Fixes for WayFinder and ZoomControl mouse interactions

Westermo.GraphX.Controls.Avalonia.Tests/WayfinderRenderTests.Renders_OffsetTrackableContent_WithoutClippingLowerOrRightEdges.verified.txt

@@ -0,0 +1,65 @@
+{
+  Type: Window,
+  WindowState: Normal,
+  Content: {
+    Type: StackPanel,
+    Spacing: 8.0,
+    Orientation: Vertical,
+    Children: [
+      {
+        Type: ZoomControl,
+        Content: {
+          Type: WayfinderRenderTests.TrackableCanvas,
+          Background: Transparent,
+          Width: 800.0,
+          Height: 600.0,
+          Children: [
+            {
+              Type: Rectangle,
+              Fill: SteelBlue,
+              Width: 40.0,
+              Height: 40.0
+            },
+            {
+              Type: Rectangle,
+              Fill: SteelBlue,
+              Width: 40.0,
+              Height: 40.0
+            },
+            {
+              Type: Rectangle,
+              Fill: SteelBlue,
+              Width: 40.0,
+              Height: 40.0
+            },
+            {
+              Type: Rectangle,
+              Fill: SteelBlue,
+              Width: 40.0,
+              Height: 40.0
+            },
+            {
+              Type: Rectangle,
+              Fill: SteelBlue,
+              Width: 40.0,
+              Height: 40.0
+            }
+          ]
+        },
+        Width: 400.0,
+        Height: 240.0
+      },
+      {
+        Type: Wayfinder,
+        Focusable: true,
+        Width: 200.0,
+        Height: 120.0,
+        ClipToBounds: true
+      }
+    ]
+  },
+  Background: White,
+  Width: 420.0,
+  Height: 400.0,
+  IsVisible: true
+}

Westermo.GraphX.Controls.Avalonia.Tests/WayfinderRenderTests.cs

@@ -5,7 +5,9 @@
 using Avalonia.Layout;
 using Avalonia.Media;
 using Avalonia.Threading;
+using Westermo.GraphX.Controls.Controls.Misc;
 using Westermo.GraphX.Controls.Controls.ZoomControl;
+using Westermo.GraphX.Controls.Models;
 
 namespace Westermo.GraphX.Controls.Avalonia.Tests;
 
@@ -108,6 +110,64 @@ private static (Window window, ZoomControl zc, Wayfinder wf) BuildScene(
         return (window, zc, wf);
     }
 
+    private static (Window window, ZoomControl zc, Wayfinder wf) BuildOffsetTrackableScene(
+        Rect contentRect,
+        Action<Panel> populateContent)
+    {
+        // GraphArea reports the actual child extent via ITrackableContent.
+        // Reproduce that here without depending on graph layout algorithms.
+        var content = new TrackableCanvas(contentRect)
+        {
+            Width = contentRect.Width,
+            Height = contentRect.Height,
+            Background = Brushes.Transparent
+        };
+        populateContent(content);
+
+        var zc = new ZoomControl
+        {
+            Width = 400,
+            Height = 240,
+            Content = content
+        };
+
+        var wf = new Wayfinder
+        {
+            Width = WayfinderWidth,
+            Height = WayfinderHeight,
+            ZoomControl = zc,
+            Background = new SolidColorBrush(Color.FromRgb(0xF0, 0xF0, 0xF0)),
+            ShadowBrush = null,
+            ViewportBrush = Brushes.Transparent,
+            ViewportPen = null
+        };
+
+        var root = new StackPanel
+        {
+            Orientation = Orientation.Vertical,
+            Spacing = 8,
+            Children = { zc, wf }
+        };
+
+        var window = new Window
+        {
+            Width = 420,
+            Height = 400,
+            Background = Brushes.White,
+            Content = root
+        };
+        window.Show();
+
+        for (var i = 0; i < 3; i++)
+        {
+            window.Measure(new Size(420, 400));
+            window.Arrange(new Rect(0, 0, 420, 400));
+            Dispatcher.UIThread.RunJobs();
+        }
+
+        return (window, zc, wf);
+    }
+
     private static VerifySettings GetSettings([CallerMemberName] string? testName = null)
     {
         var settings = new VerifySettings();
@@ -193,6 +253,28 @@ public async Task Viewport_ReachesLeftmostEdge_WhenPannedFully()
         await Verify(window, GetSettings());
     }
 
