Merge pull request #40 from WiseTechGlobal/RAL/WI00655146/Implement_selectionBox_while_scrolling

SelectionBox now updates when scrolling

Author: Alvarenga1

src/Blazor.Diagrams.Core/Behaviors/SelectionBoxBehavior.cs

@@ -12,20 +12,25 @@ public class SelectionBoxBehavior : DragBehavior
         private Point? _initialClientPoint;
 
         public event EventHandler<Rectangle?>? SelectionBoundsChanged;
+        private double? _lastClientX;
+        private double? _lastClientY;
+        private Point? _initialPan;
 
         public SelectionBoxBehavior(Diagram diagram)
             : base(diagram)
         {
             Diagram.PointerDown += OnPointerDown;
             Diagram.PointerMove += OnPointerMove;
             Diagram.PointerUp += OnPointerUp;
+            Diagram.PanChanged += OnPanChanged;
         }
 
         public override void Dispose()
         {
             Diagram.PointerDown -= OnPointerDown;
             Diagram.PointerMove -= OnPointerMove;
             Diagram.PointerUp -= OnPointerUp;
+            Diagram.PanChanged -= OnPanChanged;
         }
 
         protected override void OnPointerDown(Model? model, PointerEventArgs e)
@@ -34,37 +39,32 @@ protected override void OnPointerDown(Model? model, PointerEventArgs e)
                 return;
 
             _initialClientPoint = new Point(e.ClientX, e.ClientY);
+            _lastClientX = e.ClientX;
+            _lastClientY = e.ClientY;
+            _initialPan = Diagram.Pan;
         }
 
         protected override void OnPointerMove(Model? model, PointerEventArgs e)
         {
             if (_initialClientPoint == null)
                 return;
 
-            UpdateSelectionBox(e);
+            _lastClientX = e.ClientX;
+            _lastClientY = e.ClientY;
 
-            var start = Diagram.GetRelativeMousePoint(_initialClientPoint.X, _initialClientPoint.Y);
-            var end = Diagram.GetRelativeMousePoint(e.ClientX, e.ClientY);
-            var (sX, sY) = (Math.Min(start.X, end.X), Math.Min(start.Y, end.Y));
-            var (eX, eY) = (Math.Max(start.X, end.X), Math.Max(start.Y, end.Y));
-            var bounds = new Rectangle(sX, sY, eX, eY);
+            UpdateSelectionBox(e.ClientX, e.ClientY);
+            SelectNodesInBounds(e.ClientX, e.ClientY);
+        }
 
-            foreach (var node in Diagram.Nodes)
+        void UpdateSelectionBox(double clientX, double clientY)
+        {
+            if(_initialClientPoint == null || _initialPan == null)
             {
-                var nodeBounds = node.GetBounds();
-                if (nodeBounds == null)
-                    continue;
-
-                if (bounds.Overlap(nodeBounds))
-                    Diagram.SelectModel(node, false);
-                else if (node.Selected) Diagram.UnselectModel(node);
+                return;
             }
-        }
 
