Refactor into separate files + add xmldocs + rename some methods

osu.Game/Rulesets/Edit/Layers/Selection/CentreMarker.cs

@@ -0,0 +1,47 @@
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Game.Graphics;
+using OpenTK;
+
+namespace osu.Game.Rulesets.Edit.Layers.Selection
+{
+    /// <summary>
+    /// Represents the centre of a <see cref="MarkerContainer"/>.
+    /// </summary>
+    public class CentreMarker : CompositeDrawable
+    {
+        private const float marker_size = 10;
+        private const float line_width = 2;
+
+        public CentreMarker()
+        {
+            Size = new Vector2(marker_size);
+
+            InternalChildren = new[]
+            {
+                new Box
+                {
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                    RelativeSizeAxes = Axes.X,
+                    Height = line_width
+                },
+                new Box
+                {
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                    RelativeSizeAxes = Axes.Y,
+                    Width = line_width
+                },
+            };
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(OsuColour colours)
+        {
+            Colour = colours.Yellow;
+        }
+    }
+}

osu.Game/Rulesets/Edit/Layers/Selection/DragSelector.cs

@@ -0,0 +1,170 @@
+using System;
+using System.Collections.Generic;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Primitives;
+using osu.Framework.Graphics.Shapes;
+using osu.Game.Graphics;
+using osu.Game.Rulesets.Objects.Drawables;
+using OpenTK;
+using OpenTK.Graphics;
+
+namespace osu.Game.Rulesets.Edit.Layers.Selection
+{
+    /// <summary>
+    /// A box that represents a drag selection.
+    /// </summary>
+    public class DragSelector : CompositeDrawable
+    {
+        /// <summary>
+        /// The <see cref="DrawableHitObject"/>s that can be selected through a drag-selection.
+        /// </summary>
+        public IEnumerable<DrawableHitObject> CapturableObjects;
+
+        private readonly Container borderMask;
+        private readonly Drawable background;
+        private readonly MarkerContainer markers;
+
+        private Color4 captureFinishedColour;
+
+        private readonly Vector2 startPos;
+
+        /// <summary>
+        /// Creates a new <see cref="DragSelector"/>.
+        /// </summary>
+        /// <param name="startPos">The point at which the drag was initiated, in the parent's coordinates.</param>
+        public DragSelector(Vector2 startPos)
+        {
+            this.startPos = startPos;
+
+            InternalChildren = new Drawable[]
+            {
+                new Container
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Padding = new MarginPadding(-1),
+                    Child = borderMask = new Container
+                    {
+                        RelativeSizeAxes = Axes.Both,
+                        Masking = true,
+                        BorderColour = Color4.White,
+                        BorderThickness = 2,
+                        MaskingSmoothness = 1,
+                        Child = background = new Box
+                        {
+                            RelativeSizeAxes = Axes.Both,
+                            Alpha = 0.1f,
+                            AlwaysPresent = true
+                        },
+                    }
+                },
+                markers = new MarkerContainer
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Alpha = 0,
+                    GetDragRectangle = () => dragRectangle,
+                    UpdateDragRectangle = r =>
+                    {
+                        updateDragRectangle(r);
+                        BeginCapture();
+                    },
+                    FinishCapture = FinishCapture
+                }
+            };
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(OsuColour colours)
+        {
+            captureFinishedColour = colours.Yellow;
+        }
+
+        /// <summary>
+        /// The secondary corner of the drag selection box. A rectangle will be fit between the starting position and this value.
+        /// </summary>
+        public Vector2 DragEndPosition { set => updateDragRectangle(RectangleF.FromLTRB(startPos.X, startPos.Y, value.X, value.Y)); }
+
+        private RectangleF dragRectangle;
+        private void updateDragRectangle(RectangleF rectangle)
+        {
+            dragRectangle = rectangle;
+
+            Position = new Vector2(
+                Math.Min(rectangle.Left, rectangle.Right),
+                Math.Min(rectangle.Top, rectangle.Bottom));
+
+            Size = new Vector2(
+                Math.Max(rectangle.Left, rectangle.Right) - Position.X,
+                Math.Max(rectangle.Top, rectangle.Bottom) - Position.Y);
+        }
+
+        private readonly List<DrawableHitObject> capturedHitObjects = new List<DrawableHitObject>();
+        public IReadOnlyList<DrawableHitObject> CapturedHitObjects => capturedHitObjects;
+
+        /// <summary>
+        /// Processes hitobjects to determine which ones are captured by the drag selection.
+        /// Captured hitobjects will be enclosed by the drag selection upon <see cref="FinishCapture"/>.
+        /// </summary>
+        public void BeginCapture()
+        {
+            capturedHitObjects.Clear();
+
+            foreach (var obj in CapturableObjects)
+            {
+                if (!obj.IsAlive || !obj.IsPresent)
+                    continue;
+
+                var objectPosition = obj.ToScreenSpace(obj.SelectionPoint);
+                if (ScreenSpaceDrawQuad.Contains(objectPosition))
+                    capturedHitObjects.Add(obj);
+            }
+        }
+
+        /// <summary>
+        /// Encloses hitobjects captured through <see cref="BeginCapture"/> in the drag selection box.
+        /// </summary>
+        public void FinishCapture()
+        {
+            if (CapturedHitObjects.Count == 0)
+            {
+                Hide();
+                return;
+            }
+
+            // Move the rectangle to cover the hitobjects
+            var topLeft = new Vector2(float.MaxValue, float.MaxValue);
+            var bottomRight = new Vector2(float.MinValue, float.MinValue);
+
+            foreach (var obj in capturedHitObjects)
+            {
+                topLeft = Vector2.ComponentMin(topLeft, Parent.ToLocalSpace(obj.SelectionQuad.TopLeft));
+                bottomRight = Vector2.ComponentMax(bottomRight, Parent.ToLocalSpace(obj.SelectionQuad.BottomRight));
+            }
+
+            topLeft -= new Vector2(5);
+            bottomRight += new Vector2(5);
+
+            this.MoveTo(topLeft, 200, Easing.OutQuint)
+                .ResizeTo(bottomRight - topLeft, 200, Easing.OutQuint);
+
+            dragRectangle = RectangleF.FromLTRB(topLeft.X, topLeft.Y, bottomRight.X, bottomRight.Y);
+
+            borderMask.BorderThickness = 3;
+            borderMask.FadeColour(captureFinishedColour, 200);
+
+            // Transform into markers to let the user modify the drag selection further.
+            background.Delay(50).FadeOut(200);
+            markers.FadeIn(200);
+        }
+
+        private bool isActive = true;
+        public override bool HandleInput => isActive;
+
+        public override void Hide()
+        {
+            isActive = false;
+            this.FadeOut(400, Easing.OutQuint).Expire();
+        }
+    }
+}

