Merge remote-tracking branch 'upstream/master' into add-ruleset-legacy-skin

osu.Game.Rulesets.Catch/CatchRuleset.cs

@@ -23,7 +23,7 @@ namespace osu.Game.Rulesets.Catch
 {
     public class CatchRuleset : Ruleset
     {
-        public override DrawableRuleset CreateDrawableRulesetWith(WorkingBeatmap beatmap, IReadOnlyList<Mod> mods) => new DrawableCatchRuleset(this, beatmap, mods);
+        public override DrawableRuleset CreateDrawableRulesetWith(IWorkingBeatmap beatmap, IReadOnlyList<Mod> mods) => new DrawableCatchRuleset(this, beatmap, mods);
         public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => new CatchBeatmapConverter(beatmap);
         public override IBeatmapProcessor CreateBeatmapProcessor(IBeatmap beatmap) => new CatchBeatmapProcessor(beatmap);
 

osu.Game.Rulesets.Catch/Objects/Drawable/DrawableCatchHitObject.cs

@@ -60,7 +60,7 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawable
 
         protected sealed override double InitialLifetimeOffset => HitObject.TimePreempt;
 
-        protected override void UpdateInitialTransforms() => this.FadeIn(200);
+        protected override void UpdateInitialTransforms() => this.FadeInFromZero(200);
 
         protected override void UpdateStateTransforms(ArmedState state)
         {

osu.Game.Rulesets.Catch/UI/DrawableCatchRuleset.cs

@@ -25,11 +25,11 @@ namespace osu.Game.Rulesets.Catch.UI
 
         protected override bool UserScrollSpeedAdjustment => false;
 
-        public DrawableCatchRuleset(Ruleset ruleset, WorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
+        public DrawableCatchRuleset(Ruleset ruleset, IWorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
             : base(ruleset, beatmap, mods)
         {
             Direction.Value = ScrollingDirection.Down;
-            TimeRange.Value = BeatmapDifficulty.DifficultyRange(beatmap.BeatmapInfo.BaseDifficulty.ApproachRate, 1800, 1200, 450);
+            TimeRange.Value = BeatmapDifficulty.DifficultyRange(beatmap.Beatmap.BeatmapInfo.BaseDifficulty.ApproachRate, 1800, 1200, 450);
         }
 
         public override ScoreProcessor CreateScoreProcessor() => new CatchScoreProcessor(this);

osu.Game.Rulesets.Mania/Edit/DrawableManiaEditRuleset.cs

@@ -16,7 +16,7 @@ namespace osu.Game.Rulesets.Mania.Edit
     {
         public new IScrollingInfo ScrollingInfo => base.ScrollingInfo;
 
-        public DrawableManiaEditRuleset(Ruleset ruleset, WorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
+        public DrawableManiaEditRuleset(Ruleset ruleset, IWorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
             : base(ruleset, beatmap, mods)
         {
         }

osu.Game.Rulesets.Mania/Edit/ManiaHitObjectComposer.cs

@@ -21,7 +21,7 @@ namespace osu.Game.Rulesets.Mania.Edit
     [Cached(Type = typeof(IManiaHitObjectComposer))]
     public class ManiaHitObjectComposer : HitObjectComposer<ManiaHitObject>, IManiaHitObjectComposer
     {
-        protected new DrawableManiaEditRuleset DrawableRuleset { get; private set; }
+        private DrawableManiaEditRuleset drawableRuleset;
 
         public ManiaHitObjectComposer(Ruleset ruleset)
             : base(ruleset)
@@ -33,23 +33,23 @@ namespace osu.Game.Rulesets.Mania.Edit
         /// </summary>
         /// <param name="screenSpacePosition">The screen-space position.</param>
         /// <returns>The column which intersects with <paramref name="screenSpacePosition"/>.</returns>
-        public Column ColumnAt(Vector2 screenSpacePosition) => DrawableRuleset.GetColumnByPosition(screenSpacePosition);
+        public Column ColumnAt(Vector2 screenSpacePosition) => drawableRuleset.GetColumnByPosition(screenSpacePosition);
 
         private DependencyContainer dependencies;
 
         protected override IReadOnlyDependencyContainer CreateChildDependencies(IReadOnlyDependencyContainer parent)
             => dependencies = new DependencyContainer(base.CreateChildDependencies(parent));
 
-        public int TotalColumns => ((ManiaPlayfield)DrawableRuleset.Playfield).TotalColumns;
+        public int TotalColumns => ((ManiaPlayfield)drawableRuleset.Playfield).TotalColumns;
 
-        protected override DrawableRuleset<ManiaHitObject> CreateDrawableRuleset(Ruleset ruleset, WorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
+        protected override DrawableRuleset<ManiaHitObject> CreateDrawableRuleset(Ruleset ruleset, IWorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
         {
-            DrawableRuleset = new DrawableManiaEditRuleset(ruleset, beatmap, mods);
+            drawableRuleset = new DrawableManiaEditRuleset(ruleset, beatmap, mods);
 
             // This is the earliest we can cache the scrolling info to ourselves, before masks are added to the hierarchy and inject it
-            dependencies.CacheAs(DrawableRuleset.ScrollingInfo);
+            dependencies.CacheAs(drawableRuleset.ScrollingInfo);
 
-            return DrawableRuleset;
+            return drawableRuleset;
         }
 
         protected override IReadOnlyList<HitObjectCompositionTool> CompositionTools => new HitObjectCompositionTool[]

osu.Game.Rulesets.Mania/ManiaRuleset.cs

@@ -31,7 +31,7 @@ namespace osu.Game.Rulesets.Mania
 {
     public class ManiaRuleset : Ruleset
     {
-        public override DrawableRuleset CreateDrawableRulesetWith(WorkingBeatmap beatmap, IReadOnlyList<Mod> mods) => new DrawableManiaRuleset(this, beatmap, mods);
+        public override DrawableRuleset CreateDrawableRulesetWith(IWorkingBeatmap beatmap, IReadOnlyList<Mod> mods) => new DrawableManiaRuleset(this, beatmap, mods);
         public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => new ManiaBeatmapConverter(beatmap);
         public override PerformanceCalculator CreatePerformanceCalculator(WorkingBeatmap beatmap, ScoreInfo score) => new ManiaPerformanceCalculator(this, beatmap, score);
 

osu.Game.Rulesets.Mania/Objects/Drawables/DrawableManiaHitObject.cs

@@ -46,8 +46,6 @@ namespace osu.Game.Rulesets.Mania.Objects.Drawables
             Anchor = Origin = e.NewValue == ScrollingDirection.Up ? Anchor.TopCentre : Anchor.BottomCentre;
         }
 
-        protected override void UpdateInitialTransforms() => this.FadeIn();
-
         protected override void UpdateStateTransforms(ArmedState state)
         {
             switch (state)

osu.Game.Rulesets.Mania/UI/DrawableManiaRuleset.cs

@@ -36,11 +36,13 @@ namespace osu.Game.Rulesets.Mania.UI
 
         public IEnumerable<BarLine> BarLines;
 
+        protected override bool RelativeScaleBeatLengths => true;
+
         protected new ManiaRulesetConfigManager Config => (ManiaRulesetConfigManager)base.Config;
 
         private readonly Bindable<ManiaScrollingDirection> configDirection = new Bindable<ManiaScrollingDirection>();
 
-        public DrawableManiaRuleset(Ruleset ruleset, WorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
+        public DrawableManiaRuleset(Ruleset ruleset, IWorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
             : base(ruleset, beatmap, mods)
         {
             // Generate the bar lines

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

@@ -12,7 +12,7 @@ namespace osu.Game.Rulesets.Osu.Edit
 {
     public class DrawableOsuEditRuleset : DrawableOsuRuleset
     {
-        public DrawableOsuEditRuleset(Ruleset ruleset, WorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
+        public DrawableOsuEditRuleset(Ruleset ruleset, IWorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
             : base(ruleset, beatmap, mods)
         {
         }

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

@@ -24,7 +24,7 @@ namespace osu.Game.Rulesets.Osu.Edit
         {
         }
 
-        protected override DrawableRuleset<OsuHitObject> CreateDrawableRuleset(Ruleset ruleset, WorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
+        protected override DrawableRuleset<OsuHitObject> CreateDrawableRuleset(Ruleset ruleset, IWorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
             => new DrawableOsuEditRuleset(ruleset, beatmap, mods);
 
         protected override IReadOnlyList<HitObjectCompositionTool> CompositionTools => new HitObjectCompositionTool[]

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

@@ -29,6 +29,8 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
 
         private readonly HitArea hitArea;
 
+        private readonly SkinnableDrawable mainContent;
+
         public DrawableHitCircle(HitCircle h)
             : base(h)
         {
@@ -56,7 +58,7 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
                                 return true;
                             },
                         },
-                        new SkinnableDrawable("Play/osu/hitcircle", _ => new MainCirclePiece(HitObject.IndexInCurrentCombo)),
+                        mainContent = new SkinnableDrawable("Play/osu/hitcircle", _ => new MainCirclePiece(HitObject.IndexInCurrentCombo)),
                         ApproachCircle = new ApproachCircle
                         {
                             Alpha = 0,
@@ -108,6 +110,8 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
         {
             base.UpdateInitialTransforms();
 
