Add a button to albums that plays the album

This works by clearing the queue, adding all the tracks from the album
to the queue and playing the first track.

Fix bug where resize might leave a play button visible

Had to refactor the QueueView somewhat as there was a bug that only
surfaced on clearing and refilling the playlist. The bug was due to the
way NSOutlineView reuses subviews.

Add screenshot with album play button

Move queue datasource and refactor view controller

Move album datasource out of the view controller

Persephone.xcodeproj/project.pbxproj

@@ -16,20 +16,21 @@
 		E408D3B9220DE98F0006D9BE /* NSUserInterfaceItemIdentifier.swift in Sources */ = {isa = PBXBuildFile; fileRef = E408D3B8220DE98F0006D9BE /* NSUserInterfaceItemIdentifier.swift */; };
 		E408D3BE220E03EE0006D9BE /* RawRepresentable.swift in Sources */ = {isa = PBXBuildFile; fileRef = E408D3BD220E03EE0006D9BE /* RawRepresentable.swift */; };
 		E408D3C2220E134F0006D9BE /* AlbumViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = E408D3C1220E134F0006D9BE /* AlbumViewController.swift */; };
-		E408D3CA220E341D0006D9BE /* AlbumItem.swift in Sources */ = {isa = PBXBuildFile; fileRef = E408D3C8220E341D0006D9BE /* AlbumItem.swift */; };
 		E408D3CB220E341D0006D9BE /* AlbumItem.xib in Resources */ = {isa = PBXBuildFile; fileRef = E408D3C9220E341D0006D9BE /* AlbumItem.xib */; };
+		E40F41F3221EDE27004B6CB8 /* Preferences.swift in Sources */ = {isa = PBXBuildFile; fileRef = E40F41F2221EDE27004B6CB8 /* Preferences.swift */; };
 		E40FE719221B48E300A4223F /* AlbumViewLayout.swift in Sources */ = {isa = PBXBuildFile; fileRef = E40FE718221B48E300A4223F /* AlbumViewLayout.swift */; };
 		E40FE71B221B904300A4223F /* NSEvent.swift in Sources */ = {isa = PBXBuildFile; fileRef = E40FE71A221B904300A4223F /* NSEvent.swift */; };
 		E41B22C021FB6BBA00D544F6 /* libmpdclient.2.dylib in Frameworks */ = {isa = PBXBuildFile; fileRef = E41B22BF21FB6BBA00D544F6 /* libmpdclient.2.dylib */; settings = {ATTRIBUTES = (Required, ); }; };
 		E41B22C121FB6C3300D544F6 /* libmpdclient.2.dylib in Embed Libraries */ = {isa = PBXBuildFile; fileRef = E41B22BF21FB6BBA00D544F6 /* libmpdclient.2.dylib */; settings = {ATTRIBUTES = (CodeSignOnCopy, ); }; };
 		E41B22C621FB932700D544F6 /* MPDClient.swift in Sources */ = {isa = PBXBuildFile; fileRef = E41B22C521FB932700D544F6 /* MPDClient.swift */; };
 		E41EA46C221636AF0068EF46 /* PreferencesViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = E41EA46B221636AF0068EF46 /* PreferencesViewController.swift */; };
-		E41EA46F221715910068EF46 /* Preferences.swift in Sources */ = {isa = PBXBuildFile; fileRef = E41EA46E221715910068EF46 /* Preferences.swift */; };
 		E42A8F3B22176D6400A13ED9 /* LICENSE.md in Resources */ = {isa = PBXBuildFile; fileRef = E42A8F3922176D6400A13ED9 /* LICENSE.md */; };
 		E42A8F3C22176D6400A13ED9 /* README.md in Resources */ = {isa = PBXBuildFile; fileRef = E42A8F3A22176D6400A13ED9 /* README.md */; };
 		E465049A21E94DF500A70F4C /* WindowController.swift in Sources */ = {isa = PBXBuildFile; fileRef = E465049921E94DF500A70F4C /* WindowController.swift */; };
 		E47E2FD122205C4600F747E6 /* MainSplitViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = E47E2FD022205C4600F747E6 /* MainSplitViewController.swift */; };
 		E47E2FD322205D2500F747E6 /* MainWindow.swift in Sources */ = {isa = PBXBuildFile; fileRef = E47E2FD222205D2500F747E6 /* MainWindow.swift */; };
+		E47E2FD5222071FD00F747E6 /* AlbumItem.swift in Sources */ = {isa = PBXBuildFile; fileRef = E47E2FD4222071FD00F747E6 /* AlbumItem.swift */; };
+		E47E2FD72220720300F747E6 /* AlbumItemView.swift in Sources */ = {isa = PBXBuildFile; fileRef = E47E2FD62220720300F747E6 /* AlbumItemView.swift */; };
 		E4928E0B2218D62A001D4BEA /* CGColor.swift in Sources */ = {isa = PBXBuildFile; fileRef = E4928E0A2218D62A001D4BEA /* CGColor.swift */; };
 		E4A642DA22090CBE00067D21 /* Status.swift in Sources */ = {isa = PBXBuildFile; fileRef = E4A642D922090CBE00067D21 /* Status.swift */; };
 		E4E8CC902204EC7F0024217A /* Delegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = E4E8CC8F2204EC7F0024217A /* Delegate.swift */; };
@@ -38,6 +39,9 @@
 		E4E8CC9A22075D370024217A /* Song.swift in Sources */ = {isa = PBXBuildFile; fileRef = E4E8CC9922075D370024217A /* Song.swift */; };
 		E4EB2379220F10B8008C70C0 /* Pair.swift in Sources */ = {isa = PBXBuildFile; fileRef = E4EB2378220F10B8008C70C0 /* Pair.swift */; };
 		E4EB237B220F7CF1008C70C0 /* Album.swift in Sources */ = {isa = PBXBuildFile; fileRef = E4EB237A220F7CF1008C70C0 /* Album.swift */; };
+		E4F6B460221E119B00ACF42A /* QueueDataSource.swift in Sources */ = {isa = PBXBuildFile; fileRef = E4F6B45F221E119B00ACF42A /* QueueDataSource.swift */; };
+		E4F6B463221E125900ACF42A /* SongItem.swift in Sources */ = {isa = PBXBuildFile; fileRef = E4F6B462221E125900ACF42A /* SongItem.swift */; };
+		E4F6B467221E233200ACF42A /* AlbumDataSource.swift in Sources */ = {isa = PBXBuildFile; fileRef = E4F6B466221E233200ACF42A /* AlbumDataSource.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -88,8 +92,8 @@
 		E408D3B8220DE98F0006D9BE /* NSUserInterfaceItemIdentifier.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NSUserInterfaceItemIdentifier.swift; sourceTree = "<group>"; };
 		E408D3BD220E03EE0006D9BE /* RawRepresentable.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RawRepresentable.swift; sourceTree = "<group>"; };
 		E408D3C1220E134F0006D9BE /* AlbumViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AlbumViewController.swift; sourceTree = "<group>"; };
-		E408D3C8220E341D0006D9BE /* AlbumItem.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AlbumItem.swift; sourceTree = "<group>"; };
