protected function renderRowCells(PHPRtfLite_Table_Row $row)
    {
        $rowIndex = $row->getRowIndex();

        foreach ($this->getColumns() as $columnIndex => $column) {
            $cell = $this->getCell($rowIndex, $columnIndex + 1);
            if (!$cell->isHorizontalMerged()) {
                $cell->render();
            }
        }
    }