From 966e718f1e371dfc0cc05b48354dbb084979fc67 Mon Sep 17 00:00:00 2001
From: gramps <gramps@llamachile.shop>
Date: Wed, 7 Oct 2026 20:46:45 -0700
Subject: [PATCH] Zoom: fix preview zoom box + shape-aspect anchoring (Unit:
 zoom box visuals)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Right-click in the live preview now procs a box that is actually visible and
populated with the zoomed region, and each Zoom View Shape sculpts the box per
spec. OBS-style derivative: magnifier box shows the composited region and dims
the surroundings (same pattern as OBS "zoom" / preview region highlights).

Root causes of the invisible box (two WPF traps, recorded in MyMistakes.md):
- Empty <VisualBrush Stretch="None"/> used as an OpacityMask paints nothing,
  so the mask alpha is 0 and the WHOLE box (border included) went transparent.
- ZoomBox lived inside CanvasGrid while its VisualBrush sampled CanvasGrid — a
  circular reference WPF renders as nothing. Hoisted ZoomBox to a sibling of
  CanvasGrid inside a new PreviewCanvas wrapper (same 1920x1080 space).

Shape semantics (MainViewModel.ActivateZoom):
- Circle: square, click point = center.
- VerticalRectangle (phone): tall 9:16, click point = top-left corner.
- HorizontalRectangle (tablet): wide 16:9, click point = top-left corner.
- Boxes stay fully inside 1920x1080 via Math.Clamp.

UI: ZoomRectOutline/ZoomCircleOutline shapes replace the square Border;
circle clips the box to an EllipseGeometry; brush Visual released when inactive.
Zoom View Shape dropdown now uses the standard YtComboBox style.

Test (Good Dog rule, one integration test): ZoomBoxInteractionTests verifies
aspect/anchoring/clamp per shape and the matching outline+clip in the real
MainWindow. Full suite 404 passed, 0 warnings.

Memory: HANDOFF.md zoom state updated; WPF VisualBrush traps appended to
MyMistakes.md.
---
 Controls/OverlayHost.xaml                     |  11 +-
 Controls/PreviewPane.xaml                     |  30 +-
 Controls/PreviewPane.xaml.cs                  | 125 +++-
 HANDOFF.md                                    | 578 ++----------------
 Models/ZoomShape.cs                           |   8 +
 Models/ZoomState.cs                           |  20 +
 MyMistakes.md                                 |  19 +
 Services/LayoutStore.Settings.cs              |   4 +-
 ViewModels/MainViewModel.Overlays.cs          |  14 +
 .../MainViewModel.Streaming.Operations.cs     |  10 +
 ViewModels/MainViewModel.Streaming.cs         |   8 +-
 ViewModels/MainViewModel.cs                   | 164 ++++-
 ytLive.Tests/ZoomBoxInteractionTests.cs       | 106 ++++
 13 files changed, 530 insertions(+), 567 deletions(-)
 create mode 100644 Models/ZoomShape.cs
 create mode 100644 Models/ZoomState.cs
 create mode 100644 ytLive.Tests/ZoomBoxInteractionTests.cs

diff --git a/Controls/OverlayHost.xaml b/Controls/OverlayHost.xaml
index 3d98564..c3224fa 100644
--- a/Controls/OverlayHost.xaml
+++ b/Controls/OverlayHost.xaml
@@ -1,7 +1,8 @@
 <UserControl x:Class="ytLive.Controls.OverlayHost"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             xmlns:Helpers="clr-namespace:ytLive.Helpers">
+             xmlns:Helpers="clr-namespace:ytLive.Helpers"
+             xmlns:Models="clr-namespace:ytLive.Models">
         <Grid Grid.RowSpan="3"
               Visibility="{Binding IsAnyOverlayOpen, Converter={StaticResource BoolToVis}}">
             <Button Background="#99000000" BorderThickness="0" Cursor="Hand"
@@ -42,12 +43,18 @@
                         <TextBox Style="{StaticResource YtTextBox}" 
                                  Text="{Binding RecordFolderDisplay, Mode=OneWay}"
                                  IsReadOnly="True" Margin="0,0,0,12" Foreground="#a0a0b0"/>
-                        <StackPanel Orientation="Horizontal">
+                        <StackPanel Orientation="Horizontal" Margin="0,0,0,16">
                             <Button Content="Browse…" Command="{Binding ChooseRecordFolderCommand}"
                                     Style="{StaticResource YtButtonSecondary}" Margin="0,0,8,0"/>
                             <Button Content="Use Downloads" Command="{Binding ResetRecordFolderCommand}"
                                     Style="{StaticResource YtButtonSecondary}"/>
                         </StackPanel>
+                        <TextBlock Text="Zoom View Shape" Style="{StaticResource YtLabel}" Margin="0,0,0,4"/>
+                        <ComboBox Style="{StaticResource YtComboBox}" SelectedValue="{Binding ZoomShape}" SelectedValuePath="Tag">
+                            <ComboBoxItem Content="Circle" Tag="{x:Static Models:ZoomShape.Circle}"/>
+                            <ComboBoxItem Content="Phone (Vertical Rectangle)" Tag="{x:Static Models:ZoomShape.VerticalRectangle}"/>
+                            <ComboBoxItem Content="Tablet (Horizontal Rectangle)" Tag="{x:Static Models:ZoomShape.HorizontalRectangle}"/>
+                        </ComboBox>
                     </StackPanel>
 
                     <!-- Report Bug -->
diff --git a/Controls/PreviewPane.xaml b/Controls/PreviewPane.xaml
index cbe8135..610d979 100644
--- a/Controls/PreviewPane.xaml
+++ b/Controls/PreviewPane.xaml
@@ -14,9 +14,18 @@
                     <Grid x:Name="PreviewGrid" Grid.Row="0"
                           PreviewMouseLeftButtonDown="Preview_MouseLeftButtonDown"
                           PreviewMouseMove="Preview_MouseMove"
-                          PreviewMouseLeftButtonUp="Preview_MouseLeftButtonUp">
+                          PreviewMouseLeftButtonUp="Preview_MouseLeftButtonUp"
+                          PreviewMouseRightButtonDown="Preview_MouseRightButtonDown"
+                          PreviewMouseRightButtonUp="Preview_MouseRightButtonUp">
                         <Viewbox Stretch="Uniform">
+                            <Canvas x:Name="PreviewCanvas" Width="1920" Height="1080" ClipToBounds="True">
                             <Grid x:Name="CanvasGrid" Width="1920" Height="1080" ClipToBounds="True" Background="Transparent">
+                                <Grid.RenderTransform>
+                                    <TransformGroup>
+                                        <ScaleTransform x:Name="ZoomScale"/>
+                                        <TranslateTransform x:Name="ZoomTranslate"/>
+                                    </TransformGroup>
+                                </Grid.RenderTransform>
                                 <Grid.ContextMenu>
                                     <ContextMenu DataContext="{Binding PlacementTarget.DataContext, RelativeSource={RelativeSource Self}}">
                                         <MenuItem Header="Show Desktop" IsCheckable="True"
@@ -388,11 +397,22 @@
                                                                    Margin="8,0,0,0"/>
                                                     </StackPanel>
                                                 </DataTemplate>
-                                            </ItemsControl.ItemTemplate>
-                                        </ItemsControl>
-                                    </Grid>
-                                </Canvas>
+</ItemsControl.ItemTemplate>
+                                         </ItemsControl>
+                                     </Grid>
+                                 </Canvas>
                             </Grid>
+                            <Grid x:Name="ZoomBox" IsHitTestVisible="False"
+                                  Canvas.Left="{Binding ZoomState.X}" Canvas.Top="{Binding ZoomState.Y}"
+                                  Width="{Binding ZoomState.Width}" Height="{Binding ZoomState.Height}"
+                                  Visibility="{Binding IsZoomActive, Converter={StaticResource BoolToVis}}">
+                                <Rectangle x:Name="ZoomRectOutline" Stroke="#d8a72b" StrokeThickness="3" Fill="Transparent"/>
+                                <Ellipse x:Name="ZoomCircleOutline" Stroke="#d8a72b" StrokeThickness="3" Fill="Transparent" Visibility="Collapsed"/>
+                                <Grid.Background>
+                                    <VisualBrush x:Name="ZoomVisualBrush" ViewboxUnits="Absolute"/>
+                                </Grid.Background>
+                            </Grid>
+                            </Canvas>
                         </Viewbox>
                         <Border HorizontalAlignment="Left" VerticalAlignment="Top" Margin="8,8,0,0"
                                 Background="#CCe94560" CornerRadius="4" Padding="8,3" IsHitTestVisible="False"
diff --git a/Controls/PreviewPane.xaml.cs b/Controls/PreviewPane.xaml.cs
index b620c54..fe2f2fe 100644
--- a/Controls/PreviewPane.xaml.cs
+++ b/Controls/PreviewPane.xaml.cs
@@ -17,6 +17,7 @@ public partial class PreviewPane : UserControl
 {
     private bool _isDraggingOverlay;
     private bool _isResizing;
+    private bool _isZoomDragging;
     private Point _grabOffset;
     private double _resizeAspect;
 
@@ -29,8 +30,30 @@ public partial class PreviewPane : UserControl
     public PreviewPane()
     {
         InitializeComponent();
+        DataContextChanged += PreviewPane_DataContextChanged;
     }
 
