How to use

getActiveOverlay

method

in

net.imagej.display.OverlayService

@Override
public Overlay getValue() {
  if (imageDisplayService == null) return null;
  final ImageDisplay display = imageDisplayService.getActiveImageDisplay();
  return display == null ? null : overlayService.getActiveOverlay(display);
}

/**
 * Updates the given {@link ImagePlus}'s Roi and Overlay to match the modern
 * ImageJ {@link Overlay}s being visualized in the given {@link ImageDisplay}.
 */
@Override
public void
  updateLegacyImage(final ImageDisplay display, final ImagePlus imp)
{
  final List<Overlay> overlays = overlayService.getOverlays(display);
  setOverlays(overlays, overlayService.getActiveOverlay(display), imp);
  setLegacyThreshold(display, imp);
}