fix(canvas): compact page pill + pen diagnostic

Page slider is no longer persistent: a compact prev/'n/total'/next pill;
tapping the label reveals the slider (collapses again), so it stops
blocking the page. Add a pen-pressure diagnostic toggle (bug icon) that
shows the live kind/pressure/min/max Windows delivers — to pin down why
pressure reads flat on the Surface Pen.

lib/editor/canvas/pen_canvas.dart

@@ -42,8 +42,14 @@ class PenCanvas extends StatefulWidget {
     this.allowFingerDrawing = false,
     this.minScale = 0.5,
     this.maxScale = 8.0,
+    this.onPenDebug,
   });
 
+  /// Debug hook: called with a readout of the latest pen event
+  /// (kind / pressure / pressureMin / pressureMax) so we can see what Windows
+  /// actually delivers. Null in release UI.
+  final void Function(String readout)? onPenDebug;
+
   /// The rendered PDF page bitmap, already sized to [pageSize].
   final Widget pageWidget;
 
@@ -249,8 +255,18 @@ class _PenCanvasState extends State<PenCanvas> {
 
   // --- Listener callbacks ---------------------------------------------------
 
+  void _emitPenDebug(PointerEvent event) {
+    final cb = widget.onPenDebug;
+    if (cb == null) return;
+    cb('${event.kind.name}  p=${event.pressure.toStringAsFixed(3)}  '
+        'min=${event.pressureMin.toStringAsFixed(2)} '
+        'max=${event.pressureMax.toStringAsFixed(2)}  '
+        'tilt=${event.tilt.toStringAsFixed(2)}');
+  }
+
   void _onPointerHover(PointerHoverEvent event) {
     if (_isStylus(event.kind)) {
+      _emitPenDebug(event);
       // Detect eraser (barrel button / inverted) while hovering.
       _eraserActive = _isEraserSignal(event);
     }
@@ -258,6 +274,7 @@ class _PenCanvasState extends State<PenCanvas> {
 
   void _onPointerDown(PointerDownEvent event) {
     if (event.kind == PointerDeviceKind.trackpad) return;
+    if (_isStylus(event.kind)) _emitPenDebug(event);
 
     _activePointers[event.pointer] = event.kind;
 
@@ -282,6 +299,7 @@ class _PenCanvasState extends State<PenCanvas> {
   }
 
   void _onPointerMove(PointerMoveEvent event) {
+    if (_isStylus(event.kind)) _emitPenDebug(event);
     if (event.pointer != _drawPointer) return;
     if (_activePointers.length >= 2) return; // pinch owns it
     _extendStroke(event);

lib/editor/canvas/pen_editor_screen.dart

@@ -40,6 +40,15 @@ class _PenEditorScreenState extends State<PenEditorScreen> {
   /// Live page value while dragging the page slider (null when not dragging).
   double? _scrub;
 
+  /// Whether the page-jump slider is expanded (NOT persistent — toggled by
+  /// tapping the page label; collapses after a jump).
+  bool _showSlider = false;
+
+  /// Latest pen-event debug readout (kind/pressure/min/max) — shown only when
+  /// the diagnostic toggle is on, to inspect what Windows delivers.
+  String _penDebug = '';
+  bool _showPenDebug = false;
+
   // Tool state.
   CanvasTool _tool = CanvasTool.pen;
   Color _color = Colors.black;
@@ -164,6 +173,34 @@ class _PenEditorScreenState extends State<PenEditorScreen> {
               ),
             ),
           ),
+          // Pen diagnostic readout (top-right) — shows what Windows delivers.
+          if (_showPenDebug)
+            SafeArea(
+              child: Align(
+                alignment: Alignment.topRight,
+                child: Padding(
+                  padding: const EdgeInsets.all(8),
+                  child: Material(
+                    color: Theme.of(context).colorScheme.inverseSurface,
+                    borderRadius: BorderRadius.circular(8),
+                    child: Padding(
+                      padding: const EdgeInsets.symmetric(
+                          horizontal: 10, vertical: 6),
+                      child: Text(
+                        _penDebug.isEmpty
+                            ? 'hover / draw with the pen…'
+                            : _penDebug,
+                        style: TextStyle(
+                          fontFamily: 'monospace',
+                          fontSize: 12,
+                          color: Theme.of(context).colorScheme.onInverseSurface,
+                        ),
+                      ),
+                    ),
+                  ),
+                ),
+              ),
+            ),
         ],
       ),
     );
@@ -213,6 +250,9 @@ class _PenEditorScreenState extends State<PenEditorScreen> {
                 ? _highlighterWidthFraction
                 : _penWidthFraction,
             allowFingerDrawing: _allowFingerDrawing,
+            onPenDebug: _showPenDebug
+                ? (s) => setState(() => _penDebug = s)
+                : null,
             onStrokeComplete: _commitStroke,
             onEraseStroke: _eraseStroke,
             pageWidget: PdfPageView(
@@ -272,6 +312,12 @@ class _PenEditorScreenState extends State<PenEditorScreen> {
               onPressed: () =>
                   setState(() => _allowFingerDrawing = !_allowFingerDrawing),
             ),
+            _ToolButton(
+              icon: Icons.bug_report_outlined,
+              selected: _showPenDebug,
+              tooltip: 'Pen pressure diagnostic',
+              onPressed: () => setState(() => _showPenDebug = !_showPenDebug),
+            ),
           ],
         ),
       ),
@@ -299,67 +345,85 @@ class _PenEditorScreenState extends State<PenEditorScreen> {
     );
   }
 