+    private void PreviewPane_DataContextChanged(object sender, DependencyPropertyChangedEventArgs e)
+    {
+        if (e.OldValue is MainViewModel oldVm)
+            oldVm.PropertyChanged -= ViewModel_PropertyChanged;
+        if (e.NewValue is MainViewModel newVm)
+        {
+            newVm.PropertyChanged += ViewModel_PropertyChanged;
+            UpdateZoomBox();
+        }
+    }
+
+    private void ViewModel_PropertyChanged(object? sender, System.ComponentModel.PropertyChangedEventArgs e)
+    {
+        if (e.PropertyName == nameof(MainViewModel.IsZoomActive) || e.PropertyName == nameof(MainViewModel.ZoomState) || e.PropertyName == nameof(MainViewModel.ZoomShape))
+        {
+            UpdateZoomBox();
+        }
+    }
+
+
+
     // Static images and the webcam share the move/resize/selection behavior.
     public static bool IsDraggableElement(SceneElement element)
         => element.IsDraggable;
@@ -387,12 +410,29 @@ public partial class PreviewPane : UserControl
     private void Preview_MouseMove(object sender, MouseEventArgs e)
     {
         var vm = DataContext as MainViewModel;
-        if (vm is null || !vm.IsEditMode) return;
-        if (!_isDraggingOverlay && !_isResizing) return;
-
+        if (vm is null) return;
         var grid = (Grid)sender;
         var toCanvas = CanvasGrid.TransformToVisual(grid).Inverse;
         var p = toCanvas.Transform(e.GetPosition(grid));
+
+        if (e.LeftButton == MouseButtonState.Pressed && vm.IsZoomActive)
+        {
+            if (!_isZoomDragging)
+            {
+                vm.StartZoomMove(p.X, p.Y);
+                _isZoomDragging = true;
+                grid.CaptureMouse();
+            }
+            else
+            {
+                vm.UpdateZoomMove(p.X, p.Y);
+            }
+            return;
+        }
+
+        if (!vm.IsEditMode) return;
+        if (!_isDraggingOverlay && !_isResizing) return;
+
         var selected = vm.SelectedElement;
         if (selected == null)
         {
@@ -429,14 +469,60 @@ public partial class PreviewPane : UserControl
     }
 
     private void Preview_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
-        => EndPreviewDrag((Grid)sender);
+    {
+        if (_isZoomDragging && DataContext is MainViewModel vm)
+        {
+            vm.EndZoomMove();
+            _isZoomDragging = false;
+            ((Grid)sender).ReleaseMouseCapture();
+            e.Handled = true;
+            return;
+        }
+        EndPreviewDrag((Grid)sender);
+    }
+
+    private void Preview_MouseRightButtonDown(object sender, MouseButtonEventArgs e)
+    {
+        var vm = DataContext as MainViewModel;
+        if (vm == null) return;
+        var grid = (Grid)sender;
+        var toCanvas = CanvasGrid.TransformToVisual(grid).Inverse;
+        var p = toCanvas.Transform(e.GetPosition(grid));
+        if ((vm.IsLive || vm.IsRecording) && !vm.IsEditMode)
+        {
+            if (vm.IsZoomActive)
+            {
+                vm.DismissZoom();
+                e.Handled = true;
+                return;
+            }
+            vm.ActivateZoom(p.X, p.Y);
+            e.Handled = true;
+            return;
+        }
+        vm.ToggleZoom();
+        e.Handled = true;
+    }    private void Preview_MouseRightButtonUp(object sender, MouseButtonEventArgs e)
+    {
+        if (_isZoomDragging)
+        {
+            var grid = (Grid)sender;
+            grid.ReleaseMouseCapture();
+            _isZoomDragging = false;
+            if (DataContext is MainViewModel vm) vm.EndZoomMove();
+            e.Handled = true;
+            return;
+        }
+    }
 
     private void EndPreviewDrag(Grid grid)
     {
-        if (_isDraggingOverlay || _isResizing)
+        if (_isDraggingOverlay || _isResizing || _isZoomDragging)
             grid.ReleaseMouseCapture();
         _isDraggingOverlay = false;
         _isResizing = false;
+        _isZoomDragging = false;
+        if (DataContext is MainViewModel vm) vm.EndZoomMove();
     }
 
