[BOUNTY #3] feat: Implement InkCanvas and InkPresenter controls

.gitignore

@@ -40,6 +40,9 @@ scripts/
 # Local agent instructions
 AGENTS.md
 agents.md
+CLAUDE.md
+.Claude/
+.claude/settings.local.json
 
 # Local diagnostics notes
 diagnostics-instrumentation-guide.md

InkkSlinger.Tests/ControlDemoDataGridSampleTests.cs

@@ -370,6 +370,45 @@ public void DataGridView_WheelScrollingToBottom_ShouldNotLeaveBlankSpaceAfterLas
             $"Expected last row to align with viewport bottom after wheel scroll. LastRowBottom={lastRowBottom}, ViewportBottom={viewportBottom}, Offset={scrollViewer.VerticalOffset}, Extent={scrollViewer.ExtentHeight}, Viewport={scrollViewer.ViewportHeight}.");
     }
 
+    [Fact]
+    public void DataGridView_WheelScroll_WhenAllRowsAreRealized_DoesNotInvalidateLayout()
+    {
+        var view = new DataGridView
+        {
+            Width = 1200f,
+            Height = 520f
+        };
+
+        var host = new Canvas
+        {
+            Width = 1200f,
+            Height = 520f
+        };
+        host.AddChild(view);
+
+        var uiRoot = new UiRoot(host);
+        RunLayout(uiRoot, 1200, 520);
+
+        var dataGrid = FindFirstVisualChild<DataGrid>(view);
+        Assert.NotNull(dataGrid);
+        Assert.Equal(12, dataGrid!.RealizedRowCountForTesting);
+
+        var scrollViewer = dataGrid.ScrollViewerForTesting;
+        var pointer = new Vector2(
+            scrollViewer.LayoutSlot.X + (scrollViewer.LayoutSlot.Width * 0.5f),
+            scrollViewer.LayoutSlot.Y + (scrollViewer.LayoutSlot.Height * 0.5f));
+        var measureInvalidationsBefore = uiRoot.MeasureInvalidationCount;
+        var arrangeInvalidationsBefore = uiRoot.ArrangeInvalidationCount;
+
+        uiRoot.ResetDirtyStateForTests();
+        uiRoot.RunInputDeltaForTests(CreatePointerDelta(pointer, pointerMoved: true, wheelDelta: -120));
+        RunLayout(uiRoot, 1200, 520);
+
+        Assert.True(scrollViewer.VerticalOffset > 0f);
+        Assert.Equal(measureInvalidationsBefore, uiRoot.MeasureInvalidationCount);
+        Assert.Equal(arrangeInvalidationsBefore, uiRoot.ArrangeInvalidationCount);
+    }
+
     [Fact]
     public void DataGridView_DraggingVerticalScrollBarToBottom_ShouldNotLeaveBlankSpaceAfterLastRow()
     {
@@ -461,12 +500,14 @@ public void DataGridView_DraggingHorizontalScrollBar_KeepsFrozenLanesAligned()
             thumbCenter.Y >= horizontalBar.LayoutSlot.Y &&
             thumbCenter.Y <= horizontalBar.LayoutSlot.Y + horizontalBar.LayoutSlot.Height,
             $"Expected horizontal thumb center to stay within the horizontal scrollbar bounds. Thumb={thumb.LayoutSlot}, CachedThumb={horizontalBar.GetThumbRectForInput()}, ScrollBar={horizontalBar.LayoutSlot}.");
+        Assert.Same(thumb, VisualTreeHelper.HitTest(host, thumbCenter));
         var rightPointer = new Vector2(horizontalBar.LayoutSlot.X + horizontalBar.LayoutSlot.Width - 2f, thumbCenter.Y);
 
-        Assert.True(thumb.HandlePointerDownFromInput(thumbCenter));
-        Assert.True(thumb.HandlePointerMoveFromInput(rightPointer));
+        uiRoot.RunInputDeltaForTests(CreatePointerDelta(thumbCenter, pointerMoved: true));
+        uiRoot.RunInputDeltaForTests(CreatePointerDelta(thumbCenter, leftPressed: true));
+        uiRoot.RunInputDeltaForTests(CreatePointerDelta(rightPointer, pointerMoved: true));
         RunLayout(uiRoot, 780, 520);
-        Assert.True(thumb.HandlePointerUpFromInput());
+        uiRoot.RunInputDeltaForTests(CreatePointerDelta(rightPointer, leftReleased: true));
         RunLayout(uiRoot, 780, 520);
 
