Handle all selection events within SelectionBox (incl. single-mask)

osu.Game/Rulesets/Edit/HitObjectComposer.cs

@@ -253,8 +253,8 @@ namespace osu.Game.Rulesets.Edit
         /// Creates a <see cref="SelectionBox"/> which outlines <see cref="DrawableHitObject"/>s
         /// and handles hitobject pattern adjustments.
         /// </summary>
-        /// <param name="overlays">The <see cref="DrawableHitObject"/> overlays.</param>
+        /// <param name="maskContainer">The <see cref="HitObjectMask"/> container.</param>
-        public virtual SelectionBox CreateSelectionBox() => new SelectionBox();
+        public virtual SelectionBox CreateSelectionBox(MaskContainer maskContainer) => new SelectionBox(maskContainer);
 
         /// <summary>
         /// Creates a <see cref="ScalableContainer"/> which provides a layer above or below the <see cref="Playfield"/>.

osu.Game/Rulesets/Edit/HitObjectMask.cs

@@ -4,8 +4,6 @@
 using System;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Primitives;
-using osu.Framework.Input;
-using osu.Game.Rulesets.Edit.Types;
 using osu.Game.Rulesets.Objects.Drawables;
 using OpenTK;
 
@@ -26,12 +24,6 @@ namespace osu.Game.Rulesets.Edit
         /// </summary>
         public event Action<HitObjectMask> Deselected;
 
-        /// <summary>
-        /// Invoked when this <see cref="HitObjectMask"/> is requesting to be the single selection.
-        /// This <see cref="HitObjectMask"/> has not been selected at this point, but will be selected immediately afterwards.
-        /// </summary>
-        public event Action<HitObjectMask> SingleSelectionRequested;
-
         /// <summary>
         /// The <see cref="DrawableHitObject"/> which this <see cref="HitObjectMask"/> applies to.
         /// </summary>
@@ -77,29 +69,6 @@ namespace osu.Game.Rulesets.Edit
             return true;
         }
 
-        protected override bool OnMouseDown(InputState state, MouseDownEventArgs args)
-        {
-            SingleSelectionRequested?.Invoke(this);
-            Select();
-            return true;
-        }
-
-        protected override bool OnDragStart(InputState state) => true;
-
-        protected override bool OnDrag(InputState state)
-        {
-            // Todo: Various forms of snapping
-            switch (HitObject.HitObject)
-            {
-                case IHasEditablePosition editablePosition:
-                    editablePosition.OffsetPosition(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/Screens/Edit/Screens/Compose/Layers/DragBox.cs

@@ -2,7 +2,6 @@
 // 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;
@@ -24,17 +23,17 @@ namespace osu.Game.Screens.Edit.Screens.Compose.Layers
         /// </summary>
         public event Action DragEnd;
 
-        private readonly IEnumerable<HitObjectMask> selectableMasks;
+        private readonly MaskContainer maskContainer;
 
         private Drawable box;
 
         /// <summary>
         /// Creates a new <see cref="DragBox"/>.
         /// </summary>
-        /// <param name="selectableMasks">The selectable <see cref="HitObjectMask"/>s.</param>
+        /// <param name="maskContainer">The selectable <see cref="HitObjectMask"/>s.</param>
-        public DragBox(IEnumerable<HitObjectMask> selectableMasks)
+        public DragBox(MaskContainer maskContainer)
         {
-            this.selectableMasks = selectableMasks;
+            this.maskContainer = maskContainer;
 
             RelativeSizeAxes = Axes.Both;
             AlwaysPresent = true;
@@ -79,7 +78,7 @@ namespace osu.Game.Screens.Edit.Screens.Compose.Layers
             box.Position = topLeft;
             box.Size = bottomRight - topLeft;
 
-            foreach (var mask in selectableMasks)
+            foreach (var mask in maskContainer.AliveMasks)
             {
                 if (mask.IsPresent && dragRectangle.Contains(mask.SelectionPoint))
                     mask.Select();

osu.Game/Screens/Edit/Screens/Compose/Layers/HitObjectMaskLayer.cs

@@ -1,7 +1,6 @@
 // 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.Allocation;
 using osu.Framework.Graphics;
@@ -21,8 +20,6 @@ namespace osu.Game.Screens.Edit.Screens.Compose.Layers
         private MaskContainer maskContainer;
         private SelectionBox selectionBox;
 
-        private readonly HashSet<HitObjectMask> selectedMasks = new HashSet<HitObjectMask>();
-
         public HitObjectMaskLayer(Playfield playfield, HitObjectComposer composer)
         {
             this.playfield = playfield;
@@ -36,9 +33,9 @@ namespace osu.Game.Screens.Edit.Screens.Compose.Layers
         {
             maskContainer = new MaskContainer();
 
-            selectionBox = composer.CreateSelectionBox();
+            selectionBox = composer.CreateSelectionBox(maskContainer);
 
-            var dragBox = new DragBox(maskContainer.AliveChildren);
+            var dragBox = new DragBox(maskContainer);
             dragBox.DragEnd += () => selectionBox.UpdateVisibility();
 
