exif thumbnail decoding: use raw image descriptor in Flutter on decoded bytes from Android

android/app/src/main/kotlin/deckers/thibault/aves/channel/calls/EmbeddedDataHandler.kt

@@ -10,7 +10,6 @@ import com.adobe.internal.xmp.XMPUtils
 import com.bumptech.glide.load.resource.bitmap.TransformationUtils
 import com.drew.metadata.xmp.XmpDirectory
 import deckers.thibault.aves.channel.calls.Coresult.Companion.safe
-import deckers.thibault.aves.channel.calls.Coresult.Companion.safeSuspend
 import deckers.thibault.aves.metadata.Metadata
 import deckers.thibault.aves.metadata.MultiPage
 import deckers.thibault.aves.metadata.metadataextractor.Helper
@@ -23,7 +22,7 @@ import deckers.thibault.aves.model.FieldMap
 import deckers.thibault.aves.model.provider.ImageProvider
 import deckers.thibault.aves.model.provider.ImageProviderFactory.getProvider
 import deckers.thibault.aves.utils.BitmapUtils
-import deckers.thibault.aves.utils.BitmapUtils.getEncodedBytes
+import deckers.thibault.aves.utils.BitmapUtils.getDecodedBytes
 import deckers.thibault.aves.utils.FileUtils.transferFrom
 import deckers.thibault.aves.utils.LogUtils
 import deckers.thibault.aves.utils.MimeTypes
@@ -47,7 +46,7 @@ class EmbeddedDataHandler(private val context: Context) : MethodCallHandler {
 
     override fun onMethodCall(call: MethodCall, result: MethodChannel.Result) {
         when (call.method) {
-            "getExifThumbnails" -> ioScope.launch { safeSuspend(call, result, ::getExifThumbnails) }
+            "getExifThumbnails" -> ioScope.launch { safe(call, result, ::getExifThumbnails) }
             "extractGoogleDeviceItem" -> ioScope.launch { safe(call, result, ::extractGoogleDeviceItem) }
             "extractJpegMpfItem" -> ioScope.launch { safe(call, result, ::extractJpegMpfItem) }
             "extractMotionPhotoImage" -> ioScope.launch { safe(call, result, ::extractMotionPhotoImage) }
@@ -58,7 +57,7 @@ class EmbeddedDataHandler(private val context: Context) : MethodCallHandler {
         }
     }
 
-    private suspend fun getExifThumbnails(call: MethodCall, result: MethodChannel.Result) {
+    private fun getExifThumbnails(call: MethodCall, result: MethodChannel.Result) {
         val mimeType = call.argument<String>("mimeType")
         val uri = call.argument<String>("uri")?.toUri()
         val sizeBytes = call.argument<Number>("sizeBytes")?.toLong()
@@ -75,7 +74,7 @@ class EmbeddedDataHandler(private val context: Context) : MethodCallHandler {
                     val orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL)
                     exif.thumbnailBitmap?.let { bitmap ->
                         TransformationUtils.rotateImageExif(BitmapUtils.getBitmapPool(context), bitmap, orientation)?.let {
-                            it.getEncodedBytes(canHaveAlpha = false, recycle = false)?.let { bytes -> thumbnails.add(bytes) }
+                            it.getDecodedBytes(recycle = false)?.let { bytes -> thumbnails.add(bytes) }
                         }
                     }
                 }

lib/image_providers/descriptor_provider.dart

@@ -0,0 +1,45 @@
+import 'dart:ui' as ui;
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/widgets.dart';
+
+@immutable
+class DescriptorImageProvider extends ImageProvider<DescriptorImageProvider> {
+  const DescriptorImageProvider(this.descriptor, {this.scale = 1.0});
+
+  final ui.ImageDescriptor descriptor;
+  final double scale;
+
+  @override
+  Future<DescriptorImageProvider> obtainKey(ImageConfiguration configuration) {
+    return SynchronousFuture<DescriptorImageProvider>(this);
+  }
+
+  @override
+  ImageStreamCompleter loadImage(DescriptorImageProvider key, ImageDecoderCallback decode) {
+    return MultiFrameImageStreamCompleter(
+      codec: _loadAsync(key, decode: decode),
+      scale: key.scale,
+      debugLabel: 'DescriptorImageProvider(${describeIdentity(key.descriptor)})',
+    );
+  }
+
+  Future<ui.Codec> _loadAsync(DescriptorImageProvider key, {required ImageDecoderCallback decode}) async {
+    assert(key == this);
+    return descriptor.instantiateCodec();
+  }
+
+  @override
+  bool operator ==(Object other) {
+    if (other.runtimeType != runtimeType) {
+      return false;
+    }
+    return other is DescriptorImageProvider && other.descriptor == descriptor && other.scale == scale;
+  }
+
+  @override
+  int get hashCode => Object.hash(descriptor.hashCode, scale);
+
+  @override
+  String toString() => '${objectRuntimeType(this, 'DescriptorImageProvider')}(${describeIdentity(descriptor)}, scale: ${scale.toStringAsFixed(1)})';
+}