-        void UpdateSelectionBox(MouseEventArgs e)
-        {
-            var start = Diagram.GetRelativePoint(_initialClientPoint!.X, _initialClientPoint.Y);
-            var end = Diagram.GetRelativePoint(e.ClientX, e.ClientY);
+            var start = Diagram.GetRelativePoint(_initialClientPoint.X + Diagram.Pan.X - _initialPan.X, _initialClientPoint.Y + Diagram.Pan.Y - _initialPan.Y);
+            var end = Diagram.GetRelativePoint(clientX, clientY);
             var (sX, sY) = (Math.Min(start.X, end.X), Math.Min(start.Y, end.Y));
             var (eX, eY) = (Math.Max(start.X, end.X), Math.Max(start.Y, end.Y));
             SelectionBoundsChanged?.Invoke(this, new Rectangle(sX, sY, eX, eY));
@@ -74,6 +74,42 @@ protected override void OnPointerUp(Model? model, PointerEventArgs e)
         {
             _initialClientPoint = null;
             SelectionBoundsChanged?.Invoke(this, null);
+            _lastClientX = null;
+            _lastClientY = null;
+            _initialPan = null;
+        }
+
+        public void OnPanChanged(double deltaX, double deltaY)
+        {
+            if (_initialClientPoint == null || _lastClientX == null || _lastClientY == null)
+                return;
+
+            UpdateSelectionBox((double) _lastClientX, (double) _lastClientY);
+            SelectNodesInBounds((double) _lastClientX, (double) _lastClientY);
+        }
+
+        void SelectNodesInBounds(double clientX, double clientY)
+        {
+            if(_initialClientPoint == null || _initialPan == null)
+            {
+                return;
+            }
+
+            var start = Diagram.GetRelativeMousePoint(_initialClientPoint.X + Diagram.Pan.X - _initialPan.X, _initialClientPoint.Y + Diagram.Pan.Y - _initialPan.Y);
+            var end = Diagram.GetRelativeMousePoint(clientX, clientY);
+            var (sX, sY) = (Math.Min(start.X, end.X), Math.Min(start.Y, end.Y));
+            var (eX, eY) = (Math.Max(start.X, end.X), Math.Max(start.Y, end.Y));
+            var bounds = new Rectangle(sX, sY, eX, eY);
+
+            foreach (var node in Diagram.Nodes)
+            {
+                var nodeBounds = node.GetBounds();
+                if (nodeBounds == null)
+                    continue;
+                if (bounds.Overlap(nodeBounds))
+                    Diagram.SelectModel(node, false);
+                else if (node.Selected) Diagram.UnselectModel(node);
+            }
         }
     }
 }

tests/Blazor.Diagrams.Core.Tests/Behaviors/SelectionBoxBehaviorTests.cs

@@ -39,6 +39,38 @@ public void Behavior_WhenBehaviorEnabled_ShouldUpdateSelectionBounds()
             Assert.Equal(100, lastBounds.Left);
         }
 
+        [Fact]
+        public void Behavior_WhenBehaviorEnabled_ShouldUpdateSelectionBoundsOnScroll()
+        {
+            // Arrange
+            var diagram = new TestDiagram();
+            diagram.BehaviorOptions.DiagramDragBehavior = diagram.GetBehavior<PanBehavior>();
+            diagram.BehaviorOptions.DiagramShiftDragBehavior = diagram.GetBehavior<SelectionBoxBehavior>();
+            diagram.BehaviorOptions.DiagramWheelBehavior = diagram.GetBehavior<ScrollBehavior>();
+            diagram.SetContainer(new Rectangle(Point.Zero, new Size(100, 100)));
+
+            var selectionBoxBehavior = diagram.GetBehavior<SelectionBoxBehavior>()!;
+            bool boundsChangedEventInvoked = false;
+            Rectangle? lastBounds = null;
+            selectionBoxBehavior.SelectionBoundsChanged += (_, newBounds) =>
+            {
+                boundsChangedEventInvoked = true;
+                lastBounds = newBounds;
+            };
+
+            // Act
+            diagram.TriggerPointerDown(null,
+                new PointerEventArgs(100, 100, 0, 0, false, true, false, 0, 0, 0, 0, 0, 0, string.Empty, true));
+            diagram.TriggerWheel(new WheelEventArgs(100, 100, 0, 0, false, true, false, 200, 150, 0, 0));
+
+            // Assert
+            Assert.True(boundsChangedEventInvoked);
+            Assert.Equal(200, lastBounds!.Width);
+            Assert.Equal(150, lastBounds.Height);
+            Assert.Equal(-50, lastBounds.Top);
+            Assert.Equal(-100, lastBounds.Left);
+        }
+
         [Fact]
         public void Behavior_WhenBehaviorDisabled_ShouldNotUpdateSelectionBounds()
         {
@@ -99,6 +131,39 @@ public void Behavior_WithBoundsChangedDelegate_ShouldSelectNodesInsideArea()
             Assert.False(node.Selected);
         }
 
