int[] getRowGaps(ContainerWrapper parent,
            BoundSize defGap, int refSize, boolean before) {
        BoundSize gap = before ? gapBefore : gapAfter;
        if (gap == null || gap.isUnset()) {
            gap = defGap;
        }
        if (gap == null || gap.isUnset()) {
            return null;
        }
        int[] ret = new int[3];
        for (int i = LayoutUtil.MIN; i <= LayoutUtil.MAX;
                i++) {
            UnitValue uv = gap.getSize(i);
            ret[i] =uv != null ? uv.getPixels(refSize, parent, null)
                    : LayoutUtil.NOT_SET;
        }
        return ret;
    }