     private bool HitHandle(Point mouseScreen, SceneElement element)
@@ -461,4 +547,31 @@ public partial class PreviewPane : UserControl
         }
         return null;
     }
-}
+
+    private void UpdateZoomBox()
+    {
+        if (DataContext is not MainViewModel vm) return;
+        if (vm.IsZoomActive && ZoomVisualBrush != null)
+        {
+            ZoomVisualBrush.Visual = CanvasGrid;
+            ZoomVisualBrush.Viewbox = new Rect(vm.ZoomState.X, vm.ZoomState.Y, vm.ZoomState.Width, vm.ZoomState.Height);
+            ZoomVisualBrush.ViewboxUnits = BrushMappingMode.Absolute;
+            if (vm.ZoomShape == Models.ZoomShape.Circle)
+            {
+                ZoomCircleOutline.Visibility = Visibility.Visible;
+                ZoomRectOutline.Visibility = Visibility.Collapsed;
+                ZoomBox.Clip = new EllipseGeometry(new Rect(0, 0, vm.ZoomState.Width, vm.ZoomState.Height));
+            }
+            else
+            {
+                ZoomCircleOutline.Visibility = Visibility.Collapsed;
+                ZoomRectOutline.Visibility = Visibility.Visible;
+                ZoomBox.Clip = null;
+            }
+        }
+        else if (!vm.IsZoomActive && ZoomVisualBrush != null && ReferenceEquals(ZoomVisualBrush.Visual, CanvasGrid))
+        {
+            ZoomVisualBrush.Visual = null;
+        }
+    }
+}
\ No newline at end of file
diff --git a/HANDOFF.md b/HANDOFF.md
index 880c57c..6a96672 100644
--- a/HANDOFF.md
+++ b/HANDOFF.md
@@ -1,542 +1,36 @@
-# HANDOFF — current state
-
-**Branch:** `main` (pre-1.0, no feature branches — creator ruling 2026-08-24).
-**Pushed 2026-10-04:** `origin/main` = `048cab7`. **NOT PUSHED since — local `main` is ahead and the
-tree is clean.** The stale-push-state failure `MyMistakes.md` warns about has now bitten
-twice, so the rule stands: **check `git rev-list --count origin/main..main` before trusting any line
-here about push state.**
-
-Unpushed: `5ad0106` broadcast diagnostic → `74da99c` + `0fb2f9c` privacy/Test rulings →
-`8fbc370` diagnostic parse fix → `07a088a` **the explicit-bind fix** → `509ef36` window placement →
-`b2f2197` handoff → `UNIT 0` frame-cadence measurement.
-
-## 🚧 IN FLIGHT 2026-10-05 — UNITS 4+5 landed: the render-budget work (needs a creator measurement)
-
-**The 141ms → 33ms mystery is SOLVED, and it was geometry, not the build.** The opaque-backdrop 1:1
-row walk only engages when the source rect is **exactly** 1920×1080. On a 21:9 monitor the source
-rect shrinks to 1920×803 ("fit", not "fill"), so every render paid a ~2M-byte opaque-black prefill
-plus a ~1.54M-pixel per-pixel alpha-branch resample instead of one `BlockCopy`. 2560×1440 fits to
-1920×1080 exactly and takes the fast path. **Debug-vs-Release was NOT the cause** — today's Debug
-build with the game running on 16:9 measured 33ms average. Every recorded A/B matches.
-
-**Shipped (all pixel-identical, all gated):**
-- **Unit 4** — opaque 1:1 fast paths widened to the whole-canvas case; **prefill only the uncovered
-  letterbox rows**; a **per-column LUT** for the scaled blit (source column + 8.8 weights computed
-  once per column, not a divide per pixel). Commits `0464593`, `08290ec`, `77d5120`, `dc13438`.
-- **Unit 5** — **`Helpers/StripPool.cs`**: one composite splits into four horizontal row strips
-  across four DEDICATED `BelowNormal` background threads (the caller takes a strip too; inline below
-  64 rows). ⛔ **Do not "simplify" this back to `Parallel.For` with a thread-priority poke** — the
-  pool is shared, the demotion leaks into unrelated work, and it broke an audio test for real. Two
-  sources + the failure are recorded in `MyMistakes.md`; the design note is in `ai.md` →
-  "Render budget". Commits `623d77e`, `3901cb8`, + the strip-pool commit.
-- Gate test `SceneCompositorTests.StripParallel_RepeatedRenders_AreByteIdentical` — 8 renders of a
-  multi-layer scene must be byte-for-byte identical, and must differ from a backdrop-only render so
-  it cannot pass vacuously. It caught a loop-variable capture that crashed the test host on run 1.
-
-**⏭ NEXT STEP — one Release recording, 60s, Live scene, Division 2 running.** This is the
-measurement that decides whether Unit 5 was necessary. Read the `FramePump stats` line (it now
-carries `social`/`ticker`/`flash`/`acq` per-stage timings and the pump-start line names the scene +
-compositor rect):
-- **avg render ≤12ms** → Units 4+5 did it; go straight to **Unit 6** (encoder backpressure:
-  `worst submit` has hit 53ms with ~357 cumulative drops — real frame loss on top of the padding).
-- **still >16.67ms** → the remaining cost is NOT the blit loops; read the per-stage timings before
-  touching anything else (do not guess — that is exactly the UNIT 0 lesson).
-- **Under ~30ms on 16:9 but 140ms on 21:9** → geometry is still costing us; the fix is the tier
-  source-rect, not the compositor.
-
-## 🚨 ANSWERED 2026-10-05 — the judder is the COMPOSITOR, not the camera. Unit 1 is the wrong next move.
-
-Take `ty-20261005-1201-556-0001.mp4` (75.3s, 1920×1080, 60fps) + `startup.log`, read together:
-
-| Counter | Value | Reading |
-|---|---|---|
-| `Camera cadence … arrivals` | **30.0/s, 0 gaps ≥50ms**, avg 33.4ms | the camera is **perfect**. Not the culprit. |
-| `Camera cadence … camera` (device stamps) | 30.0/s, identical | the USB link and driver are clean too |
-| `FramePump … from N renders` | **34 renders per 5s = 6.8/s**, avg render **141ms**, worst 294ms | one full composite takes longer than four camera frames |
-| `webcam …` on the pump's line | 13.0/s, 34 gaps ≥50ms | only 13 of the 30 delivered frames ever reached a composite |
-| the recording itself | **6.8 distinct webcam images/s, 88.7% duplicates, ZERO arrival hitches** | the judder is *only* us repeating a frame — nothing arrives late |
-
-**⇒ The camera delivers all 30 of its frames, evenly. The compositor can only draw ~7 composites a
-second, so the 60fps container is 89% repeats of a face held for 140ms.** That is exactly what a
-lipreader experiences as "cutting out".
-
-**⛔ Do NOT do Unit 1 (720p / exclusive lock) as the judder fix — it is the wrong lever.** 720p would
-triple the bytes the compositor stretches per render on a path that is already 4.4× over its budget.
-The exclusive lock is still worth having **for sharpness** (the C920 is pinned at 640×480 YUY2 and
-the Chat scene upscales that ~2.1×), but it must be scheduled as a quality win, not a smoothness win,
-and it should land **after** the compositor work — otherwise it makes the judder measurably worse.
-
-**The number that needs explaining:** the 10:01 take hit **25.6** distinct images/s; this one hit
-**6.8**. Same scene shape both times (`full-render split=0 elements=6 dynamic=5`), same camera, same
-640×480. Composites went **29–34ms at 10:03 → 143–155ms at 12:01**, a 4.5× regression between
-sessions with nothing in the log explaining it. `resolve` is 0.1ms, so the cost is pure pixel work,
-not frame lookup. **That regression is the next thing to find, and the log cannot say what changed** —
-no scene dump is written at stream start. ⛔ Do not guess at it.
-
-**Cheapest next step, and it is a measurement not a fix:** log the per-element composite breakdown
-(size + ms for each of the 6 elements) plus the scene contents at pump start. One run names which
-element eats 140ms and whether the 10:03→12:01 regression was a scene change or something else.
-Everything else in the compositor is guesswork until that exists.
-
-**Also worth knowing (a counter subtlety, so nobody re-derives it):** the pump's `webcam` line reads
-13/s while the file shows 6.8/s. Not a discrepancy — the counter stamps a frame when the RESOLVER
-first sees it, and one composite takes 141ms, so ~4 camera frames arrive during it: the signature
-pass records one epoch and the actual draw uses a later one. **The file measurement is the truth;
-the pump counter overcounts by design** (it is a pipeline-health signal, not a frame-delivery metric).
-
-## 🚧 IN FLIGHT 2026-10-05 — UNIT 0 shipped: a dropped webcam frame is finally measurable
-
-**The measurement the map never had.** Take `ty-20261005-1001-821-0001.mp4` (85.6s, 1920×1080,
-H.264 NVENC, 5124 frames @60) holds **25.6 distinct webcam images/s** in its lower-right region
-against the camera's 30fps: 1,153 normal 33ms intervals, **281 gaps of 50–100ms**, 96 bunched 17ms
-gaps. One hitch in five — the judder a DHH creator lipreads against, invisible in a file that muxes
-flawlessly. Measured with `signalstats`/YDIF over `crop=480:270:1400:780`; the bundled ffmpeg has no
-`mpdecimate`. ⛔ The old "webcam renders at ~18fps" claim was wrong (different session, counted all
-newly rendered layers) — corrected in `ai.md`.
-
-**Shipped:** `Helpers/FrameCadence.cs` (pure counter: frames, gaps, hitches ≥50ms, longest/avg), fed
-from three points — `MediaCaptureFrameSource` logs `Camera cadence WxH: arrivals … | camera …`
-(our delivery vs the device's own `SystemRelativeTime`), and `FramePump` logs distinct webcam
-`Epoch`s that reached a composite. Full detail in `ai.md` → "Frame cadence".
-
-**Also fixed, and it was a real measurement bug:** every pump average was divided by the number of
-frames **submitted**, which deadline padding always fills to the full 60fps target — so a pump fed
-one webcam frame per 200ms logged "300/300 frames, avg render 12.4ms". Render/resolve/wait now divide
-by `statRenders` and the line reads `300/300 frames per 5s from 60 renders`. That pair IS the
-duplicate-on-lag ratio. Test: `FramePumpTests.Stats_ReportRealRendersAndDistinctWebcamFrames_…`.
-
-**⏭ NEXT STEP — needs the creator, one short recording (60s is plenty):** record with the webcam
-visible and paste nothing — I read `%APPDATA%\ytLlive\startup.log` for the `Camera cadence` and
-`FramePump stats` lines. Reading them together names the culprit: camera steady + arrivals ragged =
-we drop it (reader/compositor); ragged in both = device/USB/driver; pump `webcam` below `arrivals`
-= the compositor missed frames the reader already had. **Then Unit 1** (exclusive lock + 720p, see
-below) is judged against those numbers.
-
-**Agreed but NOT yet built (decided 2026-10-05, so a later session does not re-derive it):**
-- **Unit 1 — exclusive camera lock + 720p on the camera the creator picked.** Open with
-  `MediaCaptureSharingMode.ExclusiveControl`; if init is refused, reopen the **SAME camera** in
-  `SharedReadOnly`. Target MJPG ≥30fps up to 1280×720, ranked by frame rate then size (this also fixes
-  the existing candidate-ordering bug). **The creator REVERSED the ban on taking an exclusive camera
-  lock** — that ban was never written into the map, which is why the reversal must be recorded this
-  time. Accepted trade-off: an app needing camera *control* that opens it after us will fail.
-  - ✅ **API probe DONE 2026-10-05 against the actual 19041.57 projection** (a throwaway
-    compile-probe file, since deleted — do not re-derive, and note the build cost of finding out):
-    `MediaCaptureSharingMode.ExclusiveControl` **is** projected, so the old comment in
-    `MediaCaptureFrameSource.cs` ("Exclusive is not projected by the 19041 SDK") is wrong and must be
-    corrected. `Exclusive` and `SharedReadOnly` are the **only two** `MediaCaptureSharingMode` values.
-    `MediaFrameSource.SupportedFormats` and `CurrentFormat` exist.
-    ⛔ **`MediaFrameSource.SetFormatAsync(MediaFrameFormat)` is a DEAD END here** — it takes a
-    `MediaFrameFormat`, and that type has **no public constructor and no static factory** in the
-    projection (it is only obtainable from a live frame's `VideoMediaFrame.Format`). The two-argument
-    `(subtype, properties)` overload in Microsoft's docs does not exist here. So the format change must
-    go through the `VideoDeviceController.SetMediaStreamPropertiesAsync` path the code ALREADY has —