             InternalChildren = new Drawable[]
@@ -63,12 +60,7 @@ namespace osu.Game.Screens.Edit.Screens.Compose.Layers
             if (mask == null)
                 return;
 
-            mask.Selected += onSelected;
-            mask.Deselected += onDeselected;
-            mask.SingleSelectionRequested += onSingleSelectionRequested;
-
             maskContainer.Add(mask);
-            selectionBox.AddMask(mask);
         }
 
         /// <summary>
@@ -81,34 +73,13 @@ namespace osu.Game.Screens.Edit.Screens.Compose.Layers
             if (mask == null)
                 return;
 
-            mask.Selected -= onSelected;
-            mask.Deselected -= onDeselected;
-            mask.SingleSelectionRequested -= onSingleSelectionRequested;
-
             maskContainer.Remove(mask);
-            selectionBox.RemoveMask(mask);
         }
 
-        private void onSelected(HitObjectMask mask) => selectedMasks.Add(mask);
-
-        private void onDeselected(HitObjectMask mask) => selectedMasks.Remove(mask);
-
-        private void onSingleSelectionRequested(HitObjectMask mask) => DeselectAll();
-
         protected override bool OnMouseDown(InputState state, MouseDownEventArgs args)
         {
-            DeselectAll();
+            selectionBox.DeselectAll();
             return true;
         }
-
-        /// <summary>
-        /// Deselects all selected <see cref="DrawableHitObject"/>s.
-        /// </summary>
-        public void DeselectAll() => selectedMasks.ToList().ForEach(m => m.Deselect());
-
-        private class MaskContainer : Container<HitObjectMask>
-        {
-            public new IEnumerable<HitObjectMask> AliveChildren => AliveInternalChildren.Cast<HitObjectMask>();
-        }
     }
 }

osu.Game/Screens/Edit/Screens/Compose/Layers/MaskContainer.cs

@@ -0,0 +1,50 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using osu.Framework.Graphics.Containers;
+using osu.Game.Rulesets.Edit;
+
+namespace osu.Game.Screens.Edit.Screens.Compose.Layers
+{
+    public class MaskContainer : Container<HitObjectMask>
+    {
+        /// <summary>
+        /// Invoked when any <see cref="HitObjectMask"/> is selected.
+        /// </summary>
+        public event Action<HitObjectMask> MaskSelected;
+
+        /// <summary>
+        /// Invoked when any <see cref="HitObjectMask"/> is deselected.
+        /// </summary>
+        public event Action<HitObjectMask> MaskDeselected;
+
+        /// <summary>
+        /// All the <see cref="HitObjectMask"/>s with <see cref="IsAlive"/> == true.
+        /// </summary>
+        public IEnumerable<HitObjectMask> AliveMasks => AliveInternalChildren.Cast<HitObjectMask>();
+
+        public override void Add(HitObjectMask drawable)
+        {
+            base.Add(drawable);
+
+            drawable.Selected += onMaskSelected;
+            drawable.Deselected += onMaskDeselected;
+        }
+
+        public override bool Remove(HitObjectMask drawable)
+        {
+            var result = base.Remove(drawable);
+
+            if (result)
+            {
+                drawable.Selected -= onMaskSelected;
+                drawable.Deselected += onMaskDeselected;
+            }
+
+            return result;
+        }
+
+        private void onMaskSelected(HitObjectMask mask) => MaskSelected?.Invoke(mask);
+        private void onMaskDeselected(HitObjectMask mask) => MaskDeselected?.Invoke(mask);
+    }
+}

osu.Game/Screens/Edit/Screens/Compose/Layers/SelectionBox.cs

@@ -1,7 +1,6 @@
 // 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 System.Linq;
 using osu.Framework.Allocation;
@@ -23,15 +22,23 @@ namespace osu.Game.Screens.Edit.Screens.Compose.Layers
     {
         public const float BORDER_RADIUS = 2;
 
-        private readonly HashSet<HitObjectMask> selectedMasks = new HashSet<HitObjectMask>();
+        private readonly MaskContainer maskContainer;
+
+        private readonly List<HitObjectMask> selectedMasks = new List<HitObjectMask>();
+        private IEnumerable<HitObjectMask> selectableMasks => maskContainer.AliveMasks;
 
         private Drawable box;
 
-        public SelectionBox()
+        public SelectionBox(MaskContainer maskContainer)
         {
+            this.maskContainer = maskContainer;
+
             RelativeSizeAxes = Axes.Both;
             AlwaysPresent = true;
             Alpha = 0;
+
+            maskContainer.MaskSelected += onSelected;
+            maskContainer.MaskDeselected += onDeselected;
         }
 
         [BackgroundDependencyLoader]
@@ -51,58 +58,34 @@ namespace osu.Game.Screens.Edit.Screens.Compose.Layers
             };
         }
 