+            mainContent.FadeInFromZero(HitObject.TimeFadeIn);
+
             ApproachCircle.FadeIn(Math.Min(HitObject.TimeFadeIn * 2, HitObject.TimePreempt));
             ApproachCircle.ScaleTo(1f, HitObject.TimePreempt);
             ApproachCircle.Expire(true);

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

@@ -36,8 +36,6 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
 
         protected sealed override double InitialLifetimeOffset => HitObject.TimePreempt;
 
-        protected override void UpdateInitialTransforms() => this.FadeIn(HitObject.TimeFadeIn);
-
         private OsuInputManager osuActionInputManager;
         internal OsuInputManager OsuActionInputManager => osuActionInputManager ?? (osuActionInputManager = GetContainingInputManager() as OsuInputManager);
 

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

@@ -93,6 +93,13 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
             }
         }
 
+        protected override void UpdateInitialTransforms()
+        {
+            base.UpdateInitialTransforms();
+
+            Body.FadeInFromZero(HitObject.TimeFadeIn);
+        }
+
         [BackgroundDependencyLoader]
         private void load()
         {

osu.Game.Rulesets.Osu/OsuRuleset.cs

@@ -30,7 +30,7 @@ namespace osu.Game.Rulesets.Osu
 {
     public class OsuRuleset : Ruleset
     {
-        public override DrawableRuleset CreateDrawableRulesetWith(WorkingBeatmap beatmap, IReadOnlyList<Mod> mods) => new DrawableOsuRuleset(this, beatmap, mods);
+        public override DrawableRuleset CreateDrawableRulesetWith(IWorkingBeatmap beatmap, IReadOnlyList<Mod> mods) => new DrawableOsuRuleset(this, beatmap, mods);
         public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => new OsuBeatmapConverter(beatmap);
         public override IBeatmapProcessor CreateBeatmapProcessor(IBeatmap beatmap) => new OsuBeatmapProcessor(beatmap);
 

osu.Game.Rulesets.Osu/UI/DrawableOsuRuleset.cs

@@ -25,7 +25,7 @@ namespace osu.Game.Rulesets.Osu.UI
     {
         protected new OsuRulesetConfigManager Config => (OsuRulesetConfigManager)base.Config;
 
-        public DrawableOsuRuleset(Ruleset ruleset, WorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
+        public DrawableOsuRuleset(Ruleset ruleset, IWorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
             : base(ruleset, beatmap, mods)
         {
         }

osu.Game.Rulesets.Taiko/Objects/Drawables/DrawableTaikoHitObject.cs

@@ -78,8 +78,6 @@ namespace osu.Game.Rulesets.Taiko.Objects.Drawables
         public abstract bool OnPressed(TaikoAction action);
         public virtual bool OnReleased(TaikoAction action) => false;
 
-        protected override void UpdateInitialTransforms() => this.FadeIn();
-
         public override double LifetimeStart
         {
             get => base.LifetimeStart;

osu.Game.Rulesets.Taiko/TaikoRuleset.cs

@@ -23,7 +23,7 @@ namespace osu.Game.Rulesets.Taiko
 {
     public class TaikoRuleset : Ruleset
     {
-        public override DrawableRuleset CreateDrawableRulesetWith(WorkingBeatmap beatmap, IReadOnlyList<Mod> mods) => new DrawableTaikoRuleset(this, beatmap, mods);
+        public override DrawableRuleset CreateDrawableRulesetWith(IWorkingBeatmap beatmap, IReadOnlyList<Mod> mods) => new DrawableTaikoRuleset(this, beatmap, mods);
         public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => new TaikoBeatmapConverter(beatmap);
 
         public override IEnumerable<KeyBinding> GetDefaultKeyBindings(int variant = 0) => new[]

osu.Game.Rulesets.Taiko/UI/DrawableTaikoRuleset.cs

@@ -28,7 +28,7 @@ namespace osu.Game.Rulesets.Taiko.UI
 
         protected override bool UserScrollSpeedAdjustment => false;
 
-        public DrawableTaikoRuleset(Ruleset ruleset, WorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
+        public DrawableTaikoRuleset(Ruleset ruleset, IWorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
             : base(ruleset, beatmap, mods)
         {
             Direction.Value = ScrollingDirection.Left;

osu.Game.Tests/Visual/Editor/TestSceneHitObjectComposer.cs

@@ -16,15 +16,13 @@ using osu.Game.Rulesets.Osu.Edit;
 using osu.Game.Rulesets.Osu.Edit.Blueprints.HitCircles;
 using osu.Game.Rulesets.Osu.Edit.Blueprints.HitCircles.Components;
 using osu.Game.Rulesets.Osu.Objects;
-using osu.Game.Screens.Edit.Compose;
 using osu.Game.Screens.Edit.Compose.Components;
 using osuTK;
 
 namespace osu.Game.Tests.Visual.Editor
 {
     [TestFixture]
-    [Cached(Type = typeof(IPlacementHandler))]
+    public class TestSceneHitObjectComposer : OsuTestScene
-    public class TestSceneHitObjectComposer : OsuTestScene, IPlacementHandler
     {
         public override IReadOnlyList<Type> RequiredTypes => new[]
         {
@@ -39,8 +37,6 @@ namespace osu.Game.Tests.Visual.Editor
             typeof(HitCirclePlacementBlueprint),
         };
 
-        private HitObjectComposer composer;
-
         [BackgroundDependencyLoader]
         private void load()
         {
@@ -67,15 +63,7 @@ namespace osu.Game.Tests.Visual.Editor
             Dependencies.CacheAs<IAdjustableClock>(clock);
             Dependencies.CacheAs<IFrameBasedClock>(clock);
 
-            Child = composer = new OsuHitObjectComposer(new OsuRuleset());
+            Child = new OsuHitObjectComposer(new OsuRuleset());
         }
-
-        public void BeginPlacement(HitObject hitObject)
-        {
-        }
-
-        public void EndPlacement(HitObject hitObject) => composer.Add(hitObject);
-
-        public void Delete(HitObject hitObject) => composer.Remove(hitObject);
     }
 }

