feat: merge tempo bar + timebar into beat-based TimelineRuler

Replace old seconds-based ruler (0.00s, 1.00s...) and TempoTrackLane
with unified 48px canvas ruler showing bar:beat grid lines, snap
sub-ticks, and BPM label. WaveformLane grid aligns with ruler
positions — items snap to same beat grid visually.

app/static/js/app.jsx

@@ -1190,6 +1190,115 @@ const WaveformLane = ({
     }
   }));
 };
+const TimelineRuler = ({
+  bpm, zoom, timelineWidth, viewportWidth,
+  onPlayheadSet, snapValue, onRulerMouseDown, scrollLeft, canvasRedrawCount
+}) => {
+  const canvasRef = useRef(null);
+  const RULER_HEIGHT = 48;
+  const drawWidth = Math.min(timelineWidth, viewportWidth);
+  useEffect(() => {
+    const canvas = canvasRef.current;
+    if (!canvas) return;
+    const ctx = canvas.getContext('2d');
+    const dpr = window.devicePixelRatio || 1;
+    const scrollLeftVal = scrollLeft || 0;
+    const height = RULER_HEIGHT;
+    canvas.width = Math.min(Math.round(drawWidth * dpr), 32768);
+    canvas.height = Math.min(Math.round(height * dpr), 32768);
+    ctx.scale(dpr, dpr);
+    ctx.imageSmoothingEnabled = false;
+    canvas.style.width = `${drawWidth}px`;
+    canvas.style.height = `${height}px`;
+    ctx.fillStyle = '#242424';
+    ctx.fillRect(0, 0, drawWidth, height);
+    ctx.strokeStyle = 'rgba(255,255,255,0.08)';
+    ctx.lineWidth = 1;
+    ctx.beginPath();
+    ctx.moveTo(0, height - 0.5);
+    ctx.lineTo(drawWidth, height - 0.5);
+    ctx.stroke();
+    const beatDuration = 60 / bpm;
+    const barDuration = beatDuration * 4;
+    const PADDING_LEFT = barDuration;
+    const tStart = scrollLeftVal / zoom - PADDING_LEFT;
+    const tEnd = (scrollLeftVal + drawWidth) / zoom + PADDING_LEFT;
+    const firstBeat = Math.floor(tStart / beatDuration) * beatDuration;
+    for (let t = firstBeat; t <= tEnd; t += beatDuration) {
+      const beatNum = Math.floor(t / beatDuration) + 1;
+      const isBar = beatNum % 4 === 1;
+      const localX = (t - tStart) * zoom;
+      if (localX < -200 || localX > drawWidth + 200) continue;
+      if (isBar) {
+        ctx.strokeStyle = 'rgba(255, 255, 255, 0.4)';
+        ctx.lineWidth = 1.5;
+        ctx.beginPath();
+        ctx.moveTo(localX, 0);
+        ctx.lineTo(localX, height);
+        ctx.stroke();
+        ctx.fillStyle = 'rgba(255, 255, 255, 0.85)';
+        ctx.font = 'bold 10px Inter, sans-serif';
+        ctx.textAlign = 'left';
+        ctx.fillText(`${Math.ceil(beatNum / 4)}`, localX + 4, 13);
+      } else {
+        ctx.strokeStyle = 'rgba(255, 255, 255, 0.12)';
+        ctx.lineWidth = 0.8;
+        ctx.beginPath();
+        ctx.moveTo(localX, 0);
+        ctx.lineTo(localX, height);
+        ctx.stroke();
+        if (zoom >= 40) {
+          const bar = Math.ceil(beatNum / 4);
+          const beat = ((beatNum - 1) % 4) + 1;
+          ctx.fillStyle = 'rgba(255, 255, 255, 0.4)';
+          ctx.font = '7px Inter, sans-serif';
+          ctx.textAlign = 'center';
+          ctx.fillText(`${bar}.${beat}`, localX, height - 4);
+        }
+      }
+    }
+    if (snapValue && snapValue !== 'free') {
+      ctx.strokeStyle = 'rgba(255, 255, 255, 0.2)';
+      ctx.lineWidth = 0.8;
+      let divisor = 1;
+      if (snapValue === '4') divisor = 4; else if (snapValue === '1') divisor = 1; else if (snapValue === '1/2') divisor = 0.5; else if (snapValue === '1/4') divisor = 0.25; else if (snapValue === '1/8') divisor = 0.125; else if (snapValue === '1/16') divisor = 0.0625; else if (snapValue === '1/32') divisor = 0.03125;
+      const snapInterval = beatDuration * divisor;
+      if (snapInterval * zoom >= 4) {
+        const firstSnap = Math.floor(tStart / snapInterval) * snapInterval;
+        for (let t = firstSnap; t <= tEnd; t += snapInterval) {
+          const onBeat = Math.abs(t / beatDuration - Math.round(t / beatDuration)) < 0.001;
+          if (!onBeat) {
+            const localX = (t - tStart) * zoom;
+            ctx.beginPath();
+            ctx.moveTo(localX, height - 6);
+            ctx.lineTo(localX, height);
+            ctx.stroke();
+          }
+        }
+      }
+    }
+    ctx.fillStyle = 'rgba(255, 255, 255, 0.4)';
+    ctx.font = 'bold 10px Inter, sans-serif';
+    ctx.textAlign = 'right';
+    ctx.fillText(`${bpm} BPM`, drawWidth - 6, 13);
+  }, [bpm, zoom, timelineWidth, viewportWidth, snapValue, scrollLeft, canvasRedrawCount]);
+  return React.createElement(React.Fragment, null, React.createElement("div", {
+    key: "virtual-spacer-ruler",
+    style: { width: `${timelineWidth}px`, height: '1px', pointerEvents: 'none' }
+  }), React.createElement("canvas", {
+    ref: canvasRef,
+    style: { position: 'sticky', left: 0, imageRendering: 'pixelated' },
+    className: "cursor-crosshair",
+    onMouseDown: e => {
+      const rect = canvasRef.current.getBoundingClientRect();
+      const x = e.clientX - rect.left + (scrollLeft || 0);
+      const time = Math.max(0, x / zoom);
+      if (e.shiftKey) { e.preventDefault(); e.stopPropagation(); }
+      if (onRulerMouseDown) onRulerMouseDown(e);
