Round clip: true circle (Viewbox/1x1 ellipse) + grabbable corner handle (transparent source grid, non-hit-testable selection overlay); resize locks square in round mode

2026-08-06 15:05:21 -07:00
parent b64830ed11
commit 7bc70872d9
4 changed files with 169 additions and 24 deletions
@@ -0,0 +1,132 @@
+using System;
+using System.Threading;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Media;
+using System.Windows.Shapes;
+using System.Windows.Threading;
+using Xunit;
+using ytLive.Models;
+using ytLive.ViewModels;
+
+namespace ytLive.Tests;
+
+/// <summary>
+/// Reproduces the real MainWindow preview to check the round-clip corner
+/// handle: whether a click at the corner actually stays inside the preview
+/// (doesn't fall through and deselect the source) and whether the round clip
+/// renders as a circle rather than an oval.
+/// </summary>
+public sealed class RoundClipInteractionTests
+{
+    [Fact]
+    public void Round_Clip_Corner_Is_Grabbable_And_Shape_Is_Circle()
+    {
+        Exception? failure = null;
+        var thread = new Thread(() =>
+        {
+            try
+            {
+                Run();
+            }
+            catch (Exception ex)
+            {
+                failure = ex;
+            }
+        });
+        thread.SetApartmentState(ApartmentState.STA);
+        thread.Start();
+        thread.Join();
+
+        if (failure != null)
+            throw new Xunit.Sdk.XunitException("Round-clip interaction failed: " + failure);
+    }
+
+    private void Run()
+    {
+        var app = new App();
+        app.InitializeComponent();
+
+        var window = new MainWindow();
+        var vm = (MainViewModel)window.DataContext;
+        try
+        {
+            window.Show();
+            window.UpdateLayout();
+
+            var scene = vm.ActiveScene!;
+            var source = new Source
+            {
+                Name = "Webcam",
+                Type = SourceType.Webcam,
+                DeviceId = "test-camera",
+                X = 1408,
+                Y = 778,
+                Width = 480,
+                Height = 270,
+            };
+            scene.Sources.Add(source);
+            vm.SelectedSource = source;
+            window.UpdateLayout();
+
+            var previewGrid = (Grid)window.FindName("PreviewGrid")!;
+            var canvasGrid = (Grid)window.FindName("CanvasGrid")!;
+            var toWindow = canvasGrid.TransformToVisual(window);
+
+            var corner = new Point(source.X + source.Width, source.Y + source.Height);
+
+            foreach (var shape in new[] { ClipShape.Traditional, ClipShape.Round })
+            {
+                source.ClipShape = shape;
+                window.UpdateLayout();
+
+                var cornerInWindow = toWindow.Transform(corner);
+
+                // A click on the corner must land inside the preview (descendant
+                // of PreviewGrid); otherwise Window_PreviewMouseLeftButtonDown
+                // deselects the source and the handle can never be grabbed.
+                var hit = VisualTreeHelper.HitTest(window, cornerInWindow);
+                var grabbable = hit != null && IsDescendantOf(hit.VisualHit, previewGrid);
+
+                Assert.True(grabbable,
+                    $"{shape}: corner click fell through to '{hit?.VisualHit.GetType().Name ?? "null"}' " +
+                    "so the source gets deselected before the resize handler runs");
+            }
+
+            // The round clip must render as a circle (square bounding box), not an oval.
+            source.ClipShape = ClipShape.Round;
+            window.UpdateLayout();
+            var ellipse = FindRoundEllipse(window);
+            Assert.NotNull(ellipse);
+            Assert.Equal(ellipse!.RenderSize.Width, ellipse.RenderSize.Height, 1.0);
+        }
+        finally
+        {
+            window.Close();
+        }
+    }
+
+    private static Ellipse? FindRoundEllipse(Window window)
+    {
+        return Walk(window, element => element is Ellipse e && e.IsVisible) as Ellipse;
+    }
+
+    private static DependencyObject? Walk(DependencyObject parent, Func<DependencyObject, bool> predicate)
+    {
+        for (var i = 0; i < VisualTreeHelper.GetChildrenCount(parent); i++)
+        {
+            var child = VisualTreeHelper.GetChild(parent, i);
+            if (predicate(child)) return child;
+            var found = Walk(child, predicate);
+            if (found != null) return found;
+        }
+        return null;
+    }
+
+    private static bool IsDescendantOf(DependencyObject? child, DependencyObject ancestor)
+    {
+        while (child != null && !ReferenceEquals(child, ancestor))
+            child = VisualTreeHelper.GetParent(child);
+        return child != null;
+    }
+}