Tweak slider ball fade to be less present after slider ends

osu.Game.Rulesets.Osu/Skinning/Argon/ArgonSliderBall.cs

@@ -1,11 +1,14 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Colour;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Shapes;
 using osu.Framework.Graphics.Sprites;
+using osu.Game.Rulesets.Objects.Drawables;
+using osu.Game.Rulesets.Osu.Objects.Drawables;
 using osuTK;
 using osuTK.Graphics;
 
@@ -16,6 +19,11 @@ public class ArgonSliderBall : CircularContainer
         private readonly Box fill;
         private readonly SpriteIcon icon;
 
+        private readonly Vector2 defaultIconScale = new Vector2(0.6f, 0.8f);
+
+        [Resolved(canBeNull: true)]
+        private DrawableHitObject? parentObject { get; set; }
+
         public ArgonSliderBall()
         {
             Size = new Vector2(ArgonMainCirclePiece.OUTER_GRADIENT_SIZE);
@@ -37,7 +45,7 @@ public ArgonSliderBall()
                 icon = new SpriteIcon
                 {
                     Size = new Vector2(48),
-                    Scale = new Vector2(0.6f, 0.8f),
+                    Scale = defaultIconScale,
                     Icon = FontAwesome.Solid.AngleRight,
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre,
@@ -45,11 +53,57 @@ public ArgonSliderBall()
             };
         }
 
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            if (parentObject != null)
+            {
+                parentObject.ApplyCustomUpdateState += updateStateTransforms;
+                updateStateTransforms(parentObject, parentObject.State.Value);
+            }
+        }
+
+        private void updateStateTransforms(DrawableHitObject drawableObject, ArmedState _)
+        {
+            // Gets called by slider ticks, tails, etc., leading to duplicated
+            // animations which in this case have no visual impact (due to
+            // instant fade) but may negatively affect performance
+            if (drawableObject is not DrawableSlider)
+                return;
+
+            const float duration = 200;
+            const float icon_scale = 0.9f;
+
+            using (BeginAbsoluteSequence(drawableObject.StateUpdateTime))
+            {
+                this.FadeInFromZero(duration, Easing.OutQuint);
+                icon.ScaleTo(0).Then().ScaleTo(defaultIconScale, duration, Easing.OutElasticHalf);
+            }
+
+            using (BeginAbsoluteSequence(drawableObject.HitStateUpdateTime))
+            {
+                this.FadeOut(duration, Easing.OutQuint);
+                icon.ScaleTo(defaultIconScale * icon_scale, duration, Easing.OutQuint);
+            }
+        }
+
         protected override void Update()
         {
             base.Update();
 
-            fill.Rotation = -Rotation;
+            //undo rotation on layers which should not be rotated.
+            float appliedRotation = Parent.Rotation;
+
+            fill.Rotation = -appliedRotation;
+        }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+
+            if (parentObject != null)
+                parentObject.ApplyCustomUpdateState -= updateStateTransforms;
         }
     }
 }