 		E408D3C9220E341D0006D9BE /* AlbumItem.xib */ = {isa = PBXFileReference; lastKnownFileType = file.xib; path = AlbumItem.xib; sourceTree = "<group>"; };
+		E40F41F2221EDE27004B6CB8 /* Preferences.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Preferences.swift; sourceTree = "<group>"; };
 		E40FE718221B48E300A4223F /* AlbumViewLayout.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AlbumViewLayout.swift; sourceTree = "<group>"; };
 		E40FE71A221B904300A4223F /* NSEvent.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NSEvent.swift; sourceTree = "<group>"; };
 		E41B22BF21FB6BBA00D544F6 /* libmpdclient.2.dylib */ = {isa = PBXFileReference; lastKnownFileType = "compiled.mach-o.dylib"; name = libmpdclient.2.dylib; path = libmpdclient/output/libmpdclient.2.dylib; sourceTree = "<group>"; };
@@ -131,12 +135,13 @@
 		E41B22EA21FB966C00D544F6 /* queue.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = queue.h; sourceTree = "<group>"; };
 		E41B22EB21FB966C00D544F6 /* playlist.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = playlist.h; sourceTree = "<group>"; };
 		E41EA46B221636AF0068EF46 /* PreferencesViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PreferencesViewController.swift; sourceTree = "<group>"; };
-		E41EA46E221715910068EF46 /* Preferences.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Preferences.swift; sourceTree = "<group>"; };
 		E42A8F3922176D6400A13ED9 /* LICENSE.md */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = net.daringfireball.markdown; path = LICENSE.md; sourceTree = "<group>"; };
 		E42A8F3A22176D6400A13ED9 /* README.md */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = net.daringfireball.markdown; path = README.md; sourceTree = "<group>"; };
 		E465049921E94DF500A70F4C /* WindowController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WindowController.swift; sourceTree = "<group>"; };
 		E47E2FD022205C4600F747E6 /* MainSplitViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MainSplitViewController.swift; sourceTree = "<group>"; };
 		E47E2FD222205D2500F747E6 /* MainWindow.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MainWindow.swift; sourceTree = "<group>"; };
+		E47E2FD4222071FD00F747E6 /* AlbumItem.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = AlbumItem.swift; sourceTree = "<group>"; };
+		E47E2FD62220720300F747E6 /* AlbumItemView.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = AlbumItemView.swift; sourceTree = "<group>"; };
 		E4928E0A2218D62A001D4BEA /* CGColor.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CGColor.swift; sourceTree = "<group>"; };
 		E4A642D922090CBE00067D21 /* Status.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Status.swift; sourceTree = "<group>"; };
 		E4E8CC8F2204EC7F0024217A /* Delegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Delegate.swift; sourceTree = "<group>"; };
@@ -145,6 +150,9 @@
 		E4E8CC9922075D370024217A /* Song.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Song.swift; sourceTree = "<group>"; };
 		E4EB2378220F10B8008C70C0 /* Pair.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Pair.swift; sourceTree = "<group>"; };
 		E4EB237A220F7CF1008C70C0 /* Album.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Album.swift; sourceTree = "<group>"; };
+		E4F6B45F221E119B00ACF42A /* QueueDataSource.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = QueueDataSource.swift; sourceTree = "<group>"; };
+		E4F6B462221E125900ACF42A /* SongItem.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SongItem.swift; sourceTree = "<group>"; };
+		E4F6B466221E233200ACF42A /* AlbumDataSource.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AlbumDataSource.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -200,7 +208,8 @@
 			isa = PBXGroup;
 			children = (
 				E40FE717221B48CE00A4223F /* Layouts */,
-				E41EA46D221715820068EF46 /* Models */,
+				E4F6B461221E124700ACF42A /* Models */,
+				E4F6B45E221E117600ACF42A /* DataSources */,
 				E407861F2110CE70006887B1 /* Assets.xcassets */,
 				E408D3B7220DE8CC0006D9BE /* Extensions */,
 				E4D1B598220BA3C90026F233 /* Resources */,
@@ -255,7 +264,7 @@
 		E408D3C3220E138B0006D9BE /* Views */ = {
 			isa = PBXGroup;
 			children = (
-				E408D3C8220E341D0006D9BE /* AlbumItem.swift */,
+				E47E2FD62220720300F747E6 /* AlbumItemView.swift */,
 				E47E2FD222205D2500F747E6 /* MainWindow.swift */,
 			);
 			path = Views;
@@ -328,14 +337,6 @@
 			path = mpd;
 			sourceTree = "<group>";
 		};
-		E41EA46D221715820068EF46 /* Models */ = {
-			isa = PBXGroup;
-			children = (
-				E41EA46E221715910068EF46 /* Preferences.swift */,
-			);
-			path = Models;
-			sourceTree = "<group>";
-		};
 		E4A642DB220912FA00067D21 /* MPDClient */ = {
 			isa = PBXGroup;
 			children = (
@@ -369,6 +370,7 @@
 		E4D1B597220BA3A20026F233 /* Controllers */ = {
 			isa = PBXGroup;
 			children = (
+				E47E2FD4222071FD00F747E6 /* AlbumItem.swift */,
 				E408D3C1220E134F0006D9BE /* AlbumViewController.swift */,
 				E41EA46B221636AF0068EF46 /* PreferencesViewController.swift */,
 				E4E8CC932206097F0024217A /* NotificationsController.swift */,
@@ -388,6 +390,24 @@
 			path = Resources;
 			sourceTree = "<group>";
 		};
+		E4F6B45E221E117600ACF42A /* DataSources */ = {
+			isa = PBXGroup;
+			children = (
+				E4F6B45F221E119B00ACF42A /* QueueDataSource.swift */,
+				E4F6B466221E233200ACF42A /* AlbumDataSource.swift */,
+			);
+			path = DataSources;
+			sourceTree = "<group>";
+		};
+		E4F6B461221E124700ACF42A /* Models */ = {
+			isa = PBXGroup;
+			children = (
+				E40F41F2221EDE27004B6CB8 /* Preferences.swift */,
+				E4F6B462221E125900ACF42A /* SongItem.swift */,
+			);
+			path = Models;
+			sourceTree = "<group>";
+		};
 /* End PBXGroup section */
 