+      else onPlayheadSet(time, e.shiftKey);
+    }
+  }));
+};
 const TempoTrackLane = ({
   bpm,
   zoom,
@@ -14843,42 +14952,7 @@ const App = () => {
         width: `${timelineWidth}px`
       },
       className: "relative flex flex-col min-h-full"
-    }, /*#__PURE__*/React.createElement("div", {
+    }, /*#__PURE__*/React.createElement(TimelineRuler, {
-      className: "sticky top-0 z-45 flex h-10 border-b border-zinc-900 bg-[#242424] shrink-0"
-    }, /*#__PURE__*/React.createElement("div", {
-      ref: rulerRef,
-      className: "flex-1 relative h-full flex items-center select-none cursor-ew-resize overflow-hidden",
-      onMouseDown: handleRulerMouseDown
-    }, Array.from({
-      length: Math.ceil(maxDuration)
-    }).map((_, i) => {
-      const sec = i;
-      const x = sec * zoom;
-      return /*#__PURE__*/React.createElement("div", {
-        key: i,
-        className: "absolute h-full border-l border-zinc-700 pl-1 pt-1 text-[14px] font-mono text-zinc-300 pointer-events-none",
-        style: {
-          left: `${x}px`
-        }
-      }, formatTimeSimple(sec));
-    }))), selectionMode === 'global' && selLeft !== null && selRight !== null && selRight > selLeft && /*#__PURE__*/React.createElement("div", {
-      className: "absolute inset-0 pointer-events-none z-20",
-      style: {
-        left: `${selLeft * zoom}px`,
-        width: `${(selRight - selLeft) * zoom}px`,
-        top: '40px'
-      }
-    }, /*#__PURE__*/React.createElement("div", {
-      className: "w-full h-full bg-amber-500/10",
-      style: {
-        borderLeft: '1px solid #f59e0b',
-        borderRight: '1px solid #f59e0b'
-      }
-    })), /*#__PURE__*/React.createElement("div", {
-      className: "sticky top-10 z-35 flex h-[40px] border-b border-purple-500/30 bg-[#1a1a2e] shrink-0"
-    }, /*#__PURE__*/React.createElement("div", {
-      className: "flex-1 relative h-full overflow-hidden bg-[#1a1a2e]"
-    }, /*#__PURE__*/React.createElement(TempoTrackLane, {
       bpm: parseInt(bpm) || 120,
       zoom: zoom,
       timelineWidth: timelineWidth,
@@ -14888,7 +14962,20 @@ const App = () => {
       onRulerMouseDown: handleRulerMouseDown,
       scrollLeft: scrollLeft,
       canvasRedrawCount: canvasRedrawCount
-    }))), /*#__PURE__*/React.createElement("div", {
+    }), selectionMode === 'global' && selLeft !== null && selRight !== null && selRight > selLeft && /*#__PURE__*/React.createElement("div", {
+      className: "absolute inset-0 pointer-events-none z-20",
+      style: {
+        left: `${selLeft * zoom}px`,
+        width: `${(selRight - selLeft) * zoom}px`,
+        top: '48px'
+      }
+    }, /*#__PURE__*/React.createElement("div", {
+      className: "w-full h-full bg-amber-500/10",
+      style: {
+        borderLeft: '1px solid #f59e0b',
+        borderRight: '1px solid #f59e0b'
+      }
+    })), /*#__PURE__*/React.createElement("div", {
       className: "flex-1 flex flex-col divide-y divide-[#141414] relative bg-[#111111] min-h-full"
     }, activeTracks.map((track, idx) => {
       const isSelected = selectedTrackId === track.id;
@@ -15373,37 +15460,17 @@ const App = () => {
           width: `${subTabTimelineWidth}px`
         },
         className: "relative flex flex-col min-h-full"
-      }, /*#__PURE__*/React.createElement("div", {
+      }, /*#__PURE__*/React.createElement(TimelineRuler, {
-        className: "sticky top-0 z-45 flex h-10 border-b border-zinc-900 bg-[#242424] shrink-0"
-      }, /*#__PURE__*/React.createElement("div", {
-        className: "flex-1 relative h-full flex items-center select-none cursor-ew-resize overflow-hidden",
-        onMouseDown: handleRulerMouseDown
-      }, Array.from({
-        length: Math.ceil(st.buffer ? st.buffer.duration : 0)
-      }).map((_, i) => {
-        const sec = i;
-        const x = sec * zoom;
-        return /*#__PURE__*/React.createElement("div", {
-          key: i,
-          className: "absolute h-full border-l border-zinc-700 pl-1 pt-1 text-[14px] font-mono text-zinc-300 pointer-events-none",
-          style: {
-            left: `${x}px`
-          }
-        }, formatTimeSimple(sec));
-      }))), /*#__PURE__*/React.createElement("div", {
-        className: "sticky top-10 z-35 flex h-[40px] border-b border-purple-500/30 bg-[#1a1a2e] shrink-0"
-      }, /*#__PURE__*/React.createElement("div", {
-        className: "flex-1 relative h-full overflow-hidden bg-[#1a1a2e]"
-      }, /*#__PURE__*/React.createElement(TempoTrackLane, {
         bpm: parseInt(bpm) || 120,
         zoom: zoom,
         timelineWidth: subTabTimelineWidth,
         viewportWidth: viewportWidth,
         onPlayheadSet: setCurrentTime,
         snapValue: snapValue,
+        onRulerMouseDown: handleRulerMouseDown,
         scrollLeft: scrollLeft,
         canvasRedrawCount: canvasRedrawCount
-      }))), /*#__PURE__*/React.createElement("div", {
+      }), /*#__PURE__*/React.createElement("div", {
         className: "flex-1 flex flex-col relative bg-[#111111] min-h-full"
       }, vTrack && /*#__PURE__*/React.createElement("div", {
         style: {

