blob: 8641e2139305790219259c865e7f846b5b134014 [file] [log] [blame]
// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'dart:async';
import 'dart:ui' as ui;
import 'package:flutter/foundation.dart';
import 'image_provider.dart' as image_provider;
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 {
/// Creates an object that fetches the image at the given URL.
///
/// The arguments [url] and [scale] must not be null.
const NetworkImage(this.url, {this.scale = 1.0, this.headers})
: assert(url != null),
assert(scale != null);
@override
final String url;
@override
final double scale;
@override
final Map<String, String> headers;
@override
Future<NetworkImage> obtainKey(image_provider.ImageConfiguration configuration) {
return SynchronousFuture<NetworkImage>(this);
}
@override
ImageStreamCompleter load(image_provider.NetworkImage key, image_provider.DecoderCallback decode) {
return MultiFrameImageStreamCompleter(
codec: _loadAsync(key as NetworkImage, decode),
scale: key.scale,
informationCollector: () {
return <DiagnosticsNode>[
DiagnosticsProperty<image_provider.ImageProvider>('Image provider', this),
DiagnosticsProperty<NetworkImage>('Image key', key as NetworkImage),
];
},
);
}
// TODO(garyq): We should eventually support custom decoding of network images on Web as
// well, see https://github.com/flutter/flutter/issues/42789.
//
// 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) {
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
}
@override
bool operator ==(Object other) {
if (other.runtimeType != runtimeType) {
return false;
}
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)';
}