 /* Begin PBXNativeTarget section */
@@ -530,25 +550,29 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				E4F6B467221E233200ACF42A /* AlbumDataSource.swift in Sources */,
 				E408D3C2220E134F0006D9BE /* AlbumViewController.swift in Sources */,
 				E40FE71B221B904300A4223F /* NSEvent.swift in Sources */,
 				E4928E0B2218D62A001D4BEA /* CGColor.swift in Sources */,
+				E4F6B460221E119B00ACF42A /* QueueDataSource.swift in Sources */,
 				E4A642DA22090CBE00067D21 /* Status.swift in Sources */,
+				E47E2FD72220720300F747E6 /* AlbumItemView.swift in Sources */,
 				E4E8CC942206097F0024217A /* NotificationsController.swift in Sources */,
 				E40FE719221B48E300A4223F /* AlbumViewLayout.swift in Sources */,
 				E408D3B6220DD8970006D9BE /* Notification.swift in Sources */,
 				E408D3B9220DE98F0006D9BE /* NSUserInterfaceItemIdentifier.swift in Sources */,
 				E4EB2379220F10B8008C70C0 /* Pair.swift in Sources */,
-				E41EA46F221715910068EF46 /* Preferences.swift in Sources */,
+				E4F6B463221E125900ACF42A /* SongItem.swift in Sources */,
 				E465049A21E94DF500A70F4C /* WindowController.swift in Sources */,
 				E41B22C621FB932700D544F6 /* MPDClient.swift in Sources */,
+				E40F41F3221EDE27004B6CB8 /* Preferences.swift in Sources */,
 				E407861C2110CE6E006887B1 /* AppDelegate.swift in Sources */,
 				E47E2FD322205D2500F747E6 /* MainWindow.swift in Sources */,
 				E47E2FD122205C4600F747E6 /* MainSplitViewController.swift in Sources */,
 				E4E8CC9A22075D370024217A /* Song.swift in Sources */,
-				E408D3CA220E341D0006D9BE /* AlbumItem.swift in Sources */,
 				E41EA46C221636AF0068EF46 /* PreferencesViewController.swift in Sources */,
 				E4E8CC902204EC7F0024217A /* Delegate.swift in Sources */,
+				E47E2FD5222071FD00F747E6 /* AlbumItem.swift in Sources */,
 				E408D3BE220E03EE0006D9BE /* RawRepresentable.swift in Sources */,
 				E4E8CC922204F4B80024217A /* QueueViewController.swift in Sources */,
 				E4EB237B220F7CF1008C70C0 /* Album.swift in Sources */,

Persephone/Assets.xcassets/playButtonLarge.imageset/Contents.json

@@ -0,0 +1,25 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "filename" : "playButtonLarge.png",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "filename" : "playButtonLarge@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  },
+  "properties" : {
+    "template-rendering-intent" : "template"
+  }
+}

Persephone/Controllers/AlbumItem.swift

@@ -10,6 +10,7 @@ import Cocoa
 
 class AlbumItem: NSCollectionViewItem {
   var observer: NSKeyValueObservation?
+  var album: MPDClient.Album?
 
   override func viewDidLoad() {
     super.viewDidLoad()
@@ -27,6 +28,7 @@ class AlbumItem: NSCollectionViewItem {
   }
 
   func setAlbum(_ album: MPDClient.Album) {
+    self.album = album
     albumTitle.stringValue = album.title
     albumArtist.stringValue = album.artist
   }
@@ -42,6 +44,12 @@ class AlbumItem: NSCollectionViewItem {
     }
   }
 
+  @IBAction func playAlbum(_ sender: Any) {
+    guard let album = album else { return }
+    
+    AppDelegate.mpdClient.playAlbum(album)
+  }
+
   @IBOutlet var albumCoverView: NSImageView!
   @IBOutlet var albumTitle: NSTextField!
   @IBOutlet var albumArtist: NSTextField!