osu.Game/Rulesets/Edit/Layers/Selection/Marker.cs

@@ -0,0 +1,102 @@
+using System;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Primitives;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Input;
+using osu.Game.Graphics;
+using OpenTK;
+using OpenTK.Graphics;
+
+namespace osu.Game.Rulesets.Edit.Layers.Selection
+{
+    /// <summary>
+    /// Represents a marker visible on the border of a <see cref="MarkerContainer"/> which exposes
+    /// properties that are used to resize a <see cref="DragSelector"/>.
+    /// </summary>
+    public class Marker : CompositeDrawable
+    {
+        private const float marker_size = 10;
+
+        /// <summary>
+        /// Invoked when this <see cref="Marker"/> requires the current drag rectangle.
+        /// </summary>
+        public Func<RectangleF> GetDragRectangle;
+
+        /// <summary>
+        /// Invoked when this <see cref="Marker"/> wants to update the drag rectangle.
+        /// </summary>
+        public Action<RectangleF> UpdateDragRectangle;
+
+        /// <summary>
+        /// Invoked when this <see cref="Marker"/> has finished updates to the drag rectangle.
+        /// </summary>
+        public Action FinishCapture;
+
+        private Color4 normalColour;
+        private Color4 hoverColour;
+
+        public Marker()
+        {
+            Size = new Vector2(marker_size);
+
+            InternalChild = new CircularContainer
+            {
+                RelativeSizeAxes = Axes.Both,
+                Masking = true,
+                Child = new Box { RelativeSizeAxes = Axes.Both }
+            };
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(OsuColour colours)
+        {
+            Colour = normalColour = colours.Yellow;
+            hoverColour = colours.YellowDarker;
+        }
+
+        protected override bool OnDragStart(InputState state) => true;
+
+        protected override bool OnDrag(InputState state)
+        {
+            var currentRectangle = GetDragRectangle();
+
+            float left = currentRectangle.Left;
+            float right = currentRectangle.Right;
+            float top = currentRectangle.Top;
+            float bottom = currentRectangle.Bottom;
+
+            // Apply modifications to the capture rectangle
+            if ((Anchor & Anchor.y0) > 0)
+                top += state.Mouse.Delta.Y;
+            else if ((Anchor & Anchor.y2) > 0)
+                bottom += state.Mouse.Delta.Y;
+
+            if ((Anchor & Anchor.x0) > 0)
+                left += state.Mouse.Delta.X;
+            else if ((Anchor & Anchor.x2) > 0)
+                right += state.Mouse.Delta.X;
+
+            UpdateDragRectangle(RectangleF.FromLTRB(left, top, right, bottom));
+            return true;
+        }
+
+        protected override bool OnDragEnd(InputState state)
+        {
+            FinishCapture();
+            return true;
+        }
+
+        protected override bool OnHover(InputState state)
+        {
+            this.FadeColour(hoverColour, 100);
+            return true;
+        }
+
+        protected override void OnHoverLost(InputState state)
+        {
+            this.FadeColour(normalColour, 100);
+        }
+    }
+}