osu.Game.Tests/Visual/Gameplay/TestSceneDrawableScrollingRuleset.cs

@@ -0,0 +1,305 @@
+// 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.Collections.Generic;
+using System.Linq;
+using NUnit.Framework;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Input;
+using osu.Framework.MathUtils;
+using osu.Framework.Timing;
+using osu.Game.Beatmaps;
+using osu.Game.Beatmaps.ControlPoints;
+using osu.Game.Configuration;
+using osu.Game.Rulesets;
+using osu.Game.Rulesets.Difficulty;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.Objects.Drawables;
+using osu.Game.Rulesets.Objects.Types;
+using osu.Game.Rulesets.Osu;
+using osu.Game.Rulesets.UI;
+using osu.Game.Rulesets.UI.Scrolling;
+using osuTK;
+using osuTK.Graphics;
+
+namespace osu.Game.Tests.Visual.Gameplay
+{
+    public class TestSceneDrawableScrollingRuleset : OsuTestScene
+    {
+        /// <summary>
+        /// The amount of time visible by the "view window" of the playfield.
+        /// All hitobjects added through <see cref="createBeatmap"/> are spaced apart by this value, such that for a beat length of 1000,
+        /// there will be at most 2 hitobjects visible in the "view window".
+        /// </summary>
+        private const double time_range = 1000;
+
+        private readonly ManualClock testClock = new ManualClock();
+        private TestDrawableScrollingRuleset drawableRuleset;
+
+        [SetUp]
+        public void Setup() => Schedule(() => testClock.CurrentTime = 0);
+
+        [Test]
+        public void TestRelativeBeatLengthScaleSingleTimingPoint()
+        {
+            var beatmap = createBeatmap(new TimingControlPoint { BeatLength = time_range / 2 });
+
+            createTest(beatmap, d => d.RelativeScaleBeatLengthsOverride = true);
+
+            assertPosition(0, 0f);
+
+            // The single timing point is 1x speed relative to itself, such that the hitobject occurring time_range milliseconds later should appear
+            // at the bottom of the view window regardless of the timing point's beat length
+            assertPosition(1, 1f);
+        }
+
+        [Test]
+        public void TestRelativeBeatLengthScaleTimingPointBeyondEndDoesNotBecomeDominant()
+        {
+            var beatmap = createBeatmap(
+                new TimingControlPoint { BeatLength = time_range / 2 },
+                new TimingControlPoint { Time = 12000, BeatLength = time_range },
+                new TimingControlPoint { Time = 100000, BeatLength = time_range });
+
+            createTest(beatmap, d => d.RelativeScaleBeatLengthsOverride = true);
+
+            assertPosition(0, 0f);
+            assertPosition(1, 1f);
+        }
+
+        [Test]
+        public void TestRelativeBeatLengthScaleFromSecondTimingPoint()
+        {
+            var beatmap = createBeatmap(
+                new TimingControlPoint { BeatLength = time_range },
+                new TimingControlPoint { Time = 3 * time_range, BeatLength = time_range / 2 });
+
+            createTest(beatmap, d => d.RelativeScaleBeatLengthsOverride = true);
+
+            // The first timing point should have a relative velocity of 2
+            assertPosition(0, 0f);
+            assertPosition(1, 0.5f);
+            assertPosition(2, 1f);
+
+            // Move to the second timing point
+            setTime(3 * time_range);
+            assertPosition(3, 0f);
+
+            // As above, this is the timing point that is 1x speed relative to itself, so the hitobject occurring time_range milliseconds later should be at the bottom of the view window
+            assertPosition(4, 1f);
+        }
+
+        [Test]
+        public void TestNonRelativeScale()
+        {
+            var beatmap = createBeatmap(
+                new TimingControlPoint { BeatLength = time_range },
+                new TimingControlPoint { Time = 3 * time_range, BeatLength = time_range / 2 });
+
+            createTest(beatmap);
+
+            assertPosition(0, 0f);
+            assertPosition(1, 1);
+
+            // Move to the second timing point
+            setTime(3 * time_range);
+            assertPosition(3, 0f);
+
+            // For a beat length of 500, the view window of this timing point is elongated 2x (1000 / 500), such that the second hitobject is two TimeRanges away (offscreen)
+            // To bring it on-screen, half TimeRange is added to the current time, bringing the second half of the view window into view, and the hitobject should appear at the bottom
+            setTime(3 * time_range + time_range / 2);
+            assertPosition(4, 1f);
+        }
+
+        private void assertPosition(int index, float relativeY) => AddAssert($"hitobject {index} at {relativeY}",
+            () => Precision.AlmostEquals(drawableRuleset.Playfield.AllHitObjects.ElementAt(index).DrawPosition.Y, drawableRuleset.Playfield.HitObjectContainer.DrawHeight * relativeY));
+
+        private void setTime(double time)
+        {
+            AddStep($"set time = {time}", () => testClock.CurrentTime = time);
+        }
+
+        /// <summary>
+        /// Creates an <see cref="IBeatmap"/>, containing 10 hitobjects and user-provided timing points.
+        /// The hitobjects are spaced <see cref="time_range"/> milliseconds apart.
+        /// </summary>
+        /// <param name="timingControlPoints">The timing points to add to the beatmap.</param>
+        /// <returns>The <see cref="IBeatmap"/>.</returns>
+        private IBeatmap createBeatmap(params TimingControlPoint[] timingControlPoints)
+        {
+            var beatmap = new Beatmap<HitObject> { BeatmapInfo = { Ruleset = new OsuRuleset().RulesetInfo } };
+
+            beatmap.ControlPointInfo.TimingPoints.AddRange(timingControlPoints);
+
+            for (int i = 0; i < 10; i++)
+                beatmap.HitObjects.Add(new HitObject { StartTime = i * time_range });
+
+            return beatmap;
+        }
+
+        private void createTest(IBeatmap beatmap, Action<TestDrawableScrollingRuleset> overrideAction = null) => AddStep("create test", () =>
+        {
+            var ruleset = new TestScrollingRuleset();
+
+            drawableRuleset = (TestDrawableScrollingRuleset)ruleset.CreateDrawableRulesetWith(CreateWorkingBeatmap(beatmap), Array.Empty<Mod>());
+            drawableRuleset.FrameStablePlayback = false;
+
+            overrideAction?.Invoke(drawableRuleset);
+
+            Child = new Container
+            {
+                Anchor = Anchor.Centre,
+                Origin = Anchor.Centre,
+                RelativeSizeAxes = Axes.Y,
+                Height = 0.75f,
+                Width = 400,
+                Masking = true,
+                Clock = new FramedClock(testClock),
+                Child = drawableRuleset
+            };
+        });
+
+        #region Ruleset
+
+        private class TestScrollingRuleset : Ruleset
+        {
+            public TestScrollingRuleset(RulesetInfo rulesetInfo = null)
+                : base(rulesetInfo)
+            {
+            }
+
+            public override IEnumerable<Mod> GetModsFor(ModType type) => throw new NotImplementedException();
+
+            public override DrawableRuleset CreateDrawableRulesetWith(IWorkingBeatmap beatmap, IReadOnlyList<Mod> mods) => new TestDrawableScrollingRuleset(this, beatmap, mods);
+
+            public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => new TestBeatmapConverter(beatmap);
+
+            public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => throw new NotImplementedException();
+
+            public override string Description { get; } = string.Empty;
+
+            public override string ShortName { get; } = string.Empty;
+        }
+
+        private class TestDrawableScrollingRuleset : DrawableScrollingRuleset<TestHitObject>
+        {
+            public bool RelativeScaleBeatLengthsOverride { get; set; }
+
+            protected override bool RelativeScaleBeatLengths => RelativeScaleBeatLengthsOverride;
+
+            protected override ScrollVisualisationMethod VisualisationMethod => ScrollVisualisationMethod.Overlapping;
+
+            public TestDrawableScrollingRuleset(Ruleset ruleset, IWorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
+                : base(ruleset, beatmap, mods)
+            {
+                TimeRange.Value = time_range;
+            }
+
+            public override DrawableHitObject<TestHitObject> CreateDrawableRepresentation(TestHitObject h) => new DrawableTestHitObject(h);
+
+            protected override PassThroughInputManager CreateInputManager() => new PassThroughInputManager();
+
+            protected override Playfield CreatePlayfield() => new TestPlayfield();
+        }
+
+        private class TestPlayfield : ScrollingPlayfield
+        {
+            public TestPlayfield()
+            {
+                AddInternal(new Container
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Children = new Drawable[]
+                    {
+                        new Box
+                        {
+                            RelativeSizeAxes = Axes.Both,
+                            Alpha = 0.2f,
+                        },
+                        new Container
+                        {
+                            RelativeSizeAxes = Axes.Both,
+                            Padding = new MarginPadding { Top = 150 },
+                            Children = new Drawable[]
+                            {
+                                new Box
+                                {
+                                    Anchor = Anchor.TopCentre,
+                                    Origin = Anchor.Centre,
+                                    RelativeSizeAxes = Axes.X,
+                                    Height = 2,
+                                    Colour = Color4.Green
+                                },
+                                HitObjectContainer
+                            }
+                        }
+                    }
+                });
+            }
+        }
+
+        private class TestBeatmapConverter : BeatmapConverter<TestHitObject>
+        {
+            public TestBeatmapConverter(IBeatmap beatmap)
+                : base(beatmap)
+            {
+            }
+
+            protected override IEnumerable<Type> ValidConversionTypes => new[] { typeof(HitObject) };
+
+            protected override IEnumerable<TestHitObject> ConvertHitObject(HitObject original, IBeatmap beatmap)
+            {
+                yield return new TestHitObject
+                {
+                    StartTime = original.StartTime,
+                    EndTime = (original as IHasEndTime)?.EndTime ?? (original.StartTime + 100)
+                };
+            }
+        }
+
+        #endregion
+
+        #region HitObject
+
+        private class TestHitObject : HitObject, IHasEndTime
+        {
+            public double EndTime { get; set; }
+
+            public double Duration => EndTime - StartTime;
+        }
+
+        private class DrawableTestHitObject : DrawableHitObject<TestHitObject>
+        {
+            public DrawableTestHitObject(TestHitObject hitObject)
+                : base(hitObject)
+            {
+                Anchor = Anchor.TopCentre;
+                Origin = Anchor.TopCentre;
+
+                Size = new Vector2(100, 25);
+
+                AddRangeInternal(new Drawable[]
+                {
+                    new Box
+                    {
+                        RelativeSizeAxes = Axes.Both,
+                        Colour = Color4.LightPink
+                    },
+                    new Box
+                    {
+                        Origin = Anchor.CentreLeft,
+                        RelativeSizeAxes = Axes.X,
+                        Height = 2,
+                        Colour = Color4.Red
+                    }
+                });
+            }
+        }
+
+        #endregion
+    }
+}

osu.Game/Beatmaps/Beatmap.cs

@@ -14,7 +14,7 @@ namespace osu.Game.Beatmaps
     /// <summary>
     /// A Beatmap containing converted HitObjects.
     /// </summary>
-    public class Beatmap<T> : IBeatmap
+    public class Beatmap<T> : IBeatmap<T>
         where T : HitObject
     {
         public BeatmapInfo BeatmapInfo { get; set; } = new BeatmapInfo
@@ -36,17 +36,13 @@ namespace osu.Game.Beatmaps
 
         public List<BreakPeriod> Breaks { get; set; } = new List<BreakPeriod>();
 
-        /// <summary>
-        /// Total amount of break time in the beatmap.
-        /// </summary>
         [JsonIgnore]
         public double TotalBreakTime => Breaks.Sum(b => b.Duration);
 
-        /// <summary>
-        /// The HitObjects this Beatmap contains.
-        /// </summary>
         [JsonConverter(typeof(TypedListConverter<HitObject>))]
-        public List<T> HitObjects = new List<T>();
+        public List<T> HitObjects { get; set; } = new List<T>();
+
+        IReadOnlyList<T> IBeatmap<T>.HitObjects => HitObjects;
 
         IReadOnlyList<HitObject> IBeatmap.HitObjects => HitObjects;
 

osu.Game/Beatmaps/ControlPoints/TimingControlPoint.cs

@@ -14,6 +14,8 @@ namespace osu.Game.Beatmaps.ControlPoints
         /// </summary>
         public TimeSignatures TimeSignature = TimeSignatures.SimpleQuadruple;
 
+        public const double DEFAULT_BEAT_LENGTH = 1000;
+
         /// <summary>
         /// The beat length at this control point.
         /// </summary>
@@ -23,7 +25,7 @@ namespace osu.Game.Beatmaps.ControlPoints
             set => beatLength = MathHelper.Clamp(value, 6, 60000);
         }
 