Persephone/Controllers/AlbumViewController.swift

@@ -9,16 +9,18 @@
 import Cocoa
 
 class AlbumViewController: NSViewController,
-                           NSCollectionViewDataSource,
                            NSCollectionViewDelegate,
                            NSCollectionViewDelegateFlowLayout {
-  var albums: [MPDClient.Album] = []
   let paddingWidth: CGFloat = 40
   let gutterWidth: CGFloat = 20
 
+  var dataSource = AlbumDataSource()
+
   override func viewDidLoad() {
     super.viewDidLoad()
 
+    albumScrollView.postsBoundsChangedNotifications = true
+
     NotificationCenter.default.addObserver(
       self,
       selector: #selector(updateAlbums(_:)),
@@ -32,6 +34,8 @@ class AlbumViewController: NSViewController,
       name: Notification.willDisconnect,
       object: AppDelegate.mpdClient
     )
+
+    albumCollectionView.dataSource = dataSource
   }
 
   override func viewWillLayout() {
@@ -44,30 +48,16 @@ class AlbumViewController: NSViewController,
     guard let albums = notification.userInfo?[Notification.albumsKey] as? [MPDClient.Album]
       else { return }
 
-    self.albums = albums
+    dataSource.albums = albums
-
     albumCollectionView.reloadData()
   }
 
   @objc func clearAlbums(_ notification: Notification) {
-    self.albums = []
+    dataSource.albums = []
 
     albumCollectionView.reloadData()
   }
 
-  func collectionView(_ collectionView: NSCollectionView, numberOfItemsInSection section: Int) -> Int {
+  @IBOutlet var albumScrollView: NSScrollView!
-    return albums.count
-  }
-
-  func collectionView(_ collectionView: NSCollectionView, itemForRepresentedObjectAt indexPath: IndexPath) -> NSCollectionViewItem {
-    let item = collectionView.makeItem(withIdentifier: .albumItem, for: indexPath)
-    guard let albumItem = item as? AlbumItem else { return item }
-
-    albumItem.view.wantsLayer = true
-    albumItem.setAlbum(albums[indexPath.item])
-
-    return albumItem
-  }
-
   @IBOutlet var albumCollectionView: NSCollectionView!
 }

Persephone/Controllers/QueueViewController.swift

@@ -8,11 +8,9 @@
 
 import Cocoa
 
-class QueueViewController: NSViewController, NSOutlineViewDataSource, NSOutlineViewDelegate {
+class QueueViewController: NSViewController,
-  var queue: [MPDClient.Song] = []
+                           NSOutlineViewDelegate {
-  var queuePos: Int = -1
+  var dataSource = QueueDataSource()
-
-  var queueIcon: NSImage? = nil
 
   let systemFontRegular = NSFont.systemFont(ofSize: 13, weight: .regular)
   let systemFontBold = NSFont.systemFont(ofSize: 13, weight: .bold)
@@ -20,16 +18,130 @@ class QueueViewController: NSViewController, NSOutlineViewDataSource, NSOutlineV
   let playIcon = NSImage(named: "playButton")
   let pauseIcon = NSImage(named: "pauseButton")
 
-  struct SongItem {
+  @IBOutlet var queueView: NSOutlineView!
-    var song: MPDClient.Song
-    var queuePos: Int
-  }
 
   override func viewDidLoad() {
     super.viewDidLoad()
 
-    queueView.columnAutoresizingStyle = .sequentialColumnAutoresizingStyle
+    setupNotificationObservers()
 