-        /// <summary>
+        #region User Input Handling
-        /// Tracks a selectable <see cref="HitObjectMask"/>.
+
-        /// </summary>
+        // Only handle input on selectable or selected masks
-        /// <param name="mask">The <see cref="HitObjectMask"/> to track.</param>
+        public override bool ReceiveMouseInputAt(Vector2 screenSpacePos) => selectableMasks.Concat(selectedMasks).Any(m => m.ReceiveMouseInputAt(screenSpacePos));
-        public void AddMask(HitObjectMask mask)
+
+        protected override bool OnMouseDown(InputState state, MouseDownEventArgs args)
         {
-            mask.Selected += onSelected;
+            if (selectedMasks.Any(m => m.ReceiveMouseInputAt(state.Mouse.NativeState.Position)))
-            mask.Deselected += onDeselected;
+                return true;
-            mask.SingleSelectionRequested += onSingleSelectionRequested;
-        }
 
-        /// <summary>
+            DeselectAll();
-        /// Stops tracking a <see cref="HitObjectMask"/>.
+            selectableMasks.First(m => m.ReceiveMouseInputAt(state.Mouse.NativeState.Position)).Select();
-        /// </summary>
-        /// <param name="mask">The <see cref="HitObjectMask"/> to stop tracking.</param>
-        public void RemoveMask(HitObjectMask mask)
-        {
-            mask.Selected -= onSelected;
-            mask.Deselected -= onDeselected;
-            mask.SingleSelectionRequested -= onSingleSelectionRequested;
-        }
 
-        private void onSelected(HitObjectMask mask) => selectedMasks.Add(mask);
-
-        private void onDeselected(HitObjectMask mask)
-        {
-            selectedMasks.Remove(mask);
-
-            // We don't want to update visibility if > 0, since we may be deselecting masks during drag-selection
-            if (selectedMasks.Count == 0)
-                UpdateVisibility();
-        }
-
-        private void onSingleSelectionRequested(HitObjectMask mask)
-        {
-            selectedMasks.Add(mask);
             UpdateVisibility();
+            return true;
         }
 
-        // Only handle input on the selected masks
-        public override bool ReceiveMouseInputAt(Vector2 screenSpacePos) => selectedMasks.Any(m => m.ReceiveMouseInputAt(screenSpacePos));
-
-        protected override bool OnMouseDown(InputState state, MouseDownEventArgs args) => true;
-
         protected override bool OnClick(InputState state)
         {
-            if (state.Mouse.NativeState.PositionMouseDown == null)
+            if (selectedMasks.Count == 1)
-                throw new InvalidOperationException("Click event received without a mouse down position.");
+                return true;
 
-            // We handled mousedown, but if the mouse has been clicked and not dragged, select the mask which would've handled the mouse down
+            var toSelect = selectedMasks.First(m => m.ReceiveMouseInputAt(state.Mouse.NativeState.Position));
-            // A mousedown event is triggered such that a single selection is requested
+
-            selectedMasks.First(m => m.ReceiveMouseInputAt(state.Mouse.NativeState.PositionMouseDown.Value)).TriggerOnMouseDown(state);
+            DeselectAll();
+            toSelect.Select();
+
+            UpdateVisibility();
             return true;
         }
 
@@ -127,10 +110,32 @@ namespace osu.Game.Screens.Edit.Screens.Compose.Layers
 
         protected override bool OnDragEnd(InputState state) => true;
 
+        #endregion
+
+        #region Selection Handling
+
+        private void onSelected(HitObjectMask mask) => selectedMasks.Add(mask);
+
+        private void onDeselected(HitObjectMask mask)
+        {
+            selectedMasks.Remove(mask);
+
+            // We don't want to update visibility if > 0, since we may be deselecting masks during drag-selection
+            if (selectedMasks.Count == 0)
+                UpdateVisibility();
+        }
+
+        /// <summary>
+        /// Deselects all selected <see cref="HitObjectMask"/>s.
+        /// </summary>
+        public void DeselectAll() => selectedMasks.ToList().ForEach(m => m.Deselect());
+
+        #endregion
+
         /// <summary>
         /// Updates whether this <see cref="SelectionBox"/> is visible.
         /// </summary>
-        public void UpdateVisibility()
+        internal void UpdateVisibility()
         {
             if (selectedMasks.Count > 0)
                 Show();
@@ -145,8 +150,6 @@ namespace osu.Game.Screens.Edit.Screens.Compose.Layers
             if (selectedMasks.Count == 0)
                 return;
 
-            // Todo: We might need to optimise this
-
             // Move the rectangle to cover the hitobjects
             var topLeft = new Vector2(float.MaxValue, float.MaxValue);
             var bottomRight = new Vector2(float.MinValue, float.MinValue);
@@ -165,5 +168,13 @@ namespace osu.Game.Screens.Edit.Screens.Compose.Layers
             box.Size = bottomRight - topLeft;
             box.Position = topLeft;
         }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+
+            maskContainer.MaskSelected -= onSelected;
+            maskContainer.MaskDeselected -= onDeselected;
+        }
     }
 }