65 lines
1.6 KiB
Swift
65 lines
1.6 KiB
Swift
//
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// CachedImageView.swift
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// Tusker
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//
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// Created by Shadowfacts on 10/4/22.
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// Copyright © 2022 Shadowfacts. All rights reserved.
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//
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import UIKit
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class CachedImageView: UIImageView {
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private let cache: ImageCache
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private var url: URL?
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private var isGrayscale = false
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private var fetchTask: Task<Void, Error>?
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init(cache: ImageCache) {
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self.cache = cache
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super.init(frame: .zero)
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NotificationCenter.default.addObserver(self, selector: #selector(preferencesChanged), name: .preferencesChanged, object: nil)
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}
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required init?(coder: NSCoder) {
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fatalError("init(coder:) has not been implemented")
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}
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func update(for url: URL?) {
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if url != self.url {
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self.url = url
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updateImage()
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}
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}
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@objc private func preferencesChanged() {
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if isGrayscale != Preferences.shared.grayscaleImages {
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updateImage()
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}
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}
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private func updateImage() {
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fetchTask?.cancel()
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fetchTask = Task(priority: .high) {
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self.image = nil
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guard let url else {
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return
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}
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let (_, image) = await cache.get(url)
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guard let image else {
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return
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}
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try Task.checkCancellation()
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// TODO: check that this isn't on the main thread
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guard let transformedImage = ImageGrayscalifier.convertIfNecessary(url: url, image: image) else {
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return
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}
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try Task.checkCancellation()
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self.image = transformedImage
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}
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}
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}
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