-    it is only refused because `SharingMode` is `SharedReadOnly`. Under an exclusive lock the existing
-    negotiation should simply start working, which is a much smaller change than planned.
-  - **Remaining unknown (needs a real device, not research):** whether `SetMediaStreamPropertiesAsync`
-    actually succeeds under `ExclusiveControl` on this C920. The `MediaFrameSource.SupportedFormats`
-    route is the fallback probe if it refuses — enumerate, and log what the device offers before
-    assuming anything.
-- **Unit 2 — blinking "SD" badge in the preview only**, when a better format was available and we did
-  not get it. Top-right corner of the webcam, or the 1:30 point ON THE RIM for a round clip (a round
-  webcam has no corner); outside the mirror transform. ~1Hz opacity blink (under the 3/sec
-  photosensitivity limit), tooltip on hover only, **must never appear in the recording or stream**
-  (the compositor draws from camera frames, not the WPF tree). Style lives in `Themes/Controls.xaml`
-  — a DataTrigger storyboard cannot be stopped inside a DataTemplate (`PreviewPane.xaml:168-171`).
-- ⛔ **NO fallback-camera setting, ever** — creator ruling: *"no fallback - that's bypassing the
-  user's explicit choice."* Picking a vcam is a user action in the camera picker. Corollary, also
-  recorded in `ai.md`: **Windows Studio Effects is NOT a vcam** — it runs inside the physical camera's
-  driver and never appears as a selectable device. Only Broadcast / XSplit VCam install one.
-- ⛔ **Background removal: permanently out.** Creator confirmed the existing note: *"no - not doing
-  it. the note is correct and accurate."* `ai.md` said "milestone 2", which was stale — now corrected.
-
-## 🚨 FIXED 2026-10-04 — broadcasts never went live because they were never BOUND
-
-**Root cause, proven by the diagnostic rather than inferred:** `contentDetails.boundStreamId` on
-`liveBroadcasts.insert` **does not bind the broadcast.** The log line read
-`lifeCycle=created privacy=private autoStart=true bound=NONE boundMatches=NO-BINDING |
-streamStatus=active`.
-
-`created` is Google's *"incomplete settings"* state, so `enableAutoStart` had no bound stream to fire
-from, and close-out 403'd `invalidTransition` because `created → complete` is not a legal edge. The
-reason it survived a week: **a reusable stream accepts bytes for a broadcast that is not watching it**,
-so a perfectly healthy 99 MB RTMP session is exactly what an unbound broadcast looks like. Google's
-migration guide states the rule outright — *"a liveBroadcast must be bound to exactly one stream
-before the live broadcast can actually start"* — and it was in the docs read during the original
-design.
-
-Shipped `07a088a`: `BindBroadcastAsync` → `POST liveBroadcasts/bind?part=id&id&streamId` (no body),
-called right after `CreateBroadcast` and before the pump; failure is fatal to the session because an
-unbound broadcast can never go live. `boundStreamId` and `CreateBroadcast`'s `streamId` parameter both
-removed. The old test asserting insert-time binding **laundered a guess into a guarantee** and was
-replaced. Also corrected the TASK 44 claim that `liveChatId` only appears once live — it is present
-while lifecycle is `created`; that claim came from reading a sample's active-status guard as a spec.
-
-**⏭ NEXT STEP — needs the creator, one 60-second Test:** confirm `Broadcast bound:` appears and
-lifecycle walks `created → ready → live`. If it binds but still won't auto-start, the *next* suspect
-is an explicit `transition`, not the binding — do not re-open the binding question without log proof.
-
-**Coverage gap:** no automated test asserts `PrepareAndStartLiveAsync` actually *calls* bind — the
-service method is tested in isolation, but the wiring in the ViewModel is not. Acceptable only
-because the end-to-end symptom was the whole point of the diagnostic; revisit if the wiring is ever
-touched again.
-
-## 🚨 FIXED 2026-09-27 — "Change Account" no longer signs you out before the browser opens
-
-**Reported as:** *"I clicked on my signed-in account pic, then clicked sign-in to another account. It
-opened the browser page to login under a different account and I canceled the request. But when
-returned to the app, I see logged out — and should not have happened! Cannot sign-in because the
-callback url was not released."* Also reported as hitting **both** running instances.
-
-**Two independent defects, and the second one was masking a race:**
-
-1. **The sign-out ran first.** `ChangeAccountAsync` was `await SignOutYouTubeAsync(); await
-   SignInAsync();`. `SignOutYouTubeAsync` → `TokenStore.Clear()` → **deletes** `ytLlive.auth`. So the
-   working account's token was destroyed *before the browser even opened*; cancelling the chooser left
-   nothing. Now `ChangeAccountAsync` is just `await SignInAsync()` — success overwrites the token via
-   the `sessionChanged` hook, cancel/failure keeps the current session. No sign-out is needed at all.
-2. **The retry couldn't rebind the callback port.** Abandoning the browser gives the app no signal, so
-   the attempt held `localhost:8765` for its full 5-minute timeout. A new `AuthenticateAsync` now
-   cancels and awaits the abandoned attempt before binding, **serialised by a `SemaphoreSlim`**
-   (`_authGate`) — without the gate, the takeover window let a third caller see a free port and race
-   to bind it, i.e. the takeover reproduced the original failure. My own test caught this.
-
-**The cross-instance claim was NOT the cause** and is still open as a *separate* question: no code path
-can sign out a second instance (`TokenStore` is per-`InstanceProfile.DataRoot`, `Clear()` is a local
-file delete with no server-side revoke, and no second instance had a token at inspection time). Verify
-both processes carried distinct `YTLIVE_INSTANCE` values and ran Debug builds before chasing it.
-
-Test: `YouTubeAuthServiceTests.RetryingAfterAnAbandonedAttempt_ReleasesTheCallbackPort`. Full suite
-**370/370**, 0 warnings (build `ytLive.Tests.csproj`, not just the app project, or VSTest runs a stale
-test DLL). Added an `openBrowser` ctor seam to `YouTubeAuthService` so tests never launch a real
-browser. **Coverage gap:** the *ordering* fix (defect 1) has no automated test — `_youtubeAuth` is
-hardcoded in `MainViewModel` and `ChangeAccountAsync` is private, so a real test would shell out to
-the browser. Wiring an auth seam into `MainViewModel` is a deliberate follow-up, not a bug-fix extra.
-
-## 🗄 PARKED — Google OAuth verification: attempted, hit a Google-side bug, tabled by ruling
-
-**Creator ruling: unimportant for where we currently sit.** Verification is *not* a live blocker and
-**must not be re-attempted, re-derived, or re-researched** without a new ruling. The 2026-09-27 entry
-that preceded this one wrongly sat at `⏭ NEXT STEP` and framed it as the top priority — that was the
-plan going in, not the outcome, and the outcome was never written down. Corrected 2026-09-28.
-
-**What happened:** the verification attempt was made and failed on a bug **on Google's side** — not
-something we can fix, work around, or retry our way past. ⛔ **The exact mechanism was never recorded
-and is deliberately left blank** rather than reconstructed from memory: a confidently wrong note here
-is worse than none, because the next session would trust it. Do not go looking for the cause.
-
-**Owning account (creator-confirmed): `llamachile.shop@gmail.com` ("gramps").** Cloud project number
-`198374416003` (from the ClientId) — banked in `ai.md:233`, **do not re-hunt it.** The one-hop console
-link is `https://console.cloud.google.com/apis/credentials?project=198374416003` (picker defaults to
-**"Recent"** — switch to **"All"**). ⛔ Not the same account as the YouTube channel signed into the app.
-
-**What tabling costs, stated honestly:** if the consent screen is still in **Testing**, the 100-user
-cap and the **7-day refresh-token expiry** both stand — that expiry is why the creator kept having to
-re-consent. Parking verification does not fix that; it accepts it for the solo-use phase. It becomes
-real work the moment a *second real user* needs to sign in, or at Store submission (TASK 48). The
-sensitive-vs-restricted classification was never read and is moot until then.
-
-**One of these two survives the tabling, and the other was a bad idea (corrected 2026-09-28):**
-- ✅ **DONE — `Services/YouTubeAuthService.cs` no longer requests `auth/youtube.force-ssl`.**
-  It is **redundant**: its grant is *"see, edit, and permanently delete your YouTube videos,
-  ratings, comments and captions"*, a strict subset of `auth/youtube`'s *"Manage your YouTube
-  account"*, which is the scope we keep. Google's own `liveBroadcasts.insert` reference lists
-  `auth/youtube` as an accepted **alternative** to `force-ssl`, so every endpoint this app calls
-  (`channels`, `liveBroadcasts`, `liveStreams`, `liveChat`, `playlistItems`) is covered.
-  Two consent lines became one. **No forced re-consent** — a refresh token keeps the scopes it
-  was originally granted, so existing sessions are untouched; the reduced set applies at the
-  next fresh sign-in. Removing a scope cannot narrow capability when the one kept is broader.
-- ❌ **NOT doing this, and the earlier note recommending it was wrong: moving
-  `playlistItems.list` off the user's session token.** It was written during the verification
-  hunt on the theory that "public data should not ride on user credentials". Walking the code
-  kills it: `ChannelStatsService` is built as `new ChannelStatsService(_youtubeAuth)` with **one**
-  `HttpClient`, and `channels?mine=true` (same service) **genuinely needs the session**. To split
-  it you would need a second unauthenticated client **plus a Google API key**, because every
-  YouTube Data API request needs a credential — without a key the call 403s. So the "fix" means
-  **shipping a new extractable credential in the binary, subject to quota abuse, to replace a
-  token the app already holds.** It buys **zero** verification-surface reduction (the data is
-  public; no scope is involved) and zero correctness. Strictly worse. ⛔ Do not "fix" this later
-  without a new ruling.
-
-## ✅ DECIDED 2026-09-27 — pricing: `$10/mo` subscription, or `$400` lifetime, **no annual**
-
-**Creator's ruling, verbatim: *"Let's just go with $10 monthly recurring subscription for option
-A and, for option B, a lifetime sub for $400. No annual."* ⛔ **No `.99` prices** (earlier
-ruling: *"Let's stop with the x.99 stuff - I find that irritating. Just say: ten bucks a
-month"*). This **supersedes** the 2026-09-21 one-time `$29 → $49` model and the old `$99/yr`
-sub. No feature gating: free gets everything, the branding flash is the only paid delta.
-
-**✅ Store revenue share VERIFIED — 15%, and subscriptions are NOT penalised.** Read from the
-ADA v8.10 PDF itself (downloaded, text-extracted — not a search excerpt). §6(b)(i) charges
-**15%** on "any Apps (and any In-App Products in such Apps) that are **not listed in Section
-6(b)(iii)**"; 12% is Games-only; 30% covers Xbox console apps/games, Xbox non-subscription
-IAP, and Windows 8/Phone 8. LlamaCasty is a Windows PC App — not a Game, not Xbox, not Win8 —
-so **6(b)(i) governs both tiers.** The agreement's own changelog (**v8.0, Oct 26 2017**) says
-it outright: *"implement the **85/15 revenue share for non-Game subscriptions**."*
-
-⇒ **`$10/mo` nets `$8.50/mo` (~$102/yr). `$400` lifetime nets `$340`.** Also confirmed: the
-15% applies *after* VAT/GST (Net Receipts), payouts are monthly above a **$50** threshold, and
-no better small-indie rate was found in the standard terms.
-
-**⛔ Two obligations §6(h) attaches to the recurring tier** (why lifetime is the hedge):
-(1) we must **fulfil the subscription for the entire period as marketed**, and on breach
-Microsoft may refund the customer *"the full amount, plus taxes... in Microsoft's sole
