47 lines
1.5 KiB
Swift
47 lines
1.5 KiB
Swift
import AppKit
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import Foundation
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import QuickLookThumbnailing
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/// サムネイル生成。QuickLook 任せなので HEIC や RAW もそのまま扱える。
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@MainActor
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final class ThumbnailLoader {
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static let shared = ThumbnailLoader()
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private let cache = NSCache<NSString, NSImage>()
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private init() {
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cache.countLimit = 600
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}
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/// すでに読み込み済みなら即座に返す。スクロールで戻ってきたときに
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/// 一瞬プレースホルダが出るのを防ぐために使う。
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func cached(for url: URL, size: CGFloat) -> NSImage? {
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cache.object(forKey: Self.key(url, size))
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}
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func thumbnail(for url: URL, size: CGFloat) async -> NSImage? {
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let key = Self.key(url, size)
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if let cached = cache.object(forKey: key) { return cached }
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let scale = NSScreen.main?.backingScaleFactor ?? 2
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let request = QLThumbnailGenerator.Request(
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fileAt: url,
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size: CGSize(width: size, height: size),
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scale: scale,
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representationTypes: .thumbnail
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)
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guard let representation = try? await QLThumbnailGenerator.shared
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.generateBestRepresentation(for: request)
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else { return nil }
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let image = NSImage(cgImage: representation.cgImage, size: representation.contentRect.size)
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cache.setObject(image, forKey: key)
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return image
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}
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private static func key(_ url: URL, _ size: CGFloat) -> NSString {
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"\(url.path)|\(Int(size))" as NSString
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}
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}
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