Apply remaining changes required to restore previous functionality

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

@@ -1,6 +1,19 @@
 // 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 System.Linq;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Input;
+using osu.Framework.Input.Events;
+using osu.Game.Rulesets.Edit;
+using osu.Game.Rulesets.Edit.Tools;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.Objects.Drawables;
+using osuTK;
+
 namespace osu.Game.Screens.Edit.Compose.Components
 {
     /// <summary>
@@ -8,5 +21,129 @@ namespace osu.Game.Screens.Edit.Compose.Components
     /// </summary>
     public class ComposeBlueprintContainer : BlueprintContainer
     {
+        [Resolved]
+        private HitObjectComposer composer { get; set; }
+
+        private PlacementBlueprint currentPlacement;
+
+        private readonly Container<PlacementBlueprint> placementBlueprintContainer;
+
+        private InputManager inputManager;
+
+        private readonly IEnumerable<DrawableHitObject> drawableHitObjects;
+
+        public ComposeBlueprintContainer(IEnumerable<DrawableHitObject> drawableHitObjects)
+        {
+            this.drawableHitObjects = drawableHitObjects;
+
+            placementBlueprintContainer = new Container<PlacementBlueprint>
+            {
+                RelativeSizeAxes = Axes.Both
+            };
+        }
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            AddInternal(placementBlueprintContainer);
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            inputManager = GetContainingInputManager();
+        }
+
+        #region Placement
+
+        /// <summary>
+        /// Refreshes the current placement tool.
+        /// </summary>
+        private void refreshTool()
+        {
+            placementBlueprintContainer.Clear();
+            currentPlacement = null;
+
+            var blueprint = CurrentTool?.CreatePlacementBlueprint();
+
+            if (blueprint != null)
+            {
+                placementBlueprintContainer.Child = currentPlacement = blueprint;
+
+                // Fixes a 1-frame position discrepancy due to the first mouse move event happening in the next frame
+                updatePlacementPosition(inputManager.CurrentState.Mouse.Position);
+            }
+        }
+
+        private void updatePlacementPosition(Vector2 screenSpacePosition)
+        {
+            Vector2 snappedGridPosition = composer.GetSnappedPosition(ToLocalSpace(screenSpacePosition), 0).position;
+            Vector2 snappedScreenSpacePosition = ToScreenSpace(snappedGridPosition);
+
+            currentPlacement.UpdatePosition(snappedScreenSpacePosition);
+        }
+
+        #endregion
+
+        protected override bool OnMouseMove(MouseMoveEvent e)
+        {
+            if (currentPlacement != null)
+            {
+                updatePlacementPosition(e.ScreenSpaceMousePosition);
+                return true;
+            }
+
+            return base.OnMouseMove(e);
+        }
+
+        protected override void Update()
+        {
+            base.Update();
+
+            if (currentPlacement != null)
+            {
+                if (composer.CursorInPlacementArea)
+                    currentPlacement.State = PlacementState.Shown;
+                else if (currentPlacement?.PlacementBegun == false)
+                    currentPlacement.State = PlacementState.Hidden;
+            }
+        }
+
+        protected sealed override SelectionBlueprint CreateBlueprintFor(HitObject hitObject)
+        {
+            var drawable = drawableHitObjects.FirstOrDefault(d => d.HitObject == hitObject);
+            if (drawable == null)
+                return null;
+
+            return CreateBlueprintFor(drawable);
+        }
+
+        public virtual SelectionBlueprint CreateBlueprintFor(DrawableHitObject hitObject) => null;
+
+        protected override void AddBlueprintFor(HitObject hitObject)
+        {
+            refreshTool();
+            base.AddBlueprintFor(hitObject);
+        }
+
+        private HitObjectCompositionTool currentTool;
+
+        /// <summary>
+        /// The current placement tool.
+        /// </summary>
+        public HitObjectCompositionTool CurrentTool
+        {
+            get => currentTool;
+            set
+            {
+                if (currentTool == value)
+                    return;
+
+                currentTool = value;
+
+                refreshTool();
+            }
+        }
     }
 }