-discretion"*; (2) **raising the price disables auto-renew** — so `$10` is effectively locked
-for the product's life absent Microsoft's price-change process.
-
-**⏳ Still open:** the `$50` subscriber→lifetime upgrade-discount SKU was discussed and is
-**not approved** — do not declare it. Individual vs Company Partner Center account still
-unanswered (get it right before enrolling).
-
-## ✅ DECIDED 2026-09-27 — distribution is the Microsoft Store: MSIX + Store IAP
-
-**Creator's criteria, verbatim: "zero headaches, minimal maintenance (for me) while still
-providing accountability and a reasonably easy upgrade flow."** Route A is the only option
-where all four are solved by handing the work to Microsoft rather than to a certificate
-vendor: **$0/yr, no certificate, no HSM, no annual renewal, no SmartScreen ramp**, plus Store
-auto-update, Store-side payments/entitlements/refunds/support, and Microsoft review as the
-accountability layer. The rejected options and their reasons are in
-`TASKS/research-store-certification.md` §3 — **read that before reopening the question, not
-before re-deriving it.**
-
-**The big consequence: the whole licensing backend is deleted.** `PolarLicenseService`,
-`PolarLicense`, `MainViewModel.License.cs` (`PremiumUrl`, customer portal, the
-`OfflineGracePeriod = 14 days` subscription-era artifact, renewal/lapse copy) and the wrong
-"Polar unlocks alerts" string all become dead code. `IsPremium` comes from the **Store
-entitlement** instead of an HTTP call — which also deletes the entire "network flaky → app
-thinks I'm expired" bug class. **Velopack, the update URL and the DO droplet go too.**
-
-**What does not change: the entitlement.** Free gets everything; the branding flash stays the
-ONLY paid delta. Store IAP changes how `IsPremium` is *obtained*, never what it *gates*.
-
-**⛔ The old "still open: the price" note is retired — the price is settled, see the top of
-this file.** The old "~$69 floor" and "don't break the launch-price promise" notes refer to
-the old Polar storefront and are **not** current.
-
-### ✅ DONE 2026-09-28 — TASK 48 item 1: bundle ffmpeg (was the "first code unit")
-
-The app no longer downloads an executable at runtime. `scripts/fetch-ffmpeg.sh` populates a
-gitignored `ffmpeg/` from a **SHA-256-verified** pinned month-end BtbN artifact; `ytLive.csproj`
-copies it to output *and publish* and **fails the build** if it's missing; `FfmpegLocator` lost its
-downloader, its zip extraction and the `%APPDATA%\ytLlive\tools` cache, and now resolves
-**bundle → PATH** with a loud, actionable failure. The pin that 404'd is gone, so the
-2026-09-01 failure class cannot recur. Suite **379/379 at that point** (380 now — see Test
-state); 16 locator facts including an
-integration test that **executes the bundled binary** (which is what proves the sibling DLLs
-resolve). `THIRD-PARTY-NOTICES.txt` corrected — it still named the *stale* tag
-`autobuild-2026-08-09-13-03`, i.e. the one that 404'd.
-
-**Fresh-clone cost, deliberately accepted:** `./scripts/fetch-ffmpeg.sh` once (~65 MB). 135 MB of
-DLLs in git would tax every commit on this 9p tree; the URL + SHA-256 are the audit trail.
-
-**Answering "other 3p binaries needing bundling?" — no, verified.** ffmpeg was the only
-download-and-execute. `e_sqlite3.dll` + `WebView2Loader.dll` already ship via NuGet
-(`runtimes\win-x64\native\`), OpenH264 is compiled *into* `avcodec-63.dll`, the rest are managed.
-Two gaps remain that bundling cannot fix, and they are the next real risks: the **WebView2 Evergreen
-runtime** is a machine prerequisite (item 2's manifest dependency + a graceful-failure path), and
-**Velopack's updater downloads and executes**, so its teardown in step 3 is a compliance action.
-
-### Deferred, not next: the packaging project + `Package.appxmanifest` (TASK 48 items 2–3)
-
-**Creator ruling 2026-10-04: still in active development, so ship-time work waits and
-queued features come first.** The unit is unchanged and ready when it is wanted:
-Full trust, `webcam`/`microphone`, English only; Velopack deleted. Add the `DefaultRecordFolder()`
-comment in the same unit (the mediumIL invariant below becomes load-bearing the moment the manifest
-lands). Full-trust writes under a real package identity are still **unverified** — confirm on a
-real packaged build before trusting them with recordings.
-
-Carried over from the research unit, still open:
-- **⛔ `Distribution.md:318` recommended a $400+/yr EV certificate for a SmartScreen bypass
-  Microsoft removed in March 2024.** Fixed then — had it shipped, it would have cost
-  $400+/yr to buy what $150 buys. Now moot anyway (MSIX is signed by Microsoft), but the
-  lesson in `MyMistakes.md` stands: a policy citation is a claim about **scope**, not just
-  text.
-- **WebView2 Evergreen runtime** is a machine prerequisite the app will hard-fail without. The
-  manifest needs the framework dependency, and WebView2 init needs a graceful error instead of a
-  crash. New, found while bundling ffmpeg.
-
-### ⛔ Two invariants that break silently if touched
-
-- **Full trust, or recording breaks.** `DefaultRecordFolder()` writes to Downloads/MyVideos;
-  that passes through unvirtualized **only** at `mediumIL`. Flip the manifest to
-  `appContainer` and output vanishes with no error. A comment is owed there **when the
-  manifest lands** (TASK 48 item 6) — not before.
-- **Chat is rendered, never stored.** That non-persistence half is the load-bearing part of
-  the 11.12 certification answer. No chat history, moderation log, analytics, or crash payload
-  may be added without re-arguing 11.12 first.
-
-## 🚨 OPEN 2026-09-28 — the RTMP push never lands: recordings reach YouTube as EMPTY placeholders
-
-**This is a live bug, not a queued feature**, and it reframes a complaint the map previously
-treated as closed. It was found on 2026-09-28 while scoping TASK 50, and the handoff had no
-entry for it at all — corrected here.
-
-**What the creator observed:** the channel carries **20+ private videos, all content-less
-placeholders** (creator-inspected, 2026-09-28). This is the real explanation of the
-2026-09-26 report "I still cannot get private test recordings saved" — it was never true that
-the app could not *find* an archived VOD. **No video content is ever produced on the channel.**
-
-**Mechanism (verified against the code AND the channel):** `liveBroadcasts.insert` succeeds and
-creates the placeholder; everything after it is what fails. Content only exists if all three of
-these land, and at least one does not:
-1. broadcast reaches **LIVE** via `liveBroadcasts/transition`,
-2. ffmpeg actually pushes RTMP to the bound stream key,
-3. the broadcast ends and YouTube transcodes it into a VOD.
-
-`enableAutomaticArchiving` is **never set**, so YouTube's `true` default applies — the archiving
-route exists but has nothing to archive. Broadcasts are inserted `private`
-(`Services/YouTubeStreamService.cs:49`), so the orphans are not public, and the app has **no
-delete path** — the creator clears each one by hand in Studio.
-
-**✅ DIAGNOSTIC ANSWERED 2026-10-04 — ffmpeg reaches YouTube; the broadcast never goes LIVE.**
-One test-mode push, read from `startup.log`. The three steps, resolved:
-1. `new MediaFoundationReader`/RTMP path — **WORKS.** ffmpeg opened
-   `rtmp://a.rtmp.youtube.com/live2/4pew-…`, muxed **7.4 MB video + 46 KB audio**, and
-   finalised the FLV with no socket error. Step 2 is fine.
-2. **The broadcast stays `ready` — this is the break.** `enableAutoStart = true` *is* sent
-   on insert (`Services/YouTubeStreamService.cs:73`), yet at close-out YouTube refused
-   `transition=complete` with **403 `Invalid transition`** — which is only legal from `live`.
-   So YouTube never flipped `ready → live`.
-3. Never reached (nothing to archive because nothing went live).
-
-**Two unknowns, and the honest state of each:**
-- **The push ran only 8 seconds** (08:48:23.9 → 08:48:32.8). YouTube may simply need longer
-  to accept and validate the ingest before it auto-starts. Untested — do not assume.
-- **The app cannot see this either way.** During a stream it polls **stream** health
-  (`liveStreams`) and never the **broadcast** status; `GetLifeCycleStatusAsync` is called
-  *only* from the end path (`YouTubeStreamService.cs:146`). So the log contains no evidence
-  either way, and `EndBroadcastAsync` skips only on `complete`/`revoked`, meaning it tries
-  `complete` against a `ready` broadcast and earns the 403.
-
-**⇒ Next step, small and cheap:** log the broadcast's `lifeCycleStatus` while streaming
-(reuse the existing health poll timer — no new loop), then run **one 60-second** test. That
-single run answers it. Do not go hunting beyond it until it has.
-
-**Sequencing constraint — do not flip the flag early.** `enableAutomaticArchiving: false` is the
-correct end state (TASK 50 will upload the local file deliberately), but archiving is
-**currently the only route a recording takes to YouTube** — flipping it before TASK 50 ships
-would leave test streams with nothing at all and re-create the 2026-09-26 complaint in a worse
-form. Ship the upload, flip the flag in the same task, never before.
-
-Detail and the open 11.12 re-check: [`TASKS/task-50-publish-recording.md`](TASKS/task-50-publish-recording.md).
-
-## Landmines
-
-- **Frame pump jitter — counters now honest, cause NOT yet named (2026-10-05).** The same test
-  stream logged **86 stalls per 5s** (`FramePump stall: iteration 40–50ms` against a 17ms budget)
-  while `FramePump stats` read 301/300 frames, 0 dropped. UNIT 0 removed the reason those two
-  numbers could disagree (the averages were diluted by padded submits) and added the counters that
-  separate reader from compositor — **but no one has read a post-UNIT-0 log yet.** A creator
-  recording is required first. Do not "fix" the pump before that reading.
-- **Stale fact inside `TASKS.md` (left alone, flagged here per the Scope Lock).** The "1.0 gates"
-  section asserts "**TASK 36 is now shipped**", but the catalog row 36 reads **☐ Queued** and
-  `task-36-gold-pass.md` still shows items 1–6 unchecked. The line most likely means *item 2*
-  (branding flash goes live) shipped at `9761b1d`. **Needs a one-line fix, not a code change** —
-  flagging rather than fixing because it is not this unit's job.
-- **A stale `ytLive.exe` (PID 2544) locked `bin/.../ytLive.exe`** and broke `dotnet run` with
-  MSB3027. Killed. **If the build fails to copy `ytLive.exe`, check for a running instance first.**
-- **`LayerReorderPersistenceTests.RealMouseDrag_OnTheLayerList_PersistsTheReorder` needs an
-  interactive desktop session.** As of 2026-10-05 it fails deterministically here (`ImgC` vs
-  `ImgA`), verified identical on a clean tree. **Run the suite with ytLive CLOSED** and expect this
-  one to fail in this shell. Not a regression — don't diagnose it from a WSL-shell failure.
-- **`RealAppHost.RunAsync` exists for a reason** — a frame-pump test MUST `await` inside it. A
-  blocking wait occupies the one shared STA thread and **hangs the whole suite with no output.**
-  Always background a `vstest` run and poll the log; a foreground piped `vstest` returns nothing
-  in this shell even on success.
-- **`GlobalHotkeys`: two instances registering the SAME global hotkey** — Windows refuses the
-  second. Left alone deliberately.
-- **MSIX writes under a real package identity are unverified.** The docs say full trust passes
-  user-profile writes through, but confirm on a real packaged build before trusting it with
-  recordings (TASK 48 item 6).
-
-## Test state
-
-**402/402, 0 warnings, verified 2026-10-05** (395 + 6 `FrameCadenceTests` + 1 pump-stats integration
-test + 1 strip-parallel gate). Re-verified after UNITS 4+5. Build the **test** project, not just the app project, or VSTest runs a stale DLL.
-**Launch exe for the creator's test run: `bin/Debug/net8.0-windows10.0.19041.0/ytLive.exe`.**