+    queueView.dataSource = dataSource
+    queueView.columnAutoresizingStyle = .sequentialColumnAutoresizingStyle
+ }
+
+  override func keyDown(with event: NSEvent) {
+    switch event.keyCode {
+    case NSEvent.keyCodeSpace:
+      nextResponder?.keyDown(with: event)
+    default:
+      super.keyDown(with: event)
+    }
+  }
+
+  @IBAction func playTrack(_ sender: Any) {
+    if dataSource.queuePos >= 0 {
+      AppDelegate.mpdClient.playTrack(queuePos: dataSource.queuePos)
+    }
+  }
+
+  @objc func stateChanged(_ notification: Notification) {
+    guard let state = notification.userInfo?[Notification.stateKey] as? MPDClient.Status.State
+      else { return }
+
+    dataSource.setQueueIcon(state)
+  }
+
+  @objc func queueChanged(_ notification: Notification) {
+    guard let queue = notification.userInfo?[Notification.queueKey] as? [MPDClient.Song]
+      else { return }
+
+    dataSource.updateQueue(queue)
+    queueView.reloadData()
+  }
+
+  @objc func queuePosChanged(_ notification: Notification) {
+    guard let queuePos = notification.userInfo?[Notification.queuePosKey] as? Int
+      else { return }
+
+    dataSource.setQueuePos(queuePos)
+
+    queueView.reloadData()
+  }
+
+  func outlineView(
+    _ outlineView: NSOutlineView,
+    selectionIndexesForProposedSelection proposedSelectionIndexes: IndexSet
+    ) -> IndexSet {
+    if proposedSelectionIndexes.contains(0) {
+      return IndexSet()
+    } else {
+      return proposedSelectionIndexes
+    }
+  }
+
+  func outlineView(_ outlineView: NSOutlineView, viewFor tableColumn: NSTableColumn?, item: Any) -> NSView? {
+    if let songItem = item as? SongItem {
+      switch tableColumn?.identifier.rawValue {
+      case "songTitleColumn":
+        return cellForSongTitle(outlineView, with: songItem)
+      case "songArtistColumn":
+        return cellForSongArtist(outlineView, with: songItem)
+      default:
+        return nil
+      }
+    } else if tableColumn?.identifier.rawValue == "songTitleColumn" {
+      return cellForQueueHeading(outlineView)
+    } else {
+      return nil
+    }
+  }
+
+  func cellForSongTitle(_ outlineView: NSOutlineView, with songItem: SongItem) -> NSView {
+    let cellView = outlineView.makeView(
+      withIdentifier: .queueSongTitle,
+      owner: self
+      ) as! NSTableCellView
+
+    cellView.textField?.stringValue = songItem.song.getTag(.title)
+    if songItem.isPlaying {
+      cellView.textField?.font = systemFontBold
+      cellView.imageView?.image = dataSource.queueIcon
+    } else {
+      cellView.textField?.font = systemFontRegular
+      cellView.imageView?.image = nil
+    }
+
+    return cellView
+  }
+
+  func cellForSongArtist(_ outlineView: NSOutlineView, with songItem: SongItem) -> NSView {
+    let cellView = outlineView.makeView(
+      withIdentifier: .queueSongArtist,
+      owner: self
+      ) as! NSTableCellView
+
+    cellView.textField?.stringValue = songItem.song.getTag(.artist)
+    if songItem.isPlaying {
+      cellView.textField?.font = systemFontBold
+    } else {
+      cellView.textField?.font = systemFontRegular
+    }
+
+    return cellView
+  }
+
+  func cellForQueueHeading(_ outlineView: NSOutlineView) -> NSView {
+    let cellView = outlineView.makeView(
+      withIdentifier: .queueHeading,
+      owner: self
+      ) as! NSTableCellView
+
+    cellView.textField?.stringValue = "QUEUE"
+
+    return cellView
+  }
+
+  func setupNotificationObservers() {
     NotificationCenter.default.addObserver(
       self,
       selector: #selector(stateChanged(_:)),
@@ -50,177 +162,5 @@ class QueueViewController: NSViewController, NSOutlineViewDataSource, NSOutlineV
       name: Notification.queuePosChanged,
       object: AppDelegate.mpdClient
     )
-
-    NotificationCenter.default.addObserver(
-      self,
-      selector: #selector(clearQueue(_:)),
-      name: Notification.willDisconnect,
-      object: AppDelegate.mpdClient
-    )
   }
-
-  override func keyDown(with event: NSEvent) {
-    switch event.keyCode {
-    case NSEvent.keyCodeSpace:
-      nextResponder?.keyDown(with: event)
-    default:
-      super.keyDown(with: event)
-    }
-  }
-
-  @IBAction func playTrack(_ sender: Any) {
-    guard let view = sender as? NSOutlineView
-      else { return }
-
-    let queuePos = view.selectedRow - 1
-
-    if queuePos >= 0 {
-      AppDelegate.mpdClient.playTrack(queuePos: queuePos)
-    }
-  }
-
-  @objc func stateChanged(_ notification: Notification) {
-    guard let state = notification.userInfo?[Notification.stateKey] as? MPDClient.Status.State
-      else { return }
-
-    setQueueIcon(state)
-  }
-
-  @objc func queueChanged(_ notification: Notification) {
-    guard let queue = notification.userInfo?[Notification.queueKey] as? [MPDClient.Song]
-      else { return }
-
-    self.queue = queue
-
-    queueView.reloadData()
-  }
-
-  @objc func queuePosChanged(_ notification: Notification) {
-    guard let queuePos = notification.userInfo?[Notification.queuePosKey] as? Int
-      else { return }
-
-    let oldSongRowPos = self.queuePos + 1
-    let newSongRowPos = queuePos + 1
-    self.queuePos = queuePos
-
-    setQueuePos(oldSongRowPos: oldSongRowPos, newSongRowPos: newSongRowPos)
-
-    queueView.reloadData(
-      forRowIndexes: [oldSongRowPos, newSongRowPos],
-      columnIndexes: [0, 1]
-    )
-  }
-
-  @objc func clearQueue(_ notification: Notification) {
-    self.queue = []
-
-    queueView.reloadData()
-  }
-
-  func setQueueIcon(_ state: MPDClient.Status.State) {
-    switch state {
-    case .playing:
-      self.queueIcon = playIcon
-    case .paused:
-      self.queueIcon = pauseIcon
-    default:
-      self.queueIcon = nil
-    }
-  }
-
-  func setQueuePos(oldSongRowPos: Int, newSongRowPos: Int) {
-    if oldSongRowPos > 0 {
-      guard let oldSongRow = queueView.rowView(atRow: oldSongRowPos, makeIfNecessary: true),
-        let oldSongTitleCell = oldSongRow.view(atColumn: 0) as? NSTableCellView
-        else { return }
-
-      setRowFont(rowView: oldSongRow, font: systemFontRegular)
-      oldSongTitleCell.imageView?.image = nil
-    }
-
-    guard let songRow = queueView.rowView(atRow: newSongRowPos, makeIfNecessary: true),
-      let newSongTitleCell = songRow.view(atColumn: 0) as? NSTableCellView
-      else { return }
-
-    setRowFont(rowView: songRow, font: systemFontBold)
-    newSongTitleCell.imageView?.image = self.queueIcon
-  }
-
-  func setRowFont(rowView: NSTableRowView, font: NSFont) {
-    guard let songTitleCell = rowView.view(atColumn: 0) as? NSTableCellView,
-      let songArtistCell = rowView.view(atColumn: 1) as? NSTableCellView
-      else { return }
-
-    songTitleCell.textField?.font = font
-    songArtistCell.textField?.font = font
-  }
-
-  func outlineView(_ outlineView: NSOutlineView, numberOfChildrenOfItem item: Any?) -> Int {
-    return queue.count + 1
-  }
-
-  func outlineView(_ outlineView: NSOutlineView, isItemExpandable item: Any) -> Bool {
-    return false
-  }
-
-  func outlineView(_ outlineView: NSOutlineView, child index: Int, ofItem item: Any?) -> Any {
-    if index > 0 {
-      return SongItem(song: queue[index - 1], queuePos: index - 1)
-    } else {
-      return false
-    }
-  }
-
-  func outlineView(_ outlineView: NSOutlineView, viewFor tableColumn: NSTableColumn?, item: Any) -> NSView? {
-    if let songItem = item as? SongItem {
-      switch tableColumn?.identifier.rawValue {
-      case "songTitleColumn":
-        let cellView = outlineView.makeView(
-          withIdentifier: .queueSongTitle,
-          owner: self
-        ) as! NSTableCellView
-
-        cellView.textField?.stringValue = songItem.song.getTag(.title)
-
-        return cellView
-      case "songArtistColumn":
-        let cellView = outlineView.makeView(
-          withIdentifier: .queueSongArtist,
-          owner: self
-        ) as! NSTableCellView
-
-        cellView.textField?.stringValue = songItem.song.getTag(.artist)
-
-        return cellView
-      default:
-        return nil
-      }
-    } else {
-      if tableColumn?.identifier.rawValue == "songTitleColumn" {
-        let cellView = outlineView.makeView(
-          withIdentifier: .queueHeading,
-          owner: self
-        ) as! NSTableCellView
-
-        cellView.textField?.stringValue = "QUEUE"
-
-        return cellView
-      } else {
-        return nil
-      }
-    }
-  }
-
-  func outlineView(
-    _ outlineView: NSOutlineView,
-    selectionIndexesForProposedSelection proposedSelectionIndexes: IndexSet
-  ) -> IndexSet {
-    if proposedSelectionIndexes.contains(0) {
-      return IndexSet()
-    } else {
-      return proposedSelectionIndexes
-    }
-  }
-
-  @IBOutlet var queueView: NSOutlineView!
 }

