Allow dragging anywhere in a capture box to move objects

osu.Game/Rulesets/Edit/HitObjectComposer.cs

@@ -108,6 +108,7 @@ private void load(OsuGameBase osuGame)
 
             selectionLayer.ObjectSelected += hitObjectOverlayLayer.AddOverlay;
             selectionLayer.ObjectDeselected += hitObjectOverlayLayer.RemoveOverlay;
+            selectionLayer.SelectionMovementRequested += hitObjectOverlayLayer.MoveObjects;
 
             toolboxCollection.Items =
                 new[] { new RadioButton("Select", () => setCompositionTool(null)) }

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

@@ -1,11 +1,13 @@
 // Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
+using System;
 using System.Collections.Generic;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Shapes;
+using osu.Framework.Input;
 using osu.Game.Graphics;
 using osu.Game.Rulesets.Objects.Drawables;
 using OpenTK;
@@ -17,6 +19,11 @@ namespace osu.Game.Rulesets.Edit.Layers.Selection
     /// </summary>
     public class CaptureBox : VisibilityContainer
     {
+        /// <summary>
+        /// Invoked when the captured <see cref="DrawableHitObject"/>s should be moved.
+        /// </summary>
+        public event Action<Vector2> MovementRequested;
+
         private readonly IDrawable captureArea;
         private readonly IReadOnlyList<DrawableHitObject> capturedObjects;
 
@@ -67,6 +74,18 @@ protected override void Update()
             Position = topLeft;
         }
 
+        protected override bool OnMouseDown(InputState state, MouseDownEventArgs args) => true;
+
+        protected override bool OnDragStart(InputState state) => true;
+
+        protected override bool OnDrag(InputState state)
+        {
+            MovementRequested?.Invoke(state.Mouse.Delta);
+            return true;
+        }
+
+        protected override bool OnDragEnd(InputState state) => true;
+
         public override bool DisposeOnDeathRemoval => true;
 
         protected override void PopIn() => this.FadeIn();

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

@@ -2,42 +2,17 @@
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
 using osu.Framework.Graphics.Containers;
-using osu.Framework.Input;
-using osu.Game.Rulesets.Edit.Types;
 using osu.Game.Rulesets.Objects.Drawables;
 
 namespace osu.Game.Rulesets.Edit.Layers.Selection
 {
-    public class HitObjectOverlay : OverlayContainer
+    public class HitObjectOverlay : Container
     {
-        // ReSharper disable once NotAccessedField.Local
-        // This will be used later to handle drag movement, etc
-        private readonly DrawableHitObject hitObject;
+        public readonly DrawableHitObject HitObject;
 
         public HitObjectOverlay(DrawableHitObject hitObject)
         {
-            this.hitObject = hitObject;
-
-            State = Visibility.Visible;
+            HitObject = hitObject;
         }
-
-        protected override bool OnDragStart(InputState state) => hitObject.HitObject is IHasEditablePosition;
-
-        protected override bool OnDrag(InputState state)
-        {
-            switch (hitObject.HitObject)
-            {
-                case IHasEditablePosition editablePosition:
-                    editablePosition.SetPosition(state.Mouse.Delta);
-                    break;
-            }
-
-            return true;
-        }
-
-        protected override bool OnDragEnd(InputState state) => true;
-
-        protected override void PopIn() => Alpha = 1;
-        protected override void PopOut() => Alpha = 0;
     }
 }

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

@@ -1,20 +1,25 @@
 // Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
-using System.Collections.Generic;
+using System.Linq;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
+using osu.Framework.Input;
+using osu.Game.Rulesets.Edit.Types;
 using osu.Game.Rulesets.Objects.Drawables;
+using OpenTK;
 
 namespace osu.Game.Rulesets.Edit.Layers.Selection
 {
     public class HitObjectOverlayLayer : CompositeDrawable
     {
-        private readonly Dictionary<DrawableHitObject, HitObjectOverlay> existingOverlays = new Dictionary<DrawableHitObject, HitObjectOverlay>();
+        private readonly Container<HitObjectOverlay> overlayContainer;
 
         public HitObjectOverlayLayer()
         {
             RelativeSizeAxes = Axes.Both;
+
+            InternalChild = overlayContainer = new Container<HitObjectOverlay> { RelativeSizeAxes = Axes.Both };
         }
 
         /// <summary>
@@ -27,8 +32,7 @@ public void AddOverlay(DrawableHitObject hitObject)
             if (overlay == null)
                 return;
 
-            existingOverlays[hitObject] = overlay;
-            AddInternal(overlay);
+            overlayContainer.Add(overlay);
         }
 
         /// <summary>
@@ -37,13 +41,28 @@ public void AddOverlay(DrawableHitObject hitObject)
         /// <param name="hitObject">The <see cref="DrawableHitObject"/> to remove the overlay for.</param>
         public void RemoveOverlay(DrawableHitObject hitObject)
         {
-            if (!existingOverlays.TryGetValue(hitObject, out var existing))
+            var existing = overlayContainer.FirstOrDefault(h => h.HitObject == hitObject);
+            if (existing == null)
                 return;
 
             existing.Hide();
             existing.Expire();
         }
 
+        public void MoveObjects(Vector2 offset)
+        {
+            // Todo: Various forms of snapping
+            foreach (var hitObject in overlayContainer.Select(o => o.HitObject.HitObject))
+            {
+                switch (hitObject)
+                {
+                    case IHasEditablePosition editablePosition:
+                        editablePosition.SetPosition(offset);
+                        break;
+                }
+            }
+        }
+
         /// <summary>
         /// Creates a <see cref="HitObjectOverlay"/> for a specific <see cref="DrawableHitObject"/>.
         /// </summary>

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

@@ -27,6 +27,11 @@ public class SelectionLayer : CompositeDrawable
         /// </summary>
         public event Action<DrawableHitObject> ObjectDeselected;
 
+        /// <summary>
+        /// Invoked when the selected <see cref="DrawableHitObject"/>s should be moved.
+        /// </summary>
+        public event Action<Vector2> SelectionMovementRequested;
+
         private readonly Playfield playfield;
 
         public SelectionLayer(Playfield playfield)
@@ -192,6 +197,7 @@ private void finishSelection()
                 return;
 
             AddInternal(captureBox = new CaptureBox(this, selectedHitObjects.ToList()));
+            captureBox.MovementRequested += v => SelectionMovementRequested?.Invoke(v);
         }
     }
 }