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[web] Add support for ChunkEvents during image loading (#52558)

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* Add support for ChunkEvents for web
* Add lint skip for webOnly call in _network_image_web
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Ferhat 2020-03-17 16:07:21 -07:00 committed by GitHub
parent 757b39ba99
commit d3a66e3107
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 42 additions and 15 deletions
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57
packages/flutter/lib/src/painting/_network_image_web.dart
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@ -13,7 +13,9 @@ import 'image_stream.dart';
/// The dart:html implementation of [image_provider.NetworkImage].
///
/// NetworkImage on the web does not support decoding to a specified size.
class NetworkImage extends image_provider.ImageProvider<image_provider.NetworkImage> implements image_provider.NetworkImage {
class NetworkImage
extends image_provider.ImageProvider<image_provider.NetworkImage>
implements image_provider.NetworkImage {
/// Creates an object that fetches the image at the given URL.
///
/// The arguments [url] and [scale] must not be null.
@ -31,22 +33,41 @@ class NetworkImage extends image_provider.ImageProvider<image_provider.NetworkIm
final Map<String, String> headers;
@override
Future<NetworkImage> obtainKey(image_provider.ImageConfiguration configuration) {
Future<NetworkImage> obtainKey(
image_provider.ImageConfiguration configuration) {
return SynchronousFuture<NetworkImage>(this);
}
@override
ImageStreamCompleter load(image_provider.NetworkImage key, image_provider.DecoderCallback decode) {
ImageStreamCompleter load(
image_provider.NetworkImage key, image_provider.DecoderCallback decode) {
// Ownership of this controller is handed off to [_loadAsync]; it is that
// method's responsibility to close the controller's stream when the image
// has been loaded or an error is thrown.
final StreamController<ImageChunkEvent> chunkEvents =
StreamController<ImageChunkEvent>();
return MultiFrameImageStreamCompleter(
codec: _loadAsync(key as NetworkImage, decode),
scale: key.scale,
informationCollector: () {
chunkEvents: chunkEvents.stream,
codec: _loadAsync(key as NetworkImage, decode, chunkEvents),
scale: key.scale,
informationCollector: _imageStreamInformationCollector(key));
}
InformationCollector _imageStreamInformationCollector(
image_provider.NetworkImage key) {
InformationCollector collector;
assert(() {
collector = () {
return <DiagnosticsNode>[
DiagnosticsProperty<image_provider.ImageProvider>('Image provider', this),
DiagnosticsProperty<image_provider.ImageProvider>(
'Image provider', this),
DiagnosticsProperty<NetworkImage>('Image key', key as NetworkImage),
];
},
);
};
return true;
}());
return collector;
}
// TODO(garyq): We should eventually support custom decoding of network images on Web as
@ -55,13 +76,20 @@ class NetworkImage extends image_provider.ImageProvider<image_provider.NetworkIm
// Web does not support decoding network images to a specified size. The decode parameter
// here is ignored and the web-only `ui.webOnlyInstantiateImageCodecFromUrl` will be used
// directly in place of the typical `instantiateImageCodec` method.
Future<ui.Codec> _loadAsync(NetworkImage key, image_provider.DecoderCallback decode) {
Future<ui.Codec> _loadAsync(
NetworkImage key,
image_provider.DecoderCallback decode,
StreamController<ImageChunkEvent> chunkEvents) {
assert(key == this);
final Uri resolved = Uri.base.resolve(key.url);
// This API only exists in the web engine implementation and is not
// contained in the analyzer summary for Flutter.
return ui.webOnlyInstantiateImageCodecFromUrl(resolved) as Future<ui.Codec>; // ignore: undefined_function
return ui.webOnlyInstantiateImageCodecFromUrl(resolved, // ignore: undefined_function
chunkCallback: (int bytes, int total) {
chunkEvents.add(ImageChunkEvent(
cumulativeBytesLoaded: bytes, expectedTotalBytes: total));
}) as Future<ui.Codec>; // ignore: undefined_function
}
@override
@ -69,14 +97,13 @@ class NetworkImage extends image_provider.ImageProvider<image_provider.NetworkIm
if (other.runtimeType != runtimeType) {
return false;
}
return other is NetworkImage
&& other.url == url
&& other.scale == scale;
return other is NetworkImage && other.url == url && other.scale == scale;
}
@override
int get hashCode => ui.hashValues(url, scale);
@override
String toString() => '${objectRuntimeType(this, 'NetworkImage')}("$url", scale: $scale)';
String toString() =>
'${objectRuntimeType(this, 'NetworkImage')}("$url", scale: $scale)';
}