Hide the album play button when scrolling starts

Persephone/Controllers/AlbumViewController.swift

@@ -19,6 +19,8 @@ class AlbumViewController: NSViewController,
   override func viewDidLoad() {
     super.viewDidLoad()
 
+    albumScrollView.postsBoundsChangedNotifications = true
+
     NotificationCenter.default.addObserver(
       self,
       selector: #selector(updateAlbums(_:)),
@@ -69,5 +71,23 @@ class AlbumViewController: NSViewController,
     return albumItem
   }
 
+  func collectionView(_ collectionView: NSCollectionView, layout: NSCollectionViewLayout, sizeForItemAt: IndexPath) -> NSSize {
+    let width = collectionView.frame.size.width
+    var divider: CGFloat = 1
+    var itemWidth: CGFloat = 0
+
+    repeat {
+      let totalPaddingWidth = paddingWidth * 2
+      let totalGutterWidth = (divider - 1) * (gutterWidth + 1)
+      itemWidth = (width - totalPaddingWidth - totalGutterWidth) / divider
+      divider = divider + 1
+    } while itemWidth > 180
+
+    let itemHeight = itemWidth + 39
+
+    return NSSize(width: itemWidth, height: itemHeight)
+  }
+
+  @IBOutlet var albumScrollView: NSScrollView!
   @IBOutlet var albumCollectionView: NSCollectionView!
 }

Persephone/Views/AlbumItemView.swift

@@ -31,15 +31,38 @@ class AlbumItemView: NSView {
     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) {
-    playButton.isHidden = true
+    hidePlayButton()
   }
 
   override func mouseEntered(with event: NSEvent) {
-    playButton.isHidden = false
+    showPlayButton()
   }
 
   override func mouseExited(with event: NSEvent) {
+    hidePlayButton()
+  }
+
+  func showPlayButton() {
+    playButton.isHidden = false
+  }
+
+  func hidePlayButton() {
     playButton.isHidden = true
   }