Function zoomToDefault

frontend/src/components/ImageLightbox.tsx:89–96

()

  const zoomToFit = () => setZoom(1);

  const zoomToDefault = () => {
    if (!naturalSize || fitScale <= 0 || !viewportRef.current) return;
    const viewportWidth = viewportRef.current.clientWidth - 64;
    const targetScale = DEFAULT_DISPLAY_WIDTH / naturalSize.width;
    const maxWidthScale = viewportWidth / naturalSize.width;
    const clampedScale = Math.min(targetScale, maxWidthScale);
    setZoom(Math.max(MIN_ZOOM, Math.min(MAX_ZOOM, clampedScale / fitScale)));
  };

  const handleMouseDown = useCallback((e: React.MouseEvent) => {
    if (!viewportRef.current || e.button !== 0) return;