osx: implements quicklook

osx/kordophone2/Transcript/PreviewPanel.swift

@@ -0,0 +1,39 @@
+//
+//  PreviewPanel.swift
+//  Kordophone
+//
+//  Created by James Magahern on 9/12/25.
+//
+
+import AppKit
+import QuickLook
+import QuickLookUI
+
+internal class PreviewPanel
+{
+    static let shared = PreviewPanel()
+
+    private var displayedURL: URL? = nil
+    private var impl: QLPreviewPanel { QLPreviewPanel.shared() }
+
+    private init() {
+        impl.dataSource = self
+    }
+
+    public func show(url: URL) {
+        self.displayedURL = url
+        impl.makeKeyAndOrderFront(self)
+    }
+}
+
+
+extension PreviewPanel: QLPreviewPanelDataSource
+{
+    func numberOfPreviewItems(in panel: QLPreviewPanel!) -> Int {
+        1
+    }
+
+    func previewPanel(_ panel: QLPreviewPanel!, previewItemAt index: Int) -> (any QLPreviewItem)! {
+        return displayedURL! as NSURL
+    }
+}