Persephone/DataSources/AlbumDataSource.swift

@@ -0,0 +1,27 @@
+//
+//  AlbumDataSource.swift
+//  Persephone
+//
+//  Created by Daniel Barber on 2019/2/20.
+//  Copyright © 2019 Dan Barber. All rights reserved.
+//
+
+import Cocoa
+
+class AlbumDataSource: NSObject, NSCollectionViewDataSource {
+  var albums: [MPDClient.Album] = []
+
+  func collectionView(_ collectionView: NSCollectionView, numberOfItemsInSection section: Int) -> Int {
+    return albums.count
+  }
+
+  func collectionView(_ collectionView: NSCollectionView, itemForRepresentedObjectAt indexPath: IndexPath) -> NSCollectionViewItem {
+    let item = collectionView.makeItem(withIdentifier: .albumItem, for: indexPath)
+    guard let albumItem = item as? AlbumItem else { return item }
+
+    albumItem.view.wantsLayer = true
+    albumItem.setAlbum(albums[indexPath.item])
+
+    return albumItem
+  }
+}

Persephone/DataSources/QueueDataSource.swift

@@ -0,0 +1,65 @@
+//
+//  QueueDataSource.swift
+//  Persephone
+//
+//  Created by Daniel Barber on 2019/2/20.
+//  Copyright © 2019 Dan Barber. All rights reserved.
+//
+
+import Cocoa
+
+class QueueDataSource: NSObject, NSOutlineViewDataSource {
+  var queue: [SongItem] = []
+  var queuePos: Int = -1
+
+  var queueIcon: NSImage? = nil
+
+  let playIcon = NSImage(named: "playButton")
+  let pauseIcon = NSImage(named: "pauseButton")
+
+  func updateQueue(_ queue: [MPDClient.Song]) {
+    self.queue = queue.enumerated().map { index, song in
+      SongItem(song: song, queuePos: index, isPlaying: index == queuePos)
+    }
+  }
+
+  func setQueuePos(_ queuePos: Int) {
+    let oldSongRowPos = self.queuePos
+    let newSongRowPos = queuePos
+    self.queuePos = queuePos
+
+    if oldSongRowPos >= 0 {
+      queue[oldSongRowPos].isPlaying = false
+    }
+    if newSongRowPos >= 0 {
+      queue[newSongRowPos].isPlaying = true
+    }
+  }
+
+  func setQueueIcon(_ state: MPDClient.Status.State) {
+    switch state {
+    case .playing:
+      queueIcon = playIcon
+    case .paused:
+      queueIcon = pauseIcon
+    default:
+      queueIcon = nil
+    }
+  }
+
+  func outlineView(_ outlineView: NSOutlineView, numberOfChildrenOfItem item: Any?) -> Int {
+    return queue.count + 1
+  }
+
+  func outlineView(_ outlineView: NSOutlineView, isItemExpandable item: Any) -> Bool {
+    return false
+  }
+
+  func outlineView(_ outlineView: NSOutlineView, child index: Int, ofItem item: Any?) -> Any {
+    if index > 0 {
+      return queue[index - 1]
+    } else {
+      return false
+    }
+  }
+}

Persephone/MPDClient/MPDClient.swift

@@ -119,6 +119,27 @@ class MPDClient {
     idle()
   }
 
+  func playAlbum(_ album: Album) {
+    noIdle()
+    commandQueue.async { [unowned self] in
+      var songs: [Song] = []
+
+      mpd_run_clear(self.connection)
+      mpd_search_db_songs(self.connection, true)
+      mpd_search_add_tag_constraint(self.connection, MPD_OPERATOR_DEFAULT, MPD_TAG_ALBUM, album.title)
+      mpd_search_add_tag_constraint(self.connection, MPD_OPERATOR_DEFAULT, MPD_TAG_ALBUM_ARTIST, album.artist)
+      mpd_search_commit(self.connection)
+      while let mpdSong = mpd_recv_song(self.connection) {
+        songs.append(Song(mpdSong))
+      }
+      for song in songs {
+        mpd_run_add(self.connection, song.uri)
+      }
+      mpd_run_play_pos(self.connection, 0)
+    }
+    idle()
+  }
+
   func queueCommand(command: Command) {
     guard isConnected else { return }
     

Persephone/MPDClient/Models/Song.swift

@@ -41,6 +41,10 @@ extension MPDClient {
       mpd_song_free(mpdSong)
     }
 
+    var uri: UnsafePointer<Int8> {
+      return mpd_song_get_uri(mpdSong)
+    }
+
     func getTag(_ tagType: TagType) -> String {
       let mpdTagType = mpd_tag_type(rawValue: Int32(tagType.rawValue))
 

Persephone/Models/SongItem.swift

@@ -0,0 +1,15 @@
+//
+//  SongItem.swift
+//  Persephone
+//
+//  Created by Daniel Barber on 2019/2/20.
+//  Copyright © 2019 Dan Barber. All rights reserved.
+//
+
+import Foundation
+
+struct SongItem {
+  var song: MPDClient.Song
+  var queuePos: Int
+  var isPlaying: Bool
+}

