feat: thumbnail icon

QLThumbnail/ThumbnailProvider.swift

@@ -0,0 +1,43 @@
+import QuickLookThumbnailing
+import os // OSLog
+
+// show Console logs with subsystem:de.relikd.QLApps
+private let log = OSLog(subsystem: Bundle.main.bundleIdentifier!, category: "thumbnail-plugin")
+
+extension QLThumbnailReply {
+	/// call private method `setIconFlavor:`
+	/// see https://medium.com/swlh/calling-ios-and-macos-hidden-api-in-style-1a924f244ad1
+	fileprivate func setFlavor(_ flavor: Int) {
+		typealias setIconFlavorMethod = @convention(c) (NSObject, Selector, NSInteger) -> Bool
+		let selector = NSSelectorFromString("setIconFlavor:")
+		let imp = self.method(for: selector)
+		let method = unsafeBitCast(imp, to: setIconFlavorMethod.self)
+		_ = method(self, selector, flavor)
+	}
+}
+
+class ThumbnailProvider: QLThumbnailProvider {
+	
+	// TODO: sadly, this does not seem to work for .xarchive and .appex
+	// Probably overwritten by Apple somehow
+	
+	override func provideThumbnail(for request: QLFileThumbnailRequest, _ handler: @escaping (QLThumbnailReply?, Error?) -> Void) {
+		let meta = QuickLookInfo(request.fileURL)
+		let icon = AppIcon(meta)
+		let plistApp = meta.readPlistApp()
+		let img = icon.extractImage(from: plistApp).withRoundCorners()
+		
+		// First way: Draw the thumbnail into the current context, set up with UIKit's coordinate system.
+		let reply = QLThumbnailReply(contextSize: request.maximumSize, currentContextDrawing: { () -> Bool in
+			img.draw(in: CGRect(origin: .zero, size: request.maximumSize))
+			return true
+		})
+		// defer in case `setFlavor` fails
+		defer {
+			handler(reply, nil)
+		}
+		// 0: Plain transparent, 1: Shadow, 2: Book, 3: Movie, 4: Address, 5: Image,
+		// 6: Gloss, 7: Slide, 8: Square, 9: Border, 11: Calendar, 12: Pattern
+		reply.setFlavor(meta.type == .Archive ? 12 : 0) // .archive looks like "in development"
+	}
+}