Add selecting methods to NodifyEditor (#156)

* Add selecting methods to NodifyEditor

Author: miroiu

CHANGELOG.md

@@ -6,9 +6,11 @@
 >	- Made the setter of NodifyEditor.IsPanning private
 >	- Renamed StartCutting to BeginCutting in NodifyEditor
 >	- Renamed PushItems to UpdatePushedArea and StartPushingItems to BeginPushingItems in NodifyEditor
+>	- Renamed UnselectAllConnection to UnselectAllConnections in NodifyEditor
 > - Features:
 >	- Added BeginPanning, UpdatePanning, EndPanning, CancelPanning and AllowPanningCancellation to NodifyEditor
 >	- Added UpdateCuttingLine to NodifyEditor
+>	- Added BeginSelecting, UpdateSelection, EndSelecting, CancelSelecting and AllowSelectionCancellation to NodifyEditor
 > - Bugfixes:
 	
 #### **Version 6.6.0**

Nodify/EditorStates/EditorCuttingState.cs

@@ -4,7 +4,7 @@ namespace Nodify
 {
     public class EditorCuttingState : EditorState
     {
-        public bool Canceled { get; set; } = CuttingLine.AllowCuttingCancellation;
+        private bool Canceled { get; set; } = CuttingLine.AllowCuttingCancellation;
 
         public EditorCuttingState(NodifyEditor editor) : base(editor)
         {

Nodify/EditorStates/EditorDefaultState.cs

@@ -1,6 +1,5 @@
 using System.Windows;
 using System.Windows.Input;
-using static Nodify.SelectionHelper;
 
 namespace Nodify
 {
@@ -32,23 +31,22 @@ public EditorDefaultState(NodifyEditor editor) : base(editor)
         public override void HandleMouseDown(MouseButtonEventArgs e)
         {
             EditorGestures.NodifyEditorGestures gestures = EditorGestures.Mappings.Editor;
-            if (gestures.Cutting.Matches(e.Source, e))
+            if (Editor.CanSelectMultipleItems && gestures.Selection.Select.Matches(e.Source, e))
             {
-                PushState(new EditorCuttingState(Editor));
+                SelectionType selectionType = SelectionHelper.GetSelectionType(e);
+                PushState(new EditorSelectingState(Editor, selectionType));
             }
-            else if (gestures.PushItems.Matches(e.Source, e))
+            else if (!Editor.DisablePanning && gestures.Pan.Matches(e.Source, e))
             {
-                PushState(new EditorPushingItemsState(Editor));
+                PushState(new EditorPanningState(Editor));
             }
-            else if (gestures.Selection.Select.Matches(e.Source, e))
+            else if (gestures.Cutting.Matches(e.Source, e))
             {
-                SelectionType selectionType = GetSelectionType(e);
-                var selecting = new EditorSelectingState(Editor, selectionType);
-                PushState(selecting);
+                PushState(new EditorCuttingState(Editor));
             }
-            else if (!Editor.DisablePanning && gestures.Pan.Matches(e.Source, e))
+            else if (gestures.PushItems.Matches(e.Source, e))
             {
-                PushState(new EditorPanningState(Editor));
+                PushState(new EditorPushingItemsState(Editor));
             }
         }
 

Nodify/EditorStates/EditorPushingItemsState.cs

@@ -10,7 +10,7 @@ public class EditorPushingItemsState : EditorState
         private Point _prevPosition;
         private const int _minDragDistance = 10;
 
-        public bool Canceled { get; set; } = NodifyEditor.AllowPushItemsCancellation;
+        private bool Canceled { get; set; } = NodifyEditor.AllowPushItemsCancellation;
 
         public EditorPushingItemsState(NodifyEditor editor) : base(editor)
         {

Nodify/EditorStates/EditorSelectingState.cs

@@ -1,51 +1,46 @@
 using System.Windows.Input;
-using static Nodify.SelectionHelper;
 
 namespace Nodify
 {
     /// <summary>The selecting state of the editor.</summary>
     public class EditorSelectingState : EditorState
     {
         private readonly SelectionType _type;
-        private bool _canceled;
-
-        /// <summary>The selection helper.</summary>
-        protected SelectionHelper Selection { get; }
+        private bool Canceled { get; set; } = NodifyEditor.AllowSelectionCancellation;
 
         /// <summary>Constructs an instance of the <see cref="EditorSelectingState"/> state.</summary>
         /// <param name="editor">The owner of the state.</param>
         /// <param name="type">The selection strategy.</param>
         public EditorSelectingState(NodifyEditor editor, SelectionType type) : base(editor)
         {
-            Selection = new SelectionHelper(editor);
             _type = type;
         }
 
         /// <inheritdoc />
         public override void Enter(EditorState? from)
         {
-            Editor.UnselectAllConnection();
+            Canceled = false;
 