-        private double beatLength = 1000;
+        private double beatLength = DEFAULT_BEAT_LENGTH;
 
         public bool Equals(TimingControlPoint other)
             => base.Equals(other)

osu.Game/Beatmaps/DummyWorkingBeatmap.cs

@@ -54,7 +54,7 @@ namespace osu.Game.Beatmaps
             {
                 public override IEnumerable<Mod> GetModsFor(ModType type) => new Mod[] { };
 
-                public override DrawableRuleset CreateDrawableRulesetWith(WorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
+                public override DrawableRuleset CreateDrawableRulesetWith(IWorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
                 {
                     throw new NotImplementedException();
                 }

osu.Game/Beatmaps/Formats/LegacyDifficultyCalculatorBeatmapDecoder.cs

@@ -31,7 +31,7 @@ namespace osu.Game.Beatmaps.Formats
 
         private class LegacyDifficultyCalculatorControlPoint : TimingControlPoint
         {
-            public override double BeatLength { get; set; } = 1000;
+            public override double BeatLength { get; set; } = DEFAULT_BEAT_LENGTH;
         }
     }
 }

osu.Game/Beatmaps/IBeatmap.cs

@@ -53,4 +53,13 @@ namespace osu.Game.Beatmaps
         /// <returns>The shallow-cloned beatmap.</returns>
         IBeatmap Clone();
     }
+
+    public interface IBeatmap<out T> : IBeatmap
+        where T : HitObject
+    {
+        /// <summary>
+        /// The hitobjects contained by this beatmap.
+        /// </summary>
+        new IReadOnlyList<T> HitObjects { get; }
+    }
 }

osu.Game/Beatmaps/IWorkingBeatmap.cs

@@ -0,0 +1,61 @@
+// 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.Collections.Generic;
+using osu.Framework.Audio.Track;
+using osu.Framework.Graphics.Textures;
+using osu.Game.Rulesets;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.UI;
+using osu.Game.Skinning;
+using osu.Game.Storyboards;
+
+namespace osu.Game.Beatmaps
+{
+    public interface IWorkingBeatmap
+    {
+        /// <summary>
+        /// Retrieves the <see cref="IBeatmap"/> which this <see cref="WorkingBeatmap"/> represents.
+        /// </summary>
+        IBeatmap Beatmap { get; }
+
+        /// <summary>
+        /// Retrieves the background for this <see cref="WorkingBeatmap"/>.
+        /// </summary>
+        Texture Background { get; }
+
+        /// <summary>
+        /// Retrieves the audio track for this <see cref="WorkingBeatmap"/>.
+        /// </summary>
+        Track Track { get; }
+
+        /// <summary>
+        /// Retrieves the <see cref="Waveform"/> for the <see cref="Track"/> of this <see cref="WorkingBeatmap"/>.
+        /// </summary>
+        Waveform Waveform { get; }
+
+        /// <summary>
+        /// Retrieves the <see cref="Storyboard"/> which this <see cref="WorkingBeatmap"/> provides.
+        /// </summary>
+        Storyboard Storyboard { get; }
+
+        /// <summary>
+        /// Retrieves the <see cref="Skin"/> which this <see cref="WorkingBeatmap"/> provides.
+        /// </summary>
+        Skin Skin { get; }
+
+        /// <summary>
+        /// Constructs a playable <see cref="IBeatmap"/> from <see cref="Beatmap"/> using the applicable converters for a specific <see cref="RulesetInfo"/>.
+        /// <para>
+        /// The returned <see cref="IBeatmap"/> is in a playable state - all <see cref="HitObject"/> and <see cref="BeatmapDifficulty"/> <see cref="Mod"/>s
+        /// have been applied, and <see cref="HitObject"/>s have been fully constructed.
+        /// </para>
+        /// </summary>
+        /// <param name="ruleset">The <see cref="RulesetInfo"/> to create a playable <see cref="IBeatmap"/> for.</param>
+        /// <param name="mods">The <see cref="Mod"/>s to apply to the <see cref="IBeatmap"/>.</param>
+        /// <returns>The converted <see cref="IBeatmap"/>.</returns>
+        /// <exception cref="BeatmapInvalidForRulesetException">If <see cref="Beatmap"/> could not be converted to <paramref name="ruleset"/>.</exception>
+        IBeatmap GetPlayableBeatmap(RulesetInfo ruleset, IReadOnlyList<Mod> mods);
+    }
+}

osu.Game/Beatmaps/WorkingBeatmap.cs

@@ -16,14 +16,13 @@ using osu.Framework.Audio;
 using osu.Framework.Statistics;
 using osu.Game.IO.Serialization;
 using osu.Game.Rulesets;
-using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Objects.Types;
 using osu.Game.Rulesets.UI;
 using osu.Game.Skinning;
 
 namespace osu.Game.Beatmaps
 {
-    public abstract class WorkingBeatmap : IDisposable
+    public abstract class WorkingBeatmap : IWorkingBeatmap, IDisposable
     {
         public readonly BeatmapInfo BeatmapInfo;
 
@@ -97,17 +96,6 @@ namespace osu.Game.Beatmaps
         /// <returns>The applicable <see cref="IBeatmapConverter"/>.</returns>
         protected virtual IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap, Ruleset ruleset) => ruleset.CreateBeatmapConverter(beatmap);
 
-        /// <summary>
-        /// Constructs a playable <see cref="IBeatmap"/> from <see cref="Beatmap"/> using the applicable converters for a specific <see cref="RulesetInfo"/>.
-        /// <para>
-        /// The returned <see cref="IBeatmap"/> is in a playable state - all <see cref="HitObject"/> and <see cref="BeatmapDifficulty"/> <see cref="Mod"/>s
-        /// have been applied, and <see cref="HitObject"/>s have been fully constructed.
-        /// </para>
-        /// </summary>
-        /// <param name="ruleset">The <see cref="RulesetInfo"/> to create a playable <see cref="IBeatmap"/> for.</param>
-        /// <param name="mods">The <see cref="Mod"/>s to apply to the <see cref="IBeatmap"/>.</param>
-        /// <returns>The converted <see cref="IBeatmap"/>.</returns>
-        /// <exception cref="BeatmapInvalidForRulesetException">If <see cref="Beatmap"/> could not be converted to <paramref name="ruleset"/>.</exception>
         public IBeatmap GetPlayableBeatmap(RulesetInfo ruleset, IReadOnlyList<Mod> mods)
         {
             var rulesetInstance = ruleset.CreateInstance();

osu.Game/Graphics/Containers/OsuFocusedOverlayContainer.cs

@@ -62,15 +62,23 @@ namespace osu.Game.Graphics.Containers
 
         protected override bool OnClick(ClickEvent e)
         {
-            if (!base.ReceivePositionalInputAt(e.ScreenSpaceMousePosition))
+            closeIfOutside(e);
-            {
-                Hide();
-                return true;
-            }
 
             return base.OnClick(e);
         }
 
+        protected override bool OnDragEnd(DragEndEvent e)
+        {
+            closeIfOutside(e);
+            return base.OnDragEnd(e);
+        }
+
+        private void closeIfOutside(MouseEvent e)
+        {
+            if (!base.ReceivePositionalInputAt(e.ScreenSpaceMousePosition))
+                Hide();
+        }
+
         public virtual bool OnPressed(GlobalAction action)
         {
             switch (action)

osu.Game/Graphics/DrawableDate.cs

@@ -2,11 +2,11 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
-using Humanizer;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Cursor;
 using osu.Game.Graphics.Sprites;
+using osu.Game.Utils;
 
 namespace osu.Game.Graphics
 {
@@ -71,7 +71,7 @@ namespace osu.Game.Graphics
             Scheduler.AddDelayed(updateTimeWithReschedule, timeUntilNextUpdate);
         }
 
-        protected virtual string Format() => Date.Humanize();
+        protected virtual string Format() => HumanizerUtils.Humanize(Date);
 
         private void updateTime() => Text = Format();
 

osu.Game/Overlays/BeatmapSet/Scores/TopScoreUserSection.cs

@@ -1,7 +1,6 @@
 // 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 Humanizer;
 using osu.Framework.Allocation;
 using osu.Framework.Extensions.Color4Extensions;
 using osu.Framework.Graphics;
@@ -14,6 +13,7 @@ using osu.Game.Graphics.Sprites;
 using osu.Game.Online.Leaderboards;
 using osu.Game.Scoring;
 using osu.Game.Users.Drawables;
+using osu.Game.Utils;
 using osuTK;
 using osuTK.Graphics;
 