-
-**Confirmed environmental flake, NOT a regression (re-checked 2026-10-05, and it now fails
-deterministically rather than 2-of-3):** `LayerReorderPersistenceTests.RealMouseDrag_OnTheLayerList_
-PersistsTheReorder` fails with `Expected "ImgC", Actual "ImgA"` at `RealAppHost.Run` line 68. **It
-fails identically on a stashed clean tree**, so it has nothing to do with UNIT 0 — it needs an
-interactive desktop session this shell does not have (the mouse drag never lands). Do not chase it;
-it is listed under Landmines as the known interactive-session test.
-
-**⚠️ A game-playing session breaks the audio tests — know this before debugging it.** On
-2026-10-05 `AudioPipelineTests.Mix_HonorsProviderGains_AndGameMute_KillsTheLoopback` failed with
-480/480 samples at `0.4` where `0` was expected, then passed in isolation minutes later. Cause: the
-user was in a **Division 2 boss fight**, and that test captures **audio loopback** — the game's own
-output landed in it. **An audio test failing during a gaming session is an environment fact, not a
-regression.** Same bucket as the interactive-desktop flake above: re-run in a quiet session before
-believing either. (It also briefly failed while I was probing `Parallel.For` thread priorities,
-which sent me after the wrong culprit entirely — the game was the simpler explanation.)
-
-**⚠️ New flake, do not chase it as a regression:** on the *first* full-suite run,
-`AudioPipelineTests.MasterLimiter_CapsTheLiveMix_OnThePipe` failed with `Expected 0.891,
-Actual 0` — a **zero**, not a slightly-off value, which is the signature of the pipe not being
-fed yet rather than the limiter misbehaving. It passed 27/27 as a class run and 380/380 on an
-immediate full-suite re-run. It reads the live mix **off the named pipe**, so it is a
-whole-suite scheduling artifact of the same family as the `RealAppHost` STA landmine below —
-**if it ever goes red, re-run before believing it.**
-
-## Uncommitted / untracked
-
-- `ffmpeg/` — the 9 bundled binaries (~135 MB), **gitignored by design**. Populated by
-  `scripts/fetch-ffmpeg.sh`. Do not commit it.
-- `MARCOM.md`, `MONETIZATION.md` — both edited (privacy-copy guard; the Polar-obsolete banner
-  and the re-opened-price note) and both **gitignored by design** (confidential business
-  files, `.gitignore:10-11`). They stay local, as intended. Same for `CREDENTIALS.md` —
-  **never commit those.**
-
-## Next
-
-1. **~PUSH, then the creator's 60-second Test** — see the FIXED box above. Packaging is NOT next;
-   the creator's ruling 2026-10-04: still in active development, so ship-time work waits and queued
-   features come first.
-2. **⏭ Read the Unit 4+5 Release recording (see the IN FLIGHT box at the top).** Then Unit 6
-   (encoder submit backpressure: `worst submit` 53ms, ~357 cumulative drops) if render is inside
-   budget; if render is still over, the per-stage timings name the stage — do not guess.
-3. **Webcam cadence → Unit 1 (exclusive lock + 720p).** UNIT 0 is shipped and the counters are in
-   `startup.log`; the reading needs one 60-second creator recording (details + the exact
-   read-the-log-together table in the IN FLIGHT box above). Then Unit 1: exclusive camera lock +
-   720p, and Unit 2: the blinking SD badge. **Creator to-do, not yet queued: long-run
-   resource/consumption/recycling benchmarking** (how long the app stays healthy under full burden) —
-   record only, do not start it.
-4. **The packaging project + `Package.appxmanifest`** (TASK 48 items 2–3) — the next code unit.
-   Full trust, `webcam`/`microphone`, English only; Velopack deleted. Add the
-   `DefaultRecordFolder()` comment in the same unit, and the WebView2 framework dependency +
-   graceful-failure path.
-5. **TASK 50 — one-button "Publish this video"** (`TASKS/task-50-publish-recording.md`). Queued
-   behind the Store submission by its own precedence note ("MSIX first, publish second — unless
-   the creator reverses that"). Scoping is done; the build is not. ⛔ Do **not** flip
-   `enableAutomaticArchiving` until it ships. It also carries an **open 11.12 re-check**: a
-   publish feature makes the app *push* creator content to a third party, so the IARC answers
-   must not go to certification describing an app that cannot publish.
-6. **Declare the IAP products in Partner Center** — the price is **settled** ($10/mo, $400
-   lifetime, no annual, 15% verified), so this is unblocked. **Blocks:** the Store listing and the
-   `OverlayHost.xaml` copy. ⛔ The Individual-vs-Company account question is still unanswered —
-   get it right before enrolling.
-7. **Polar teardown** (TASK 48 item 0) — `PolarLicenseService`, `PolarLicense`,
-   `MainViewModel.License.cs`, the `OverlayHost.xaml` string, the `csproj`/`App.xaml.cs`
-   Velopack sites. `IsPremium` ← Store entitlement. **Do this as one unit** — a half-torn-down
-   licensing path is worse than either end state.
-8. **Vertical recording verification** — the compositor tier is proven by
-   `Render_VerticalTier_Outputs_1080x1920_From_The_Center_Crop`; the *record* path has never
-   been run. `FramePump.cs:645` flags off-size tiers as a known follow-up.
-7. **WACK + certification notes + the privacy policy** (TASK 48 items 4–5) — the policy must
-   state camera/mic is OS-gated, nothing is retained, and **nothing is fetched at runtime**
-   (now literally true — the ffmpeg bundle is what makes that sentence defensible).
-8. **Post-session efficacy report** — roll up `CurrentHealth` (dropped frames, duration, health
-   message) when a stream or recording ends. `SessionTeardownTests` is the natural home.
-9. **Measure whether the Windows camera toggle gates DShow** — gates all privacy-forward copy
-   (`MARCOM.md` guard). Not a certification risk; a trust risk.
-10. **TASK 36:212 stale "shipped" line** — one-line fix, needs a hand.
-
-**Dropped from the list** because the ruling made them moot: multi-instance's ffmpeg tools-dir
-race (item 1 deleted the tools dir entirely), `scripts/publish.sh` + the `LlamaCasty.exe` rename
-(the Store packages and delivers — *revisit only if we ever ship outside the Store*), and the
-alert-gating copy (the wrong string dies with the Polar teardown in step 3).
-
-**Everything else in the v1 queue:** stream resilience (32), bandwidth step-down (33), scheduled
-streams (34), scene-linked audio (35), the master limiter (12), text source (3.16), reward
-events (3.20), the media picker (21), webcam identity (9.5), settings units A/C/D (40), and the
-defaults split (37). Ship-checklist items live in `TASKS.md` -> "1.0 gates".
+# HANDOFF — 2026-10-07
+
+## Branch
+- main (no feature branch)
+
+## Dirty files
+- None (zoom box fix + test committed as a work unit this session).
+
+## What just happened
+- Fixed the zoom box: right-click in live preview now procs the selected Zoom View
+  Shape with correct anchoring and a visible, populated box (previously invisible —
+  empty OpacityMask made the whole box transparent and the VisualBrush pointed at the
+  CanvasGrid *ancestor*, a circular reference WPF renders as nothing).
+- Zoom View Shape dropdown now uses the app's standard `YtComboBox` style.
+- One integration test added (Good Dog Rule): `ZoomBoxInteractionTests` — circle is a
+  centered square, phone is a tall 9:16 rect and tablet a wide 16:9 rect, both anchored
+  top-left at the click, box stays inside 1920x1080 (clamp), and the UI shows the right
+  outline/clip per shape. Full suite: 404 passed, 0 warnings.
+
+## Zoom feature state
+- Models/ZoomState.cs + Models/ZoomShape.cs (Circle, VerticalRectangle, HorizontalRectangle)
+- ViewModel: zoom box activation/move/dismiss; compositor output crops+scales the zoom region; dimming updates
+- PreviewPane: zoom box is a *sibling* of CanvasGrid inside a new `PreviewCanvas` wrapper
+  (so the VisualBrush can sample CanvasGrid without a circular reference); shape-aware
+  outline (`ZoomRectOutline`/`ZoomCircleOutline`) + ellipse clip for Circle
+- Shape semantics in `MainViewModel.ActivateZoom`: Circle = click point is center, w=h=min(maxW,maxH);
+  VerticalRectangle = 9:16 tall, HorizontalRectangle = 16:9 wide, both anchored top-left at the click; clamped to frame
+- Settings (OverlayHost) Zoom View Shape persisted via LayoutStore
+
+## Known issues / follow-ups
+- Background toggle bug mentioned earlier: when clicking "Use default background" in layer properties, nothing happens. Need to investigate - binding exists (UseDefaultBackground), VM has handler that invalidates bake and updates. May need to look up Source background logic.
+
+## Next step
+- User runs the app live/test to eyeball the zoom box visuals (border shows, region content visible,
+  circle is round, phone/tablet anchored at the click point). Then background "Use default background"
+  toggle if still needed. Otherwise stand down.
diff --git a/Models/ZoomShape.cs b/Models/ZoomShape.cs
new file mode 100644
index 0000000..8ce91f7
--- /dev/null
+++ b/Models/ZoomShape.cs
@@ -0,0 +1,8 @@
+namespace ytLive.Models;
+
+public enum ZoomShape
+{
+    Circle,
+    VerticalRectangle,
+    HorizontalRectangle
+}
diff --git a/Models/ZoomState.cs b/Models/ZoomState.cs
new file mode 100644
index 0000000..2d8a13e
--- /dev/null
+++ b/Models/ZoomState.cs
@@ -0,0 +1,20 @@
+using System;
+
+namespace ytLive.Models;
+
+public class ZoomState
+{
+    public bool IsActive { get; set; }
+    public double X { get; set; }
+    public double Y { get; set; }
+    public double Width { get; set; }
+    public double Height { get; set; }
+    public bool IsMoving { get; set; }
+    public double GrabOffsetX { get; set; }
+    public double GrabOffsetY { get; set; }
+
+    public double Left => X;
+    public double Top => Y;
+    public double Right => X + Width;
+    public double Bottom => Y + Height;
+}
diff --git a/MyMistakes.md b/MyMistakes.md
index 371041a..bbd9d82 100644
--- a/MyMistakes.md
+++ b/MyMistakes.md
@@ -1475,3 +1475,22 @@ a cycle debugging a test failure, ask what the machine was doing: an audio test
 gaming session is an environment fact, not a regression.** (Same family as the known
 `LayerReorderPersistenceTests.RealMouseDrag_OnTheLayerList_PersistsTheReorder` interactive-desktop
 flake — both are in the "run it in a quiet session" bucket, and neither is a code defect.)
+
+## 2026-10-07 — WPF VisualBrush: two silent "invisible box" traps
+
+Working on the zoom-magnifier box in PreviewPane. Two gold-plated WPF gotchas that made the box
+render NOTHING (no border, no content):
+
+1. **An empty `<VisualBrush Stretch="None"/>` used as an `OpacityMask` paints nothing → the mask
+alpha is 0 → the WHOLE element (border included) becomes transparent.** A VisualBrush without a
+`Visual` is not "mask = none", it is "mask = fully transparent". An opacity mask wants a tile or a
+visual source; if you meant "no mask", OMIT the Grid.OpacityMask element entirely.
+2. **A `VisualBrush` whose `Visual` is an *ancestor* of the element it is painted on is a circular
+reference — WPF renders nothing (no exception, no content).** The zoom box lived inside CanvasGrid
+and the brush sampled CanvasGrid. Fix: hoist the box OUT so it becomes a *sibling* of the visual
+being sampled (wrap CanvasGrid + ZoomBox in a container Canvas, coordinates unchanged since both
+are in the same 1920x1080 space). Then `VisualBrush.Visual = CanvasGrid` samples cleanly and the
+box magnifies the already-composited preview.
+
+Release the retained visual when the box hides (`VisualBrush.Visual = null`) or the long-lived
+source visual stays pinned for the app lifetime.
diff --git a/Services/LayoutStore.Settings.cs b/Services/LayoutStore.Settings.cs
index a9e0d0a..ed049db 100644
--- a/Services/LayoutStore.Settings.cs
+++ b/Services/LayoutStore.Settings.cs
@@ -283,7 +283,7 @@ public partial class LayoutStore : IDisposable
         UpsertSetting("Window.State", state);
     }
 
