103 lines
3.7 KiB
Swift
103 lines
3.7 KiB
Swift
//
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// Copyright 2023 New Vector Ltd
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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import SwiftUI
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struct LoadableImage<TransformerView: View, PlaceholderView: View>: View {
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private let mediaSource: MediaSourceProxy?
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private let blurhash: String?
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private let size: CGSize?
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private let imageProvider: ImageProviderProtocol?
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private var transformer: (Image) -> TransformerView
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private let placeholder: () -> PlaceholderView
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@State private var cachedImage: UIImage?
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/// A SwiftUI view that automatically fetches images
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/// It will try fetching the image from in-memory cache and if that's not available
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/// it will fire a task to load it through the image provider
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/// - Parameters:
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/// - mediaSource: the source of the image
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/// - blurhash: an optional blurhash
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/// - transformer: entry point for configuring the resulting image view
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/// - placeholder: a view to show while the image or blurhash are not available
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init(mediaSource: MediaSourceProxy?,
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blurhash: String? = nil,
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size: CGSize? = nil,
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imageProvider: ImageProviderProtocol?,
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transformer: @escaping (Image) -> TransformerView = { $0 },
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placeholder: @escaping () -> PlaceholderView) {
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self.mediaSource = mediaSource
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self.blurhash = blurhash
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self.size = size
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self.imageProvider = imageProvider
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self.transformer = transformer
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self.placeholder = placeholder
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}
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init(url: URL?,
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blurhash: String? = nil,
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size: CGSize? = nil,
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imageProvider: ImageProviderProtocol?,
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transformer: @escaping (Image) -> TransformerView = { $0 },
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placeholder: @escaping () -> PlaceholderView) {
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let mediaSource = url.map { MediaSourceProxy(url: $0, mimeType: nil) }
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self.init(mediaSource: mediaSource,
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blurhash: blurhash,
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size: size,
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imageProvider: imageProvider,
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transformer: transformer,
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placeholder: placeholder)
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}
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var body: some View {
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let _ = Task {
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// Future improvement: Does guarding against a nil image prevent the image being updated when the URL changes?
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guard image == nil, let mediaSource else { return }
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if case let .success(image) = await imageProvider?.loadImageFromSource(mediaSource, size: size) {
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self.cachedImage = image
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}
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}
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ZStack {
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if let image {
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transformer(
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Image(uiImage: image)
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.resizable()
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)
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} else if let blurhash,
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// Build a small blurhash image so that it's fast
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let image = UIImage(blurHash: blurhash, size: .init(width: 10.0, height: 10.0)) {
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transformer(
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Image(uiImage: image)
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.resizable()
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)
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} else {
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placeholder()
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}
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}
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.animation(.elementDefault, value: image)
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}
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private var image: UIImage? {
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cachedImage ?? imageProvider?.imageFromSource(mediaSource, size: size)
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}
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}
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