osu.Game/Rulesets/Edit/Layers/Selection/MarkerContainer.cs

@@ -0,0 +1,89 @@
+using System;
+using System.Linq;
+using osu.Framework.Extensions.IEnumerableExtensions;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Primitives;
+
+namespace osu.Game.Rulesets.Edit.Layers.Selection
+{
+    /// <summary>
+    /// A <see cref="CompositeDrawable"/> that has <see cref="Marker"/>s around its border.
+    /// </summary>
+    public class MarkerContainer : CompositeDrawable
+    {
+        /// <summary>
+        /// Invoked when a <see cref="Marker"/> requires the current drag rectangle.
+        /// </summary>
+        public Func<RectangleF> GetDragRectangle;
+
+        /// <summary>
+        /// Invoked when a <see cref="Marker"/> wants to update the drag rectangle.
+        /// </summary>
+        public Action<RectangleF> UpdateDragRectangle;
+
+        /// <summary>
+        /// Invoked when a <see cref="Marker"/> has finished updates to the drag rectangle.
+        /// </summary>
+        public Action FinishCapture;
+
+        public MarkerContainer()
+        {
+            InternalChildren = new Drawable[]
+            {
+                new Marker
+                {
+                    Anchor = Anchor.TopLeft,
+                    Origin = Anchor.Centre
+                },
+                new Marker
+                {
+                    Anchor = Anchor.TopCentre,
+                    Origin = Anchor.Centre
+                },
+                new Marker
+                {
+                    Anchor = Anchor.TopRight,
+                    Origin = Anchor.Centre
+                },
+                new Marker
+                {
+                    Anchor = Anchor.CentreLeft,
+                    Origin = Anchor.Centre
+                },
+                new Marker
+                {
+                    Anchor = Anchor.BottomLeft,
+                    Origin = Anchor.Centre
+                },
+                new Marker
+                {
+                    Anchor = Anchor.CentreRight,
+                    Origin = Anchor.Centre
+                },
+                new Marker
+                {
+                    Anchor = Anchor.BottomRight,
+                    Origin = Anchor.Centre
+                },
+                new Marker
+                {
+                    Anchor = Anchor.BottomCentre,
+                    Origin = Anchor.Centre
+                },
+                new CentreMarker
+                {
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre
+                }
+            };
+
+            InternalChildren.OfType<Marker>().ForEach(m =>
+            {
+                m.GetDragRectangle = () => GetDragRectangle();
+                m.UpdateDragRectangle = r => UpdateDragRectangle(r);
+                m.FinishCapture = () => FinishCapture();
+            });
+        }
+    }
+}

osu.Game/Rulesets/Edit/Layers/Selection/SelectionLayer.cs

@@ -0,0 +1,55 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Input;
+using osu.Game.Rulesets.UI;
+
+namespace osu.Game.Rulesets.Edit.Layers.Selection
+{
+    public class SelectionLayer : CompositeDrawable
+    {
+        private readonly Playfield playfield;
+
+        public SelectionLayer(Playfield playfield)
+        {
+            this.playfield = playfield;
+
+            RelativeSizeAxes = Axes.Both;
+        }
+
+        private DragSelector selector;
+
+        protected override bool OnDragStart(InputState state)
+        {
+            // Hide the previous drag box - we won't be working with it any longer
+            selector?.Hide();
+            AddInternal(selector = new DragSelector(ToLocalSpace(state.Mouse.NativeState.Position))
+            {
+                CapturableObjects = playfield.HitObjects.Objects
+            });
+
+            return true;
+        }
+
+        protected override bool OnDrag(InputState state)
+        {
+            selector.DragEndPosition = ToLocalSpace(state.Mouse.NativeState.Position);
+            selector.BeginCapture();
+            return true;
+        }
+
+        protected override bool OnDragEnd(InputState state)
+        {
+            selector.FinishCapture();
+            return true;
+        }
+
+        protected override bool OnClick(InputState state)
+        {
+            selector?.Hide();
+            return true;
+        }
+    }
+}

