Fix cursor scale animation not matching stable on classic skins

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

@@ -13,7 +13,7 @@
 
 namespace osu.Game.Rulesets.Osu.Skinning.Argon
 {
-    public partial class ArgonCursor : OsuCursorSprite
+    public partial class ArgonCursor : SkinnableCursor
     {
         public ArgonCursor()
         {

osu.Game.Rulesets.Osu/Skinning/Legacy/LegacyCursor.cs

@@ -9,8 +9,11 @@
 
 namespace osu.Game.Rulesets.Osu.Skinning.Legacy
 {
-    public partial class LegacyCursor : OsuCursorSprite
+    public partial class LegacyCursor : SkinnableCursor
     {
+        private const float pressed_scale = 1.3f;
+        private const float released_scale = 1f;
+
         private readonly ISkin skin;
         private bool spin;
 
@@ -51,5 +54,16 @@ protected override void LoadComplete()
             if (spin)
                 ExpandTarget.Spin(10000, RotationDirection.Clockwise);
         }
+
+        public override void Expand()
+        {
+            ExpandTarget?.ScaleTo(released_scale)
+                        .ScaleTo(pressed_scale, 100, Easing.Out);
+        }
+
+        public override void Contract()
+        {
+            ExpandTarget?.ScaleTo(released_scale, 100, Easing.Out);
+        }
     }
 }

osu.Game.Rulesets.Osu/UI/Cursor/OsuCursor.cs

@@ -24,15 +24,12 @@ public partial class OsuCursor : SkinReloadableDrawable
     {
         public const float SIZE = 28;
 
-        private const float pressed_scale = 1.2f;
-        private const float released_scale = 1f;
-
         private bool cursorExpand;
 
         private SkinnableDrawable cursorSprite;
         private Container cursorScaleContainer = null!;
 
-        private Drawable expandTarget => (cursorSprite.Drawable as OsuCursorSprite)?.ExpandTarget ?? cursorSprite;
+        private SkinnableCursor skinnableCursor => (SkinnableCursor)cursorSprite.Drawable;
 
         public IBindable<float> CursorScale => cursorScale;
 
@@ -108,18 +105,18 @@ public void Expand()
         {
             if (!cursorExpand) return;
 
-            expandTarget.ScaleTo(released_scale).ScaleTo(pressed_scale, 400, Easing.OutElasticHalf);
+            skinnableCursor.Expand();
         }
 
-        public void Contract() => expandTarget.ScaleTo(released_scale, 400, Easing.OutQuad);
+        public void Contract() => skinnableCursor.Contract();
 
         /// <summary>
         /// Get the scale applicable to the ActiveCursor based on a beatmap's circle size.
         /// </summary>
         public static float GetScaleForCircleSize(float circleSize) =>
             1f - 0.7f * (1f + circleSize - BeatmapDifficulty.DEFAULT_DIFFICULTY) / BeatmapDifficulty.DEFAULT_DIFFICULTY;
 
-        private partial class DefaultCursor : OsuCursorSprite
+        private partial class DefaultCursor : SkinnableCursor
         {
             public DefaultCursor()
             {

osu.Game.Rulesets.Osu/UI/Cursor/SkinnableCursor.cs

@@ -0,0 +1,31 @@
+// 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.Graphics;
+using osu.Framework.Graphics.Containers;
+
+namespace osu.Game.Rulesets.Osu.UI.Cursor
+{
+    public abstract partial class SkinnableCursor : CompositeDrawable
+    {
+        private const float pressed_scale = 1.2f;
+        private const float released_scale = 1f;
+
+        public virtual void Expand()
+        {
+            ExpandTarget?.ScaleTo(released_scale)
+                        .ScaleTo(pressed_scale, 400, Easing.OutElasticHalf);
+        }
+
+        public virtual void Contract()
+        {
+            ExpandTarget?.ScaleTo(released_scale, 400, Easing.OutQuad);
+        }
+
+        /// <summary>
+        /// The an optional piece of the cursor to expand when in a clicked state.
+        /// If null, the whole cursor will be affected by expansion.
+        /// </summary>
+        public Drawable? ExpandTarget { get; protected set; }
+    }
+}