         Assert.True(scrollViewer.HorizontalOffset > 0f);
@@ -476,6 +517,52 @@ public void DataGridView_DraggingHorizontalScrollBar_KeepsFrozenLanesAligned()
         Assert.Equal(dataGrid.ColumnHeadersForTesting[1].LayoutSlot.X, row.Cells[1].LayoutSlot.X);
     }
 
+    [Fact]
+    public void DataGridView_DraggingHorizontalScrollBar_DoesNotInvalidateWorkbenchLayout()
+    {
+        var view = new DataGridView
+        {
+            Width = 780f,
+            Height = 520f
+        };
+
+        var host = new Canvas
+        {
+            Width = 780f,
+            Height = 520f
+        };
+        host.AddChild(view);
+
+        var uiRoot = new UiRoot(host);
+        RunLayout(uiRoot, 780, 520);
+
+        var dataGrid = FindFirstVisualChild<DataGrid>(view);
+        Assert.NotNull(dataGrid);
+
+        var scrollViewer = dataGrid!.ScrollViewerForTesting;
+        var horizontalBar = GetPrivateScrollBar(scrollViewer, "_horizontalBar");
+        var thumb = FindFirstVisualChild<Thumb>(horizontalBar);
+        Assert.NotNull(thumb);
+
+        var thumbCenter = GetCenter(thumb!.LayoutSlot);
+        Assert.Same(thumb, VisualTreeHelper.HitTest(host, thumbCenter));
+        var rightPointer = new Vector2(horizontalBar.LayoutSlot.X + horizontalBar.LayoutSlot.Width - 2f, thumbCenter.Y);
+        var measureInvalidationsBefore = uiRoot.MeasureInvalidationCount;
+        var arrangeInvalidationsBefore = uiRoot.ArrangeInvalidationCount;
+
+        uiRoot.ResetDirtyStateForTests();
+        uiRoot.RunInputDeltaForTests(CreatePointerDelta(thumbCenter, pointerMoved: true));
+        uiRoot.RunInputDeltaForTests(CreatePointerDelta(thumbCenter, leftPressed: true));
+        uiRoot.RunInputDeltaForTests(CreatePointerDelta(rightPointer, pointerMoved: true));
+        RunLayout(uiRoot, 780, 520);
+        uiRoot.RunInputDeltaForTests(CreatePointerDelta(rightPointer, leftReleased: true));
+        RunLayout(uiRoot, 780, 520);
+
+        Assert.True(scrollViewer.HorizontalOffset > 0f);
+        Assert.Equal(measureInvalidationsBefore, uiRoot.MeasureInvalidationCount);
+        Assert.Equal(arrangeInvalidationsBefore, uiRoot.ArrangeInvalidationCount);
+    }
+
     private static TElement? FindFirstVisualChild<TElement>(UIElement root)
         where TElement : UIElement
     {
@@ -566,4 +653,5 @@ private static ScrollBar GetPrivateScrollBar(ScrollViewer viewer, string fieldNa
         Assert.NotNull(field);
         return Assert.IsType<ScrollBar>(field!.GetValue(viewer));
     }
+
 }

InkkSlinger.Tests/ControlsCatalogHoverRegressionTests.cs

@@ -5,6 +5,7 @@
 using Microsoft.Xna.Framework.Graphics;
 using Microsoft.Xna.Framework.Input;
 using Xunit;
+using InkkSlinger.Tests.TestDoubles;
 
 namespace InkkSlinger.Tests;
 
@@ -31,14 +32,48 @@ public void HoveringFromViewerGutterIntoButton_ShouldActivateButtonHover()
         var gutterPoint = new Vector2(
             verticalBar!.LayoutSlot.X - 0.25f,
             button.LayoutSlot.Y + (button.LayoutSlot.Height * 0.5f));
-        MovePointer(uiRoot, gutterPoint);
 
-        Assert.False(button.IsMouseOver);
+        // Capture instrumentation during the hover sequence
+        using var capture = new InstrumentationCapture();
+        MovePointer(uiRoot, gutterPoint);
+        RunLayout(uiRoot, 1280, 820, 16);
 