osu.Game/Rulesets/Edit/SelectionLayer.cs

@@ -1,378 +0,0 @@
-// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
-// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
-
-using System;
-using osu.Framework.Graphics;
-using osu.Framework.Graphics.Containers;
-using osu.Framework.Graphics.Primitives;
-using osu.Framework.Graphics.Shapes;
-using osu.Framework.Input;
-using OpenTK;
-using OpenTK.Graphics;
-using System.Collections.Generic;
-using osu.Game.Rulesets.Objects.Drawables;
-using osu.Game.Rulesets.UI;
-using System.Linq;
-using osu.Game.Graphics;
-using osu.Framework.Allocation;
-using osu.Framework.Extensions.IEnumerableExtensions;
-
-namespace osu.Game.Rulesets.Edit
-{
-    public class SelectionLayer : CompositeDrawable
-    {
-        private readonly Playfield playfield;
-
-        public SelectionLayer(Playfield playfield)
-        {
-            this.playfield = playfield;
-
-            RelativeSizeAxes = Axes.Both;
-        }
-
-        private DragContainer dragBox;
-
-        protected override bool OnDragStart(InputState state)
-        {
-            dragBox?.Hide();
-            AddInternal(dragBox = new DragContainer(ToLocalSpace(state.Mouse.NativeState.Position))
-            {
-                CapturableObjects = playfield.HitObjects.Objects
-            });
-
-            return true;
-        }
-
-        protected override bool OnDrag(InputState state)
-        {
-            dragBox.Track(ToLocalSpace(state.Mouse.NativeState.Position));
-            dragBox.UpdateCapture();
-            return true;
-        }
-
-        protected override bool OnDragEnd(InputState state)
-        {
-            if (dragBox.CapturedHitObjects.Count == 0)
-                dragBox.Hide();
-            else
-                dragBox.FinishCapture();
-            return true;
-        }
-
-        protected override bool OnClick(InputState state)
-        {
-            dragBox?.Hide();
-            return true;
-        }
-    }
-
-    public class DragContainer : CompositeDrawable
-    {
-        public IEnumerable<DrawableHitObject> CapturableObjects;
-
-        private readonly Container borderMask;
-        private readonly Drawable background;
-        private readonly MarkerContainer markers;
-
-        private Color4 captureFinishedColour;
-
-        private readonly Vector2 startPos;
-
-        public DragContainer(Vector2 startPos)
-        {
-            this.startPos = startPos;
-
-            InternalChildren = new Drawable[]
-            {
-                new Container
-                {
-                    RelativeSizeAxes = Axes.Both,
-                    Padding = new MarginPadding(-1),
-                    Child = borderMask = new Container
-                    {
-                        RelativeSizeAxes = Axes.Both,
-                        Masking = true,
-                        BorderColour = Color4.White,
-                        BorderThickness = 2,
-                        MaskingSmoothness = 1,
-                        Child = background = new Box
-                        {
-                            RelativeSizeAxes = Axes.Both,
-                            Alpha = 0.1f,
-                            AlwaysPresent = true
-                        },
-                    }
-                },
-                markers = new MarkerContainer
-                {
-                    RelativeSizeAxes = Axes.Both,
-                    Alpha = 0,
-                    GetCaptureRectangle = () => trackingRectangle,
-                    UpdateCapture = r =>
-                    {
-                        trackRectangle(r);
-                        UpdateCapture();
-                    },
-                    FinishCapture = FinishCapture
-                }
-            };
-        }
-
-        [BackgroundDependencyLoader]
-        private void load(OsuColour colours)
-        {
-            captureFinishedColour = colours.Yellow;
-        }
-
-        public void Track(Vector2 position) => trackRectangle(RectangleF.FromLTRB(startPos.X, startPos.Y, position.X, position.Y));
-
-        private RectangleF trackingRectangle;
-        private void trackRectangle(RectangleF rectangle)
-        {
-            trackingRectangle = rectangle;
-
-            Position = new Vector2(
-                Math.Min(rectangle.Left, rectangle.Right),
-                Math.Min(rectangle.Top, rectangle.Bottom));
-
-            Size = new Vector2(
-                Math.Max(rectangle.Left, rectangle.Right) - Position.X,
-                Math.Max(rectangle.Top, rectangle.Bottom) - Position.Y);
-        }
-
-        private List<DrawableHitObject> capturedHitObjects = new List<DrawableHitObject>();
-        public IReadOnlyList<DrawableHitObject> CapturedHitObjects => capturedHitObjects;
-
-        public void UpdateCapture()
-        {
-            capturedHitObjects.Clear();
-
-            foreach (var obj in CapturableObjects)
-            {
-                if (!obj.IsAlive || !obj.IsPresent)
-                    continue;
-
-                var objectPosition = obj.ToScreenSpace(obj.SelectionPoint);
-                if (ScreenSpaceDrawQuad.Contains(objectPosition))
-                    capturedHitObjects.Add(obj);
-            }
-        }
-
-        public void FinishCapture()
-        {
-            if (CapturedHitObjects.Count == 0)
-            {
-                Hide();
-                return;
-            }
-
-            // Move the rectangle to cover the hitobjects
-            var topLeft = new Vector2(float.MaxValue, float.MaxValue);
-            var bottomRight = new Vector2(float.MinValue, float.MinValue);
-
-            foreach (var obj in capturedHitObjects)
-            {
-                topLeft = Vector2.ComponentMin(topLeft, Parent.ToLocalSpace(obj.SelectionQuad.TopLeft));
-                bottomRight = Vector2.ComponentMax(bottomRight, Parent.ToLocalSpace(obj.SelectionQuad.BottomRight));
-            }
-
-            topLeft -= new Vector2(5);