-            _canceled = false;
-            Selection.Start(Editor.MouseLocation, _type);
+            Editor.BeginSelecting(Editor.MouseLocation, _type);
         }
 
         /// <inheritdoc />
         public override void Exit()
         {
-            if (_canceled)
+            // TODO: This is not canceled on LostMouseCapture (add OnLostMouseCapture/OnCancel callback?)
+            if (Canceled)
             {
-                Selection.Abort();
+                Editor.CancelSelecting();
             }
             else
             {
-                Selection.End();
+                Editor.EndSelecting();
             }
         }
 
         /// <inheritdoc />
-        public override void HandleMouseMove(MouseEventArgs e)
-            => Selection.Update(Editor.MouseLocation);
+        public override void HandleMouseMove(MouseEventArgs e) 
+            => Editor.UpdateSelection(Editor.MouseLocation);
 
         /// <inheritdoc />
         public override void HandleMouseDown(MouseButtonEventArgs e)
@@ -60,12 +55,15 @@ public override void HandleMouseDown(MouseButtonEventArgs e)
         public override void HandleMouseUp(MouseButtonEventArgs e)
         {
             EditorGestures.SelectionGestures gestures = EditorGestures.Mappings.Editor.Selection;
-
-            bool canCancel = gestures.Cancel.Matches(e.Source, e);
-            bool canComplete = gestures.Select.Matches(e.Source, e);
-            if (canCancel || canComplete)
+            if(gestures.Select.Matches(e.Source, e))
             {
-                _canceled = !canComplete && canCancel;
+                PopState();
+            }
+            else if(NodifyEditor.AllowSelectionCancellation && gestures.Cancel.Matches(e.Source, e))
+            {
+                Canceled = true;
+                e.Handled = true;   // prevents opening context menu
+
                 PopState();
             }
         }
@@ -76,9 +74,10 @@ public override void HandleAutoPanning(MouseEventArgs e)
 
         public override void HandleKeyUp(KeyEventArgs e)
         {
-            if (EditorGestures.Mappings.Editor.Selection.Cancel.Matches(e.Source, e))
+            EditorGestures.SelectionGestures gestures = EditorGestures.Mappings.Editor.Selection;
+            if (NodifyEditor.AllowSelectionCancellation && gestures.Cancel.Matches(e.Source, e))
             {
-                _canceled = true;
+                Canceled = true;
                 PopState();
             }
         }

Nodify/Helpers/SelectionHelper.cs

@@ -1,96 +1,81 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Windows;
-using System.Windows.Controls;
 using System.Windows.Input;
 
 namespace Nodify
 {
     /// <summary>
-    /// Helps with selecting <see cref="ItemContainer"/>s and updating the <see cref="NodifyEditor.SelectedArea"/> and <see cref="NodifyEditor.IsSelecting"/> properties.
+    /// Helps with selecting <see cref="ItemContainer"/>s.
     /// </summary>
-    public sealed class SelectionHelper
+    internal sealed class SelectionHelper
     {
-        private readonly NodifyEditor _host;
         private Point _startLocation;
+        private Point _endLocation;
         private SelectionType _selectionType;
         private bool _isRealtime;
-        private IReadOnlyList<ItemContainer> _initialSelection = new List<ItemContainer>();
-
-        /// <summary>Constructs a new instance of a <see cref="SelectionHelper"/>.</summary>
-        /// <param name="host">The editor to select items from.</param>
-        public SelectionHelper(NodifyEditor host)
-            => _host = host;
-
-        /// <summary>Available selection logic.</summary>
-        public enum SelectionType
-        {
-            /// <summary>Replaces the old selection.</summary>
-            Replace,
-            /// <summary>Removes items from existing selection.</summary>
-            Remove,
-            /// <summary>Adds items to the current selection.</summary>
-            Append,
-            /// <summary>Inverts the selection.</summary>
-            Invert
-        }
+        private IReadOnlyCollection<ItemContainer> _items = Array.Empty<ItemContainer>();
+        private IReadOnlyList<ItemContainer> _initialSelection = Array.Empty<ItemContainer>();
+        private Rect _selectedArea;
 
         /// <summary>Attempts to start a new selection.</summary>
+        /// <param name="containers">The containers that can be part of the selection.</param>
         /// <param name="location">The location inside the graph.</param>
         /// <param name="selectionType">The type of selection.</param>
         /// <remarks>Will not do anything if selection is in progress.</remarks>
-        public void Start(Point location, SelectionType selectionType)
+        public Rect Start(IEnumerable<ItemContainer> containers, Point location, SelectionType selectionType, bool realtime)
         {
-            if (!_host.IsSelecting)
-            {
-                _selectionType = selectionType;
-                _initialSelection = _host.SelectedContainers;
+            _items = containers.Where(x => x.IsSelectable).ToList();
+            _initialSelection = containers.Where(x => x.IsSelected).ToList();
 
