Add optional support for cyclic selection to BlueprintContainer

osu.Game/Overlays/SkinEditor/SkinBlueprintContainer.cs

@@ -25,6 +25,8 @@ namespace osu.Game.Overlays.SkinEditor
         [Resolved]
         private SkinEditor editor { get; set; } = null!;
 
+        protected override bool AllowCyclicSelection => true;
+
         public SkinBlueprintContainer(ISerialisableDrawableContainer targetContainer)
         {
             this.targetContainer = targetContainer;

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

@@ -45,6 +45,15 @@ namespace osu.Game.Screens.Edit.Compose.Components
 
         protected readonly BindableList<T> SelectedItems = new BindableList<T>();
 
+        /// <summary>
+        /// Whether to allow cyclic selection on clicking multiple times.
+        /// </summary>
+        /// <remarks>
+        /// Disabled by default as it does not work well with editors that support double-clicking or other advanced interactions.
+        /// Can probably be made to work with more thought.
+        /// </remarks>
+        protected virtual bool AllowCyclicSelection => false;
+
         protected BlueprintContainer()
         {
             RelativeSizeAxes = Axes.Both;
@@ -167,7 +176,7 @@ namespace osu.Game.Screens.Edit.Compose.Components
             Schedule(() =>
             {
                 endClickSelection(e);
-                clickSelectionBegan = false;
+                clickSelectionHandled = false;
                 isDraggingBlueprint = false;
             });
 
@@ -339,7 +348,12 @@ namespace osu.Game.Screens.Edit.Compose.Components
         /// <summary>
         /// Whether a blueprint was selected by a previous click event.
         /// </summary>
-        private bool clickSelectionBegan;
+        private bool clickSelectionHandled;
+
+        /// <summary>
+        /// Whether the selected blueprint(s) were already selected on mouse down. Generally used to perform selection cycling on mouse up in such a case.
+        /// </summary>
+        private bool selectedBlueprintAlreadySelectedOnMouseDown;
 
         /// <summary>
         /// Attempts to select any hovered blueprints.
@@ -354,7 +368,8 @@ namespace osu.Game.Screens.Edit.Compose.Components
             {
                 if (!blueprint.IsHovered) continue;
 
-                return clickSelectionBegan = SelectionHandler.MouseDownSelectionRequested(blueprint, e);
+                selectedBlueprintAlreadySelectedOnMouseDown = blueprint.State == SelectionState.Selected;
+                return clickSelectionHandled = SelectionHandler.MouseDownSelectionRequested(blueprint, e);
             }
 
             return false;
@@ -367,18 +382,45 @@ namespace osu.Game.Screens.Edit.Compose.Components
         /// <returns>Whether a click selection was active.</returns>
         private bool endClickSelection(MouseButtonEvent e)
         {
-            if (!clickSelectionBegan && !isDraggingBlueprint)
+            if (!clickSelectionHandled && !isDraggingBlueprint)
             {
-                // if a selection didn't occur, we may want to trigger a deselection.
+                if (e.Button == MouseButton.Left)
-                if (e.ControlPressed && e.Button == MouseButton.Left)
                 {
-                    // Iterate from the top of the input stack (blueprints closest to the front of the screen first).
+                    if (e.ControlPressed)
-                    // Priority is given to already-selected blueprints.
-                    foreach (SelectionBlueprint<T> blueprint in SelectionBlueprints.AliveChildren.Reverse().OrderByDescending(b => b.IsSelected))
                     {
-                        if (!blueprint.IsHovered) continue;
+                        // if a selection didn't occur, we may want to trigger a deselection.
 
-                        return clickSelectionBegan = SelectionHandler.MouseUpSelectionRequested(blueprint, e);
+                        // Iterate from the top of the input stack (blueprints closest to the front of the screen first).
+                        // Priority is given to already-selected blueprints.
+                        foreach (SelectionBlueprint<T> blueprint in SelectionBlueprints.AliveChildren.OrderByDescending(b => b.IsSelected))
+                        {
+                            if (!blueprint.IsHovered) continue;
+
+                            return clickSelectionHandled = SelectionHandler.MouseUpSelectionRequested(blueprint, e);
+                        }
+                    }
+                    else if (selectedBlueprintAlreadySelectedOnMouseDown && AllowCyclicSelection)
+                    {
+                        // If a click occurred and was handled by the currently selected blueprint but didn't result in a drag,
+                        // cycle between other blueprints which are also under the cursor.
+
+                        // The depth of blueprints is constantly changing (see above where selected blueprints are brought to the front).
+                        // For this logic, we want a stable sort order so we can correctly cycle, thus using the blueprintMap instead.
+                        IEnumerable<SelectionBlueprint<T>> cyclingSelectionBlueprints = blueprintMap.Values;
+
+                        // If there's already a selection, let's start from the blueprint after the selection.
+                        cyclingSelectionBlueprints = cyclingSelectionBlueprints.SkipWhile(b => !b.IsSelected).Skip(1);
+
+                        // Add the blueprints from before the selection to the end of the enumerable to allow for cyclic selection.
+                        cyclingSelectionBlueprints = cyclingSelectionBlueprints.Concat(blueprintMap.Values.TakeWhile(b => !b.IsSelected));
+
+                        foreach (SelectionBlueprint<T> blueprint in cyclingSelectionBlueprints)
+                        {
+                            if (!blueprint.IsHovered) continue;
+
+                            // We are performing a mouse up, but selection handlers perform selection on mouse down, so we need to call that instead.
+                            return clickSelectionHandled = SelectionHandler.MouseDownSelectionRequested(blueprint, e);
+                        }
                     }
                 }
 
@@ -441,7 +483,11 @@ namespace osu.Game.Screens.Edit.Compose.Components
 
         private Vector2[][] movementBlueprintsOriginalPositions;
         private SelectionBlueprint<T>[] movementBlueprints;
-        private bool isDraggingBlueprint;
+
+        /// <summary>
+        /// Whether a blueprint is currently being dragged.
+        /// </summary>
+        private bool isDraggingBlueprint { get; set; }
 
         /// <summary>
         /// Attempts to begin the movement of any selected blueprints.
@@ -454,7 +500,7 @@ namespace osu.Game.Screens.Edit.Compose.Components
 
             // Any selected blueprint that is hovered can begin the movement of the group, however only the first item (according to SortForMovement) is used for movement.
             // A special case is added for when a click selection occurred before the drag
-            if (!clickSelectionBegan && !SelectionHandler.SelectedBlueprints.Any(b => b.IsHovered))
+            if (!clickSelectionHandled && !SelectionHandler.SelectedBlueprints.Any(b => b.IsHovered))
                 return false;
 
             // Movement is tracked from the blueprint of the earliest item, since it only makes sense to distance snap from that item