Chart background on dark theme

lib/session/session_controller.dart

@@ -41,6 +41,7 @@ class SessionController {
   final ValueNotifier<int> _logTick = ValueNotifier(0);
   final ValueNotifier<StatusSnapshot> _snapshot =
       ValueNotifier(StatusSnapshot.empty());
+  final ValueNotifier<bool> cursorEnabled = ValueNotifier(false);
 
   ValueListenable<int> get frameTick => _frameTick;
   ValueListenable<int> get logTick => _logTick;
@@ -138,6 +139,7 @@ class SessionController {
     _frameTick.dispose();
     _logTick.dispose();
     _snapshot.dispose();
+    cursorEnabled.dispose();
     await decoder.dispose();
     await transport.dispose();
     viewState.dispose();

lib/ui/chart_painter.dart

@@ -11,11 +11,15 @@ class ChartPainter extends CustomPainter {
     required this.channel,
     required this.session,
     required this.layout,
+    required this.isDark,
+    this.hoverLocalPos,
   });
 
   final int channel;
   final SessionController session;
   final LayoutController layout;
+  final bool isDark;
+  final Offset? hoverLocalPos;
 
   @override
   void paint(Canvas canvas, Size size) {
@@ -24,8 +28,19 @@ class ChartPainter extends CustomPainter {
     final plotH = size.height - padTop - padBottom;
     if (plotW <= 0 || plotH <= 0) return;
 
+    // Theme-dependent palette.
+    final bgColor = isDark ? const Color(0xFF1E1F22) : const Color(0xFFF7F7F4);
+    final lineColor =
+        isDark ? const Color(0xFF5EA8FF) : const Color(0xFF185FA5);
+    final hatchColor =
+        isDark ? const Color(0x66D17050) : const Color(0x55993C1D);
+    final markerColor =
+        isDark ? const Color(0xCCD17050) : const Color(0xAA993C1D);
+    final cursorColor =
+        isDark ? const Color(0xCCBBBBBB) : const Color(0xAA444444);
+
     // Background.
-    final bgPaint = Paint()..color = const Color(0xFFF7F7F4);
+    final bgPaint = Paint()..color = bgColor;
     canvas.drawRect(
       Rect.fromLTWH(padLeft, padTop, plotW, plotH),
       bgPaint,
@@ -86,7 +101,7 @@ class ChartPainter extends CustomPainter {
 
     // Hatched gap rectangles.
     final hatchPaint = Paint()
-      ..color = const Color(0x55993C1D)
+      ..color = hatchColor
       ..style = PaintingStyle.fill;
     for (final g in gaps.hatchedRanges) {
       final x0 = xForCol(g.startPx);
@@ -99,7 +114,7 @@ class ChartPainter extends CustomPainter {
 
     // Polyline.
     final linePaint = Paint()
-      ..color = const Color(0xFF185FA5)
+      ..color = lineColor
       ..strokeWidth = 1.2
       ..style = PaintingStyle.stroke;
     final path = Path();
@@ -132,7 +147,7 @@ class ChartPainter extends CustomPainter {
 
     // Sub-pixel marker lines.
     final markerPaint = Paint()
-      ..color = const Color(0xAA993C1D)
+      ..color = markerColor
       ..strokeWidth = 1;
     for (final px in gaps.markerPixels) {
       final x = xForCol(px);
@@ -143,8 +158,56 @@ class ChartPainter extends CustomPainter {
       );
     }
 
+    // Cursor crosshair + data dot (still inside the plot clip).
+    int? hoverCol;
+    double? hoverY;
+    int? hoverTsUs;
+    if (hoverLocalPos != null) {
+      final hx = hoverLocalPos!.dx;
+      final hy = hoverLocalPos!.dy;
+      if (hx >= padLeft &&
+          hx <= padLeft + plotW &&
+          hy >= padTop &&
+          hy <= padTop + plotH) {
+        final col = (hx - padLeft).floor().clamp(0, cols.length - 1);
+        hoverCol = col;
+        hoverTsUs = win.startUs +
+            (((col + 0.5) / plotW) * (win.endUs - win.startUs)).round();
+        final cursorPaint = Paint()
+          ..color = cursorColor
+          ..strokeWidth = 1;
+        canvas.drawLine(
+          Offset(xForCol(col), padTop),
+          Offset(xForCol(col), padTop + plotH),
+          cursorPaint,
+        );
+        if (cols[col].hasData) {
+          hoverY = (cols[col].min + cols[col].max) / 2;
+          final yPx = yForVal(hoverY);
+          canvas.drawLine(
+            Offset(padLeft, yPx),
+            Offset(padLeft + plotW, yPx),
+            cursorPaint,
+          );
+          canvas.drawCircle(
+            Offset(xForCol(col), yPx),
+            3,
+            Paint()..color = lineColor,
+          );
+        }
+      }
+    }
+
     canvas.restore();
 
