Show osu!taiko centre/rim colouring in editor timeline

Closes #13443.

osu.Game.Rulesets.Taiko/Objects/Hit.cs

@@ -3,14 +3,19 @@
 
 using System.Linq;
 using osu.Framework.Bindables;
+using osu.Framework.Extensions.Color4Extensions;
 using osu.Game.Audio;
+using osu.Game.Rulesets.Objects.Types;
+using osuTK.Graphics;
 
 namespace osu.Game.Rulesets.Taiko.Objects
 {
-    public class Hit : TaikoStrongableHitObject
+    public class Hit : TaikoStrongableHitObject, IHasDisplayColour
     {
         public readonly Bindable<HitType> TypeBindable = new Bindable<HitType>();
 
+        public Bindable<Color4> DisplayColour { get; } = new Bindable<Color4>(colour_centre);
+
         /// <summary>
         /// The <see cref="HitType"/> that actuates this <see cref="Hit"/>.
         /// </summary>
@@ -20,9 +25,17 @@ namespace osu.Game.Rulesets.Taiko.Objects
             set => TypeBindable.Value = value;
         }
 
+        private static readonly Color4 colour_centre = Color4Extensions.FromHex(@"bb1177");
+        private static readonly Color4 colour_rim = Color4Extensions.FromHex(@"2299bb");
+
         public Hit()
         {
-            TypeBindable.BindValueChanged(_ => updateSamplesFromType());
+            TypeBindable.BindValueChanged(_ =>
+            {
+                updateSamplesFromType();
+                DisplayColour.Value = Type == HitType.Centre ? colour_centre : colour_rim;
+            });
+
             SamplesBindable.BindCollectionChanged((_, __) => updateTypeFromSamples());
         }
 

osu.Game/Rulesets/Objects/Types/IHasAccentColour.cs

@@ -0,0 +1,19 @@
+// 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.Bindables;
+using osuTK.Graphics;
+
+namespace osu.Game.Rulesets.Objects.Types
+{
+    /// <summary>
+    /// A HitObject which has a preferred display colour. Will be used for editor timeline display.
+    /// </summary>
+    public interface IHasDisplayColour
+    {
+        /// <summary>
+        /// The current display colour of this hit object.
+        /// </summary>
+        Bindable<Color4> DisplayColour { get; }
+    }
+}

osu.Game/Screens/Edit/Compose/Components/Timeline/TimelineHitObjectBlueprint.cs

@@ -39,6 +39,7 @@ namespace osu.Game.Screens.Edit.Compose.Components.Timeline
 
         private Bindable<int> indexInCurrentComboBindable;
         private Bindable<int> comboIndexBindable;
+        private Bindable<Color4> displayColourBindable;
 
         private readonly ExtendableCircle circle;
         private readonly Border border;
@@ -108,44 +109,64 @@ namespace osu.Game.Screens.Edit.Compose.Components.Timeline
         {
             base.LoadComplete();
 
-            if (Item is IHasComboInformation comboInfo)
+            switch (Item)
             {
-                indexInCurrentComboBindable = comboInfo.IndexInCurrentComboBindable.GetBoundCopy();
+                case IHasDisplayColour displayColour:
-                indexInCurrentComboBindable.BindValueChanged(_ => updateComboIndex(), true);
+                    displayColourBindable = displayColour.DisplayColour.GetBoundCopy();
+                    displayColourBindable.BindValueChanged(_ => updateColour(), true);
+                    break;
 
-                comboIndexBindable = comboInfo.ComboIndexBindable.GetBoundCopy();
+                case IHasComboInformation comboInfo:
-                comboIndexBindable.BindValueChanged(_ => updateComboColour(), true);
+                    indexInCurrentComboBindable = comboInfo.IndexInCurrentComboBindable.GetBoundCopy();
+                    indexInCurrentComboBindable.BindValueChanged(_ => updateComboIndex(), true);
 
-                skin.SourceChanged += updateComboColour;
+                    comboIndexBindable = comboInfo.ComboIndexBindable.GetBoundCopy();
+                    comboIndexBindable.BindValueChanged(_ => updateColour(), true);
+
+                    skin.SourceChanged += updateColour;
+                    break;
             }
         }
 
         protected override void OnSelected()
         {
             // base logic hides selected blueprints when not selected, but timeline doesn't do that.
-            updateComboColour();
+            updateColour();
         }
 
         protected override void OnDeselected()
         {
             // base logic hides selected blueprints when not selected, but timeline doesn't do that.
-            updateComboColour();
+            updateColour();
         }
 
         private void updateComboIndex() => comboIndexText.Text = (indexInCurrentComboBindable.Value + 1).ToString();
 
-        private void updateComboColour()
+        private void updateColour()
         {
-            if (!(Item is IHasComboInformation combo))
+            Color4 colour;
-                return;
 
-            var comboColours = skin.GetConfig<GlobalSkinColours, IReadOnlyList<Color4>>(GlobalSkinColours.ComboColours)?.Value ?? Array.Empty<Color4>();
+            switch (Item)
-            var comboColour = combo.GetComboColour(comboColours);
+            {
+                case IHasDisplayColour displayColour:
+                    colour = displayColour.DisplayColour.Value;
+                    break;
+
+                case IHasComboInformation combo:
+                {
+                    var comboColours = skin.GetConfig<GlobalSkinColours, IReadOnlyList<Color4>>(GlobalSkinColours.ComboColours)?.Value ?? Array.Empty<Color4>();
+                    colour = combo.GetComboColour(comboColours);
+                    break;
+                }
+
+                default:
+                    return;
+            }
 
             if (IsSelected)
             {
                 border.Show();
-                comboColour = comboColour.Lighten(0.3f);
+                colour = colour.Lighten(0.3f);
             }
             else
             {
@@ -153,9 +174,9 @@ namespace osu.Game.Screens.Edit.Compose.Components.Timeline
             }
 
             if (Item is IHasDuration duration && duration.Duration > 0)
-                circle.Colour = ColourInfo.GradientHorizontal(comboColour, comboColour.Lighten(0.4f));
+                circle.Colour = ColourInfo.GradientHorizontal(colour, colour.Lighten(0.4f));
             else
-                circle.Colour = comboColour;
+                circle.Colour = colour;
 
             var col = circle.Colour.TopLeft.Linear;
             colouredComponents.Colour = OsuColour.ForegroundTextColourFor(col);