Fix issues with colour and skin application

osu.Game.Rulesets.Osu/Mods/OsuModTraceable.cs

@@ -5,12 +5,12 @@ using System;
 using System.Linq;
 using osu.Framework.Bindables;
 using System.Collections.Generic;
+using osu.Framework.Extensions.Color4Extensions;
 using osu.Framework.Graphics.Sprites;
 using osu.Game.Configuration;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Objects.Drawables;
 using osu.Game.Rulesets.Osu.Objects.Drawables;
-using osuTK.Graphics;
 
 namespace osu.Game.Rulesets.Osu.Mods
 {
@@ -22,7 +22,8 @@ namespace osu.Game.Rulesets.Osu.Mods
         public override ModType Type => ModType.Fun;
         public override string Description => "Put your faith in the approach circles...";
         public override double ScoreMultiplier => 1;
-        public override Type[] IncompatibleMods => new[] { typeof(OsuModHidden), typeof(OsuModeObjectScaleTween) };
+
+        public override Type[] IncompatibleMods => new[] { typeof(OsuModHidden), typeof(OsuModSpinIn) };
         private Bindable<bool> increaseFirstObjectVisibility = new Bindable<bool>();
 
         public void ReadFromConfig(OsuConfigManager config)
@@ -38,26 +39,28 @@ namespace osu.Game.Rulesets.Osu.Mods
 
         protected void ApplyTraceableState(DrawableHitObject drawable, ArmedState state)
         {
-            if (!(drawable is DrawableOsuHitObject d))
+            if (!(drawable is DrawableOsuHitObject drawableOsu))
                 return;
 
-            var h = d.HitObject;
+            var h = drawableOsu.HitObject;
 
             switch (drawable)
             {
                 case DrawableHitCircle circle:
                     // we only want to see the approach circle
                     using (circle.BeginAbsoluteSequence(h.StartTime - h.TimePreempt, true))
-                    {
+                        circle.CirclePiece.Hide();
-                        circle.ApproachCircle.Show();
-                    }
 
                     break;
 
                 case DrawableSlider slider:
-                    ApplyTraceableState(slider.HeadCircle, state);
+                    slider.AccentColour.BindValueChanged(_ =>
-                    slider.Body.AccentColour = Color4.Transparent;
+                    {
-                    slider.Body.BorderColour = slider.HeadCircle.AccentColour.Value;
+                        //will trigger on skin change.
+                        slider.Body.AccentColour = slider.AccentColour.Value.Opacity(0);
+                        slider.Body.BorderColour = slider.AccentColour.Value;
+                    }, true);
+
                     break;
 
                 case DrawableSpinner spinner:

osu.Game.Rulesets.Osu/Objects/Drawables/DrawableHitCircle.cs

@@ -18,7 +18,7 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
 {
     public class DrawableHitCircle : DrawableOsuHitObject, IDrawableHitObjectWithProxiedApproach
     {
-        public ApproachCircle ApproachCircle;
+        public ApproachCircle ApproachCircle { get; }
 
         private readonly IBindable<Vector2> positionBindable = new Bindable<Vector2>();
         private readonly IBindable<int> stackHeightBindable = new Bindable<int>();
@@ -30,7 +30,7 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
 
         private readonly HitArea hitArea;
 
-        private readonly SkinnableDrawable mainContent;
+        public SkinnableDrawable CirclePiece { get; }
 
         public DrawableHitCircle(HitCircle h)
             : base(h)
@@ -59,7 +59,7 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
                                 return true;
                             },
                         },
-                        mainContent = new SkinnableDrawable(new OsuSkinComponent(OsuSkinComponents.HitCircle), _ => new MainCirclePiece(HitObject.IndexInCurrentCombo)),
+                        CirclePiece = new SkinnableDrawable(new OsuSkinComponent(OsuSkinComponents.HitCircle), _ => new MainCirclePiece(HitObject.IndexInCurrentCombo)),
                         ApproachCircle = new ApproachCircle
                         {
                             Alpha = 0,
@@ -133,7 +133,7 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
         {
             base.UpdateInitialTransforms();
 
-            mainContent.FadeInFromZero(HitObject.TimeFadeIn);
+            CirclePiece.FadeInFromZero(HitObject.TimeFadeIn);
 
             ApproachCircle.FadeIn(Math.Min(HitObject.TimeFadeIn * 2, HitObject.TimePreempt));
             ApproachCircle.ScaleTo(1f, HitObject.TimePreempt);

osu.Game.Rulesets.Osu/Objects/Drawables/DrawableSlider.cs

@@ -163,9 +163,9 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
 
         private float sliderPathRadius;
 
-        protected override void SkinChanged(ISkinSource skin, bool allowFallback)
+        protected override void ApplySkin(ISkinSource skin, bool allowFallback)
         {
-            base.SkinChanged(skin, allowFallback);
+            base.ApplySkin(skin, allowFallback);
 
             Body.BorderSize = skin.GetConfig<OsuSkinConfiguration, float>(OsuSkinConfiguration.SliderBorderSize)?.Value ?? SliderBody.DEFAULT_BORDER_SIZE;
             sliderPathRadius = skin.GetConfig<OsuSkinConfiguration, float>(OsuSkinConfiguration.SliderPathRadius)?.Value ?? OsuHitObject.OBJECT_RADIUS;

osu.Game/Rulesets/Objects/Drawables/DrawableHitObject.cs

@@ -240,7 +240,7 @@ namespace osu.Game.Rulesets.Objects.Drawables
 
         #endregion
 
-        protected override void SkinChanged(ISkinSource skin, bool allowFallback)
+        protected sealed override void SkinChanged(ISkinSource skin, bool allowFallback)
         {
             base.SkinChanged(skin, allowFallback);
 
@@ -250,6 +250,19 @@ namespace osu.Game.Rulesets.Objects.Drawables
 
                 AccentColour.Value = comboColours?.Count > 0 ? comboColours[combo.ComboIndex % comboColours.Count] : Color4.White;
             }
+
+            ApplySkin(skin, allowFallback);
+
+            updateState(State.Value, true);
+        }
+
+        /// <summary>
+        /// Called when a change is made to the skin.
+        /// </summary>
+        /// <param name="skin">The new skin.</param>
+        /// <param name="allowFallback">Whether fallback to default skin should be allowed if the custom skin is missing this resource.</param>
+        protected virtual void ApplySkin(ISkinSource skin, bool allowFallback)
+        {
         }
 
         /// <summary>