-            bottomRight += new Vector2(5);
-
-            this.MoveTo(topLeft, 200, Easing.OutQuint)
-                .ResizeTo(bottomRight - topLeft, 200, Easing.OutQuint);
-
-            trackingRectangle = RectangleF.FromLTRB(topLeft.X, topLeft.Y, bottomRight.X, bottomRight.Y);
-
-            borderMask.BorderThickness = 3;
-            borderMask.FadeColour(captureFinishedColour, 200);
-
-            background.Delay(50).FadeOut(200);
-            markers.FadeIn(200);
-        }
-
-        private bool isActive = true;
-        public override bool HandleInput => isActive;
-
-        public override void Hide()
-        {
-            isActive = false;
-            this.FadeOut(400, Easing.OutQuint).Expire();
-        }
-    }
-
-    public class MarkerContainer : CompositeDrawable
-    {
-        public Func<RectangleF> GetCaptureRectangle;
-        public Action<RectangleF> UpdateCapture;
-        public Action FinishCapture;
-
-        public MarkerContainer()
-        {
-            InternalChildren = new Drawable[]
-            {
-                new Marker
-                {
-                    Anchor = Anchor.TopLeft,
-                    Origin = Anchor.Centre
-                },
-                new Marker
-                {
-                    Anchor = Anchor.TopCentre,
-                    Origin = Anchor.Centre
-                },
-                new Marker
-                {
-                    Anchor = Anchor.TopRight,
-                    Origin = Anchor.Centre
-                },
-                new Marker
-                {
-                    Anchor = Anchor.CentreLeft,
-                    Origin = Anchor.Centre
-                },
-                new Marker
-                {
-                    Anchor = Anchor.BottomLeft,
-                    Origin = Anchor.Centre
-                },
-                new Marker
-                {
-                    Anchor = Anchor.CentreRight,
-                    Origin = Anchor.Centre
-                },
-                new Marker
-                {
-                    Anchor = Anchor.BottomRight,
-                    Origin = Anchor.Centre
-                },
-                new Marker
-                {
-                    Anchor = Anchor.BottomCentre,
-                    Origin = Anchor.Centre
-                },
-                new CentreMarker
-                {
-                    Anchor = Anchor.Centre,
-                    Origin = Anchor.Centre
-                }
-            };
-
-            InternalChildren.OfType<Marker>().ForEach(m =>
-            {
-                m.GetCaptureRectangle = () => GetCaptureRectangle();
-                m.UpdateCapture = r => UpdateCapture(r);
-                m.FinishCapture = () => FinishCapture();
-            });
-        }
-    }
-
-    public class Marker : CompositeDrawable
-    {
-        private const float marker_size = 10;
-
-        public Func<RectangleF> GetCaptureRectangle;
-        public Action<RectangleF> UpdateCapture;
-        public Action FinishCapture;
-
-        private Color4 normalColour;
-        private Color4 hoverColour;
-
-        public Marker()
-        {
-            Size = new Vector2(marker_size);
-
-            InternalChild = new CircularContainer
-            {
-                RelativeSizeAxes = Axes.Both,
-                Masking = true,
-                Child = new Box { RelativeSizeAxes = Axes.Both }
-            };
-        }
-
-        [BackgroundDependencyLoader]
-        private void load(OsuColour colours)
-        {
-            Colour = normalColour = colours.Yellow;
-            hoverColour = colours.YellowDarker;
-        }
-
-        protected override bool OnDragStart(InputState state) => true;
-
-        protected override bool OnDrag(InputState state)
-        {
-            var currentRectangle = GetCaptureRectangle();
-
-            float left = currentRectangle.Left;
-            float right = currentRectangle.Right;
-            float top = currentRectangle.Top;
-            float bottom = currentRectangle.Bottom;
-
-            // Apply modifications to the capture rectangle
-            if ((Anchor & Anchor.y0) > 0)
-                top += state.Mouse.Delta.Y;
-            else if ((Anchor & Anchor.y2) > 0)
-                bottom += state.Mouse.Delta.Y;
-
-            if ((Anchor & Anchor.x0) > 0)
-                left += state.Mouse.Delta.X;
-            else if ((Anchor & Anchor.x2) > 0)
-                right += state.Mouse.Delta.X;
-
-            UpdateCapture(RectangleF.FromLTRB(left, top, right, bottom));
-            return true;
-        }
-
-        protected override bool OnDragEnd(InputState state)
-        {
-            FinishCapture();
-            return true;
-        }
-
-        protected override bool OnHover(InputState state)
-        {
-            this.FadeColour(hoverColour, 100);
-            return true;
-        }
-
-        protected override void OnHoverLost(InputState state)
-        {
-            this.FadeColour(normalColour, 100);
-        }
-    }
-
-    public class CentreMarker : CompositeDrawable
-    {
-        private const float marker_size = 10;
-        private const float line_width = 2;
-
-        public CentreMarker()
-        {
-            Size = new Vector2(marker_size);
-
-            InternalChildren = new[]
-            {
-                new Box
-                {
-                    Anchor = Anchor.Centre,
-                    Origin = Anchor.Centre,
-                    RelativeSizeAxes = Axes.X,
-                    Height = line_width
-                },
-                new Box
-                {
-                    Anchor = Anchor.Centre,
-                    Origin = Anchor.Centre,
-                    RelativeSizeAxes = Axes.Y,
-                    Width = line_width
-                },
-            };
-        }
-
-        [BackgroundDependencyLoader]
-        private void load(OsuColour colours)
-        {
-            Colour = colours.Yellow;
-        }
-    }
-}

