experiment(PodcastPlayerView): add MPMediaItemArtwork to Now Playing — waveform rendered image

Marks/Views/PodcastPlayerView.swift

@@ -282,12 +282,32 @@ final class PodcastPlayerViewModel {
         var info: [String: Any] = [:]
         info[MPMediaItemPropertyTitle] = currentPodcastTitle
         info[MPMediaItemPropertyArtist] = currentArticleTitle.isEmpty ? "Marks" : currentArticleTitle
-        info[MPNowPlayingInfoPropertyPlaybackRate] = isPlaying ? 1.0 : 0.0
+        info[MPNowPlayingInfoPropertyPlaybackRate] = isPlaying ? Double(playbackSpeed) : 0.0
         info[MPNowPlayingInfoPropertyElapsedPlaybackTime] = currentTime
         if duration > 1 { info[MPMediaItemPropertyPlaybackDuration] = duration }
+        if let artwork = Self.nowPlayingArtwork {
+            info[MPMediaItemPropertyArtwork] = artwork
+        }
         MPNowPlayingInfoCenter.default().nowPlayingInfo = info
     }
 
+    private static let nowPlayingArtwork: MPMediaItemArtwork? = {
+        let size = CGSize(width: 300, height: 300)
+        let renderer = UIGraphicsImageRenderer(size: size)
+        let image = renderer.image { ctx in
+            UIColor.systemBlue.withAlphaComponent(0.15).setFill()
+            ctx.fill(CGRect(origin: .zero, size: size))
+            let config = UIImage.SymbolConfiguration(pointSize: 140, weight: .regular)
+            if let symbol = UIImage(systemName: "waveform.circle.fill", withConfiguration: config) {
+                let tinted = symbol.withTintColor(.systemBlue, renderingMode: .alwaysOriginal)
+                let origin = CGPoint(x: (size.width - tinted.size.width) / 2,
+                                     y: (size.height - tinted.size.height) / 2)
+                tinted.draw(at: origin)
+            }
+        }
+        return MPMediaItemArtwork(boundsSize: size) { _ in image }
+    }()
+
     private static func statusLabel(_ status: String) -> String {
         switch status {
         case "queued":    return "Queued…"