@@ -132,7 +132,7 @@ namespace osu.Game.Overlays.BeatmapSet.Scores
             {
                 avatar.User = value.User;
                 flag.Country = value.User.Country;
-                date.Text = $@"achieved {value.Date.Humanize()}";
+                date.Text = $@"achieved {HumanizerUtils.Humanize(value.Date)}";
 
                 usernameText.Clear();
                 usernameText.AddUserLink(value.User);

osu.Game/Rulesets/Edit/DrawableEditRuleset.cs

@@ -1,116 +0,0 @@
-// 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.Linq;
-using osu.Framework.Allocation;
-using osu.Framework.Graphics;
-using osu.Framework.Graphics.Containers;
-using osu.Game.Beatmaps;
-using osu.Game.Rulesets.Objects;
-using osu.Game.Rulesets.Objects.Drawables;
-using osu.Game.Rulesets.UI;
-
-namespace osu.Game.Rulesets.Edit
-{
-    public abstract class DrawableEditRuleset : CompositeDrawable
-    {
-        /// <summary>
-        /// The <see cref="Playfield"/> contained by this <see cref="DrawableEditRuleset"/>.
-        /// </summary>
-        public abstract Playfield Playfield { get; }
-
-        public abstract PlayfieldAdjustmentContainer CreatePlayfieldAdjustmentContainer();
-
-        internal DrawableEditRuleset()
-        {
-            RelativeSizeAxes = Axes.Both;
-        }
-
-        /// <summary>
-        /// Adds a <see cref="HitObject"/> to the <see cref="Beatmap"/> and displays a visual representation of it.
-        /// </summary>
-        /// <param name="hitObject">The <see cref="HitObject"/> to add.</param>
-        /// <returns>The visual representation of <paramref name="hitObject"/>.</returns>
-        internal abstract DrawableHitObject Add(HitObject hitObject);
-
-        /// <summary>
-        /// Removes a <see cref="HitObject"/> from the <see cref="Beatmap"/> and the display.
-        /// </summary>
-        /// <param name="hitObject">The <see cref="HitObject"/> to remove.</param>
-        /// <returns>The visual representation of the removed <paramref name="hitObject"/>.</returns>
-        internal abstract DrawableHitObject Remove(HitObject hitObject);
-    }
-
-    public class DrawableEditRuleset<TObject> : DrawableEditRuleset
-        where TObject : HitObject
-    {
-        public override Playfield Playfield => drawableRuleset.Playfield;
-
-        public override PlayfieldAdjustmentContainer CreatePlayfieldAdjustmentContainer() => drawableRuleset.CreatePlayfieldAdjustmentContainer();
-
-        private Ruleset ruleset => drawableRuleset.Ruleset;
-        private Beatmap<TObject> beatmap => drawableRuleset.Beatmap;
-
-        private readonly DrawableRuleset<TObject> drawableRuleset;
-
-        public DrawableEditRuleset(DrawableRuleset<TObject> drawableRuleset)
-        {
-            this.drawableRuleset = drawableRuleset;
-
-            InternalChild = drawableRuleset;
-        }
-
-        [BackgroundDependencyLoader]
-        private void load()
-        {
-            drawableRuleset.FrameStablePlayback = false;
-            Playfield.DisplayJudgements.Value = false;
-        }
-
-        internal override DrawableHitObject Add(HitObject hitObject)
-        {
-            var tObject = (TObject)hitObject;
-
-            // Add to beatmap, preserving sorting order
-            var insertionIndex = beatmap.HitObjects.FindLastIndex(h => h.StartTime <= hitObject.StartTime);
-            beatmap.HitObjects.Insert(insertionIndex + 1, tObject);
-
-            // Process object
-            var processor = ruleset.CreateBeatmapProcessor(beatmap);
-
-            processor?.PreProcess();
-            tObject.ApplyDefaults(beatmap.ControlPointInfo, beatmap.BeatmapInfo.BaseDifficulty);
-            processor?.PostProcess();
-
-            // Add visual representation
-            var drawableObject = drawableRuleset.CreateDrawableRepresentation(tObject);
-
-            drawableRuleset.Playfield.Add(drawableObject);
-            drawableRuleset.Playfield.PostProcess();
-
-            return drawableObject;
-        }
-
-        internal override DrawableHitObject Remove(HitObject hitObject)
-        {
-            var tObject = (TObject)hitObject;
-
-            // Remove from beatmap
-            beatmap.HitObjects.Remove(tObject);
-
-            // Process the beatmap
-            var processor = ruleset.CreateBeatmapProcessor(beatmap);
-
-            processor?.PreProcess();
-            processor?.PostProcess();
-
-            // Remove visual representation
-            var drawableObject = Playfield.AllHitObjects.Single(d => d.HitObject == hitObject);
-
-            drawableRuleset.Playfield.Remove(drawableObject);
-            drawableRuleset.Playfield.PostProcess();
-
-            return drawableObject;
-        }
-    }
-}

osu.Game/Rulesets/Edit/DrawableEditRulesetWrapper.cs

@@ -0,0 +1,80 @@
+// 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.Linq;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.UI;
+using osu.Game.Screens.Edit;
+
+namespace osu.Game.Rulesets.Edit
+{
+    /// <summary>
+    /// A wrapper for a <see cref="DrawableRuleset{TObject}"/>. Handles adding visual representations of <see cref="HitObject"/>s to the underlying <see cref="DrawableRuleset{TObject}"/>.
+    /// </summary>
+    internal class DrawableEditRulesetWrapper<TObject> : CompositeDrawable
+        where TObject : HitObject
+    {
+        public Playfield Playfield => drawableRuleset.Playfield;
+
+        private readonly DrawableRuleset<TObject> drawableRuleset;
+
+        [Resolved]
+        private IEditorBeatmap<TObject> beatmap { get; set; }
+
+        public DrawableEditRulesetWrapper(DrawableRuleset<TObject> drawableRuleset)
+        {
+            this.drawableRuleset = drawableRuleset;
+
+            RelativeSizeAxes = Axes.Both;
+
+            InternalChild = drawableRuleset;
+        }
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            drawableRuleset.FrameStablePlayback = false;
+            Playfield.DisplayJudgements.Value = false;
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            beatmap.HitObjectAdded += addHitObject;
+            beatmap.HitObjectRemoved += removeHitObject;
+        }
+
+        private void addHitObject(HitObject hitObject)
+        {
+            var drawableObject = drawableRuleset.CreateDrawableRepresentation((TObject)hitObject);
+
+            drawableRuleset.Playfield.Add(drawableObject);
+            drawableRuleset.Playfield.PostProcess();
+        }
+
+        private void removeHitObject(HitObject hitObject)
+        {
+            var drawableObject = Playfield.AllHitObjects.Single(d => d.HitObject == hitObject);
+
+            drawableRuleset.Playfield.Remove(drawableObject);
+            drawableRuleset.Playfield.PostProcess();
+        }
+
+        public PlayfieldAdjustmentContainer CreatePlayfieldAdjustmentContainer() => drawableRuleset.CreatePlayfieldAdjustmentContainer();
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+
+            if (beatmap != null)
+            {
+                beatmap.HitObjectAdded -= addHitObject;
+                beatmap.HitObjectRemoved -= removeHitObject;
+            }
+        }
+    }
+}

osu.Game/Rulesets/Edit/HitObjectComposer.cs

@@ -18,45 +18,47 @@ using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Objects.Drawables;
 using osu.Game.Rulesets.UI;
+using osu.Game.Screens.Edit;
 using osu.Game.Screens.Edit.Components.RadioButtons;
+using osu.Game.Screens.Edit.Compose;
 using osu.Game.Screens.Edit.Compose.Components;
 
 namespace osu.Game.Rulesets.Edit
 {
-    public abstract class HitObjectComposer : CompositeDrawable
+    [Cached(Type = typeof(IPlacementHandler))]
+    public abstract class HitObjectComposer<TObject> : HitObjectComposer, IPlacementHandler
+        where TObject : HitObject
     {
-        public IEnumerable<DrawableHitObject> HitObjects => DrawableRuleset.Playfield.AllHitObjects;
+        protected IRulesetConfigManager Config { get; private set; }
 
         protected readonly Ruleset Ruleset;
 
-        protected readonly IBindable<WorkingBeatmap> Beatmap = new Bindable<WorkingBeatmap>();
+        private IWorkingBeatmap workingBeatmap;
-
+        private Beatmap<TObject> playableBeatmap;
-        protected IRulesetConfigManager Config { get; private set; }
+        private EditorBeatmap<TObject> editorBeatmap;
-
+        private IBeatmapProcessor beatmapProcessor;
-        private readonly List<Container> layerContainers = new List<Container>();
-
-        protected DrawableEditRuleset DrawableRuleset { get; private set; }
 
+        private DrawableEditRulesetWrapper<TObject> drawableRulesetWrapper;
         private BlueprintContainer blueprintContainer;
+        private readonly List<Container> layerContainers = new List<Container>();
 
         private InputManager inputManager;
 
-        internal HitObjectComposer(Ruleset ruleset)
+        protected HitObjectComposer(Ruleset ruleset)
         {
             Ruleset = ruleset;
-
             RelativeSizeAxes = Axes.Both;
         }
 
         [BackgroundDependencyLoader]
-        private void load(IBindable<WorkingBeatmap> beatmap, IFrameBasedClock framedClock)
+        private void load(IFrameBasedClock framedClock)
         {
-            Beatmap.BindTo(beatmap);
-
             try
             {
-                DrawableRuleset = CreateDrawableRuleset();
+                drawableRulesetWrapper = new DrawableEditRulesetWrapper<TObject>(CreateDrawableRuleset(Ruleset, workingBeatmap, Array.Empty<Mod>()))
-                DrawableRuleset.Clock = framedClock;
+                {
+                    Clock = framedClock
+                };
             }
             catch (Exception e)
             {
@@ -64,10 +66,10 @@ namespace osu.Game.Rulesets.Edit
                 return;
             }
 
-            var layerBelowRuleset = DrawableRuleset.CreatePlayfieldAdjustmentContainer();
+            var layerBelowRuleset = drawableRulesetWrapper.CreatePlayfieldAdjustmentContainer();
             layerBelowRuleset.Child = new EditorPlayfieldBorder { RelativeSizeAxes = Axes.Both };
 
