feat(mq_editor): add iso-contour tracking mode for bass/diffuse regions

trackIsoContour() follows constant energy level through STFT frames
instead of peaks. Useful for broad bass areas where peak detector finds
nothing. Preview in cyan, auto-detects spread on commit (naturally large).

Toggle: ≋ Contour button or C key. Mutually exclusive with ⊕ Explore.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 33 insertions, 18 deletions

diff --git a/tools/mq_editor/app.js b/tools/mq_editor/app.js
index 62c1bb7..59849da 100644
--- a/tools/mq_editor/app.js
+++ b/tools/mq_editor/app.js
@@ -45,13 +45,13 @@ let audioContext = null;
 let currentSource = null;
 let extractedPartials = null;
 let stftCache = null;
-let exploreModeActive = false;
+let exploreMode = false; // false | 'peak' | 'contour'
 
-function setExploreMode(enabled) {
-  exploreModeActive = enabled;
-  const btn = document.getElementById('exploreBtn');
-  btn.classList.toggle('explore-active', enabled);
-  if (viewer) viewer.setExploreMode(enabled);
+function setExploreMode(mode) { // false | 'peak' | 'contour'
+  exploreMode = mode;
+  document.getElementById('exploreBtn').classList.toggle('explore-active', mode === 'peak');
+  document.getElementById('contourBtn').classList.toggle('contour-active', mode === 'contour');
+  if (viewer) viewer.setExploreMode(mode);
 }
 
 // Undo/redo
@@ -171,29 +171,40 @@ function loadAudioBuffer(buffer, label) {
     viewer = new SpectrogramViewer(canvas, audioBuffer, stftCache);
     viewer.setFrames(peakFrames);
     document.getElementById('exploreBtn').disabled = false;
+    document.getElementById('contourBtn').disabled = false;
     editor.setViewer(viewer);
     viewer.onPartialSelect = (i) => editor.onPartialSelect(i);
     viewer.onRender        = ()  => editor.onRender();
     viewer.onBeforeChange  = pushUndo;
     viewer.onExploreMove = (time, freq) => {
-      if (!viewer.frames || viewer.frames.length === 0) return;
-      const params = {
-        hopSize: Math.max(64, parseInt(hopSize.value) || 64),
-        sampleRate: audioBuffer.sampleRate,
-        deathAge: parseInt(deathAgeEl.value),
-        phaseErrorWeight: parseFloat(phaseErrorWeightEl.value),
-      };
-      viewer.setPreviewPartial(trackFromSeed(viewer.frames, time, freq, params));
+      let partial = null;
+      if (exploreMode === 'peak') {
+        if (!viewer.frames || viewer.frames.length === 0) return;
+        partial = trackFromSeed(viewer.frames, time, freq, {
+          hopSize: Math.max(64, parseInt(hopSize.value) || 64),
+          sampleRate: audioBuffer.sampleRate,
+          deathAge: parseInt(deathAgeEl.value),
+          phaseErrorWeight: parseFloat(phaseErrorWeightEl.value),
+        });
+      } else if (exploreMode === 'contour') {
+        partial = trackIsoContour(stftCache, time, freq, {
+          sampleRate: audioBuffer.sampleRate,
+          deathAge: parseInt(deathAgeEl.value),
+        });
+      }
+      viewer.setPreviewPartial(partial);
     };
     viewer.onExploreCommit = (partial) => {
       if (!extractedPartials) extractedPartials = [];
       pushUndo();
+      const {spread_above, spread_below} = autodetectSpread(partial, stftCache, fftSize, audioBuffer.sampleRate);
+      partial.replicas = { ...partial.replicas, spread_above, spread_below };
       extractedPartials.unshift(partial);
       editor.setPartials(extractedPartials);
       viewer.setPartials(extractedPartials);
       viewer.setKeepCount(getKeepCount());
       viewer.selectPartial(0);
-      setStatus(`Explore: added partial (${extractedPartials.length} total)`, 'info');
+      setStatus(`${exploreMode}: added partial (${extractedPartials.length} total)`, 'info');
     };
     if (label.startsWith('Test WAV')) validateTestWAVPeaks(stftCache);
   }, 10);
@@ -348,7 +359,8 @@ function clearAllPartials() {
 
 document.getElementById('newPartialBtn').addEventListener('click', createNewPartial);
 document.getElementById('clearAllBtn').addEventListener('click', clearAllPartials);
-document.getElementById('exploreBtn').addEventListener('click', () => setExploreMode(!exploreModeActive));
+document.getElementById('exploreBtn').addEventListener('click', () => setExploreMode(exploreMode === 'peak' ? false : 'peak'));
+document.getElementById('contourBtn').addEventListener('click', () => setExploreMode(exploreMode === 'contour' ? false : 'contour'));
 document.getElementById('undoBtn').addEventListener('click', undo);
 document.getElementById('redoBtn').addEventListener('click', redo);
 
@@ -526,9 +538,12 @@ document.addEventListener('keydown', (e) => {
     if (!extractBtn.disabled) extractBtn.click();
   } else if (e.code === 'KeyX' && !e.ctrlKey && !e.metaKey) {
     e.preventDefault();
-    if (!document.getElementById('exploreBtn').disabled) setExploreMode(!exploreModeActive);
+    if (!document.getElementById('exploreBtn').disabled) setExploreMode(exploreMode === 'peak' ? false : 'peak');
+  } else if (e.code === 'KeyC' && !e.ctrlKey && !e.metaKey) {
+    e.preventDefault();
+    if (!document.getElementById('contourBtn').disabled) setExploreMode(exploreMode === 'contour' ? false : 'contour');
   } else if (e.code === 'Escape') {
-    if (exploreModeActive) { setExploreMode(false); return; }
+    if (exploreMode) { setExploreMode(false); return; }
     if (viewer) viewer.selectPartial(-1);
   }
 });