From e159b76e0d615e015a0863dd3c380216a952512b Mon Sep 17 00:00:00 2001
From: Armin <armin@cherry>
Date: Mon, 6 Jul 2026 18:09:41 +0200
Subject: [PATCH] Add peak hold decay rate selector
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Introduce a new dropdown to control how fast the peak-hold line
decays on the live spectrum. Options:
  Off   — peaks never decay (manual reset only)
  Slow  — slow fade (0.005/frame)
  Medium — moderate fade (0.015/frame, matches previous fixed rate)
  Fast   — quick fade (0.03/frame)

Previously the decay rate was hardcoded at 0.015/frame.
---
 index.html | 6 ++++++
 js/app.js  | 4 +++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/index.html b/index.html
index 5f08161..17f4aea 100644
--- a/index.html
+++ b/index.html
@@ -32,6 +32,12 @@
         <button id="resetBtn" class="player-btn" title="Reset Peaks">↺</button>
         <span id="playTime" class="player-time">0:00.0 / 0:00.0</span>
         <select id="windowSelect" class="window-select" title="Spectrum window function"><option value="none">None</option><option value="hanning" selected>Hanning</option><option value="hamming">Hamming</option><option value="blackman">Blackman-Harris</option><option value="bartlett">Bartlett</option><option value="gaussian">Gaussian</option><option value="kaiser">Kaiser</option><option value="flatTop">Flat Top</option></select>
+        <select id="peakHoldDecay" class="window-select" title="Peak hold decay rate">
+          <option value="off">Hold: Off</option>
+          <option value="slow">Hold: Slow</option>
+          <option value="medium" selected>Hold: Medium</option>
+          <option value="fast">Hold: Fast</option>
+        </select>
       </div>
       <div class="chart-container" style="position:relative">
         <canvas id="waveformChart"></canvas>
diff --git a/js/app.js b/js/app.js
index 0943fce..2960e9f 100644
--- a/js/app.js
+++ b/js/app.js
@@ -616,7 +616,9 @@ const App = {
     ctx.stroke();
 
     if (this.holdPeaks) {
-      const decay = 0.015;
+      const decaySel = document.getElementById('peakHoldDecay');
+      const decayMap = { off: 0, slow: 0.005, medium: 0.015, fast: 0.03 };
+      const decay = decaySel ? (decayMap[decaySel.value] ?? 0.015) : 0.015;
       ctx.beginPath();
       let started = false;
       for (let x = 0; x < chartW; x++) {