-            var layerAboveRuleset = DrawableRuleset.CreatePlayfieldAdjustmentContainer();
+            var layerAboveRuleset = drawableRulesetWrapper.CreatePlayfieldAdjustmentContainer();
             layerAboveRuleset.Child = blueprintContainer = new BlueprintContainer();
 
             layerContainers.Add(layerBelowRuleset);
@@ -98,7 +100,7 @@ namespace osu.Game.Rulesets.Edit
                             Children = new Drawable[]
                             {
                                 layerBelowRuleset,
-                                DrawableRuleset,
+                                drawableRulesetWrapper,
                                 layerAboveRuleset
                             }
                         }
@@ -118,6 +120,28 @@ namespace osu.Game.Rulesets.Edit
             toolboxCollection.Items[0].Select();
         }
 
+        protected override IReadOnlyDependencyContainer CreateChildDependencies(IReadOnlyDependencyContainer parent)
+        {
+            var parentWorkingBeatmap = parent.Get<IBindable<WorkingBeatmap>>().Value;
+
+            playableBeatmap = (Beatmap<TObject>)parentWorkingBeatmap.GetPlayableBeatmap(Ruleset.RulesetInfo, Array.Empty<Mod>());
+            workingBeatmap = new EditorWorkingBeatmap<TObject>(playableBeatmap, parentWorkingBeatmap);
+
+            beatmapProcessor = Ruleset.CreateBeatmapProcessor(playableBeatmap);
+
+            editorBeatmap = new EditorBeatmap<TObject>(playableBeatmap);
+            editorBeatmap.HitObjectAdded += addHitObject;
+            editorBeatmap.HitObjectRemoved += removeHitObject;
+
+            var dependencies = new DependencyContainer(parent);
+            dependencies.CacheAs<IEditorBeatmap>(editorBeatmap);
+            dependencies.CacheAs<IEditorBeatmap<TObject>>(editorBeatmap);
+
+            Config = dependencies.Get<RulesetConfigCache>().GetConfigFor(Ruleset);
+
+            return base.CreateChildDependencies(dependencies);
+        }
+
         protected override void LoadComplete()
         {
             base.LoadComplete();
@@ -125,45 +149,76 @@ namespace osu.Game.Rulesets.Edit
             inputManager = GetContainingInputManager();
         }
 
-        protected override IReadOnlyDependencyContainer CreateChildDependencies(IReadOnlyDependencyContainer parent)
-        {
-            var dependencies = new DependencyContainer(base.CreateChildDependencies(parent));
-
-            dependencies.CacheAs(this);
-            Config = dependencies.Get<RulesetConfigCache>().GetConfigFor(Ruleset);
-
-            return dependencies;
-        }
-
         protected override void UpdateAfterChildren()
         {
             base.UpdateAfterChildren();
 
             layerContainers.ForEach(l =>
             {
-                l.Anchor = DrawableRuleset.Playfield.Anchor;
+                l.Anchor = drawableRulesetWrapper.Playfield.Anchor;
-                l.Origin = DrawableRuleset.Playfield.Origin;
+                l.Origin = drawableRulesetWrapper.Playfield.Origin;
-                l.Position = DrawableRuleset.Playfield.Position;
+                l.Position = drawableRulesetWrapper.Playfield.Position;
-                l.Size = DrawableRuleset.Playfield.Size;
+                l.Size = drawableRulesetWrapper.Playfield.Size;
             });
         }
 
+        private void addHitObject(HitObject hitObject)
+        {
+            beatmapProcessor?.PreProcess();
+            hitObject.ApplyDefaults(playableBeatmap.ControlPointInfo, playableBeatmap.BeatmapInfo.BaseDifficulty);
+            beatmapProcessor?.PostProcess();
+        }
+
+        private void removeHitObject(HitObject hitObject)
+        {
+            beatmapProcessor?.PreProcess();
+            beatmapProcessor?.PostProcess();
+        }
+
+        public override IEnumerable<DrawableHitObject> HitObjects => drawableRulesetWrapper.Playfield.AllHitObjects;
+        public override bool CursorInPlacementArea => drawableRulesetWrapper.Playfield.ReceivePositionalInputAt(inputManager.CurrentState.Mouse.Position);
+
+        protected abstract IReadOnlyList<HitObjectCompositionTool> CompositionTools { get; }
+
+        protected abstract DrawableRuleset<TObject> CreateDrawableRuleset(Ruleset ruleset, IWorkingBeatmap beatmap, IReadOnlyList<Mod> mods);
+
+        public void BeginPlacement(HitObject hitObject)
+        {
+        }
+
+        public void EndPlacement(HitObject hitObject) => editorBeatmap.Add(hitObject);
+
+        public void Delete(HitObject hitObject) => editorBeatmap.Remove(hitObject);
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+
+            if (editorBeatmap != null)
+            {
+                editorBeatmap.HitObjectAdded -= addHitObject;
+                editorBeatmap.HitObjectRemoved -= removeHitObject;
+            }
+        }
+    }
+
+    [Cached(typeof(HitObjectComposer))]
+    public abstract class HitObjectComposer : CompositeDrawable
+    {
+        internal HitObjectComposer()
+        {
+            RelativeSizeAxes = Axes.Both;
+        }
+
+        /// <summary>
+        /// All the <see cref="DrawableHitObject"/>s.
+        /// </summary>
+        public abstract IEnumerable<DrawableHitObject> HitObjects { get; }
+
         /// <summary>
         /// Whether the user's cursor is currently in an area of the <see cref="HitObjectComposer"/> that is valid for placement.
         /// </summary>
-        public virtual bool CursorInPlacementArea => DrawableRuleset.Playfield.ReceivePositionalInputAt(inputManager.CurrentState.Mouse.Position);
+        public abstract bool CursorInPlacementArea { get; }
-
-        /// <summary>
-        /// Adds a <see cref="HitObject"/> to the <see cref="Beatmaps.Beatmap"/> and visualises it.
-        /// </summary>
-        /// <param name="hitObject">The <see cref="HitObject"/> to add.</param>
-        public void Add(HitObject hitObject) => blueprintContainer.AddBlueprintFor(DrawableRuleset.Add(hitObject));
-
-        public void Remove(HitObject hitObject) => blueprintContainer.RemoveBlueprintFor(DrawableRuleset.Remove(hitObject));
-
-        internal abstract DrawableEditRuleset CreateDrawableRuleset();
-
-        protected abstract IReadOnlyList<HitObjectCompositionTool> CompositionTools { get; }
 
         /// <summary>
         /// Creates a <see cref="SelectionBlueprint"/> for a specific <see cref="DrawableHitObject"/>.
@@ -176,18 +231,4 @@ namespace osu.Game.Rulesets.Edit
         /// </summary>
         public virtual SelectionHandler CreateSelectionHandler() => new SelectionHandler();
     }
-
-    public abstract class HitObjectComposer<TObject> : HitObjectComposer
-        where TObject : HitObject
-    {
-        protected HitObjectComposer(Ruleset ruleset)
-            : base(ruleset)
-        {
-        }
-
-        internal override DrawableEditRuleset CreateDrawableRuleset()
-            => new DrawableEditRuleset<TObject>(CreateDrawableRuleset(Ruleset, Beatmap.Value, Array.Empty<Mod>()));
-
-        protected abstract DrawableRuleset<TObject> CreateDrawableRuleset(Ruleset ruleset, WorkingBeatmap beatmap, IReadOnlyList<Mod> mods);
-    }
 }

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

@@ -7,6 +7,7 @@ using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Extensions.TypeExtensions;
+using osu.Framework.Graphics;
 using osu.Framework.Graphics.Primitives;
 using osu.Game.Audio;
 using osu.Game.Rulesets.Judgements;
@@ -186,6 +187,8 @@ namespace osu.Game.Rulesets.Objects.Drawables
         /// <summary>
         /// Apply (generally fade-in) transforms leading into the <see cref="HitObject"/> start time.
         /// The local drawable hierarchy is recursively delayed to <see cref="LifetimeStart"/> for convenience.
+        ///
+        /// By default this will fade in the object from zero with no duration.
         /// </summary>
         /// <remarks>
         /// This is called once before every <see cref="UpdateStateTransforms"/>. This is to ensure a good state in the case
@@ -193,6 +196,7 @@ namespace osu.Game.Rulesets.Objects.Drawables
         /// </remarks>
         protected virtual void UpdateInitialTransforms()
         {
+            this.FadeInFromZero();
         }
 
         /// <summary>

osu.Game/Rulesets/Ruleset.cs

@@ -59,7 +59,7 @@ namespace osu.Game.Rulesets
         /// <param name="mods">The <see cref="Mod"/>s to apply.</param>
         /// <exception cref="BeatmapInvalidForRulesetException">Unable to successfully load the beatmap to be usable with this ruleset.</exception>
         /// <returns></returns>
-        public abstract DrawableRuleset CreateDrawableRulesetWith(WorkingBeatmap beatmap, IReadOnlyList<Mod> mods);
+        public abstract DrawableRuleset CreateDrawableRulesetWith(IWorkingBeatmap beatmap, IReadOnlyList<Mod> mods);
 
         /// <summary>
         /// Creates a <see cref="IBeatmapConverter"/> to convert a <see cref="IBeatmap"/> to one that is applicable for this <see cref="Ruleset"/>.