Persephone/Resources/AlbumItem.xib

@@ -9,7 +9,7 @@
         <customObject id="-2" userLabel="File's Owner" customClass="AlbumItem" customModule="Persephone" customModuleProvider="target">
             <connections>
                 <outlet property="albumArtist" destination="5Uu-j1-qyT" id="2Et-tX-InT"/>
-                <outlet property="albumCoverView" destination="Kfb-8f-ean" id="ZAL-jD-lHj"/>
+                <outlet property="albumCoverView" destination="Kfb-8f-ean" id="CXx-gB-gz8"/>
                 <outlet property="albumTitle" destination="KEh-NL-c2W" id="SI3-hm-H2B"/>
                 <outlet property="imageView" destination="Kfb-8f-ean" id="Ur0-hX-wJm"/>
                 <outlet property="view" destination="Hz6-mo-xeY" id="v7W-XA-Emc"/>
@@ -17,7 +17,7 @@
         </customObject>
         <customObject id="-1" userLabel="First Responder" customClass="FirstResponder"/>
         <customObject id="-3" userLabel="Application" customClass="NSObject"/>
-        <customView id="Hz6-mo-xeY">
+        <customView id="Hz6-mo-xeY" customClass="AlbumItemView" customModule="Persephone" customModuleProvider="target">
             <rect key="frame" x="0.0" y="0.0" width="128" height="167"/>
             <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
             <subviews>
@@ -41,24 +41,45 @@
                     <rect key="frame" x="0.0" y="39" width="128" height="128"/>
                     <imageCell key="cell" refusesFirstResponder="YES" alignment="left" imageScaling="proportionallyUpOrDown" image="blankAlbum" id="FsA-JX-BFh"/>
                 </imageView>
+                <button hidden="YES" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="n8W-do-HyG">
+                    <rect key="frame" x="43" y="81" width="42" height="43"/>
+                    <constraints>
+                        <constraint firstAttribute="height" constant="42" id="XXC-YE-Ego"/>
+                        <constraint firstAttribute="width" constant="42" id="zcR-GT-zym"/>
+                    </constraints>
+                    <buttonCell key="cell" type="inline" bezelStyle="inline" image="playButtonLarge" imagePosition="only" alignment="center" lineBreakMode="truncatingTail" state="on" borderStyle="border" inset="2" id="T1p-LZ-RpJ">
+                        <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
+                        <font key="font" metaFont="smallSystemBold"/>
+                    </buttonCell>
+                    <connections>
+                        <action selector="playAlbum:" target="-2" id="gNt-Rn-kte"/>
+                    </connections>
+                </button>
             </subviews>
             <constraints>
                 <constraint firstItem="5Uu-j1-qyT" firstAttribute="trailing" secondItem="KEh-NL-c2W" secondAttribute="trailing" id="64z-uz-4nY"/>
                 <constraint firstAttribute="bottom" secondItem="KEh-NL-c2W" secondAttribute="bottom" constant="18" id="8Kg-1r-wNp"/>
                 <constraint firstItem="Kfb-8f-ean" firstAttribute="leading" secondItem="Hz6-mo-xeY" secondAttribute="leading" id="JMi-4i-dgs"/>
                 <constraint firstAttribute="trailing" secondItem="Kfb-8f-ean" secondAttribute="trailing" id="KQC-Wz-Bsg"/>
+                <constraint firstItem="n8W-do-HyG" firstAttribute="centerX" secondItem="KEh-NL-c2W" secondAttribute="centerX" id="Kf1-ws-d4q"/>
                 <constraint firstItem="5Uu-j1-qyT" firstAttribute="leading" secondItem="KEh-NL-c2W" secondAttribute="leading" id="MUo-0i-fX9"/>
                 <constraint firstItem="Kfb-8f-ean" firstAttribute="top" secondItem="Hz6-mo-xeY" secondAttribute="top" id="Qbk-jx-zAi"/>
                 <constraint firstItem="KEh-NL-c2W" firstAttribute="trailing" secondItem="Kfb-8f-ean" secondAttribute="trailing" id="U0w-G4-ggX"/>
                 <constraint firstItem="KEh-NL-c2W" firstAttribute="leading" secondItem="Kfb-8f-ean" secondAttribute="leading" id="V8r-Rc-Dx7"/>
                 <constraint firstAttribute="bottom" secondItem="5Uu-j1-qyT" secondAttribute="bottom" id="gci-4h-pDZ"/>
+                <constraint firstItem="n8W-do-HyG" firstAttribute="centerY" secondItem="Kfb-8f-ean" secondAttribute="centerY" id="pgP-oA-Nxa"/>
                 <constraint firstAttribute="bottom" secondItem="Kfb-8f-ean" secondAttribute="bottom" constant="39" id="sid-zJ-YMA"/>
             </constraints>
+            <connections>
+                <outlet property="imageView" destination="Kfb-8f-ean" id="T7Z-En-dU3"/>
+                <outlet property="playButton" destination="n8W-do-HyG" id="Xw0-iI-svx"/>
+            </connections>
             <point key="canvasLocation" x="-22" y="125.5"/>
         </customView>
         <collectionViewItem id="Qgu-aI-55A" customClass="AlbumItem" customModule="Persephone" customModuleProvider="target"/>
     </objects>
     <resources>
         <image name="blankAlbum" width="128" height="128"/>
+        <image name="playButtonLarge" width="22" height="22"/>
     </resources>
 </document>

