From f39ebd96ceaa237008a1c6aeeb7597df35beff24 Mon Sep 17 00:00:00 2001
From: gramps <gramps@llamachile.shop>
Date: Fri, 28 Aug 2026 11:10:49 -0700
Subject: [PATCH] Web source: crop capture to actual content bounds (anchor
 0,0); slider click-to-position; web URI X clears; tab order

---
 HANDOFF.md                  | 34 ++++++++++++---------
 MainWindow.xaml             |  4 +--
 MainWindow.xaml.cs          |  3 +-
 Services/WebView2Manager.cs | 61 +++++++++++++++++++++++++++++++++++--
 TASKS.md                    | 25 +++++++++------
 Themes/Controls.xaml        |  1 +
 6 files changed, 98 insertions(+), 30 deletions(-)

diff --git a/HANDOFF.md b/HANDOFF.md
index 14aafeb..c63fc69 100644
--- a/HANDOFF.md
+++ b/HANDOFF.md
@@ -6,26 +6,32 @@
 working). **NOT pushed — user rule: never push without explicit instruction (2026-08-24).** No feature
 branches pre-1.0: all work lands on `main` per work unit.
 
-## The web-source rendering work (2026-08-28) — CURRENT MODEL: stable viewport + Fill
+## The web-source rendering work (2026-08-28) — CURRENT MODEL: stable viewport + content-bounds crop
 
 **Background:** viewport==box made dragging the box reflow the page (truncation, scrollbars,
 unrecoverable image, "janky at stressful geometries"). Fixed-viewport + `Uniform` left letterbox
-dead space. CSS reset enlarged the gap. Scrollbars were called "super fail".
+dead space. CSS reset enlarged the gap. Scrollbars were called "super fail". The right/bottom
+dead-space + "not anchored at (0,0)" report persisted across every model — dead space was
+page-internal (widget content smaller than the viewport), which is now cropped out.
 
-**The model that satisfies invariants (implemented, needs visual verification):**
-- `Services/WebView2Manager.cs` — the page renders ONCE at the viewport size the element was
-  created at (snapshot in `Register`, never tracked → no reflow, no truncation during resize).
-  `overflow:hidden` (html+body) + transparent-bg injection on every nav — nothing else, no
-  layout/CSS meddling. Immediate capture on `NavigationCompleted`. `FramePump` unchanged.
-- `MainWindow.xaml` — web `<Image>` uses `Stretch="Fill"`: any box the user draws is covered
-  edge-to-edge, zero dead space, zero crop (OBS free-transform: fixed browser resolution,
-  scene-item scales the texture). Aspect distortion only when the box aspect ≠ viewport aspect.
-- Invariants: **page viewport is stable; display Fill-scales texture to the box.**
+**The model that satisfies invariants (implemented, visual verification pending):**
+- `Services/WebView2Manager.cs` — stable viewport = the element's size at `Register` (snapshot,
+  never tracked → no reflow/truncation during resize). `overflow:hidden` (html+body) +
+  transparent-bg injection on every nav (nothing else). After each navigation,
+  `QueryContentBoundsAsync` reads the page's real content rect
+  (`scrollWidth/scrollHeight` vs `innerWidth/innerHeight` via `ExecuteScriptAsync` + JSON) and
+  `CaptureFrame` **crops the capture to the actual content bounds, anchored at (0,0)** — dead
+  space inside the viewport no longer reaches the box. Immediate capture on `NavigationCompleted`.
+- `MainWindow.xaml` — web `<Image>` uses `Stretch="Fill"`: the cropped frame maps edge-to-edge,
+  so the selection box always bounds the real widget. `FramePump` unchanged.
+- Invariants: **page viewport stable; display Fill-crops to content and fills the box.**
 
-Build: 0 warnings; tests 4/4 (snapshot at register, no tracking after, min 1, transparent bg).
+**Property panel / sliders (2026-08-28):** web URI ✕ clears the textbox; web ✓/✕ icon buttons
+`IsTabStop="False"` so Tab walks X→Y→W→H→URI; Slider style `IsMoveToPointEnabled="True"`
+restores click-anywhere-on-bar.
 
-**Rejected for the record:** fixed 1920×1080+`Uniform` (letterbox), CSS margin/100% reset
-(enlarged gap), viewport==box (reflow/truncation/scrollbars).
+Build: 0 warnings; tests 4/4. Rejected for the record: fixed 1920×1080+`Uniform` (letterbox),
+CSS margin/100% reset (enlarged gap), viewport==box (reflow/truncation/scrollbars).
 