osu.Game/Rulesets/Timing/MultiplierControlPoint.cs

@@ -20,7 +20,13 @@ namespace osu.Game.Rulesets.Timing
         /// <summary>
         /// The aggregate multiplier which this <see cref="MultiplierControlPoint"/> provides.
         /// </summary>
-        public double Multiplier => Velocity * DifficultyPoint.SpeedMultiplier * 1000 / TimingPoint.BeatLength;
+        public double Multiplier => Velocity * DifficultyPoint.SpeedMultiplier * BaseBeatLength / TimingPoint.BeatLength;
+
+        /// <summary>
+        /// The base beat length to scale the <see cref="TimingPoint"/> provided multiplier relative to.
+        /// </summary>
+        /// <example>For a <see cref="BaseBeatLength"/> of 1000, a <see cref="TimingPoint"/> with a beat length of 500 will increase the multiplier by 2.</example>
+        public double BaseBeatLength = TimingControlPoint.DEFAULT_BEAT_LENGTH;
 
         /// <summary>
         /// The velocity multiplier.

osu.Game/Rulesets/UI/DrawableRuleset.cs

@@ -113,7 +113,7 @@ namespace osu.Game.Rulesets.UI
         /// <param name="ruleset">The ruleset being represented.</param>
         /// <param name="workingBeatmap">The beatmap to create the hit renderer for.</param>
         /// <param name="mods">The <see cref="Mod"/>s to apply.</param>
-        protected DrawableRuleset(Ruleset ruleset, WorkingBeatmap workingBeatmap, IReadOnlyList<Mod> mods)
+        protected DrawableRuleset(Ruleset ruleset, IWorkingBeatmap workingBeatmap, IReadOnlyList<Mod> mods)
             : base(ruleset)
         {
             if (workingBeatmap == null)

osu.Game/Rulesets/UI/Scrolling/DrawableScrollingRuleset.cs

@@ -69,6 +69,11 @@ namespace osu.Game.Rulesets.UI.Scrolling
         /// </summary>
         protected virtual bool UserScrollSpeedAdjustment => true;
 
+        /// <summary>
+        /// Whether <see cref="TimingControlPoint"/> beat lengths should scale relative to the most common beat length in the <see cref="Beatmap"/>.
+        /// </summary>
+        protected virtual bool RelativeScaleBeatLengths => false;
+
         /// <summary>
         /// Provides the default <see cref="MultiplierControlPoint"/>s that adjust the scrolling rate of <see cref="HitObject"/>s
         /// inside this <see cref="DrawableRuleset{TObject}"/>.
@@ -81,7 +86,7 @@ namespace osu.Game.Rulesets.UI.Scrolling
         [Cached(Type = typeof(IScrollingInfo))]
         private readonly LocalScrollingInfo scrollingInfo;
 
-        protected DrawableScrollingRuleset(Ruleset ruleset, WorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
+        protected DrawableScrollingRuleset(Ruleset ruleset, IWorkingBeatmap beatmap, IReadOnlyList<Mod> mods)
             : base(ruleset, beatmap, mods)
         {
             scrollingInfo = new LocalScrollingInfo();
@@ -107,16 +112,38 @@ namespace osu.Game.Rulesets.UI.Scrolling
         [BackgroundDependencyLoader]
         private void load()
         {
-            // Calculate default multiplier control points
+            double lastObjectTime = (Objects.LastOrDefault() as IHasEndTime)?.EndTime ?? Objects.LastOrDefault()?.StartTime ?? double.MaxValue;
+            double baseBeatLength = TimingControlPoint.DEFAULT_BEAT_LENGTH;
+
+            if (RelativeScaleBeatLengths)
+            {
+                IReadOnlyList<TimingControlPoint> timingPoints = Beatmap.ControlPointInfo.TimingPoints;
+                double maxDuration = 0;
+
+                for (int i = 0; i < timingPoints.Count; i++)
+                {
+                    if (timingPoints[i].Time > lastObjectTime)
+                        break;
+
+                    double endTime = i < timingPoints.Count - 1 ? timingPoints[i + 1].Time : lastObjectTime;
+                    double duration = endTime - timingPoints[i].Time;
+
+                    if (duration > maxDuration)
+                    {
+                        maxDuration = duration;
+                        baseBeatLength = timingPoints[i].BeatLength;
+                    }
+                }
+            }
+
+            // Merge sequences of timing and difficulty control points to create the aggregate "multiplier" control point
             var lastTimingPoint = new TimingControlPoint();
             var lastDifficultyPoint = new DifficultyControlPoint();
-
-            // Merge timing + difficulty points
             var allPoints = new SortedList<ControlPoint>(Comparer<ControlPoint>.Default);
             allPoints.AddRange(Beatmap.ControlPointInfo.TimingPoints);
             allPoints.AddRange(Beatmap.ControlPointInfo.DifficultyPoints);
 
-            // Generate the timing points, making non-timing changes use the previous timing change
+            // Generate the timing points, making non-timing changes use the previous timing change and vice-versa
             var timingChanges = allPoints.Select(c =>
             {
                 var timingPoint = c as TimingControlPoint;
@@ -131,14 +158,13 @@ namespace osu.Game.Rulesets.UI.Scrolling
                 return new MultiplierControlPoint(c.Time)
                 {
                     Velocity = Beatmap.BeatmapInfo.BaseDifficulty.SliderMultiplier,
+                    BaseBeatLength = baseBeatLength,
                     TimingPoint = lastTimingPoint,
                     DifficultyPoint = lastDifficultyPoint
                 };
             });
 
-            double lastObjectTime = (Objects.LastOrDefault() as IHasEndTime)?.EndTime ?? Objects.LastOrDefault()?.StartTime ?? double.MaxValue;
+            // Trim unwanted sequences of timing changes
-
-            // Perform some post processing of the timing changes
             timingChanges = timingChanges
                             // Collapse sections after the last hit object
                             .Where(s => s.StartTime <= lastObjectTime)
@@ -147,7 +173,6 @@ namespace osu.Game.Rulesets.UI.Scrolling
 
             controlPoints.AddRange(timingChanges);
 
-            // If we have no control points, add a default one
             if (controlPoints.Count == 0)
                 controlPoints.Add(new MultiplierControlPoint { Velocity = Beatmap.BeatmapInfo.BaseDifficulty.SliderMultiplier });
         }

osu.Game/Screens/Edit/Compose/Components/BlueprintContainer.cs

@@ -11,6 +11,7 @@ using osu.Framework.Input.Events;
 using osu.Framework.Input.States;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Edit.Tools;
+using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Objects.Drawables;
 
 namespace osu.Game.Screens.Edit.Compose.Components
@@ -29,6 +30,9 @@ namespace osu.Game.Screens.Edit.Compose.Components
         [Resolved]
         private HitObjectComposer composer { get; set; }
 
+        [Resolved]
+        private IEditorBeatmap beatmap { get; set; }
+
         public BlueprintContainer()
         {
             RelativeSizeAxes = Axes.Both;
@@ -53,7 +57,15 @@ namespace osu.Game.Screens.Edit.Compose.Components
             };
 
             foreach (var obj in composer.HitObjects)
-                AddBlueprintFor(obj);
+                addBlueprintFor(obj);
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            beatmap.HitObjectAdded += addBlueprintFor;
+            beatmap.HitObjectRemoved += removeBlueprintFor;
         }
 
         private HitObjectCompositionTool currentTool;
@@ -75,11 +87,32 @@ namespace osu.Game.Screens.Edit.Compose.Components
             }
         }
 
-        /// <summary>
+        private void addBlueprintFor(HitObject hitObject)
-        /// Adds a blueprint for a <see cref="DrawableHitObject"/> which adds movement support.
+        {
-        /// </summary>
+            var drawable = composer.HitObjects.FirstOrDefault(d => d.HitObject == hitObject);
-        /// <param name="hitObject">The <see cref="DrawableHitObject"/> to create a blueprint for.</param>
+            if (drawable == null)
-        public void AddBlueprintFor(DrawableHitObject hitObject)
+                return;
+
+            addBlueprintFor(drawable);
+        }
+
+        private void removeBlueprintFor(HitObject hitObject)
+        {
+            var blueprint = selectionBlueprints.Single(m => m.HitObject.HitObject == hitObject);
+            if (blueprint == null)
+                return;
+
+            blueprint.Deselect();
+
+            blueprint.Selected -= onBlueprintSelected;
+            blueprint.Deselected -= onBlueprintDeselected;
+            blueprint.SelectionRequested -= onSelectionRequested;
+            blueprint.DragRequested -= onDragRequested;
+
+            selectionBlueprints.Remove(blueprint);
+        }
+
+        private void addBlueprintFor(DrawableHitObject hitObject)
         {
             refreshTool();
 
@@ -95,25 +128,7 @@ namespace osu.Game.Screens.Edit.Compose.Components
             selectionBlueprints.Add(blueprint);
         }
 
-        /// <summary>
+        private void removeBlueprintFor(DrawableHitObject hitObject) => removeBlueprintFor(hitObject.HitObject);
-        /// Removes a blueprint for a <see cref="DrawableHitObject"/>.
-        /// </summary>
-        /// <param name="hitObject">The <see cref="DrawableHitObject"/> for which to remove the blueprint.</param>
-        public void RemoveBlueprintFor(DrawableHitObject hitObject)
-        {
-            var blueprint = selectionBlueprints.Single(m => m.HitObject == hitObject);
-            if (blueprint == null)
-                return;
-
-            blueprint.Deselect();
-
-            blueprint.Selected -= onBlueprintSelected;
-            blueprint.Deselected -= onBlueprintDeselected;
-            blueprint.SelectionRequested -= onSelectionRequested;
-            blueprint.DragRequested -= onDragRequested;
-
-            selectionBlueprints.Remove(blueprint);
-        }
 
         protected override bool OnClick(ClickEvent e)
         {
@@ -183,6 +198,17 @@ namespace osu.Game.Screens.Edit.Compose.Components
 
         private void onDragRequested(SelectionBlueprint blueprint, DragEvent dragEvent) => selectionHandler.HandleDrag(blueprint, dragEvent);
 