+    // Cursor readout box (outside the clip so it can overlay labels).
+    if (hoverCol != null) {
+      final tStr = hoverTsUs != null ? _fmtTime(hoverTsUs) : '—';
+      final yStr = hoverY != null ? hoverY.toStringAsFixed(3) : '—';
+      _drawReadout(canvas, 'x=$tStr  y=$yStr',
+          Offset(padLeft + 4, padTop + 2));
+    }
+
     // Axes labels.
     _drawText(canvas, '${yMax.toStringAsFixed(2)}',
         Offset(padLeft - 4, padTop), align: TextAlign.right);
@@ -157,6 +220,44 @@ class ChartPainter extends CustomPainter {
         align: TextAlign.right);
   }
 
+  void _drawReadout(Canvas c, String s, Offset where) {
+    final textColor =
+        isDark ? const Color(0xFFEEEEEE) : const Color(0xFF222222);
+    final bgColor =
+        isDark ? const Color(0xCC2A2B2E) : const Color(0xCCFFFFFF);
+    final borderColor =
+        isDark ? const Color(0x66FFFFFF) : const Color(0x44000000);
+    final tp = TextPainter(
+      text: TextSpan(
+        text: s,
+        style: TextStyle(
+          fontFamily: 'monospace',
+          fontSize: 10,
+          color: textColor,
+        ),
+      ),
+      textDirection: TextDirection.ltr,
+    )..layout();
+    final bgRect = Rect.fromLTWH(
+      where.dx,
+      where.dy,
+      tp.width + 8,
+      tp.height + 4,
+    );
+    c.drawRRect(
+      RRect.fromRectAndRadius(bgRect, const Radius.circular(3)),
+      Paint()..color = bgColor,
+    );
+    c.drawRRect(
+      RRect.fromRectAndRadius(bgRect, const Radius.circular(3)),
+      Paint()
+        ..color = borderColor
+        ..style = PaintingStyle.stroke
+        ..strokeWidth = 0.5,
+    );
+    tp.paint(c, Offset(where.dx + 4, where.dy + 2));
+  }
+
   void _drawText(Canvas c, String s, Offset where,
       {TextAlign align = TextAlign.left}) {
     final tp = TextPainter(

lib/ui/chart_widget.dart

@@ -19,6 +19,13 @@ class ChartWidget extends StatefulWidget {
 class _ChartWidgetState extends State<ChartWidget> {
   Offset? _dragStart;
   int? _dragStartUs;
+  final ValueNotifier<Offset?> _hover = ValueNotifier(null);
+
+  @override
+  void dispose() {
+    _hover.dispose();
+    super.dispose();
+  }
 
   @override
   Widget build(BuildContext context) {
@@ -35,7 +42,18 @@ class _ChartWidgetState extends State<ChartWidget> {
           _Header(channel: widget.channel),
           Expanded(
             child: LayoutBuilder(builder: (context, constraints) {
-              return Listener(
+              return ValueListenableBuilder<bool>(
+                valueListenable: scope.session.cursorEnabled,
+                builder: (_, cursorOn, __) {
+                  return MouseRegion(
+                    cursor: cursorOn
+                        ? SystemMouseCursors.precise
+                        : MouseCursor.defer,
+                    onHover: cursorOn
+                        ? (e) => _hover.value = e.localPosition
+                        : null,
+                    onExit: cursorOn ? (_) => _hover.value = null : null,
+                    child: Listener(
                       onPointerSignal: (ev) =>
                           _onPointerSignal(ev, constraints),
                       child: GestureDetector(
@@ -44,20 +62,30 @@ class _ChartWidgetState extends State<ChartWidget> {
                         onHorizontalDragUpdate: (d) =>
                             _dragUpdate(d, constraints),
                         onHorizontalDragEnd: (_) => _dragStart = null,
-                  child: ValueListenableBuilder<int>(
+                        child: ListenableBuilder(
-                    valueListenable: scope.session.frameTick,
+                          listenable: Listenable.merge([
-                    builder: (_, __, ___) {
+                            scope.session.frameTick,
+                            _hover,
+                          ]),
+                          builder: (_, __) {
                             return CustomPaint(
                               painter: ChartPainter(
                                 channel: widget.channel,
                                 session: scope.session,
                                 layout: scope.layout,
+                                isDark: Theme.of(context).brightness ==
+                                    Brightness.dark,
+                                hoverLocalPos:
+                                    cursorOn ? _hover.value : null,
                               ),
                               size: Size.infinite,
                             );
                           },
                         ),
                       ),
+                    ),
+                  );
+                },
               );
             }),
           ),

lib/ui/dialogs/layout_dialog.dart

@@ -125,10 +125,11 @@ class _LayoutDialogState extends State<LayoutDialog> {
   }
 
