129 lines
4 KiB
Dart
129 lines
4 KiB
Dart
import 'dart:async';
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import 'dart:math';
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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 RegionProvider extends ImageProvider<RegionProviderKey> {
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final RegionProviderKey key;
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RegionProvider(this.key) : assert(key != null);
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@override
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Future<RegionProviderKey> obtainKey(ImageConfiguration configuration) {
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return SynchronousFuture<RegionProviderKey>(key);
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}
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@override
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ImageStreamCompleter load(RegionProviderKey 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=${key.uri}, regionRect=${key.regionRect}');
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},
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);
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}
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Future<ui.Codec> _loadAsync(RegionProviderKey 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.getRegion(
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uri,
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mimeType,
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key.rotationDegrees,
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key.isFlipped,
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key.sampleSize,
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key.regionRect,
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key.imageSize,
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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) region 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('$runtimeType _loadAsync failed with mimeType=$mimeType, uri=$uri, error=$error');
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throw StateError('$mimeType region 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, RegionProviderKey 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.cancelRegion(key);
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}
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class RegionProviderKey {
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final String uri, mimeType;
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final int rotationDegrees, sampleSize;
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final bool isFlipped;
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final Rectangle<int> regionRect;
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final Size imageSize;
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final double scale;
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const RegionProviderKey({
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@required this.uri,
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@required this.mimeType,
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@required this.rotationDegrees,
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@required this.isFlipped,
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@required this.sampleSize,
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@required this.regionRect,
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@required this.imageSize,
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this.scale = 1.0,
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}) : assert(uri != null),
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assert(mimeType != null),
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assert(rotationDegrees != null),
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assert(isFlipped != null),
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assert(sampleSize != null),
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assert(regionRect != null),
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assert(imageSize != 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 RegionProviderKey.fromEntry(
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ImageEntry entry, {
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@required int sampleSize,
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@required Rectangle<int> rect,
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}) {
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return RegionProviderKey(
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uri: entry.uri,
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mimeType: entry.mimeType,
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rotationDegrees: entry.rotationDegrees,
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isFlipped: entry.isFlipped,
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sampleSize: sampleSize,
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regionRect: rect,
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imageSize: Size(entry.width.toDouble(), entry.height.toDouble()),
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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 RegionProviderKey && other.uri == uri && other.mimeType == mimeType && other.rotationDegrees == rotationDegrees && other.isFlipped == isFlipped && other.sampleSize == sampleSize && other.regionRect == regionRect && other.imageSize == imageSize && 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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rotationDegrees,
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isFlipped,
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mimeType,
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sampleSize,
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regionRect,
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imageSize,
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scale,
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);
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@override
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String toString() => '$runtimeType#${shortHash(this)}{uri=$uri, mimeType=$mimeType, rotationDegrees=$rotationDegrees, isFlipped=$isFlipped, sampleSize=$sampleSize, regionRect=$regionRect, imageSize=$imageSize, scale=$scale}';
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}
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