From 00b4fc1e1f66e66b4d77bebd11f524664ee9d341 Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Fri, 21 Feb 2020 17:38:23 +0900
Subject: [PATCH] Add fill to default skin slider ball when tracking

---
 .../Objects/Drawables/Pieces/SliderBall.cs       | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/SliderBall.cs b/osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/SliderBall.cs
index 0dc5c9b4a0..c871089acd 100644
--- a/osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/SliderBall.cs
+++ b/osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/SliderBall.cs
@@ -4,6 +4,7 @@
 using System;
 using System.Linq;
 using osu.Framework.Allocation;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Shapes;
@@ -214,9 +215,13 @@ public DefaultFollowCircle()
 
         public class DefaultSliderBall : CompositeDrawable
         {
+            private Box box;
+
             [BackgroundDependencyLoader]
             private void load(DrawableHitObject drawableObject, ISkinSource skin)
             {
+                var slider = (DrawableSlider)drawableObject;
+
                 RelativeSizeAxes = Axes.Both;
 
                 float radius = skin.GetConfig<OsuSkinConfiguration, float>(OsuSkinConfiguration.SliderPathRadius)?.Value ?? OsuHitObject.OBJECT_RADIUS;
@@ -231,14 +236,21 @@ private void load(DrawableHitObject drawableObject, ISkinSource skin)
                     BorderThickness = 10,
                     BorderColour = Color4.White,
                     Alpha = 1,
-                    Child = new Box
+                    Child = box = new Box
                     {
+                        Blending = BlendingParameters.Additive,
                         RelativeSizeAxes = Axes.Both,
                         Colour = Color4.White,
-                        Alpha = 0.4f,
+                        AlwaysPresent = true,
+                        Alpha = 0
                     }
                 };
+
+                slider.Tracking.BindValueChanged(trackingChanged, true);
             }
+
+            private void trackingChanged(ValueChangedEvent<bool> tracking) =>
+                box.FadeTo(tracking.NewValue ? 0.6f : 0.05f, 200, Easing.OutQuint);
         }
     }
 }