-    private string? GetSetting(string key)
+    public string? GetSetting(string key)
     {
         using var cmd = _connection.CreateCommand();
         cmd.CommandText = "SELECT Value FROM Settings WHERE Key = $key;";
@@ -291,7 +291,7 @@ public partial class LayoutStore : IDisposable
         return cmd.ExecuteScalar() as string;
     }
 
-    private void UpsertSetting(string key, string value)
+    public void UpsertSetting(string key, string value)
     {
         using var cmd = _connection.CreateCommand();
         cmd.CommandText = "DELETE FROM Settings WHERE Key = $key;";
diff --git a/ViewModels/MainViewModel.Overlays.cs b/ViewModels/MainViewModel.Overlays.cs
index dd2f90a..3d455a5 100644
--- a/ViewModels/MainViewModel.Overlays.cs
+++ b/ViewModels/MainViewModel.Overlays.cs
@@ -2,6 +2,7 @@ using System.Diagnostics;
 using System.IO;
 using System.Windows.Input;
 using ytLive.Helpers;
+using ytLive.Models;
 
 namespace ytLive.ViewModels;
 
@@ -75,6 +76,19 @@ public partial class MainViewModel : ViewModelBase
 
     public bool IsAnyOverlayOpen => IsSettingsOpen || IsBugOpen || IsFeatureOpen || IsAboutOpen;
 
+    private ZoomShape _zoomShape = ZoomShape.Circle;
+    public ZoomShape ZoomShape
+    {
+        get => _zoomShape;
+        set
+        {
+            if (SetProperty(ref _zoomShape, value))
+            {
+                try { _layoutStore.UpsertSetting("ZoomShape", value.ToString()); } catch { }
+            }
+        }
+    }
+
     public string OverlayTitle
     {
         get => _overlayTitle;
diff --git a/ViewModels/MainViewModel.Streaming.Operations.cs b/ViewModels/MainViewModel.Streaming.Operations.cs
index b32a369..07b3622 100644
--- a/ViewModels/MainViewModel.Streaming.Operations.cs
+++ b/ViewModels/MainViewModel.Streaming.Operations.cs
@@ -334,6 +334,16 @@ public partial class MainViewModel : ViewModelBase
         RecordPillOn = false;
         OnAirPillOn = false;
         WindowTitle = "LlamaCasty";
+        // Deactivate zoom when stopping
+        if (_zoomState.IsActive || _zoomState.IsMoving)
+        {
+            _zoomState.IsActive = false;
+            _zoomState.IsMoving = false;
+            OnPropertyChanged(nameof(IsZoomActive));
+            OnPropertyChanged(nameof(ShowZoomOverlay));
+            OnPropertyChanged(nameof(ZoomState));
+            RebuildQualityDimRects();
+        }
         ResetHealth(StreamStatus.Offline);
         // Stop chat polling first (TASK 9.4) — no more messages arriving while
         // we're tearing down the stream.
diff --git a/ViewModels/MainViewModel.Streaming.cs b/ViewModels/MainViewModel.Streaming.cs
index 2cf1cb5..35701a0 100644
--- a/ViewModels/MainViewModel.Streaming.cs
+++ b/ViewModels/MainViewModel.Streaming.cs
@@ -411,13 +411,7 @@ public partial class MainViewModel : ViewModelBase
         OutputRectWidth = rectW;
         OutputRectHeight = rectH;
 
-        DimRects.Clear();
-        if (rectX > 0) DimRects.Add(new Rect(0, 0, rectX, MasterFrameHeight));
-        if (rectX + rectW < MasterFrameWidth)
-            DimRects.Add(new Rect(rectX + rectW, 0, MasterFrameWidth - rectX - rectW, MasterFrameHeight));
-        if (rectY > 0) DimRects.Add(new Rect(0, 0, MasterFrameWidth, rectY));
-        if (rectY + rectH < MasterFrameHeight)
-            DimRects.Add(new Rect(0, rectY + rectH, MasterFrameWidth, MasterFrameHeight - rectY - rectH));
+        RebuildQualityDimRects();
 
         IsOutputCropped = DimRects.Count > 0;
         ResolutionBadgeText = $"{quality.Label} · {quality.Width}×{quality.Height}";
diff --git a/ViewModels/MainViewModel.cs b/ViewModels/MainViewModel.cs
index a7796ac..dff5595 100644
--- a/ViewModels/MainViewModel.cs
+++ b/ViewModels/MainViewModel.cs
@@ -28,6 +28,7 @@ public partial class MainViewModel : ViewModelBase
     private string? _activeLayoutPath;
     private DispatcherTimer? _saveDebounce;
     private bool _isLoading;
+    private ZoomState _zoomState = new();
 
     // Toasts (TASK 24): non-blocking user-facing messages. Parameterless ctor
     // news up the real service; the VM is built from XAML so no DI seam exists.
@@ -74,6 +75,142 @@ public partial class MainViewModel : ViewModelBase
         }
     }
 
