From fbd881af7b0b3be55fcf951220b3d15aab9e2f88 Mon Sep 17 00:00:00 2001
From: Stan Grams <sjg@haxx.space>
Date: Sun, 1 Mar 2026 18:38:17 +0100
Subject: [PATCH] [fix](trx-frontend): add peak hold off and scale waterfall
 floor

Co-authored-by: OpenAI Codex <codex@openai.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
---
 .../trx-frontend/trx-frontend-http/assets/web/app.js   | 10 +++++++---
 .../trx-frontend-http/assets/web/index.html            |  1 +
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/app.js b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/app.js
index 1b052d5..a59cc3a 100644
--- a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/app.js
+++ b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/app.js
@@ -536,7 +536,7 @@ function setStyle(style) {
 }
 
 if (overviewPeakHoldEl) {
-  if (!Number.isFinite(overviewPeakHoldMs) || overviewPeakHoldMs <= 0) {
+  if (!Number.isFinite(overviewPeakHoldMs) || overviewPeakHoldMs < 0) {
     overviewPeakHoldMs = 2000;
   }
   overviewPeakHoldEl.value = String(overviewPeakHoldMs);
@@ -1020,8 +1020,12 @@ function drawOverviewSignalHistory(ctx, w, h, pal) {
 }
 
 function waterfallColor(db, pal) {
-  const clamped = Math.max(-120, Math.min(-10, Number.isFinite(db) ? db : -120));
-  const t = (clamped + 120) / 110;
+  const minDb = Number.isFinite(spectrumFloor) ? spectrumFloor : -115;
+  const maxDb = minDb + Math.max(20, Number.isFinite(spectrumRange) ? spectrumRange : 90);
+  const safeDb = Number.isFinite(db) ? db : minDb;
+  const clamped = Math.max(minDb, Math.min(maxDb, safeDb));
+  const span = Math.max(1, maxDb - minDb);
+  const t = (clamped - minDb) / span;
   const hue = pal.waterfallHue[0] + t * (pal.waterfallHue[1] - pal.waterfallHue[0]);
   const light = pal.waterfallLight[0] + t * (pal.waterfallLight[1] - pal.waterfallLight[0]);
   const alpha = pal.waterfallAlpha[0] + t * (pal.waterfallAlpha[1] - pal.waterfallAlpha[0]);
diff --git a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/index.html b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/index.html
index 8a1ed63..ed37108 100644
--- a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/index.html
+++ b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/index.html
@@ -92,6 +92,7 @@
           <div id="spectrum-level-row">
             <label class="overview-control" id="spectrum-peak-hold-label">Peak Hold
               <select id="overview-peak-hold" class="status-input">
+                <option value="0">Off</option>
                 <option value="500">0.5 s</option>
                 <option value="1000">1 s</option>
                 <option value="2000" selected>2 s</option>