From 2c1bfd62efaba5e37651de1ea97911674c1c5539 Mon Sep 17 00:00:00 2001
From: smoogipoo <smoogipoo@smgi.me>
Date: Wed, 6 Nov 2019 17:27:41 +0900
Subject: [PATCH] Disallow selections to be moved outside of the playfield

---
 .../Edit/ManiaSelectionHandler.cs             |  4 +--
 .../Edit/OsuSelectionHandler.cs               | 25 +++++++++++++++++--
 .../Compose/Components/BlueprintContainer.cs  |  3 ++-
 .../Compose/Components/SelectionHandler.cs    |  5 ++--
 4 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/osu.Game.Rulesets.Mania/Edit/ManiaSelectionHandler.cs b/osu.Game.Rulesets.Mania/Edit/ManiaSelectionHandler.cs
index 732231b0d9..9cdf045b5b 100644
--- a/osu.Game.Rulesets.Mania/Edit/ManiaSelectionHandler.cs
+++ b/osu.Game.Rulesets.Mania/Edit/ManiaSelectionHandler.cs
@@ -29,7 +29,7 @@ namespace osu.Game.Rulesets.Mania.Edit
             editorClock = clock;
         }
 
-        public override void HandleMovement(MoveSelectionEvent moveEvent)
+        public override bool HandleMovement(MoveSelectionEvent moveEvent)
         {
             var maniaBlueprint = (ManiaSelectionBlueprint)moveEvent.Blueprint;
             int lastColumn = maniaBlueprint.DrawableObject.HitObject.Column;
@@ -38,7 +38,7 @@ namespace osu.Game.Rulesets.Mania.Edit
             performDragMovement(moveEvent);
             performColumnMovement(lastColumn, moveEvent);
 
-            base.HandleMovement(moveEvent);
+            return true;
         }
 
         /// <summary>
diff --git a/osu.Game.Rulesets.Osu/Edit/OsuSelectionHandler.cs b/osu.Game.Rulesets.Osu/Edit/OsuSelectionHandler.cs
index 472267eb66..9418565907 100644
--- a/osu.Game.Rulesets.Osu/Edit/OsuSelectionHandler.cs
+++ b/osu.Game.Rulesets.Osu/Edit/OsuSelectionHandler.cs
@@ -4,13 +4,34 @@
 using System.Linq;
 using osu.Game.Rulesets.Osu.Objects;
 using osu.Game.Screens.Edit.Compose.Components;
+using osuTK;
 
 namespace osu.Game.Rulesets.Osu.Edit
 {
     public class OsuSelectionHandler : SelectionHandler
     {
-        public override void HandleMovement(MoveSelectionEvent moveEvent)
+        public override bool HandleMovement(MoveSelectionEvent moveEvent)
         {
+            Vector2 minPosition = new Vector2(float.MaxValue, float.MaxValue);
+            Vector2 maxPosition = new Vector2(float.MinValue, float.MinValue);
+
+            // Go through all hitobjects to make sure they would remain in the bounds of the editor after movement, before any movement is attempted
+            foreach (var h in SelectedHitObjects.OfType<OsuHitObject>())
+            {
+                if (h is Spinner)
+                {
+                    // Spinners don't support position adjustments
+                    continue;
+                }
+
+                // Stacking is not considered
+                minPosition = Vector2.ComponentMin(minPosition, Vector2.ComponentMin(h.EndPosition + moveEvent.InstantDelta, h.Position + moveEvent.InstantDelta));
+                maxPosition = Vector2.ComponentMax(maxPosition, Vector2.ComponentMax(h.EndPosition + moveEvent.InstantDelta, h.Position + moveEvent.InstantDelta));
+            }
+
+            if (minPosition.X < 0 || minPosition.Y < 0 || maxPosition.X > DrawWidth || maxPosition.Y > DrawHeight)
+                return false;
+
             foreach (var h in SelectedHitObjects.OfType<OsuHitObject>())
             {
                 if (h is Spinner)
@@ -22,7 +43,7 @@ namespace osu.Game.Rulesets.Osu.Edit
                 h.Position += moveEvent.InstantDelta;
             }
 
-            base.HandleMovement(moveEvent);
+            return true;
         }
     }
 }
diff --git a/osu.Game/Screens/Edit/Compose/Components/BlueprintContainer.cs b/osu.Game/Screens/Edit/Compose/Components/BlueprintContainer.cs
index 288c712bde..c4d8176c7a 100644
--- a/osu.Game/Screens/Edit/Compose/Components/BlueprintContainer.cs
+++ b/osu.Game/Screens/Edit/Compose/Components/BlueprintContainer.cs
@@ -367,7 +367,8 @@ namespace osu.Game.Screens.Edit.Compose.Components
             (Vector2 snappedPosition, double snappedTime) = composer.GetSnappedPosition(ToLocalSpace(movePosition), draggedObject.StartTime);
 
             // Move the hitobjects
-            selectionHandler.HandleMovement(new MoveSelectionEvent(movementBlueprint, startPosition, ToScreenSpace(snappedPosition)));
+            if (!selectionHandler.HandleMovement(new MoveSelectionEvent(movementBlueprint, startPosition, ToScreenSpace(snappedPosition))))
+                return true;
 
             // Apply the start time at the newly snapped-to position
             double offset = snappedTime - draggedObject.StartTime;
diff --git a/osu.Game/Screens/Edit/Compose/Components/SelectionHandler.cs b/osu.Game/Screens/Edit/Compose/Components/SelectionHandler.cs
index 1722476e53..44bf22cfe1 100644
--- a/osu.Game/Screens/Edit/Compose/Components/SelectionHandler.cs
+++ b/osu.Game/Screens/Edit/Compose/Components/SelectionHandler.cs
@@ -68,9 +68,8 @@ namespace osu.Game.Screens.Edit.Compose.Components
         /// Handles the selected <see cref="DrawableHitObject"/>s being moved.
         /// </summary>
         /// <param name="moveEvent">The move event.</param>
-        public virtual void HandleMovement(MoveSelectionEvent moveEvent)
-        {
-        }
+        /// <returns>Whether any <see cref="DrawableHitObject"/>s were moved.</returns>
+        public virtual bool HandleMovement(MoveSelectionEvent moveEvent) => false;
 
         public bool OnPressed(PlatformAction action)
         {