-                _isRealtime = _host.EnableRealtimeSelection;
-                _startLocation = location;
+            _selectionType = selectionType;
 
-                _host.SelectedArea = new Rect();
-                _host.IsSelecting = true;
-            }
+            _isRealtime = realtime;
+            _startLocation = location;
+            _endLocation = location;
+
+            _selectedArea = new Rect();
+            return _selectedArea;
         }
 
         /// <summary>Update the end location for the selection.</summary>
         /// <param name="endLocation">An absolute location.</param>
-        public void Update(Point endLocation)
+        public Rect Update(Point endLocation)
         {
-            double left = endLocation.X < _startLocation.X ? endLocation.X : _startLocation.X;
-            double top = endLocation.Y < _startLocation.Y ? endLocation.Y : _startLocation.Y;
-            double width = Math.Abs(endLocation.X - _startLocation.X);
-            double height = Math.Abs(endLocation.Y - _startLocation.Y);
+            _endLocation = endLocation;
+
+            double left = _endLocation.X < _startLocation.X ? _endLocation.X : _startLocation.X;
+            double top = _endLocation.Y < _startLocation.Y ? _endLocation.Y : _startLocation.Y;
+            double width = Math.Abs(_endLocation.X - _startLocation.X);
+            double height = Math.Abs(_endLocation.Y - _startLocation.Y);
 
-            _host.SelectedArea = new Rect(left, top, width, height);
+            _selectedArea = new Rect(left, top, width, height);
 
             if (_isRealtime)
             {
-                PreviewSelection(_host.SelectedArea);
+                PreviewSelection(_selectedArea);
             }
+
+            return _selectedArea;
         }
 
-        /// <summary>Commits the current selection to the editor.</summary>
-        public void End()
+        /// <summary>Increase the selected area by the specified amount.</summary>
+        public Rect Update(Vector amount)
         {
-            if (_host.IsSelecting)
-            {
-                PreviewSelection(_host.SelectedArea);
+            _endLocation += amount;
 
-                _host.ApplyPreviewingSelection();
-                _host.IsSelecting = false;
-            }
+            return Update(_endLocation);
         }
 
-        /// <summary>Aborts the current selection.</summary>
-        public void Abort()
+        /// <summary>Commits the current selection to the editor.</summary>
+        public Rect End()
         {
-            if (_host.IsSelecting)
-            {
-                _host.ClearPreviewingSelection();
-                _host.IsSelecting = false;
-            }
+            PreviewSelection(_selectedArea);
+            _items = Array.Empty<ItemContainer>();
+            _initialSelection = Array.Empty<ItemContainer>();
+
+            return _selectedArea;
         }
 
         private void PreviewSelection(Rect area)
@@ -128,10 +113,8 @@ private void PreviewSelection(Rect area)
 
         private void PreviewUnselectAll()
         {
-            ItemCollection items = _host.Items;
-            for (var i = 0; i < items.Count; i++)
+            foreach (var container in _items)
             {
-                var container = (ItemContainer)_host.ItemContainerGenerator.ContainerFromIndex(i);
                 container.IsPreviewingSelection = false;
             }
         }
@@ -145,10 +128,8 @@ private void PreviewSelectArea(Rect area, bool append = false, bool fit = false)
 
             if (area.X != 0 || area.Y != 0 || area.Width > 0 || area.Height > 0)
             {
-                ItemCollection items = _host.Items;
-                for (var i = 0; i < items.Count; i++)
+                foreach (var container in _items)
                 {
-                    var container = (ItemContainer)_host.ItemContainerGenerator.ContainerFromIndex(i);
                     if (container.IsSelectableInArea(area, fit))
                     {
                         container.IsPreviewingSelection = true;
@@ -159,10 +140,8 @@ private void PreviewSelectArea(Rect area, bool append = false, bool fit = false)
 
         private void PreviewUnselectArea(Rect area, bool fit = false)
         {
-            ItemCollection items = _host.Items;
-            for (var i = 0; i < items.Count; i++)
+            foreach (var container in _items)
             {
-                var container = (ItemContainer)_host.ItemContainerGenerator.ContainerFromIndex(i);
                 if (container.IsSelectableInArea(area, fit))
                 {
                     container.IsPreviewingSelection = false;
@@ -180,10 +159,8 @@ private static void PreviewSelectContainers(IReadOnlyList<ItemContainer> contain
 
         private void PreviewInvertSelection(Rect area, bool fit = false)
         {
-            ItemCollection items = _host.Items;
-            for (var i = 0; i < items.Count; i++)
+            foreach (var container in _items)
             {
-                var container = (ItemContainer)_host.ItemContainerGenerator.ContainerFromIndex(i);
                 if (container.IsSelectableInArea(area, fit))
                 {
                     container.IsPreviewingSelection = !container.IsPreviewingSelection;