         var buttonPoint = new Vector2(
             button.LayoutSlot.X + (button.LayoutSlot.Width * 0.5f),
             button.LayoutSlot.Y + (button.LayoutSlot.Height * 0.5f));
         MovePointer(uiRoot, buttonPoint);
+        RunLayout(uiRoot, 1280, 820, 32);
+
+        var lines = capture.GetInstrumentLines();
+
+        // Parse instrumentation
+        var timings = lines.Select(l => InstrumentationCapture.TryParseTiming(l)).Where(t => t.HasValue).Select(t => t!.Value).ToList();
+        var counters = lines.Select(l => InstrumentationCapture.TryParseCounter(l)).Where(c => c.HasValue).Select(c => c!.Value).ToList();
+
+        Console.WriteLine($"[METRICS] Raw instrument lines captured: {lines.Count}");
+
+        // Aggregate by method type and show top slow and hot
+        foreach (var timing in timings.OrderByDescending(t => t.microseconds).Take(10))
+        {
+            Console.WriteLine($"[METRICS] Slow: {timing.method} = {timing.microseconds}us");
+        }
+
+        var groupedCounters = counters.GroupBy(c => c.method).Select(g => (method: g.Key, totalCalls: g.Sum(x => x.count))).OrderByDescending(x => x.totalCalls).ToList();
+        foreach (var counter in groupedCounters.Take(10))
+        {
+            Console.WriteLine($"[METRICS] Hot: {counter.method} = {counter.totalCalls} calls");
+        }
+
+        // Check for MarkFullFrameDirty calls
+        var fullFrameDirtyLines = lines.Where(l => l.Contains("MarkFullFrameDirty")).ToList();
+        if (fullFrameDirtyLines.Count > 0)
+        {
+            Console.WriteLine($"[METRICS] MarkFullFrameDirty calls: {fullFrameDirtyLines.Count}");
+            foreach (var line in fullFrameDirtyLines.Take(5))
+            {
+                Console.WriteLine($"  {line}");
+            }
+        }
 
         Assert.True(
             button.IsMouseOver,

InkkSlinger.Tests/ControlsCatalogScrollPersistenceTests.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Reflection;
 using Microsoft.Xna.Framework;
 using Microsoft.Xna.Framework.Graphics;
 using Microsoft.Xna.Framework.Input;
@@ -65,6 +66,29 @@ public void SelectingPreviewViaButtonInvoke_ShouldPreserveLeftCatalogScrollOffse
             $"Expected left catalog scroll offset to persist after direct invoke. before={beforeInvokeOffset:0.###}, after={afterInvokeOffset:0.###}");
     }
 
+    [Fact]
+    public void SidebarWheelScroll_ShouldMoveCatalogScrollViewer()
+    {
+        var view = new ControlsCatalogView();
+        var uiRoot = new UiRoot(view);
+        RunLayout(uiRoot, 1280, 820, 16);
+
+        var viewer = FindFirstVisualChild<ScrollViewer>(view);
+        Assert.NotNull(viewer);
+        var verticalBar = GetPrivateScrollBar(viewer!, "_verticalBar");
+        var beforeThumb = verticalBar.GetThumbRectForInput();
+
+        var pointer = new Vector2(viewer!.LayoutSlot.X + 24f, viewer.LayoutSlot.Y + 48f);
+        uiRoot.RunInputDeltaForTests(CreatePointerDelta(pointer, pointerMoved: true));
+        uiRoot.RunInputDeltaForTests(CreatePointerDelta(pointer, wheelDelta: -120));
+        RunLayout(uiRoot, 1280, 820, 32);
+
+        var afterThumb = verticalBar.GetThumbRectForInput();
+
+        Assert.True(viewer.VerticalOffset > 0f, $"Expected catalog sidebar wheel scroll to change offset, got {viewer.VerticalOffset:0.###}.");
+        Assert.True(afterThumb.Y > beforeThumb.Y + 0.01f, $"Expected catalog sidebar thumb to move after wheel scroll. before={beforeThumb}, after={afterThumb}");
+    }
+
     private static Vector2 GetVisibleCenter(LayoutRect slot, float verticalOffset)
     {
         var visibleY = slot.Y - verticalOffset;
@@ -80,6 +104,7 @@ private static void Click(UiRoot uiRoot, Vector2 pointer)
     private static InputDelta CreatePointerDelta(
         Vector2 pointer,
         bool pointerMoved = false,
+        int wheelDelta = 0,
         bool leftPressed = false,
         bool leftReleased = false)
     {
@@ -91,7 +116,7 @@ private static InputDelta CreatePointerDelta(
             ReleasedKeys = new List<Keys>(),
             TextInput = new List<char>(),
             PointerMoved = pointerMoved || leftPressed || leftReleased,
-            WheelDelta = 0,
+            WheelDelta = wheelDelta,
             LeftPressed = leftPressed,
             LeftReleased = leftReleased,
             RightPressed = false,
@@ -121,6 +146,13 @@ private static InputDelta CreatePointerDelta(
         return null;
     }
 