 ## Key facts / landmines
 
diff --git a/MainWindow.xaml b/MainWindow.xaml
index 7a3ad3d..8a46848 100644
--- a/MainWindow.xaml
+++ b/MainWindow.xaml
@@ -546,13 +546,13 @@
                                 <TextBlock Text="URI" Foreground="#a0a0b0" FontSize="11" Margin="0,0,0,2"/>
                                 <DockPanel>
                                     <Button DockPanel.Dock="Right" Style="{StaticResource IconButton}"
-                                            Width="22" Height="22" Margin="4,0,0,0"
+                                            Width="22" Height="22" Margin="4,0,0,0" IsTabStop="False"
                                             Click="WebAccept_Click">
                                         <Path Data="M4,9 L8,14 L16,4" Stroke="#22c55e" StrokeThickness="2"
                                               Width="14" Height="14" Stretch="Uniform"/>
                                     </Button>
                                     <Button DockPanel.Dock="Right" Style="{StaticResource IconButton}"
-                                            Width="22" Height="22" ToolTip="Revert"
+                                            Width="22" Height="22" ToolTip="Revert" IsTabStop="False"
                                             Click="WebRevert_Click" Margin="4,0,0,0">
                                         <Path Data="M5,5 L15,15 M15,5 L5,15" Stroke="#e94560" StrokeThickness="2"
                                               Width="14" Height="14" Stretch="Uniform"/>
diff --git a/MainWindow.xaml.cs b/MainWindow.xaml.cs
index 5a56cb4..70324a1 100644
--- a/MainWindow.xaml.cs
+++ b/MainWindow.xaml.cs
@@ -859,7 +859,8 @@ public partial class MainWindow : Window
     private void WebRevert_Click(object sender, RoutedEventArgs e)
     {
         if (_snapshotElement is Models.Source src)
-            src.WebUri = _snapshotWebUri;
+            src.WebUri = string.Empty;
+        _snapshotWebUri = string.Empty;
     }
 
     private void WebAccept_Click(object sender, RoutedEventArgs e)
diff --git a/Services/WebView2Manager.cs b/Services/WebView2Manager.cs
index 1fbea93..f112229 100644
--- a/Services/WebView2Manager.cs
+++ b/Services/WebView2Manager.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Drawing;
 using System.IO;
+using System.Text.Json;
 using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Media;
@@ -26,6 +27,10 @@ public sealed class WebView2Manager : IDisposable
         public required WebView2 Control { get; init; }
         public required DispatcherTimer CaptureTimer { get; init; }
         public VideoFrame? LatestFrame;
+        public double ViewportCssW;
+        public double ViewportCssH;
+        public double ContentCssW;
+        public double ContentCssH;
         public bool Disposed;
         public bool Initialized;
     }
@@ -127,6 +132,7 @@ public sealed class WebView2Manager : IDisposable
                     "document.documentElement.style.overflow='hidden';" +
                     "document.body.style.background='transparent';" +
                     "document.body.style.overflow='hidden';");
+                _ = QueryContentBoundsAsync(source.Id);
                 _ = CaptureFrame(source.Id);
             };
 
@@ -153,6 +159,35 @@ public sealed class WebView2Manager : IDisposable
         catch (Exception ex) { AppLog.Write($"WebView2Manager: navigate failed: {ex.Message}"); }
     }
 
+    // The page's real content rect (scrollWidth/Height) can be smaller than the
+    // viewport for widgets that don't fill it — the leftover area is dead space
+    // that must not stretch across the selection box. Crop the capture to the
+    // content bounds (anchored at 0,0) so the box shows exactly the widget.
+    private async Task QueryContentBoundsAsync(string sourceId)
+    {
+        if (!_sessions.TryGetValue(sourceId, out var session) || session.Disposed) return;
+        try
+        {
+            if (session.Control.CoreWebView2 is not { } cws) return;
+            var json = await cws.ExecuteScriptAsync(
+                "JSON.stringify({w:document.documentElement.scrollWidth||0," +
+                "h:document.documentElement.scrollHeight||0," +
+                "vw:window.innerWidth||0,vh:window.innerHeight||0})");
+            if (string.IsNullOrEmpty(json) || json == "null") return;
+            using var doc = JsonDocument.Parse(json);
+            var root = doc.RootElement;
+            session.ViewportCssW = root.GetProperty("vw").GetDouble();
+            session.ViewportCssH = root.GetProperty("vh").GetDouble();
+            session.ContentCssW = root.GetProperty("w").GetDouble();
+            session.ContentCssH = root.GetProperty("h").GetDouble();
+            _ = CaptureFrame(sourceId);
+        }
+        catch (Exception ex)
+        {
+            AppLog.Write($"WebView2Manager: content bounds query failed: {ex.Message}");
+        }
+    }
+
     private async Task CaptureFrame(string sourceId)
     {
         if (!_sessions.TryGetValue(sourceId, out var session) || session.Disposed) return;
@@ -187,11 +222,31 @@ public sealed class WebView2Manager : IDisposable
             formatted.CopyPixels(pixels, pixW * 4, 0);
 
