aves/lib/widgets/common/image_providers/uri_region_provider.dart
Thibault Deckers ceed01f3ed tiling (WIP)
2020-11-05 11:38:04 +09:00

81 lines
2.3 KiB
Dart

import 'dart:async';
import 'dart:ui' as ui show Codec;
import 'package:aves/services/image_file_service.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:pedantic/pedantic.dart';
class UriRegion extends ImageProvider<UriRegion> {
const UriRegion({
@required this.uri,
@required this.mimeType,
@required this.rotationDegrees,
@required this.isFlipped,
@required this.sampleSize,
@required this.rect,
this.scale = 1.0,
}) : assert(uri != null),
assert(scale != null);
final String uri, mimeType;
final int rotationDegrees, sampleSize;
final bool isFlipped;
final Rect rect;
final double scale;
@override
Future<UriRegion> obtainKey(ImageConfiguration configuration) {
return SynchronousFuture<UriRegion>(this);
}
@override
ImageStreamCompleter load(UriRegion key, DecoderCallback decode) {
final chunkEvents = StreamController<ImageChunkEvent>();
return MultiFrameImageStreamCompleter(
codec: _loadAsync(key, decode, chunkEvents),
scale: key.scale,
chunkEvents: chunkEvents.stream,
informationCollector: () sync* {
yield ErrorDescription('uri=$uri, mimeType=$mimeType');
},
);
}
Future<ui.Codec> _loadAsync(UriRegion key, DecoderCallback decode, StreamController<ImageChunkEvent> chunkEvents) async {
assert(key == this);
try {
final bytes = await ImageFileService.getRegion(
uri,
mimeType,
rotationDegrees,
isFlipped,
sampleSize,
rect,
);
if (bytes == null) {
throw StateError('$uri ($mimeType) loading failed');
}
return await decode(bytes);
} catch (error) {
debugPrint('$runtimeType _loadAsync failed with mimeType=$mimeType, uri=$uri, error=$error');
throw StateError('$mimeType decoding failed');
} finally {
unawaited(chunkEvents.close());
}
}
@override
bool operator ==(Object other) {
if (other.runtimeType != runtimeType) return false;
return other is UriRegion && other.uri == uri && other.sampleSize == sampleSize && other.rect == rect && other.scale == scale;
}
@override
int get hashCode => hashValues(uri, sampleSize, rect, scale);
@override
String toString() => '${objectRuntimeType(this, 'UriRegion')}(uri=$uri, mimeType=$mimeType, scale=$scale)';
}