session: plots carry row and width; files without row load one cell per row

src/layout_store.cpp

@@ -611,6 +611,15 @@ bool load_layout(const std::string& path, LayoutState& out) {
         st.rows.back().signals = names;
       } else if (key == "weight") {
         st.rows.back().weight = std::strtod(value.c_str(), nullptr);
+      } else if (key == "row") {
+        try {
+          const int r = std::stoi(value);
+          if (r >= 0) st.rows.back().row = r;
+        } catch (...) {
+        }
+      } else if (key == "width") {
+        const double w = std::strtod(value.c_str(), nullptr);
+        if (w > 0.0) st.rows.back().width = w;
       }
     } else if (section == Section::Math && !st.math.empty()) {
       MathChannel& m = st.math.back();
@@ -784,7 +793,11 @@ bool save_layout(const std::string& path, const LayoutState& state) {
   o << "relative_time = " << (state.relative_time ? "true" : "false") << "\n";
   if (state.capture_packets > 0) o << "capture_packets = " << state.capture_packets << "\n";
   for (const auto& row : state.rows) {
-    o << "\n[[plot]]\nweight = " << row.weight << "\nsignals = [";
+    o << "\n[[plot]]\n";
+    // A row of -1 is a state built without the split (nothing in the app does that now); leaving the
+    // key out keeps it readable as the one-cell-per-row file it is.
+    if (row.row >= 0) o << "row = " << row.row << "\nwidth = " << row.width << "\n";
+    o << "weight = " << row.weight << "\nsignals = [";
     for (std::size_t i = 0; i < row.signals.size(); ++i) {
       if (i != 0) o << ", ";
       o << toml_escape(row.signals[i]);