122 lines
3.9 KiB
Dart
122 lines
3.9 KiB
Dart
import 'dart:ui' as ui show Codec;
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import 'package:aves/model/image_entry.dart';
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import 'package:aves/services/image_file_service.dart';
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import 'package:flutter/foundation.dart';
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import 'package:flutter/material.dart';
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class ThumbnailProvider extends ImageProvider<ThumbnailProviderKey> {
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final ThumbnailProviderKey key;
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ThumbnailProvider(this.key) : assert(key != null);
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@override
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Future<ThumbnailProviderKey> obtainKey(ImageConfiguration configuration) {
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// configuration can be empty (e.g. when obtaining key for eviction)
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// so we do not compute the target width/height here
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// and pass it to the key, to use it later for image loading
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return SynchronousFuture<ThumbnailProviderKey>(key);
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}
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@override
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ImageStreamCompleter load(ThumbnailProviderKey key, DecoderCallback decode) {
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return MultiFrameImageStreamCompleter(
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codec: _loadAsync(key, decode),
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scale: key.scale,
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informationCollector: () sync* {
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yield ErrorDescription('uri=${key.uri}, extent=${key.extent}');
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},
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);
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}
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Future<ui.Codec> _loadAsync(ThumbnailProviderKey key, DecoderCallback decode) async {
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final uri = key.uri;
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final mimeType = key.mimeType;
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try {
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final bytes = await ImageFileService.getThumbnail(
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uri,
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mimeType,
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key.dateModifiedSecs,
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key.rotationDegrees,
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key.isFlipped,
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key.extent,
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key.extent,
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taskKey: key,
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);
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if (bytes == null) {
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throw StateError('$uri ($mimeType) loading failed');
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}
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return await decode(bytes);
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} catch (error) {
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debugPrint('$runtimeType _loadAsync failed with uri=$uri, error=$error');
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throw StateError('$mimeType decoding failed');
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}
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}
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@override
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void resolveStreamForKey(ImageConfiguration configuration, ImageStream stream, ThumbnailProviderKey key, ImageErrorListener handleError) {
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ImageFileService.resumeLoading(key);
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super.resolveStreamForKey(configuration, stream, key, handleError);
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}
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void pause() => ImageFileService.cancelThumbnail(key);
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}
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class ThumbnailProviderKey {
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final String uri, mimeType;
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final int dateModifiedSecs, rotationDegrees;
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final bool isFlipped;
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final double extent, scale;
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const ThumbnailProviderKey({
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@required this.uri,
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@required this.mimeType,
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@required this.dateModifiedSecs,
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@required this.rotationDegrees,
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@required this.isFlipped,
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this.extent = 0,
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this.scale = 1,
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}) : assert(uri != null),
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assert(mimeType != null),
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assert(dateModifiedSecs != null),
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assert(rotationDegrees != null),
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assert(isFlipped != null),
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assert(extent != null),
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assert(scale != null);
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// do not store the entry as it is, because the key should be constant
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// but the entry attributes may change over time
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factory ThumbnailProviderKey.fromEntry(ImageEntry entry, {double extent = 0}) {
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return ThumbnailProviderKey(
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uri: entry.uri,
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mimeType: entry.mimeType,
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// `dateModifiedSecs` can be missing in viewer mode
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dateModifiedSecs: entry.dateModifiedSecs ?? -1,
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rotationDegrees: entry.rotationDegrees,
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isFlipped: entry.isFlipped,
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extent: extent,
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);
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}
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@override
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bool operator ==(Object other) {
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if (other.runtimeType != runtimeType) return false;
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return other is ThumbnailProviderKey && other.uri == uri && other.extent == extent && other.mimeType == mimeType && other.dateModifiedSecs == dateModifiedSecs && other.rotationDegrees == rotationDegrees && other.isFlipped == isFlipped && other.scale == scale;
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}
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@override
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int get hashCode => hashValues(
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uri,
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mimeType,
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dateModifiedSecs,
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rotationDegrees,
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isFlipped,
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extent,
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scale,
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);
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@override
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String toString() {
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return 'ThumbnailProviderKey{uri=$uri, mimeType=$mimeType, dateModifiedSecs=$dateModifiedSecs, rotationDegrees=$rotationDegrees, isFlipped=$isFlipped, extent=$extent, scale=$scale}';
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}
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}
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