public function setDefaultFont($default = null)
    {
        $old = $this->_defaultFont;
        $this->_defaultFont = $default;
        if ($default) $this->value['font-family'] = $default;
        return $old;
    }
public function setDefaultFont($default = null)
    {
        $old = $this->_defaultFont;
        $this->_defaultFont = $default;
        if ($default) $this->value['font-family'] = $default;
        return $old;
    }
public function setDefaultFont ( $ default = null ) { $ old = $ this -> _defaultFont ; $ this -> _defaultFont = $ default ; if ( $ default ) $ this -> value [ 'font-family' ] = $ default ; return $ old ; }
define the Default Font to use, if the font does not exist, or if no font asked

@param  string  default font-family. If null : Arial for no font asked, and error fot ont does not exist
@return string  old default font-family
@access public
define the Default Font to use if the font does not exist or if no font asked