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silica-viewer/Thumbnail/ThumbnailProvider.swift

66 lines
3 KiB
Swift

import QuickLookThumbnailing
import ZIPFoundation
import Cocoa
class ThumbnailProvider: QLThumbnailProvider {
override func provideThumbnail(for request: QLFileThumbnailRequest, _ handler: @escaping (QLThumbnailReply?, Error?) -> Void) {
let fc: NSFileCoordinator = NSFileCoordinator()
let intent: NSFileAccessIntent = NSFileAccessIntent.readingIntent(with: request.fileURL)
fc.coordinate(with: [intent], queue: .main) { (err) in
if err == nil {
do {
guard let archive = Archive(data: try Data(contentsOf: intent.url), accessMode: Archive.AccessMode.read) else {
return
}
guard let entry = archive[ThumbnailPath] else {
return
}
guard let thumbnailData = readData(archive: archive, entry: entry) else {
return
}
let image = NSImage(data: thumbnailData)
let maximumSize = request.maximumSize
let imageSize = image?.size
var newImageSize = maximumSize
var contextSize = maximumSize
let aspectRatio = imageSize!.height / imageSize!.width
let proposedHeight = aspectRatio * maximumSize.width
if proposedHeight <= maximumSize.height {
newImageSize.height = proposedHeight
contextSize.height = max(proposedHeight.rounded(.down), request.minimumSize.height)
} else {
newImageSize.width = maximumSize.height / aspectRatio
contextSize.width = max(newImageSize.width.rounded(.down), request.minimumSize.width)
}
let reply: QLThumbnailReply = QLThumbnailReply.init(contextSize: contextSize) { () -> Bool in
if image != nil {
image!.draw(in: CGRect(x: contextSize.width/2 - newImageSize.width/2,
y: contextSize.height/2 - newImageSize.height/2,
width: newImageSize.width,
height: newImageSize.height));
return true
} else {
return false
}
}
handler(reply, nil)
} catch {
NSLog("Could not load file \(intent.url.lastPathComponent) to preview it")
handler(nil, nil)
}
} else {
NSLog("Could not find file \(intent.url.lastPathComponent) to preview it")
handler(nil, nil)
}
}
}
}