function get_font_family() {
  
    $DEBUGCSS=DEBUGCSS; //=DEBUGCSS; Allow override of global setting for ad hoc debug

    // Select the appropriate font.  First determine the subtype, then check
    // the specified font-families for a candidate.

    // Resolve font-weight
    $weight = $this->__get("font_weight");
    
    if ( is_numeric($weight) ) {

      if ( $weight < 600 )
        $weight = "normal";
      else
        $weight = "bold";

    } else if ( $weight === "bold" || $weight === "bolder" ) {
      $weight = "bold";

    } else {
      $weight = "normal";

    }

    // Resolve font-style
    $font_style = $this->__get("font_style");

    if ( $weight === "bold" && ($font_style === "italic" || $font_style === "oblique") )
      $subtype = "bold_italic";
    else if ( $weight === "bold" && $font_style !== "italic" && $font_style !== "oblique" )
      $subtype = "bold";
    else if ( $weight !== "bold" && ($font_style === "italic" || $font_style === "oblique") )
      $subtype = "italic";
    else
      $subtype = "normal";
    
    // Resolve the font family
    if ($DEBUGCSS) {
      print "<pre>[get_font_family:";
      print '('.$this->_props["font_family"].'.'.$font_style.'.'.$this->__get("font_weight").'.'.$weight.'.'.$subtype.')';
    }
    $families = explode(",", $this->_props["font_family"]);
    $families = array_map('trim',$families);
    reset($families);

    $font = null;
    while ( current($families) ) {
      list(,$family) = each($families);
      //remove leading and trailing string delimiters, e.g. on font names with spaces;
      //remove leading and trailing whitespace
      $family = trim($family, " \t\n\r\x0B\"'");
      if ($DEBUGCSS) print '('.$family.')';
      $font = Font_Metrics::get_font($family, $subtype);

      if ( $font ) {
        if ($DEBUGCSS)  print '('.$font.")get_font_family]\n</pre>";
        return $font;
      }
    }

    $family = null;
    if ($DEBUGCSS)  print '(default)';
    $font = Font_Metrics::get_font($family, $subtype);

    if ( $font ) {
      if ($DEBUGCSS) print '('.$font.")get_font_family]\n</pre>";
      return $font;
    }
    throw new DOMPDF_Exception("Unable to find a suitable font replacement for: '" . $this->_props["font_family"] ."'");
    
  }