[perf](trx-rs): optimize spectrum streaming and header overlay

Co-authored-by: OpenAI Codex <codex@openai.com>
Signed-off-by: Stan Grams <sjg@haxx.space>

src/trx-client/trx-frontend/src/lib.rs

@@ -36,6 +36,23 @@ pub trait FrontendSpawner {
     ) -> JoinHandle<()>;
 }
 
+#[derive(Debug, Default)]
+pub struct SharedSpectrum {
+    revision: u64,
+    frame: Option<SpectrumData>,
+}
+
+impl SharedSpectrum {
+    pub fn replace(&mut self, frame: Option<SpectrumData>) {
+        self.revision = self.revision.wrapping_add(1);
+        self.frame = frame;
+    }
+
+    pub fn snapshot(&self) -> (u64, Option<SpectrumData>) {
+        (self.revision, self.frame.clone())
+    }
+}
+
 pub type FrontendSpawnFn = fn(
     watch::Receiver<RigState>,
     mpsc::Sender<RigRequest>,
@@ -156,7 +173,7 @@ pub struct FrontendRuntimeContext {
     /// Owner callsign from trx-client config/CLI for frontend display.
     pub owner_callsign: Option<String>,
     /// Latest spectrum frame from the active SDR rig; None for non-SDR backends.
-    pub spectrum: Arc<Mutex<Option<SpectrumData>>>,
+    pub spectrum: Arc<Mutex<SharedSpectrum>>,
 }
 
 impl FrontendRuntimeContext {
@@ -185,7 +202,7 @@ impl FrontendRuntimeContext {
             remote_active_rig_id: Arc::new(Mutex::new(None)),
             remote_rigs: Arc::new(Mutex::new(Vec::new())),
             owner_callsign: None,
-            spectrum: Arc::new(Mutex::new(None)),
+            spectrum: Arc::new(Mutex::new(SharedSpectrum::default())),
         }
     }
 }

src/trx-client/trx-frontend/trx-frontend-http/assets/web/style.css

@@ -27,6 +27,7 @@
   --wavelength-fg: #8da3be;
   --spectrum-bg: #0a0f18;
   --jog-wheel-size: 83.2px;
+  --header-waterfall-overlap: 3.2rem;
 }
 
 [data-theme="light"] {
@@ -378,10 +379,10 @@ small { color: var(--text-muted); }
   grid-template-columns: auto minmax(0, 1fr);
   align-items: center;
   column-gap: 1rem;
-  margin-bottom: -0.45rem;
+  margin-bottom: 0;
   padding: 0.25rem 0 0.15rem;
   position: relative;
-  z-index: 2;
+  z-index: 3;
 }
 .header-text {
   width: auto;
@@ -391,17 +392,20 @@ small { color: var(--text-muted); }
 .title { font-size: 1.4rem; font-weight: 700; display: inline-flex; align-items: center; gap: 0.35rem; }
 .overview-strip {
   width: 100%;
-  margin: 0 0 0.95rem;
-  padding-top: 0.8rem;
+  margin: calc(-1 * var(--header-waterfall-overlap)) 0 0.95rem;
   position: relative;
   z-index: 1;
 }
 .overview-toolbar {
   display: flex;
   align-items: center;
-  justify-content: flex-start;
+  justify-content: flex-end;
   gap: 0.75rem;
-  margin-bottom: 0.25rem;
+  margin-bottom: 0;
+  position: absolute;
+  top: calc(var(--header-waterfall-overlap) + 0.2rem);
+  right: 0.15rem;
+  z-index: 2;
 }
 .overview-label {
   margin-left: auto;
@@ -663,6 +667,7 @@ button:focus-visible, input:focus-visible, select:focus-visible {
   .card { padding: 0.7rem 0.7rem 1rem; }
   button { min-height: 2.8rem; font-size: 0.95rem; }
   input.status-input, select.status-input { font-size: 1.1rem; }
+  :root { --header-waterfall-overlap: 2.2rem; }
   .controls-tray { width: max(100%, 52rem); padding-left: 0.85rem; padding-right: 0.85rem; }
   .freq-inline { gap: 0.5rem; }
   .freq-inline { flex-wrap: wrap; }
@@ -672,7 +677,7 @@ button:focus-visible, input:focus-visible, select:focus-visible {
   .top-bar-actions { width: 100%; justify-content: space-between; }
   .header-rig-switch { width: auto; justify-content: flex-end; }
   .header-rig-switch select { min-width: 6.5rem; }
-  .overview-toolbar { flex-wrap: wrap; }
+  .overview-toolbar { top: calc(var(--header-waterfall-overlap) + 0.15rem); }
   .controls-row { grid-template-columns: 1fr auto; }
   .controls-col-wfm { grid-column: 1 / -1; }
   .controls-col-power { grid-column: 1 / -1; }

src/trx-client/trx-frontend/trx-frontend-http/src/api.rs

@@ -299,28 +299,33 @@ pub async fn spectrum(
     context: web::Data<Arc<FrontendRuntimeContext>>,
 ) -> Result<HttpResponse, Error> {
     let context_updates = context.get_ref().clone();
-    let mut last_json: Option<String> = None;
+    let mut last_revision: Option<u64> = None;
     let updates =
         IntervalStream::new(time::interval(Duration::from_millis(200))).filter_map(move |_| {
             let context = context_updates.clone();
             std::future::ready({
-                let next_json = context
+                let next = context
                     .spectrum
                     .lock()
                     .ok()
-                    .and_then(|g| g.as_ref().and_then(|s| serde_json::to_string(s).ok()));
+                    .map(|g| g.snapshot());
 
-                let payload = match (last_json.as_ref(), next_json) {
-                    (Some(prev), Some(next)) if prev == &next => None,
-                    (_, Some(next)) => {
-                        last_json = Some(next.clone());
-                        Some(next)
+                let payload = match next {
+                    Some((revision, frame)) if last_revision == Some(revision) => None,
+                    Some((revision, Some(frame))) => {
+                        last_revision = Some(revision);
+                        serde_json::to_string(&frame).ok()
                     }
-                    (Some(_), None) => {
-                        last_json = None;
+                    Some((revision, None)) => {
+                        last_revision = Some(revision);
                         Some("null".to_string())
                     }
-                    (None, None) => None,
+                    None if last_revision.is_some() => {
+                        // Lock poisoning is transient; retry instead of breaking stream semantics.
+                        last_revision = None;
+                        Some("null".to_string())
+                    }
+                    None => None,
                 };
 
                 payload.map(|json| Ok::<Bytes, Error>(Bytes::from(format!("data: {json}\n\n"))))