osu.Game/osu.Game.csproj

@@ -310,6 +310,11 @@
     <Compile Include="Overlays\Profile\Sections\Ranks\DrawableTotalScore.cs" />
     <Compile Include="Overlays\Profile\Sections\Ranks\ScoreModsContainer.cs" />
     <Compile Include="Overlays\Settings\SettingsButton.cs" />
+    <Compile Include="Rulesets\Edit\Layers\Selection\CentreMarker.cs" />
+    <Compile Include="Rulesets\Edit\Layers\Selection\DragSelector.cs" />
+    <Compile Include="Rulesets\Edit\Layers\Selection\Marker.cs" />
+    <Compile Include="Rulesets\Edit\Layers\Selection\MarkerContainer.cs" />
+    <Compile Include="Rulesets\Edit\Layers\Selection\SelectionLayer.cs" />
     <Compile Include="Screens\Edit\Components\BottomBarContainer.cs" />
     <Compile Include="Screens\Edit\Components\PlaybackControl.cs" />
     <Compile Include="Screens\Edit\Components\TimeInfoContainer.cs" />
@@ -573,7 +578,6 @@
     <Compile Include="Rulesets\Edit\Tools\HitObjectCompositionTool.cs" />
     <Compile Include="Rulesets\Edit\Tools\ICompositionTool.cs" />
     <Compile Include="Rulesets\Edit\HitObjectComposer.cs" />
-    <Compile Include="Rulesets\Edit\SelectionLayer.cs" />
     <Compile Include="Rulesets\Edit\ToolboxGroup.cs" />
     <Compile Include="Rulesets\Judgements\DrawableJudgement.cs" />
     <Compile Include="Rulesets\Judgements\Judgement.cs" />