   Widget _gridPreview() {
+    final scheme = Theme.of(context).colorScheme;
     return Container(
       padding: const EdgeInsets.all(8),
       decoration: BoxDecoration(
-        color: Colors.grey.shade100,
+        color: scheme.surfaceContainerHighest,
         borderRadius: BorderRadius.circular(6),
       ),
       child: GridView.builder(
@@ -148,7 +149,7 @@ class _LayoutDialogState extends State<LayoutDialog> {
             return Container(
               decoration: BoxDecoration(
                 border: Border.all(
-                  color: Colors.grey.shade400,
+                  color: scheme.outlineVariant,
                   style: BorderStyle.solid,
                 ),
                 borderRadius: BorderRadius.circular(4),
@@ -159,16 +160,22 @@ class _LayoutDialogState extends State<LayoutDialog> {
                   crossAxisAlignment: CrossAxisAlignment.start,
                   mainAxisAlignment: MainAxisAlignment.spaceBetween,
                   children: [
-                    Text('$cellNumber',
+                    Text(
-                        style: const TextStyle(
+                      '$cellNumber',
+                      style: TextStyle(
                         fontFamily: 'monospace',
                         fontSize: 10,
-                            color: Colors.grey)),
+                        color: scheme.onSurfaceVariant,
-                    const Text('empty',
+                      ),
+                    ),
+                    Text(
+                      'empty',
                       style: TextStyle(
                         fontSize: 11,
-                            color: Colors.grey,
+                        color: scheme.onSurfaceVariant,
-                            fontStyle: FontStyle.italic)),
+                        fontStyle: FontStyle.italic,
+                      ),
+                    ),
                   ],
                 ),
               ),
@@ -177,8 +184,8 @@ class _LayoutDialogState extends State<LayoutDialog> {
           final cfg = _draft.configFor(ch);
           return Container(
             decoration: BoxDecoration(
-              color: Colors.white,
+              color: scheme.surface,
-              border: Border.all(color: Colors.grey.shade400),
+              border: Border.all(color: scheme.outlineVariant),
               borderRadius: BorderRadius.circular(4),
             ),
             child: Padding(
@@ -187,15 +194,23 @@ class _LayoutDialogState extends State<LayoutDialog> {
                 crossAxisAlignment: CrossAxisAlignment.start,
                 mainAxisAlignment: MainAxisAlignment.spaceBetween,
                 children: [
-                  Text('$cellNumber',
+                  Text(
-                      style: const TextStyle(
+                    '$cellNumber',
+                    style: TextStyle(
                       fontFamily: 'monospace',
                       fontSize: 10,
-                          color: Colors.grey)),
+                      color: scheme.onSurfaceVariant,
-                  Text('CH$ch · ${cfg.name}',
+                    ),
-                      style: const TextStyle(
+                  ),
-                          fontSize: 11, fontWeight: FontWeight.w500),
+                  Text(
-                      overflow: TextOverflow.ellipsis),
+                    'CH$ch · ${cfg.name}',
+                    style: TextStyle(
+                      fontSize: 11,
+                      fontWeight: FontWeight.w500,
+                      color: scheme.onSurface,
+                    ),
+                    overflow: TextOverflow.ellipsis,
+                  ),
                 ],
               ),
             ),

lib/ui/mini_log_panel.dart

@@ -26,11 +26,11 @@ class MiniLogPanel extends StatelessWidget {
             padding: EdgeInsets.symmetric(horizontal: 12, vertical: 6),
             child: Row(
               children: [
-                Text('Errors & fatals',
+                Text('Filtered log',
                     style: TextStyle(
                         fontWeight: FontWeight.w500, fontSize: 12)),
                 SizedBox(width: 6),
-                Text('· filtered view',
+                Text('· severities from settings',
                     style: TextStyle(fontSize: 11, color: Colors.grey)),
               ],
             ),

lib/ui/toolbar.dart

@@ -58,6 +58,25 @@ class Toolbar extends StatelessWidget {
               icon: const Icon(Icons.fit_screen),
               label: const Text('Reset view'),
             ),
+            const SizedBox(width: 6),
+            ValueListenableBuilder<bool>(
+              valueListenable: scope.session.cursorEnabled,
+              builder: (_, on, __) {
+                final scheme = Theme.of(context).colorScheme;
+                return OutlinedButton.icon(
+                  onPressed: () =>
+                      scope.session.cursorEnabled.value = !on,
+                  icon: const Icon(Icons.my_location),
+                  label: const Text('Cursor'),
+                  style: on
+                      ? OutlinedButton.styleFrom(
+                          backgroundColor: scheme.primaryContainer,
+                          foregroundColor: scheme.onPrimaryContainer,
+                        )
+                      : null,
+                );
+              },
+            ),
             const _Sep(),
             OutlinedButton.icon(
               onPressed: () => showDialog<void>(