             var stride = pixW * 4;
-            var wb = new WriteableBitmap(pixW, pixH, 96, 96, PixelFormats.Bgra32, null);
-            wb.WritePixels(new Int32Rect(0, 0, pixW, pixH), pixels, stride, 0);
+
+            int cropW = pixW, cropH = pixH;
+            if (session.ViewportCssW >= 1 && session.ViewportCssH >= 1 &&
+                session.ContentCssW >= 1 && session.ContentCssH >= 1)
+            {
+                var sx = pixW / session.ViewportCssW;
+                var sy = pixH / session.ViewportCssH;
+                cropW = (int)Math.Clamp(Math.Round(session.ContentCssW * sx), 1, pixW);
+                cropH = (int)Math.Clamp(Math.Round(session.ContentCssH * sy), 1, pixH);
+            }
+
+            var outPixels = pixels;
+            if (cropW != pixW || cropH != pixH)
+            {
+                var dstStride = cropW * 4;
+                outPixels = new byte[dstStride * cropH];
+                for (var r = 0; r < cropH; r++)
+                    Buffer.BlockCopy(pixels, r * stride, outPixels, r * dstStride, dstStride);
+            }
+
+            var wb = new WriteableBitmap(cropW, cropH, 96, 96, PixelFormats.Bgra32, null);
+            wb.WritePixels(new Int32Rect(0, 0, cropW, cropH), outPixels, cropW * 4, 0);
             wb.Freeze();
 
-            session.LatestFrame = new VideoFrame(pixW, pixH, pixels);
+            session.LatestFrame = new VideoFrame(cropW, cropH, outPixels);
 
             _ = _dispatcher.BeginInvoke(() =>
             {
diff --git a/TASKS.md b/TASKS.md
index d41704f..bc040b1 100644
--- a/TASKS.md
+++ b/TASKS.md
@@ -917,17 +917,22 @@ capturing the primary display (which causes the infinity mirror effect).
 8. ✅ Preview shows live web content (not just a blank rectangle)
 9. ☐ Handle navigation errors, invalid URIs, timeout gracefully
 
-**Rendering model (2026-08-28, stable-viewport + fill — the working invariant):**
+**Rendering model (2026-08-28, stable viewport + content-bounds crop):**
 the page renders ONCE at the size the element was created at (snapshot in `Register`, never
-tracked) — so dragging the box never reflows the page, never truncates it, and scrollbars are
-suppressed (`overflow:hidden` on html/body injection; background-transparent only otherwise,
-no layout meddling). The captured texture is displayed with `Stretch="Fill"`, so any box the
-user draws is covered edge-to-edge with zero dead space (OBS free-transform behavior:
-browser renders at a fixed resolution, the scene-item scales the texture). The invariants:
-the page viewport is stable; the display Fill-scales it to the box. Graceful-error handling
-(item 9) is a follow-up. Attempts rejected for the record: fixed 1920×1080 + `Uniform`
-(letterbox dead space), CSS margin/100% reset (enlarged the gap), viewport==box (page reflow
-→ truncation/scrollbars/jank).
+tracked) — dragging the box never reflows the page; scrollbars suppressed via
+`overflow:hidden` html/body injection (background-transparent only otherwise). After each
+navigation the manager queries the page's real content rect (`scrollWidth/scrollHeight` vs
+`innerWidth/innerHeight`) and **crops the capture to the actual content bounds, anchored at
+(0,0)** — widgets that don't fill their viewport no longer stretch dead space across the box.
+`Stretch="Fill"` maps the cropped frame edge-to-edge (box is covered; the fill/adornment rect
+snaps to it). Graceful-error handling (item 9) is a follow-up. Rejected for the record:
+fixed-viewport 1920×1080 + `Uniform` (letterbox), CSS margin/100% reset (enlarged gaps),
+viewport==box (page reflow → truncation/scrollbars).
+
+**Properties panel (2026-08-28):** web URI ✓/✕ icon buttons are `IsTabStop="False"` so Tab flows
+X→Y→W→H→URI; the ✕ button now clears the URI textbox (was reverting to the pre-accept snapshot).
+Slider style gained `IsMoveToPointEnabled="True"` — click-anywhere-on-bar jumps the thumb to the
+click (volume sliders keep their manual `SetSliderValueFromClick`, harmless duplication).
 
 ### Design decisions
 
diff --git a/Themes/Controls.xaml b/Themes/Controls.xaml
index 6fcb7eb..03f485d 100644
--- a/Themes/Controls.xaml
+++ b/Themes/Controls.xaml
@@ -352,6 +352,7 @@
     <Style TargetType="Slider">
         <Setter Property="Height" Value="20"/>
         <Setter Property="VerticalAlignment" Value="Center"/>
+        <Setter Property="IsMoveToPointEnabled" Value="True"/>
         <Setter Property="Template">
             <Setter.Value>
                 <ControlTemplate TargetType="Slider">