fix: brush draw per-note duration with noteStartBeats tracking

app/static/js/app.jsx

@@ -5120,7 +5120,7 @@ const PianoRollTabEditor = ({ st, zoom, bpm, viewportWidth, onClose, onUpdateNot
         visitedPitches: snapToScaleRef.current ? [snapPitchToScale(pitch, selectedScaleRef.current)] : [pitch],
         initialBeat: start,
         initialPitch: snapToScaleRef.current ? snapPitchToScale(pitch, selectedScaleRef.current) : pitch,
-        lastDrawBeat: start
+        noteStartBeats: [start]
       });
       // Play the note with SoundFont
       if (window.SonicSF) {
@@ -5206,18 +5206,27 @@ const PianoRollTabEditor = ({ st, zoom, bpm, viewportWidth, onClose, onUpdateNot
       return;
     }
     if (draggedNote.mode === 'draw') {
-      const rawDur = beat - draggedNote.startOffsetBeat;
-      const newDur = getSnapBeat(Math.max(0.125, rawDur), snapVal);
       const visited = draggedNote.visitedPitches || [];
       const snappedPitch = snapToScaleRef.current ? snapPitchToScale(pitch, selectedScaleRef.current) : pitch;
       const pitchChanged = !visited.includes(snappedPitch);
+      const noteBeats = draggedNote.noteStartBeats || [];
+      const defaultDur = getSnapDuration(snapVal);
       if (pitchChanged) {
         const brushIds = draggedNote.brushIds || [];
+        if (brushIds.length > 0 && noteBeats.length > 0) {
+          const prevNoteId = brushIds[brushIds.length - 1];
+          const prevNoteBeat = noteBeats[noteBeats.length - 1];
+          const prevDur = Math.max(0.125, beat - prevNoteBeat);
+          setNotes(prev => prev.map(n => {
+            if (n.id !== prevNoteId) return n;
+            return { ...n, duration_beats: prevDur };
+          }));
+        }
         const newNote = {
           id: 'note_' + Date.now() + Math.random().toString(36).substr(2, 8) + '_' + (visited.length + 1),
           pitch: snappedPitch,
           start_beat: beat,
-          duration_beats: getSnapDuration(snapVal),
+          duration_beats: defaultDur,
           velocity: brushVelocityRef.current,
           pan: 0.0
         };
@@ -5225,13 +5234,16 @@ const PianoRollTabEditor = ({ st, zoom, bpm, viewportWidth, onClose, onUpdateNot
         setSelectedNoteIds(prev => [...prev, newNote.id]);
         draggedNote.brushIds = [...brushIds, newNote.id];
         draggedNote.visitedPitches = [...visited, snappedPitch];
+        draggedNote.noteStartBeats = [...noteBeats, beat];
       } else {
         const brushIds = draggedNote.brushIds || [];
         const lastBrushId = brushIds.length > 0 ? brushIds[brushIds.length - 1] : draggedNote.drawNoteId;
+        const lastNoteBeat = noteBeats.length > 0 ? noteBeats[noteBeats.length - 1] : draggedNote.startOffsetBeat;
         if (lastBrushId) {
+          const extDur = Math.max(0.125, beat - lastNoteBeat);
           setNotes(prev => prev.map(n => {
             if (n.id !== lastBrushId) return n;
-            return { ...n, duration_beats: newDur };
+            return { ...n, duration_beats: extDur };
           }));
         }
       }

wiki.md

@@ -200,3 +200,8 @@
 - **Tóm tắt thay đổi:** (1) Brush draw: chỉ tạo note mới khi `pitchChanged` (pitch chưa visited). Nếu cùng pitch, extend `duration_beats` của note cuối cùng trong `brushIds` — không tạo note mới trùng pitch. (2) CC velocity: thêm check `Math.abs(currentVal - val) > 0.001` trước mỗi `setNotes` — skip render khi velocity/pan không thay đổi, loại bỏ flicker cho cả selected + non-selected mode.
 - **Các file ảnh hưởng:** `app/static/js/app.jsx`
 - **Ghi chú/Test (nếu có):** `npm run build` pass. currentVal tính: velocity = note.velocity || 0.8; pan = (note.pan || 0) / 2 + 0.5.
+
+### [2026-07-26 10:49] Task: Fix brush draw per-note duration + noteStartBeats tracking
+- **Tóm tắt thay đổi:** (1) Thêm `noteStartBeats` array trong `draggedNote` — track start beat của từng note. Khi tạo note mới (pitchChanged), fix duration của note trước đó thành `beat - prevNoteBeat`. Khi extend (cùng pitch), chỉ extend note cuối với `beat - lastNoteBeat` (không extend toàn bộ stroke). (2) Khởi tạo `noteStartBeats: [start]` trong setDraggedNote. Fix lỗi note cuối có duration dài bằng toàn bộ brush stroke.
+- **Các file ảnh hưởng:** `app/static/js/app.jsx`
+- **Ghi chú/Test (nếu có):** `npm run build` pass.