wiki.md

@@ -73,3 +73,9 @@
 - **Tóm tắt thay đổi:** (1) Xoá auto-follow phải (gây jump), chỉ giữ auto-follow trái 60px — scroll phải nhờ `autoScrollTimeline` mượt. (2) Thêm `PADDING_RIGHT` vào `tEnd` ở TempoTrackLane và WaveformLane — bar numbers + grid hiển thị đến sát rìa phải. (3) `if (localX < 0 || localX > drawWidth) continue;` — skip phần tử ngoài canvas. (4) Buffer 12 bars cho `maxDuration`. (5) Thêm `snapTime` vào section/MIDI item drag. (6) Thêm snap option `'4'` (1 bar). (7) Đồng bộ `PADDING_LEFT = barDuration` ở cả 2 lane.
 - **Các file ảnh hưởng:** `app/static/js/app.jsx`
 - **Ghi chú/Test (nếu có):** `npx babel app/static/js/app.jsx` — compile pass.
+
+### [2026-07-25 10:08] Task: Merge tempo bar + timebar, beat-based ruler, snap grid
+- **Tóm tắt thay đổi:** Thay thế seconds-based ruler (0.00s, 1.00s...) + TempoTrackLane bằng TimelineRuler (48px canvas) hiển thị bar:beat grid lines + snap sub-ticks + BPM label. Grid WaveformLane khớp ruler, snapTime() đã dùng grid spacing beat — snap items đúng vị trí ruler.
+- **Các file ảnh hưởng:** `app/static/js/app.jsx`
+- **Ghi chú/Test (nếu có):** `npm run build` — build passes.
+---