Rejig namespaces

osu.Game.Rulesets.Osu/Edit/OsuEditDrawablePool.cs

@@ -0,0 +1,63 @@
+// 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 System;
+using System.Linq;
+using osu.Framework.Graphics;
+using osu.Game.Rulesets.Objects.Drawables;
+using osu.Game.Rulesets.Osu.Objects.Drawables;
+
+namespace osu.Game.Rulesets.Osu.Edit
+{
+    public class OsuEditDrawablePool<T> : OsuDrawablePool<T>
+        where T : DrawableHitObject, new()
+    {
+        /// <summary>
+        /// Hit objects are intentionally made to fade out at a constant slower rate than in gameplay.
+        /// This allows a mapper to gain better historical context and use recent hitobjects as reference / snap points.
+        /// </summary>
+        private const double editor_hit_object_fade_out_extension = 700;
+
+        public OsuEditDrawablePool(Func<DrawableHitObject, double, bool> checkHittable, Action<Drawable> onLoaded, int initialSize, int? maximumSize = null)
+            : base(checkHittable, onLoaded, initialSize, maximumSize)
+        {
+        }
+
+        protected override T CreateNewDrawable() => base.CreateNewDrawable().With(d => d.ApplyCustomUpdateState += updateState);
+
+        private void updateState(DrawableHitObject hitObject, ArmedState state)
+        {
+            if (state == ArmedState.Idle)
+                return;
+
+            // adjust the visuals of certain object types to make them stay on screen for longer than usual.
+            switch (hitObject)
+            {
+                default:
+                    // there are quite a few drawable hit types we don't want to extent (spinners, ticks etc.)
+                    return;
+
+                case DrawableSlider _:
+                    // no specifics to sliders but let them fade slower below.
+                    break;
+
+                case DrawableHitCircle circle: // also handles slider heads
+                    circle.ApproachCircle
+                          .FadeOutFromOne(editor_hit_object_fade_out_extension)
+                          .Expire();
+                    break;
+            }
+
+            // Get the existing fade out transform
+            var existing = hitObject.Transforms.LastOrDefault(t => t.TargetMember == nameof(Alpha));
+
+            if (existing == null)
+                return;
+
+            hitObject.RemoveTransform(existing);
+
+            using (hitObject.BeginAbsoluteSequence(existing.StartTime))
+                hitObject.FadeOut(editor_hit_object_fade_out_extension).Expire();
+        }
+    }
+}