subject subject) {
+        Map<String, Object> subjectData = new HashMap<>();
+        subjectData.put("startX", subject.getStartX());
+        subjectData.put("startY", subject.getStartY());
+        subjectData.put("width", subject.getWidth());
+        subjectData.put("height", subject.getHeight());
+        FloatBuffer confidenceMask = subject.getConfidenceMask();
+        if (confidenceMask != null) {
+            subjectData.put("confidenceMask", getConfidenceMask(confidenceMask));
+        }
+        Bitmap bitmap = subject.getBitmap();
+        if (bitmap != null) {
+            subjectData.put("bitmap", getBitmapBytes(bitmap));
+        }
+        return subjectData;
+    }
+
+    private void closeDetector(MethodCall call) {
+        String id = call.argument("id");
+        com.google.mlkit.vision.segmentation.subject.SubjectSegmenter subjectSegmenter = instances.get(id);
+        if (subjectSegmenter == null) return;
+        subjectSegmenter.close();
+        instances.remove(id);
+    }
+}