Delay back button appearance when performing a quick restart

osu.Game/OsuGame.cs

@@ -1581,12 +1581,20 @@ private void screenChanged(IScreen current, IScreen newScreen)
 
             if (current is IOsuScreen currentOsuScreen)
             {
+                if (currentOsuScreen.AllowBackButton)
+                    BackButton.State.UnbindFrom(currentOsuScreen.BackButtonState);
+
                 OverlayActivationMode.UnbindFrom(currentOsuScreen.OverlayActivationMode);
                 API.Activity.UnbindFrom(currentOsuScreen.Activity);
             }
 
             if (newScreen is IOsuScreen newOsuScreen)
             {
+                if (newOsuScreen.AllowBackButton)
+                    ((IBindable<Visibility>)BackButton.State).BindTo(newOsuScreen.BackButtonState);
+                else
+                    BackButton.Hide();
+
                 OverlayActivationMode.BindTo(newOsuScreen.OverlayActivationMode);
                 API.Activity.BindTo(newOsuScreen.Activity);
 
@@ -1597,11 +1605,6 @@ private void screenChanged(IScreen current, IScreen newScreen)
                 else
                     Toolbar.Show();
 
-                if (newOsuScreen.AllowBackButton)
-                    BackButton.Show();
-                else
-                    BackButton.Hide();
-
                 if (newOsuScreen.ShowFooter)
                 {
                     BackButton.Hide();

osu.Game/Screens/IOsuScreen.cs

@@ -3,8 +3,11 @@
 
 using System.Collections.Generic;
 using osu.Framework.Bindables;
+using osu.Framework.Graphics.Containers;
 using osu.Framework.Screens;
 using osu.Game.Beatmaps;
+using osu.Game.Graphics.UserInterface;
+using osu.Game.Input.Bindings;
 using osu.Game.Overlays;
 using osu.Game.Rulesets;
 using osu.Game.Screens.Footer;
@@ -59,6 +62,15 @@ public interface IOsuScreen : IScreen
         /// </summary>
         IBindable<OverlayActivation> OverlayActivationMode { get; }
 
+        /// <summary>
+        /// Controls the visibility state of <see cref="BackButton"/> to better work with screen-specific transitions (i.e. quick restart in player).
+        /// The back button can still be triggered by the <see cref="GlobalAction.Back"/> action even while hidden.
+        /// </summary>
+        /// <remarks>
+        /// This is ignored when <see cref="AllowBackButton"/> is set to false.
+        /// </remarks>
+        IBindable<Visibility> BackButtonState { get; }
+
         /// <summary>
         /// The current <see cref="UserActivity"/> for this screen.
         /// </summary>

osu.Game/Screens/OsuScreen.cs

@@ -11,6 +11,7 @@
 using osu.Framework.Audio.Sample;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
 using osu.Framework.Screens;
 using osu.Game.Beatmaps;
 using osu.Game.Overlays;
@@ -56,6 +57,10 @@ public abstract partial class OsuScreen : Screen, IOsuScreen, IHasDescription
 
         IBindable<OverlayActivation> IOsuScreen.OverlayActivationMode => OverlayActivationMode;
 
+        public readonly Bindable<Visibility> BackButtonState = new Bindable<Visibility>(Visibility.Visible);
+
+        IBindable<Visibility> IOsuScreen.BackButtonState => BackButtonState;
+
         public virtual bool CursorVisible => true;
 
         protected new OsuGameBase Game => base.Game as OsuGameBase;

osu.Game/Screens/Play/PlayerLoader.cs

@@ -478,6 +478,8 @@ private void contentIn(double delayBeforeSideDisplays = 0)
 
             if (quickRestart)
             {
+                BackButtonState.Value = Visibility.Hidden;
+
                 // A quick restart starts by triggering a fade to black
                 AddInternal(quickRestartBlackLayer = new Box
                 {
@@ -496,6 +498,8 @@ private void contentIn(double delayBeforeSideDisplays = 0)
                     .Delay(quick_restart_initial_delay)
                     .ScaleTo(1)
                     .FadeInFromZero(500, Easing.OutQuint);
+
+                this.Delay(quick_restart_initial_delay).Schedule(() => BackButtonState.Value = Visibility.Visible);
             }
             else
             {