-  /// Floating page-control pill: prev / drag-slider / next. No keyboard input
-  /// (Windows on-screen keyboard is unreliable) — the slider scrubs pages.
+  /// Floating page control: a COMPACT pill (prev / "n / total" / next). Tapping
+  /// the label reveals a drag-slider — which is NOT persistent (collapses again
+  /// on tap) so it doesn't block the page. No keyboard input (Windows IME is
+  /// unreliable).
   Widget _buildPagePill() {
     final doc = _document!;
     final cs = Theme.of(context).colorScheme;
     final total = doc.pages.length;
     final shown = (_scrub ?? (_pageIndex + 1).toDouble()).round();
-    return Material(
-      color: cs.surfaceContainerHigh,
-      elevation: 3,
-      borderRadius: BorderRadius.circular(28),
-      child: ConstrainedBox(
-        constraints: const BoxConstraints(maxWidth: 560),
-        child: Padding(
-          padding: const EdgeInsets.symmetric(horizontal: 4, vertical: 2),
-          child: Row(
-            mainAxisSize: MainAxisSize.min,
-            children: [
-              IconButton(
-                tooltip: 'Previous page',
-                icon: const Icon(Icons.chevron_left),
-                onPressed:
-                    _pageIndex > 0 ? () => _goToPage(_pageIndex - 1) : null,
-              ),
-              if (total > 1)
-                Flexible(
-                  child: Slider(
-                    min: 1,
-                    max: total.toDouble(),
-                    value: (_scrub ?? (_pageIndex + 1).toDouble())
-                        .clamp(1, total.toDouble()),
-                    label: '$shown',
-                    divisions: total - 1,
-                    onChanged: (v) => setState(() => _scrub = v),
-                    onChangeEnd: (v) {
-                      setState(() => _scrub = null);
-                      _goToPage(v.round() - 1);
-                    },
-                  ),
-                ),
-              Padding(
-                padding: const EdgeInsets.symmetric(horizontal: 6),
-                child: Text(
-                  '$shown / $total',
-                  style: TextStyle(
-                    color: cs.onSurface,
-                    fontWeight: FontWeight.w600,
-                  ),
+    return Column(
+      mainAxisSize: MainAxisSize.min,
+      children: [
+        // Slider — shown only when expanded (not persistent).
+        if (_showSlider && total > 1)
+          Container(
+            margin: const EdgeInsets.only(bottom: 8),
+            constraints: const BoxConstraints(maxWidth: 420),
+            child: Material(
+              color: cs.surfaceContainerHigh,
+              elevation: 3,
+              borderRadius: BorderRadius.circular(28),
+              child: Padding(
+                padding: const EdgeInsets.symmetric(horizontal: 12),
+                child: Slider(
+                  min: 1,
+                  max: total.toDouble(),
+                  value: (_scrub ?? (_pageIndex + 1).toDouble())
+                      .clamp(1, total.toDouble()),
+                  label: '$shown',
+                  divisions: total - 1,
+                  onChanged: (v) => setState(() => _scrub = v),
+                  onChangeEnd: (v) {
+                    setState(() => _scrub = null);
+                    _goToPage(v.round() - 1);
+                  },
                 ),
               ),
-              IconButton(
-                tooltip: 'Next page',
-                icon: const Icon(Icons.chevron_right),
-                onPressed: _pageIndex < total - 1
-                    ? () => _goToPage(_pageIndex + 1)
-                    : null,
-              ),
-            ],
+            ),
+          ),
+        // Compact pill — always; fits content (no big frame).
+        Material(
+          color: cs.surfaceContainerHigh,
+          elevation: 3,
+          borderRadius: BorderRadius.circular(28),
+          child: Padding(
+            padding: const EdgeInsets.symmetric(horizontal: 4, vertical: 2),
+            child: Row(
+              mainAxisSize: MainAxisSize.min,
+              children: [
+                IconButton(
+                  tooltip: 'Previous page',
+                  icon: const Icon(Icons.chevron_left),
+                  onPressed:
+                      _pageIndex > 0 ? () => _goToPage(_pageIndex - 1) : null,
+                ),
+                TextButton(
+                  onPressed: total > 1
+                      ? () => setState(() => _showSlider = !_showSlider)
+                      : null,
+                  child: Text(
+                    '$shown / $total',
+                    style: TextStyle(
+                      color: cs.onSurface,
+                      fontWeight: FontWeight.w600,
+                    ),
+                  ),
+                ),
+                IconButton(
+                  tooltip: 'Next page',
+                  icon: const Icon(Icons.chevron_right),
+                  onPressed: _pageIndex < total - 1
+                      ? () => _goToPage(_pageIndex + 1)
+                      : null,
+                ),
+              ],
+            ),
           ),
         ),
-      ),
+      ],
     );
   }
 }