+    private static ScrollBar GetPrivateScrollBar(ScrollViewer viewer, string fieldName)
+    {
+        var field = typeof(ScrollViewer).GetField(fieldName, BindingFlags.Instance | BindingFlags.NonPublic);
+        Assert.NotNull(field);
+        return Assert.IsType<ScrollBar>(field!.GetValue(viewer));
+    }
+
     private static void RunLayout(UiRoot uiRoot, int width, int height, int elapsedMs)
     {
         uiRoot.Update(

InkkSlinger.Tests/DataGridParityChecklistTests.cs

@@ -828,9 +828,9 @@ public void HorizontalScroll_RepositionsHeadersWithoutGridLayoutInvalidation()
         Assert.Equal(frozenHeaderX, grid.ColumnHeadersForTesting[0].LayoutSlot.X);
         Assert.True(grid.ColumnHeadersForTesting[1].LayoutSlot.X < scrollingHeaderX);
         Assert.Equal(gridMeasureInvalidationsBefore, grid.MeasureInvalidationCount);
-        Assert.True(grid.ArrangeInvalidationCount > gridArrangeInvalidationsBefore);
+        Assert.Equal(gridArrangeInvalidationsBefore, grid.ArrangeInvalidationCount);
         Assert.Equal(rootMeasureInvalidationsBefore, uiRoot.MeasureInvalidationCount);
-        Assert.True(uiRoot.ArrangeInvalidationCount > rootArrangeInvalidationsBefore);
+        Assert.Equal(rootArrangeInvalidationsBefore, uiRoot.ArrangeInvalidationCount);
     }
 
     [Fact]

InkkSlinger.Tests/DirtyBoundsEdgeRegressionTests.cs

@@ -6,15 +6,15 @@ namespace InkkSlinger.Tests;
 public sealed class DirtyBoundsEdgeRegressionTests
 {
     [Fact]
-    public void RenderInvalidation_WithNullSource_EscalatesToFullFrameDirty()
+    public void RenderInvalidation_WithNullSource_DoesNotEscalateToFullFrameDirty()
     {
         var uiRoot = new UiRoot(new Panel());
         uiRoot.SetDirtyRegionViewportForTests(new LayoutRect(0f, 0f, 200f, 200f));
         uiRoot.ResetDirtyStateForTests();
 
         uiRoot.NotifyInvalidation(UiInvalidationType.Render, null);
 
-        Assert.True(uiRoot.IsFullDirtyForTests());
+        Assert.False(uiRoot.IsFullDirtyForTests());
     }
 
     [Fact]

InkkSlinger.Tests/Instrumentation.cs

@@ -0,0 +1,38 @@
+using System.Diagnostics;
+
+namespace InkkSlinger.Tests;
+
+public static class Instrumentation
+{
+    /// <summary>
+    /// Writes a line to the test output that can be captured by InstrumentationCapture
+    /// and also appears in the test console output.
+    /// </summary>
+    [DebuggerStepThrough]
+    public static void Trace(string message)
+    {
+        var line = $"[INSTRUMENT] {message}";
+        System.Diagnostics.Trace.WriteLine(line);
+        Console.Out.WriteLine(line);
+    }
+
+    /// <summary>
+    /// Writes a timing entry in the standard format parsed by InstrumentationCapture.TryParseTiming.
+    /// Example: "MyMethod took 1234us"
+    /// </summary>
+    [DebuggerStepThrough]
+    public static void TraceTiming(string method, long microseconds)
+    {
+        Trace($"{method} took {microseconds}us");
+    }
+
+    /// <summary>
+    /// Writes a counter entry in the standard format parsed by InstrumentationCapture.TryParseCounter.
+    /// Example: "MyMethod #42"
+    /// </summary>
+    [DebuggerStepThrough]
+    public static void TraceCounter(string method, int count)
+    {
+        Trace($"{method} #{count}");
+    }
+}

InkkSlinger.Tests/InstrumentationTests.cs

@@ -0,0 +1,32 @@
+using Xunit;
+
+namespace InkkSlinger.Tests;
+
+public sealed class InstrumentationTests
+{
+    [Fact]
+    public void Trace_WritesLineToConsole()
+    {
+        Instrumentation.Trace("Test message from InstrumentationTests");
+    }
+
+    [Fact]
+    public void TraceTiming_WritesTimingLine()
+    {
+        Instrumentation.TraceTiming("FakeMethod", 12345);
+    }
+
+    [Fact]
+    public void TraceCounter_WritesCounterLine()
+    {
+        Instrumentation.TraceCounter("FakeMethod", 42);
+    }
+
+    [Fact]
+    public void Trace_MultipleLines_AreOrdered()
+    {
+        Instrumentation.Trace("Line 1");
+        Instrumentation.Trace("Line 2");
+        Instrumentation.Trace("Line 3");
+    }
+}