Persephone/Resources/Base.lproj/Main.storyboard

@@ -932,7 +932,7 @@
                                                         </tableCellView>
                                                     </prototypeCellViews>
                                                 </tableColumn>
-                                                <tableColumn identifier="songArtistColumn" width="144" minWidth="128" maxWidth="1000" id="SPM-QP-DX8">
+                                                <tableColumn identifier="songArtistColumn" width="144" minWidth="64" maxWidth="1000" id="SPM-QP-DX8">
                                                     <tableHeaderCell key="headerCell" lineBreakMode="truncatingTail" borderStyle="border" alignment="left" title="Artist">
                                                         <font key="font" metaFont="smallSystem"/>
                                                         <color key="textColor" name="headerTextColor" catalog="System" colorSpace="catalog"/>
@@ -949,9 +949,8 @@
                                                             <rect key="frame" x="204" y="1" width="144" height="17"/>
                                                             <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                                             <subviews>
-                                                                <textField verticalHuggingPriority="750" horizontalCompressionResistancePriority="250" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="tBe-Q9-3Rw">
+                                                                <textField verticalHuggingPriority="750" horizontalCompressionResistancePriority="250" translatesAutoresizingMaskIntoConstraints="NO" id="tBe-Q9-3Rw">
-                                                                    <rect key="frame" x="0.0" y="0.0" width="222" height="17"/>
+                                                                    <rect key="frame" x="0.0" y="0.0" width="149" height="17"/>
-                                                                    <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
                                                                     <textFieldCell key="cell" lineBreakMode="truncatingTail" sendsActionOnEndEditing="YES" title="Table View Cell" id="Ceb-ec-ydU">
                                                                         <font key="font" metaFont="system"/>
                                                                         <color key="textColor" name="controlTextColor" catalog="System" colorSpace="catalog"/>
@@ -959,6 +958,11 @@
                                                                     </textFieldCell>
                                                                 </textField>
                                                             </subviews>
+                                                            <constraints>
+                                                                <constraint firstItem="tBe-Q9-3Rw" firstAttribute="centerY" secondItem="JSk-Vc-Y7e" secondAttribute="centerY" id="Tkg-cb-Bg6"/>
+                                                                <constraint firstAttribute="trailing" secondItem="tBe-Q9-3Rw" secondAttribute="trailing" constant="-3" id="VhZ-ua-QQX"/>
+                                                                <constraint firstItem="tBe-Q9-3Rw" firstAttribute="leading" secondItem="JSk-Vc-Y7e" secondAttribute="leading" constant="2" id="cTy-tR-Grg"/>
+                                                            </constraints>
                                                             <connections>
                                                                 <outlet property="textField" destination="tBe-Q9-3Rw" id="2e6-zi-tKj"/>
                                                             </connections>
@@ -968,7 +972,6 @@
                                             </tableColumns>
                                             <connections>
                                                 <action trigger="doubleAction" selector="playTrack:" target="KIP-rq-4dM" id="opa-6G-OW0"/>
-                                                <outlet property="dataSource" destination="KIP-rq-4dM" id="K1Q-7o-xXW"/>
                                                 <outlet property="delegate" destination="KIP-rq-4dM" id="60F-6x-bUE"/>
                                             </connections>
                                         </outlineView>
@@ -1024,7 +1027,6 @@
                                             <collectionViewLayout key="collectionViewLayout" id="YE8-sD-l5P" customClass="AlbumViewLayout" customModule="Persephone" customModuleProvider="target"/>
                                             <color key="primaryBackgroundColor" name="controlBackgroundColor" catalog="System" colorSpace="catalog"/>
                                             <connections>
-                                                <outlet property="dataSource" destination="gPn-fP-LFc" id="2VB-5V-ltv"/>
                                                 <outlet property="delegate" destination="gPn-fP-LFc" id="LQ2-Vl-r08"/>
                                             </connections>
                                         </collectionView>
@@ -1049,6 +1051,7 @@
                     </view>
                     <connections>
                         <outlet property="albumCollectionView" destination="lfq-AB-epE" id="p69-Fs-hCN"/>
+                        <outlet property="albumScrollView" destination="i5f-35-7x8" id="jmd-Sa-Bxt"/>
                     </connections>
                 </viewController>
                 <customObject id="uex-Ws-5X4" userLabel="First Responder" customClass="NSResponder" sceneMemberID="firstResponder"/>

Persephone/Views/AlbumItemView.swift

@@ -0,0 +1,71 @@
+//
+//  AlbumItemView.swift
+//  Persephone
+//
+//  Created by Daniel Barber on 2019/2/17.
+//  Copyright © 2019 Dan Barber. All rights reserved.
+//
+
+import Cocoa
+
+class AlbumItemView: NSView {
+  var trackingArea: NSTrackingArea?
+
+  override func updateTrackingAreas() {
+    super.updateTrackingAreas()
+
+    guard let albumImageView = imageView else { return }
+
+    if let trackingArea = self.trackingArea {
+      self.removeTrackingArea(trackingArea)
+    }
+
+    let trackingArea = NSTrackingArea(
+      rect: albumImageView.frame,
+      options: [.mouseEnteredAndExited, .activeAlways],
+      owner: self,
+      userInfo: nil
+    )
+
+    self.trackingArea = trackingArea
+    addTrackingArea(trackingArea)
+  }
+
+  required init?(coder decoder: NSCoder) {
+    super.init(coder: decoder)
+
+    NotificationCenter.default.addObserver(
+      self,
+      selector: #selector(viewWillScroll(_:)),
+      name: NSScrollView.willStartLiveScrollNotification,
+      object: nil
+    )
+  }
+
+  @objc func viewWillScroll(_ notification: Notification) {
+    hidePlayButton()
+  }
+
+  override func resize(withOldSuperviewSize oldSize: NSSize) {
+    hidePlayButton()
+  }
+
+  override func mouseEntered(with event: NSEvent) {
+    showPlayButton()
+  }
+
+  override func mouseExited(with event: NSEvent) {
+    hidePlayButton()
+  }
+
+  func showPlayButton() {
+    playButton.isHidden = false
+  }
+
+  func hidePlayButton() {
+    playButton.isHidden = true
+  }
+
+  @IBOutlet var imageView: NSImageView!
+  @IBOutlet var playButton: NSButton!
+}