lib/services/media/embedded_data_service.dart

@@ -1,10 +1,13 @@
+import 'dart:ui' as ui;
+
 import 'package:aves/model/entry/entry.dart';
+import 'package:aves/services/common/decoding.dart';
 import 'package:aves/services/common/services.dart';
 import 'package:aves/theme/text.dart';
 import 'package:flutter/services.dart';
 
 abstract class EmbeddedDataService {
-  Future<List<Uint8List>> getExifThumbnails(AvesEntry entry);
+  Future<List<ui.ImageDescriptor?>> getExifThumbnails(AvesEntry entry);
 
   Future<Map> extractGoogleDeviceItem(AvesEntry entry, String dataUri);
 
@@ -23,14 +26,20 @@ class PlatformEmbeddedDataService implements EmbeddedDataService {
   static const _platform = MethodChannel('deckers.thibault/aves/embedded');
 
   @override
-  Future<List<Uint8List>> getExifThumbnails(AvesEntry entry) async {
+  Future<List<ui.ImageDescriptor?>> getExifThumbnails(AvesEntry entry) async {
     try {
       final result = await _platform.invokeMethod('getExifThumbnails', <String, dynamic>{
         'mimeType': entry.mimeType,
         'uri': entry.uri,
         'sizeBytes': entry.sizeBytes,
       });
-      if (result != null) return (result as List).cast<Uint8List>();
+      if (result != null) {
+        final descriptors = <ui.ImageDescriptor?>[];
+        await Future.forEach((result as List).cast<Uint8List>(), (bytes) async {
+          descriptors.add(await InteropDecoding.bytesToCodec(bytes));
+        });
+        return descriptors;
+      }
     } on PlatformException catch (e, stack) {
       await reportService.recordError(e, stack);
     }

lib/widgets/viewer/info/metadata/metadata_thumbnail.dart

@@ -1,6 +1,7 @@
 import 'dart:async';
-import 'dart:typed_data';
+import 'dart:ui' as ui;
 
+import 'package:aves/image_providers/descriptor_provider.dart';
 import 'package:aves/model/entry/entry.dart';
 import 'package:aves/services/common/services.dart';
 import 'package:flutter/material.dart';
@@ -18,7 +19,7 @@ class MetadataThumbnails extends StatefulWidget {
 }
 
 class _MetadataThumbnailsState extends State<MetadataThumbnails> {
-  late Future<List<Uint8List>> _loader;
+  late Future<List<ui.ImageDescriptor?>> _loader;
 
   AvesEntry get entry => widget.entry;
 
@@ -32,7 +33,7 @@ class _MetadataThumbnailsState extends State<MetadataThumbnails> {
 
   @override
   Widget build(BuildContext context) {
-    return FutureBuilder<List<Uint8List>>(
+    return FutureBuilder<List<ui.ImageDescriptor?>>(
         future: _loader,
         builder: (context, snapshot) {
           if (!snapshot.hasError && snapshot.connectionState == ConnectionState.done && snapshot.data!.isNotEmpty) {
@@ -40,10 +41,13 @@ class _MetadataThumbnailsState extends State<MetadataThumbnails> {
               alignment: AlignmentDirectional.topStart,
               padding: const EdgeInsets.only(left: 8, top: 8, right: 8, bottom: 4),
               child: Wrap(
-                children: snapshot.data!.map((bytes) {
-                  return Image.memory(
-                    bytes,
+                children: snapshot.data!.map((descriptor) {
+                  if (descriptor == null) return const SizedBox();
+                  return Image(
+                    image: DescriptorImageProvider(
+                      descriptor,
                       scale: MediaQuery.devicePixelRatioOf(context),
+                    ),
                   );
                 }).toList(),
               ),