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+
+            if (beatmap != null)
+            {
+                beatmap.HitObjectAdded -= addBlueprintFor;
+                beatmap.HitObjectRemoved -= removeBlueprintFor;
+            }
+        }
+
         private class SelectionBlueprintContainer : Container<SelectionBlueprint>
         {
             protected override int Compare(Drawable x, Drawable y)

osu.Game/Screens/Edit/Compose/ComposeScreen.cs

@@ -9,15 +9,13 @@ using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Shapes;
 using osu.Framework.Logging;
 using osu.Game.Rulesets.Edit;
-using osu.Game.Rulesets.Objects;
 using osu.Game.Screens.Edit.Compose.Components;
 using osu.Game.Screens.Edit.Compose.Components.Timeline;
 using osuTK.Graphics;
 
 namespace osu.Game.Screens.Edit.Compose
 {
-    [Cached(Type = typeof(IPlacementHandler))]
+    public class ComposeScreen : EditorScreen
-    public class ComposeScreen : EditorScreen, IPlacementHandler
     {
         private const float vertical_margins = 10;
         private const float horizontal_margins = 20;
@@ -119,13 +117,5 @@ namespace osu.Game.Screens.Edit.Compose
 
             composerContainer.Child = composer;
         }
-
-        public void BeginPlacement(HitObject hitObject)
-        {
-        }
-
-        public void EndPlacement(HitObject hitObject) => composer.Add(hitObject);
-
-        public void Delete(HitObject hitObject) => composer.Remove(hitObject);
     }
 }

osu.Game/Screens/Edit/EditorBeatmap.cs

@@ -0,0 +1,83 @@
+// 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.Collections.Generic;
+using osu.Game.Beatmaps;
+using osu.Game.Beatmaps.ControlPoints;
+using osu.Game.Beatmaps.Timing;
+using osu.Game.Rulesets.Objects;
+
+namespace osu.Game.Screens.Edit
+{
+    public class EditorBeatmap<T> : IEditorBeatmap<T>
+        where T : HitObject
+    {
+        public event Action<HitObject> HitObjectAdded;
+        public event Action<HitObject> HitObjectRemoved;
+
+        private readonly Beatmap<T> beatmap;
+
+        public EditorBeatmap(Beatmap<T> beatmap)
+        {
+            this.beatmap = beatmap;
+        }
+
+        public BeatmapInfo BeatmapInfo
+        {
+            get => beatmap.BeatmapInfo;
+            set => beatmap.BeatmapInfo = value;
+        }
+
+        public BeatmapMetadata Metadata => beatmap.Metadata;
+
+        public ControlPointInfo ControlPointInfo => beatmap.ControlPointInfo;
+
+        public List<BreakPeriod> Breaks => beatmap.Breaks;
+
+        public double TotalBreakTime => beatmap.TotalBreakTime;
+
+        IReadOnlyList<T> IBeatmap<T>.HitObjects => beatmap.HitObjects;
+
+        IReadOnlyList<HitObject> IBeatmap.HitObjects => beatmap.HitObjects;
+
+        public IEnumerable<BeatmapStatistic> GetStatistics() => beatmap.GetStatistics();
+
+        public IBeatmap Clone() => (EditorBeatmap<T>)MemberwiseClone();
+
+        /// <summary>
+        /// Adds a <see cref="HitObject"/> to this <see cref="EditorBeatmap{T}"/>.
+        /// </summary>
+        /// <param name="hitObject">The <see cref="HitObject"/> to add.</param>
+        public void Add(T hitObject)
+        {
+            // Preserve existing sorting order in the beatmap
+            var insertionIndex = beatmap.HitObjects.FindLastIndex(h => h.StartTime <= hitObject.StartTime);
+            beatmap.HitObjects.Insert(insertionIndex + 1, hitObject);
+
+            HitObjectAdded?.Invoke(hitObject);
+        }
+
+        /// <summary>
+        /// Removes a <see cref="HitObject"/> from this <see cref="EditorBeatmap{T}"/>.
+        /// </summary>
+        /// <param name="hitObject">The <see cref="HitObject"/> to add.</param>
+        public void Remove(T hitObject)
+        {
+            if (beatmap.HitObjects.Remove(hitObject))
+                HitObjectRemoved?.Invoke(hitObject);
+        }
+
+        /// <summary>
+        /// Adds a <see cref="HitObject"/> to this <see cref="EditorBeatmap{T}"/>.
+        /// </summary>
+        /// <param name="hitObject">The <see cref="HitObject"/> to add.</param>
+        public void Add(HitObject hitObject) => Add((T)hitObject);
+
+        /// <summary>
+        /// Removes a <see cref="HitObject"/> from this <see cref="EditorBeatmap{T}"/>.
+        /// </summary>
+        /// <param name="hitObject">The <see cref="HitObject"/> to add.</param>
+        public void Remove(HitObject hitObject) => Remove((T)hitObject);
+    }
+}

osu.Game/Screens/Edit/EditorWorkingBeatmap.cs

@@ -0,0 +1,46 @@
+// 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.Collections.Generic;
+using osu.Framework.Audio.Track;
+using osu.Framework.Graphics.Textures;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Skinning;
+using osu.Game.Storyboards;
+
+namespace osu.Game.Screens.Edit
+{
+    /// <summary>
+    /// Encapsulates a <see cref="WorkingBeatmap"/> while providing an overridden <see cref="Beatmap{TObject}"/>.
+    /// </summary>
+    /// <typeparam name="TObject"></typeparam>
+    public class EditorWorkingBeatmap<TObject> : IWorkingBeatmap
+        where TObject : HitObject
+    {
+        private readonly Beatmap<TObject> playableBeatmap;
+        private readonly WorkingBeatmap workingBeatmap;
+
+        public EditorWorkingBeatmap(Beatmap<TObject> playableBeatmap, WorkingBeatmap workingBeatmap)
+        {
+            this.playableBeatmap = playableBeatmap;
+            this.workingBeatmap = workingBeatmap;
+        }
+
+        public IBeatmap Beatmap => workingBeatmap.Beatmap;
+
+        public Texture Background => workingBeatmap.Background;
+
+        public Track Track => workingBeatmap.Track;
+
+        public Waveform Waveform => workingBeatmap.Waveform;
+
+        public Storyboard Storyboard => workingBeatmap.Storyboard;
+
+        public Skin Skin => workingBeatmap.Skin;
+
+        public IBeatmap GetPlayableBeatmap(RulesetInfo ruleset, IReadOnlyList<Mod> mods) => playableBeatmap;
+    }
+}

osu.Game/Screens/Edit/IEditorBeatmap.cs

@@ -0,0 +1,36 @@
+// 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 osu.Game.Beatmaps;
+using osu.Game.Rulesets.Edit;
+using osu.Game.Rulesets.Objects;
+
+namespace osu.Game.Screens.Edit
+{
+    /// <summary>
+    /// Interface for the <see cref="IBeatmap"/> contained by the see <see cref="HitObjectComposer"/>.
+    /// Children of <see cref="HitObjectComposer"/> may resolve the beatmap via <see cref="IEditorBeatmap"/> or <see cref="IEditorBeatmap{T}"/>.
+    /// </summary>
+    public interface IEditorBeatmap : IBeatmap
+    {
+        /// <summary>
+        /// Invoked when a <see cref="HitObject"/> is added to this <see cref="IEditorBeatmap"/>.
+        /// </summary>
+        event Action<HitObject> HitObjectAdded;
+
+        /// <summary>
+        /// Invoked when a <see cref="HitObject"/> is removed from this <see cref="IEditorBeatmap"/>.
+        /// </summary>
+        event Action<HitObject> HitObjectRemoved;
+    }
+
+    /// <summary>
+    /// Interface for the <see cref="IBeatmap"/> contained by the see <see cref="HitObjectComposer"/>.
+    /// Children of <see cref="HitObjectComposer"/> may resolve the beatmap via <see cref="IEditorBeatmap"/> or <see cref="IEditorBeatmap{T}"/>.
+    /// </summary>
+    public interface IEditorBeatmap<out T> : IEditorBeatmap, IBeatmap<T>
+        where T : HitObject
+    {
+    }
+}

osu.Game/Utils/HumanizerUtils.cs

@@ -0,0 +1,30 @@
+// 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.Globalization;
+using Humanizer;
+
+namespace osu.Game.Utils
+{
+    public static class HumanizerUtils
+    {
+        /// <summary>
+        /// Turns the current or provided date into a human readable sentence
+        /// </summary>
+        /// <param name="input">The date to be humanized</param>
+        /// <returns>distance of time in words</returns>
+        public static string Humanize(DateTimeOffset input)
+        {
+            // this works around https://github.com/xamarin/xamarin-android/issues/2012 and https://github.com/Humanizr/Humanizer/issues/690#issuecomment-368536282
+            try
+            {
+                return input.Humanize();
+            }
+            catch (ArgumentException)
+            {
+                return input.Humanize(culture: new CultureInfo("en-US"));
+            }
+        }
+    }
+}