private function getUrlSparkline($customParameters = array())
    {
        $customParameters['viewDataTable'] = 'sparkline';

        $params = $this->getGraphParamsModified($customParameters);

        // convert array values to comma separated
        foreach ($params as &$value) {
            if (is_array($value)) {
                $value = rawurlencode(implode(',', $value));
            }
        }
        $url = Url::getCurrentQueryStringWithParametersModified($params);
        return $url;
    }