feat: a search's hits are marked on every row, and the panel says how many of them it is showing

src/plot_host.cpp

@@ -31,6 +31,14 @@ constexpr plot::u32 kRulerBColor = 0x8FA8C8u;
 /// mistaken for something the user placed.
 constexpr plot::u32 kMeasureColor = 0x9BE8A0u;
 constexpr plot::u32 kTriggerColor = 0xFF5B5Bu;
+/// A found hit's colour: the trigger marker's claim ("the scope fired here") in a cooler hue,
+/// because a hit is the same condition found in *history* and the two are on screen together --
+/// the live marker's red must stay the one that means "this is the event the capture is about".
+constexpr plot::u32 kSearchColor = 0x7FB2FFu;
+/// The *selected* hit's colour: the one the arrows are standing on, and the one a pause was taken
+/// around. Sixteen identical lines with no way to tell which of them the readout is quoting is a
+/// picture that cannot be read, so the current hit is brighter than its neighbours.
+constexpr plot::u32 kSearchCurrentColor = 0xE8D37Fu;
 
 /// The smallest difference a `TickFormat::Time` label can *write* at the magnitude `t` -- what
 /// the last digit of a label at that magnitude is worth. `format_time` writes three significant
@@ -202,6 +210,15 @@ void RowSet::install(Row& r, int /*row_index*/, plot::Plot& p) {
     r.plot->set_cursor_stroke(r.measure_v[mi], kMeasureStrokeWidth,
                               plot::Vec2{kMeasureDashOn, kMeasureDashOff});
   }
+  // The search hits' pool, parked, created for the same reason the measurement pool above is:
+  // `add_cursor()` only appends, so every mark a scan could ever want exists from the start.
+  for (int m = 0; m < kSearchMarks; ++m) {
+    const std::size_t mi = static_cast<std::size_t>(m);
+    r.search_v[mi] = r.plot->add_cursor(kParked, plot::Color::hex(kSearchColor));
+    r.plot->set_cursor_selectable(r.search_v[mi], false);
+    r.plot->set_cursor_stroke(r.search_v[mi], kMeasureStrokeWidth,
+                              plot::Vec2{kMeasureDashOn, kMeasureDashOff});
+  }
   r.trigger_marker = r.plot->add_cursor(kParked, plot::Color::hex(kTriggerColor));
   // A marker, not an instrument: it must sit exactly on the edge's time, so its
   // snap is Free and the controller never rounds it onto a sample.
@@ -544,6 +561,32 @@ void RowSet::set_measure_marks(const std::vector<MeasureMark>& marks) {
   }
 }
 
+void RowSet::set_search_marks(const std::vector<double>& xs, int current) {
+  const int n = static_cast<int>(xs.size()) < kSearchMarks ? static_cast<int>(xs.size())
+                                                           : kSearchMarks;
+  search_marks_placed_ = n;
+  for (int i = 0; i < kMaxRows; ++i) {
+    Row& r = row(i);
+    if (!r.plot) continue;
+    // Every row, not the hit's own row: a hit is an *instant on the shared x window*, so the
+    // mark lines up down the column the way the vertical cursors do. There is no "the hit's
+    // row" to pick -- the condition was found on the trigger's channel, which may not be
+    // plotted at all.
+    for (int m = 0; m < n; ++m) {
+      const std::size_t mi = static_cast<std::size_t>(m);
+      r.plot->set_cursor_x(r.search_v[mi], xs[mi], plot::CursorPlacement::Free);
+      // The colour is re-set every frame rather than only when the selection moves: the pool is
+      // re-ordered each frame as the view rolls, so slot `m` is not the same hit it was.
+      r.plot->set_cursor_color(r.search_v[mi],
+                               plot::Color::hex(m == current ? kSearchCurrentColor
+                                                            : kSearchColor));
+    }
+    for (int m = n; m < kSearchMarks; ++m) {
+      r.plot->set_cursor_x(r.search_v[static_cast<std::size_t>(m)], kParked);
+    }
+  }
+}
+
 bool RowSet::update_time_labels() {
   Row& first = row(0);
   if (!first.plot || !figure_) return false;
@@ -697,6 +740,9 @@ bool RowSet::readouts_locked() const noexcept {
     for (const plot::u32 id : r.measure_v) {
       if (r.plot->cursor(id).selectable) return false;
     }
+    for (const plot::u32 id : r.search_v) {
+      if (r.plot->cursor(id).selectable) return false;
+    }
   }
   return true;
 }