Pause animated background when app is in background

FreeAPS/Sources/AnimatedBackground/SnowScene.swift

@@ -1,3 +1,4 @@
+import Foundation
 import SpriteKit
 
 class SnowScene: SKScene {
@@ -9,6 +10,22 @@ class SnowScene: SKScene {
         snowEmitterNode.particleLifetime = 2
         snowEmitterNode.particleLifetimeRange = 6
         addChild(snowEmitterNode)
+        subscribe()
+    }
+
+    private func subscribe() {
+        Foundation.NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(didEnterBackground),
+            name: UIApplication.didEnterBackgroundNotification,
+            object: nil
+        )
+        Foundation.NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(willEnterForeground),
+            name: UIApplication.willEnterForegroundNotification,
+            object: nil
+        )
     }
 
     override func didChangeSize(_: CGSize) {
@@ -16,4 +33,12 @@ class SnowScene: SKScene {
         snowEmitterNode.particlePosition = CGPoint(x: size.width / 2, y: size.height)
         snowEmitterNode.particlePositionRange = CGVector(dx: size.width, dy: size.height)
     }
+
+    @objc private func didEnterBackground() {
+        isPaused = true
+    }
+
+    @objc private func willEnterForeground() {
+        isPaused = false
+    }
 }