+        [Fact]
+        public void Behavior_WithBoundsChangedDelegate_ShouldSelectNodesInsideAreaWhenScrolling()
+        {
+            // Arrange
+            var diagram = new TestDiagram();
+            diagram.BehaviorOptions.DiagramDragBehavior = diagram.GetBehavior<PanBehavior>();
+            diagram.BehaviorOptions.DiagramShiftDragBehavior = diagram.GetBehavior<SelectionBoxBehavior>();
+            diagram.BehaviorOptions.DiagramWheelBehavior = diagram.GetBehavior<ScrollBehavior>();
+            diagram.SetContainer(new Rectangle(Point.Zero, new Size(100, 100)));
+
+            var selectionBoxBehavior = diagram.GetBehavior<SelectionBoxBehavior>()!;
+            selectionBoxBehavior.SelectionBoundsChanged += (_, _) => { };
+
+            var node = new NodeModel()
+            {
+                Size = new Size(100, 100),
+                Position = new Point(150, 150)
+            };
+            diagram.Nodes.Add(node);
+
+            // Act
+            diagram.TriggerPointerDown(null,
+                new PointerEventArgs(100, 100, 0, 0, false, true, false, 0, 0, 0, 0, 0, 0, string.Empty, true));
+            diagram.TriggerWheel(new WheelEventArgs(100, 100, 0, 0, false, true, false, 200, 200, 0, 0));
+
+            // Assert
+            Assert.True(node.Selected);
+
+            diagram.TriggerWheel(new WheelEventArgs(100, 100, 0, 0, false, true, false, -200, -200, 0, 0));
+
+            Assert.False(node.Selected);
+        }
+
         [Fact]
         public void Behavior_WithoutBoundsChangedDelegate_ShouldNotSelectNodesInsideArea()
         {
@@ -127,5 +192,36 @@ public void Behavior_WithoutBoundsChangedDelegate_ShouldNotSelectNodesInsideArea
                 new PointerEventArgs(100, 100, 0, 0, false, false, false, 0, 0, 0, 0, 0, 0, string.Empty, true));
             Assert.False(node.Selected);
         }
+
+        [Fact]
+        public void Behavior_WithoutBoundsChangedDelegate_ShouldNotSelectNodesInsideAreaWhenScrolling()
+        {
+            // Arrange
+            var diagram = new TestDiagram();
+            diagram.BehaviorOptions.DiagramDragBehavior = diagram.GetBehavior<PanBehavior>();
+            diagram.BehaviorOptions.DiagramShiftDragBehavior = diagram.GetBehavior<SelectionBoxBehavior>();
+            diagram.BehaviorOptions.DiagramWheelBehavior = diagram.GetBehavior<ScrollBehavior>();
+            diagram.SetContainer(new Rectangle(Point.Zero, new Size(100, 100)));
+
+            var node = new NodeModel()
+            {
+                Size = new Size(100, 100),
+                Position = new Point(150, 150)
+            };
+            diagram.Nodes.Add(node);
+
+            // Act
+            diagram.TriggerPointerDown(null,
+                new PointerEventArgs(100, 100, 0, 0, false, true, false, 0, 0, 0, 0, 0, 0, string.Empty, true));
+            diagram.TriggerWheel(new WheelEventArgs(100, 100, 0, 0, false, true, false, 200, 200, 0, 0));
+
+
+            // Assert
+            Assert.False(node.Selected);
+
+            diagram.TriggerWheel(new WheelEventArgs(100, 100, 0, 0, false, true, false, -200, -200, 0, 0));
+
+            Assert.False(node.Selected);
+        }
     }
 }