실시간 차트 멀티모드 수정

frontend/src/utils/ChartManager.ts

@@ -363,19 +363,43 @@ export class ChartManager {
 
     this._reapplyAllPatternMarkers();
 
-    // 이전 timeScale visible range를 완전히 리셋
+    // 종목 전환·초기 로드 — bar 수가 적을 때 음수 logical from 은 캔들이 우측으로 몰림
+    this._applyDefaultVisibleRange(200, 0);
+  }
+
+  /**
+   * 표시용 visible range 설정.
+   * bar < displayCount 이면 fitContent (음수 logical index 사용 금지).
+   */
+  private _applyDefaultVisibleRange(displayCount: number, extendFutureBars = 0): void {
+    const bars = this.rawBars;
+    if (!bars || bars.length < 2) return;
+
     const ts = this.chart.timeScale();
-    if (bars.length >= 2) {
-      if (bars.length < 20) {
-        ts.setVisibleLogicalRange({ from: bars.length - 200, to: bars.length + 5 });
-      } else {
+
+    if (bars.length <= displayCount) {
+      if (extendFutureBars > 0) {
+        let to: number = bars[bars.length - 1].time as number;
+        to += extendFutureBars * this._barIntervalSecs();
         ts.setVisibleRange({
           from: bars[0].time as Time,
-          to:   bars[bars.length - 1].time as Time,
+          to:   to as Time,
         });
+      } else {
         ts.fitContent();
       }
+      return;
     }
+
+    const startIdx = Math.max(0, bars.length - displayCount);
+    let to: number = bars[bars.length - 1].time as number;
+    if (extendFutureBars > 0) {
+      to += extendFutureBars * this._barIntervalSecs();
+    }
+    ts.setVisibleRange({
+      from: bars[startIdx].time as Time,
+      to:   to as Time,
+    });
   }
 
   private _createMainSeries(chartType: ChartType, t: ThemeTokens): ISeriesApi<SeriesType> {
@@ -2397,30 +2421,7 @@ export class ChartManager {
    * @param extendFutureBars 마지막 바 이후 추가로 보여줄 바 수 (기본 0)
    */
   setInitialVisibleRange(displayCount: number, extendFutureBars = 0): void {
-    const bars = this.rawBars;
-    if (!bars || bars.length === 0) return;
-
-    const ts = this.chart.timeScale();
-
-    if (bars.length <= displayCount && extendFutureBars === 0) {
-      if (bars.length < 20) {
-        ts.setVisibleLogicalRange({ from: bars.length - displayCount, to: bars.length + 5 });
-      } else {
-        ts.fitContent();
-      }
-      return;
-    }
-
-    const startIdx   = Math.max(0, bars.length - displayCount);
-    const from       = bars[startIdx].time as number;
-    let   to: number = bars[bars.length - 1].time as number;
-
-    if (extendFutureBars > 0) {
-      const interval = this._barIntervalSecs();
-      to = to + extendFutureBars * interval;
-    }
-
-    ts.setVisibleRange({ from: from as Time, to: to as Time });
+    this._applyDefaultVisibleRange(displayCount, extendFutureBars);
   }
 
   /** 일목균형표가 활성화되어 있는지 여부 */