public ImageStack expandStack(ImageStack stackOld, int wNew, int hNew, int xOff, int yOff) {
    int nFrames = stackOld.getSize();
    ImageProcessor ipOld = stackOld.getProcessor(1);
    java.awt.Color colorBack = Toolbar.getBackgroundColor();

    ImageStack stackNew = new ImageStack(wNew, hNew, stackOld.getColorModel());
    ImageProcessor ipNew;

    for (int i = 1; i <= nFrames; i++) {
      IJ.showProgress((double) i / nFrames);
      ipNew = ipOld.createProcessor(wNew, hNew);
      if (zeroFill) ipNew.setValue(0.0);
      else ipNew.setColor(colorBack);
      ipNew.fill();
      ipNew.insert(stackOld.getProcessor(i), xOff, yOff);
      stackNew.addSlice(stackOld.getSliceLabel(i), ipNew);
    }
    return stackNew;
  }