/* get spanx as percentage */
_gspnxp(w)
{
        local xl, xr, sxl, sxr, pct;

        if (argc < 1)
        {
                sxr = getspanx(1);
                sxl = getspanx(0);
                xr = getxr;
                xl = getxl;
        }
        else
        {
                sxr = getspanx(w, 1);
                sxl = getspanx(w, 0);
                xr = getxr(w);
                xl = getxl(w);
        }

        if (sxr == 0.0 && sxl == 0.0) pct = 1.0;
        else
        {
                pct = (sxr - sxl) / (xr - xl);
        }
        if (pct > 1 || pct < 0) pct = 1;
        return(castint(100*pct + 0.5));
}