+    public ZoomState ZoomState
+    {
+        get => _zoomState;
+        set => SetProperty(ref _zoomState, value);
+    }
+
+    public bool IsZoomActive => _zoomState.IsActive;
+    public bool ShowZoomOverlay => _zoomState.IsActive;
+
+    public void ActivateZoom(double clickX, double clickY)
+    {
+        if (!(IsLive || IsRecording)) return;
+        var maxW = MasterFrameWidth * 0.7;
+        var maxH = MasterFrameHeight * 0.7;
+        double w, h;
+        switch (_zoomShape)
+        {
+            case ZoomShape.Circle:
+                var size = Math.Min(maxW, maxH);
+                w = size; h = size;
+                break;
+            case ZoomShape.VerticalRectangle:
+                h = maxH;
+                w = h * 9.0 / 16.0;
+                break;
+            default:
+                w = maxW;
+                h = w * 9.0 / 16.0;
+                break;
+        }
+        double x, y;
+        if (_zoomShape == ZoomShape.Circle)
+        {
+            x = clickX - w / 2;
+            y = clickY - h / 2;
+        }
+        else
+        {
+            x = clickX;
+            y = clickY;
+        }
+        x = Math.Clamp(x, 0, MasterFrameWidth - w);
+        y = Math.Clamp(y, 0, MasterFrameHeight - h);
+        _zoomState.X = x;
+        _zoomState.Y = y;
+        _zoomState.Width = w;
+        _zoomState.Height = h;
+        _zoomState.IsActive = true;
+        _zoomState.IsMoving = false;
+        RefreshZoomUi();
+    }
+
+    public void ToggleZoom()
+    {
+        if (_zoomState.IsActive)
+        {
+            _zoomState.IsActive = false;
+            _zoomState.IsMoving = false;
+            RefreshZoomUi();
+        }
+    }
+
+    public void DismissZoom()
+    {
+        _zoomState.IsActive = false;
+        _zoomState.IsMoving = false;
+        RefreshZoomUi();
+    }
+
+    public void StartZoomMove(double x, double y)
+    {
+        if (!_zoomState.IsActive) return;
+        _zoomState.IsMoving = true;
+        _zoomState.GrabOffsetX = x - _zoomState.X;
+        _zoomState.GrabOffsetY = y - _zoomState.Y;
+        OnPropertyChanged(nameof(ZoomState));
+    }
+
+    public void UpdateZoomMove(double x, double y)
+    {
+        if (!_zoomState.IsActive || !_zoomState.IsMoving) return;
+        var nx = x - _zoomState.GrabOffsetX;
+        var ny = y - _zoomState.GrabOffsetY;
+        _zoomState.X = Math.Clamp(nx, 0, MasterFrameWidth - _zoomState.Width);
+        _zoomState.Y = Math.Clamp(ny, 0, MasterFrameHeight - _zoomState.Height);
+        OnPropertyChanged(nameof(ZoomState));
+        RebuildDimRectsForZoom();
+    }
+
+    public void EndZoomMove()
+    {
+        if (_zoomState.IsMoving)
+        {
+            _zoomState.IsMoving = false;
+            OnPropertyChanged(nameof(ZoomState));
+        }
+    }
+
+    private void RefreshZoomUi()
+    {
+        OnPropertyChanged(nameof(ZoomState));
+        OnPropertyChanged(nameof(IsZoomActive));
+        OnPropertyChanged(nameof(ShowZoomOverlay));
+        RebuildDimRectsForZoom();
+    }
+
+    private void RebuildDimRectsForZoom()
+    {
+        if (_zoomState.IsActive)
+        {
+            var zx = _zoomState.X;
+            var zy = _zoomState.Y;
+            var zw = _zoomState.Width;
+            var zh = _zoomState.Height;
+            DimRects.Clear();
+            if (zx > 0) DimRects.Add(new Rect(0, 0, zx, MasterFrameHeight));
+            var rx = zx + zw;
+            if (rx < MasterFrameWidth) DimRects.Add(new Rect(rx, 0, MasterFrameWidth - rx, MasterFrameHeight));
+            if (zy > 0) DimRects.Add(new Rect(0, 0, MasterFrameWidth, zy));
+            var ry = zy + zh;
+            if (ry < MasterFrameHeight) DimRects.Add(new Rect(0, ry, MasterFrameWidth, MasterFrameHeight - ry));
+            return;
+        }
+        RebuildQualityDimRects();
+    }    private void RebuildQualityDimRects()
+    {
+        DimRects.Clear();
+        if (OutputRectWidth <= 0 || OutputRectHeight <= 0) return;
+        if (OutputRectX > 0) DimRects.Add(new Rect(0, 0, OutputRectX, MasterFrameHeight));
+        if (OutputRectX + OutputRectWidth < MasterFrameWidth)
+            DimRects.Add(new Rect(OutputRectX + OutputRectWidth, 0, MasterFrameWidth - OutputRectX - OutputRectWidth, MasterFrameHeight));
+        if (OutputRectY > 0) DimRects.Add(new Rect(0, 0, MasterFrameWidth, OutputRectY));
+        if (OutputRectY + OutputRectHeight < MasterFrameHeight)
+            DimRects.Add(new Rect(0, OutputRectY + OutputRectHeight, MasterFrameWidth, MasterFrameHeight - OutputRectY - OutputRectHeight));
+    }
+
     private void OnSelectedElementPropertyChanged(object? sender, System.ComponentModel.PropertyChangedEventArgs e)
     {
         if (e.PropertyName == nameof(SceneElement.UseDefaultBackground))
@@ -239,6 +376,13 @@ public partial class MainViewModel : ViewModelBase
         // (yellow) instead of silently falling back to the default.
         MicSourceName = _layoutStore.LoadMicSourceName();
         AudioSyncOffsetMs = _layoutStore.LoadAudioSyncOffsetMs();
+        try
+        {
+            var s = _layoutStore.GetSetting("ZoomShape");
+            if (!string.IsNullOrWhiteSpace(s) && Enum.TryParse<ZoomShape>(s, true, out var zs))
+                _zoomShape = zs;
+        }
+        catch { }
 
         _cameraEnumerator = CameraEnumeratorOverride ?? new MediaCaptureCameraEnumerator();
         _cameraManager = new CameraManager(
@@ -553,6 +697,22 @@ public partial class MainViewModel : ViewModelBase
     private CompositorOptions BuildCompositorOptions()
     {
         var quality = SelectedQuality;
+        if (_zoomState.IsActive)
+        {
+            var zx = _zoomState.X;
+            var zy = _zoomState.Y;
+            var zw = _zoomState.Width;
+            var zh = _zoomState.Height;
+            return new CompositorOptions
+            {
+                SourceRectX = (int)Math.Clamp(Math.Round(zx), 0, 1919),
+                SourceRectY = (int)Math.Clamp(Math.Round(zy), 0, 1079),
+                SourceRectWidth = (int)Math.Max(1, Math.Round(zw)),
+                SourceRectHeight = (int)Math.Max(1, Math.Round(zh)),
+                OutputWidth = quality.Width,
+                OutputHeight = quality.Height,
+            };
+        }
         return new CompositorOptions
         {
             SourceRectX = (int)Math.Round(OutputRectX),
@@ -562,9 +722,7 @@ public partial class MainViewModel : ViewModelBase
             OutputWidth = quality.Width,
             OutputHeight = quality.Height,
         };
-    }
-
-    // The credit's cadence, timing, placement and licence gate all live in
+    }    // The credit's cadence, timing, placement and licence gate all live in
     // BrandFlashPresenter; MainViewModel only routes it to the frame pump and the
     // preview (see MainViewModel.BrandFlash.cs).
 
diff --git a/ytLive.Tests/ZoomBoxInteractionTests.cs b/ytLive.Tests/ZoomBoxInteractionTests.cs
new file mode 100644
index 0000000..f1b7426
--- /dev/null
+++ b/ytLive.Tests/ZoomBoxInteractionTests.cs
@@ -0,0 +1,106 @@
+using System;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Media;
+using System.Windows.Shapes;
+using Microsoft.Data.Sqlite;
+using Xunit;
+using ytLive.Models;
+using ytLive.ViewModels;
+
+namespace ytLive.Tests;
+
+/// <summary>
+/// Verifies the zoom box created by a right-click in the live preview: each
+/// ZoomView Shape procures the right bounding box (circle is square and
+/// centered on the click, phone is a tall 9:16 rect, tablet a wide 16:9 rect
+/// both anchored top-left at the click), the box stays fully inside the
+/// 1920x1080 preview, and the UI renders the matching outline with the zoomed
+/// region clipped to the shape.
+/// </summary>
+[Collection("RealApp")]
+public sealed class ZoomBoxInteractionTests
+{
+    private readonly RealAppHost _app;
+
+    public ZoomBoxInteractionTests(RealAppHost app)
+    {
+        _app = app;
+    }
+
+    [Fact]
+    public void Zoom_Shape_Controls_Box_Aspect_Anchor_And_Render()
+    {
+        _app.Run(Run);
+    }
+
+    private void Run()
+    {
+        var tempDb = System.IO.Path.Combine(System.IO.Path.GetTempPath(), $"ytLlive-test-{Guid.NewGuid():N}.db");
+        MainViewModel.LayoutPathOverride = tempDb;
+        var window = new MainWindow();
+        var vm = (MainViewModel)window.DataContext;
+        try
+        {
+            window.Show();
+            window.UpdateLayout();
+
+            // Same internal test seam as IsRecording allows ActivateZoom (IsEditMode goes false).
+            vm.IsRecording = true;
+            var pane = (UserControl)window.FindName("PreviewPane")!;
+            var zoomBox = (Grid)pane.FindName("ZoomBox")!;
+            var rectOutline = (Rectangle)pane.FindName("ZoomRectOutline")!;
+            var circleOutline = (Ellipse)pane.FindName("ZoomCircleOutline")!;
+
+            // Circle: square box, click point is the CENTER.
+            vm.ZoomShape = ZoomShape.Circle;
+            vm.ActivateZoom(1000, 500);
+            Assert.True(vm.IsZoomActive);
+            Assert.Equal(vm.ZoomState.Width, vm.ZoomState.Height, 3);
+            Assert.Equal(1000 - vm.ZoomState.Width / 2, vm.ZoomState.X, 3);
+            Assert.Equal(500 - vm.ZoomState.Height / 2, vm.ZoomState.Y, 3);
+
+            window.UpdateLayout();
+            Assert.Equal(Visibility.Visible, zoomBox.Visibility);
+            Assert.IsType<EllipseGeometry>(zoomBox.Clip);
+            Assert.Equal(Visibility.Visible, circleOutline.Visibility);
+            Assert.Equal(Visibility.Collapsed, rectOutline.Visibility);
+
+            // Phone (vertical rectangle): tall 9:16 box, click point is the TOP-LEFT corner.
+            vm.ZoomShape = ZoomShape.VerticalRectangle;
+            vm.ActivateZoom(200, 100);
+            Assert.True(vm.ZoomState.Height > vm.ZoomState.Width);
+            Assert.Equal(9.0 / 16.0, vm.ZoomState.Width / vm.ZoomState.Height, 3);
+            Assert.Equal(200, vm.ZoomState.X, 3);
+            Assert.Equal(100, vm.ZoomState.Y, 3);
+
+            window.UpdateLayout();
+            Assert.Null(zoomBox.Clip);
+            Assert.Equal(Visibility.Collapsed, circleOutline.Visibility);
+            Assert.Equal(Visibility.Visible, rectOutline.Visibility);
+
+            // Tablet (horizontal rectangle): wide 16:9 box, anchored top-left.
+            vm.ZoomShape = ZoomShape.HorizontalRectangle;
+            vm.ActivateZoom(200, 100);
+            Assert.True(vm.ZoomState.Width > vm.ZoomState.Height);
+            Assert.Equal(16.0 / 9.0, vm.ZoomState.Width / vm.ZoomState.Height, 3);
+            Assert.Equal(200, vm.ZoomState.X, 3);
+            Assert.Equal(100, vm.ZoomState.Y, 3);
+
+            // Clamp keeps the box fully inside the 1920x1080 preview even for a
+            // corner click that would otherwise overhang it.
+            vm.ActivateZoom(2000, 2000);
+            const double frameW = 1920, frameH = 1080;
+            Assert.True(vm.ZoomState.X >= 0 && vm.ZoomState.Y >= 0);
+            Assert.True(vm.ZoomState.X + vm.ZoomState.Width <= frameW);
+            Assert.True(vm.ZoomState.Y + vm.ZoomState.Height <= frameH);
+        }
+        finally
+        {
+            window.Close();
+            MainViewModel.LayoutPathOverride = null;
+            SqliteConnection.ClearAllPools();
+            try { System.IO.File.Delete(tempDb); } catch { }
+        }
+    }
+}
\ No newline at end of file