+    /// <summary>
+    /// Trackable graph content may have a positive top-left extent when all
+    /// vertices live away from the origin. The minimap must still render the
+    /// bottom/right of that extent instead of clipping it by the offset amount.
+    /// </summary>
+    [Test]
+    public async Task Renders_OffsetTrackableContent_WithoutClippingLowerOrRightEdges()
+    {
+        var contentRect = new Rect(100, 80, 800, 600);
+        var (window, _, wf) = BuildOffsetTrackableScene(contentRect, canvas =>
+        {
+            AddBox(canvas, 0, 0, 40, 40);
+            AddBox(canvas, 760, 0, 40, 40);
+            AddBox(canvas, 0, 560, 40, 40);
+            AddBox(canvas, 760, 560, 40, 40);
+            AddBox(canvas, 380, 280, 40, 40);
+        });
+
+        // Verify.Avalonia takes ownership of closing the window.
+        await Verify(window, GetSettings());
+    }
+
     private static void AddBox(Panel canvas, double x, double y, double w, double h)
     {
         var rect = new Rectangle
@@ -205,4 +287,15 @@ private static void AddBox(Panel canvas, double x, double y, double w, double h)
         Canvas.SetTop(rect, y);
         canvas.Children.Add(rect);
     }
+
+    private sealed class TrackableCanvas(Rect contentSize) : Canvas, ITrackableContent
+    {
+        public event ContentSizeChangedEventHandler? ContentSizeChanged
+        {
+            add { }
+            remove { }
+        }
+
+        public Rect ContentSize { get; } = contentSize;
+    }
 }

Westermo.GraphX.Controls.Avalonia.Tests/ZoomControlTests.cs

@@ -1,5 +1,6 @@
 using Avalonia;
 using Avalonia.Controls;
+using Avalonia.Input;
 using Avalonia.Threading;
 using Westermo.GraphX.Controls.Controls.ZoomControl;
 using Westermo.GraphX.Controls.Controls.ZoomControl.SupportClasses;
@@ -228,6 +229,69 @@ public async Task Mode_SetToFill_TriggersZoomToFill()
 
     #endregion
 
+    #region Modifier Drag Gesture Tests
+
+    [Test]
+    public async Task Alt_LeftDrag_Zooms_To_Rectangle()
+    {
+        var (zc, window) = CreateZoomControlWithContent(800, 600, 1000, 1000);
+        try
+        {
+            zc.Mode = ZoomControlModes.Custom;
+            zc.Zoom = 1.0;
+
+            var areaSelectedCount = 0;
+            zc.AreaSelected += (_, _) => areaSelectedCount++;
+
+            var initialZoom = zc.Zoom;
+            var beganInteraction = zc.BeginInteractionForTest(KeyModifiers.Alt, new Point(100, 100));
+            await Assert.That(beganInteraction).IsTrue();
+            zc.MoveInteractionForTest(new Point(300, 300));
+            zc.CompleteInteractionForTest();
+
+            await Assert.That(zc.Zoom).IsGreaterThan(initialZoom);
+            await Assert.That(areaSelectedCount).IsEqualTo(0);
+            await Assert.That(zc.ZoomBox).IsEqualTo(default(Rect));
+        }
+        finally
+        {
+            window.Close();
+        }
+    }
+
+    [Test]
+    public async Task ControlAlt_LeftDrag_AreaSelects_Without_Zooming()
+    {
+        var (zc, window) = CreateZoomControlWithContent(800, 600, 1000, 1000);
+        try
+        {
+            zc.Mode = ZoomControlModes.Custom;
+            zc.Zoom = 1.0;
+
+            Rect? selectedRectangle = null;
+            zc.AreaSelected += (_, args) => selectedRectangle = args.Rectangle;
+
+            var initialZoom = zc.Zoom;
+            var beganInteraction =
+                zc.BeginInteractionForTest(KeyModifiers.Control | KeyModifiers.Alt, new Point(100, 100));
+            await Assert.That(beganInteraction).IsTrue();
+            zc.MoveInteractionForTest(new Point(300, 300));
+            zc.CompleteInteractionForTest();
+
+            await Assert.That(zc.Zoom).IsEqualTo(initialZoom);
+            await Assert.That(selectedRectangle.HasValue).IsTrue();
+            await Assert.That(Math.Abs(selectedRectangle!.Value.Width - 200)).IsLessThan(Tolerance);
+            await Assert.That(Math.Abs(selectedRectangle.Value.Height - 200)).IsLessThan(Tolerance);
+            await Assert.That(zc.ZoomBox).IsEqualTo(default(Rect));
+        }
+        finally
+        {
+            window.Close();
+        }
+    }
+
+    #endregion
+
     #region ZoomToContent Tests
 
     [Test]