protected List<Area> layoutISDInstance(Element e, LayoutState ls) {
   List<Area> areas = new java.util.ArrayList<Area>();
   try {
     double begin = Double.parseDouble(e.getAttribute("begin"));
     double end = Double.parseDouble(e.getAttribute("end"));
     Extent cellResolution =
         parseCellResolution(Documents.getAttribute(e, ttpCellResolutionAttrName, null));
     if (cellResolution == null) cellResolution = defaults.getCellResolution();
     ls.pushCanvas(e, begin, end, cellResolution);
     Extent extent = ls.getExternalExtent();
     double w = extent.getWidth();
     double h = extent.getHeight();
     boolean clip = ls.getExternalOverflow().clips();
     ls.pushViewport(e, w, h, clip);
     WritingMode wm = ls.getExternalWritingMode();
     TransformMatrix ctm = ls.getExternalTransform();
     ls.pushReference(e, 0, 0, w, h, wm, ctm);
     for (Element c : getChildElements(e)) {
       if (isElement(c, isdRegionElementName)) layoutRegion(c, ls);
       else if (isElement(c, isdComputedStyleSetElementName)) ls.saveStyles(c);
     }
     ls.pop();
     ls.pop();
     areas.add(ls.pop());
   } catch (NumberFormatException x) {
   }
   return areas;
 }
 protected static boolean isElement(Element e, QName qn) {
   return Documents.isElement(e, qn);
 }
 protected static List<Element> getChildElements(Element e) {
   return Documents.getChildElements(e);
 }