Add invert selection keybinding to editor

osu.Game/Input/Bindings/GlobalActionContainer.cs

@@ -155,6 +155,7 @@ public static IEnumerable<GlobalAction> GetGlobalActionsFor(GlobalActionCategory
             new KeyBinding(new[] { InputKey.Alt, InputKey.Left }, GlobalAction.EditorSeekToPreviousBookmark),
             new KeyBinding(new[] { InputKey.Alt, InputKey.Right }, GlobalAction.EditorSeekToNextBookmark),
             new KeyBinding(new[] { InputKey.Control, InputKey.L }, GlobalAction.EditorDiscardUnsavedChanges),
+            new KeyBinding(new[] { InputKey.Control, InputKey.I }, GlobalAction.EditorInvertSelection),
         };
 
         private static IEnumerable<KeyBinding> editorTestPlayKeyBindings => new[]
@@ -528,6 +529,9 @@ public enum GlobalAction
 
         [LocalisableDescription(typeof(GlobalActionKeyBindingStrings), nameof(GlobalActionKeyBindingStrings.NextSkin))]
         NextSkin,
+
+        [LocalisableDescription(typeof(GlobalActionKeyBindingStrings), nameof(GlobalActionKeyBindingStrings.EditorInvertSelection))]
+        EditorInvertSelection,
     }
 
     public enum GlobalActionCategory

osu.Game/Localisation/CommonStrings.cs

@@ -159,6 +159,11 @@ public static class CommonStrings
         /// </summary>
         public static LocalisableString Clone => new TranslatableString(getKey(@"clone"), @"Clone");
 
+        /// <summary>
+        /// "Invert selection"
+        /// </summary>
+        public static LocalisableString InvertSelection => new TranslatableString(getKey(@"invert_selection"), @"Invert selection");
+
         /// <summary>
         /// "Exit"
         /// </summary>

osu.Game/Localisation/GlobalActionKeyBindingStrings.cs

@@ -489,6 +489,11 @@ public static class GlobalActionKeyBindingStrings
         /// </summary>
         public static LocalisableString EditorDiscardUnsavedChanges => new TranslatableString(getKey(@"editor_discard_unsaved_changes"), @"Discard unsaved changes");
 
+        /// <summary>
+        /// "Invert selection"
+        /// </summary>
+        public static LocalisableString EditorInvertSelection => new TranslatableString(getKey(@"editor_invert_selection"), @"Invert selection");
+
         private static string getKey(string key) => $@"{prefix}:{key}";
     }
 }

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

@@ -300,6 +300,10 @@ public bool OnPressed(KeyBindingPressEvent<GlobalAction> e)
                     }
 
                     break;
+
+                case GlobalAction.EditorInvertSelection:
+                    InvertSelection();
+                    return true;
             }
 
             return false;
@@ -517,6 +521,13 @@ protected virtual void UpdateSelectionFromDragBox(HashSet<T> selectionBeforeDrag
         /// </summary>
         protected abstract void SelectAll();
 
+        /// <summary>
+        /// Invert the current selection, deselecting all selected items and selecting all unselected items.
+        /// </summary>
+        protected virtual void InvertSelection()
+        {
+        }
+
         /// <summary>
         /// Deselect all selected items.
         /// </summary>

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

@@ -129,6 +129,16 @@ protected override void SelectAll()
             SelectedItems.AddRange(Beatmap.HitObjects.Except(SelectedItems).ToArray());
         }
 
+        protected override void InvertSelection()
+        {
+            Composer.Playfield.KeepAllAlive();
+
+            var toSelect = Beatmap.HitObjects.Except(SelectedItems).ToArray();
+
+            SelectedItems.Clear();
+            SelectedItems.AddRange(toSelect);
+        }
+
         /// <summary>
         /// Ensures that newly-selected hitobjects are kept alive
         /// and drops that keep-alive from newly-deselected objects.