XLSXWriter::markMergedCell PHP Method

    public function markMergedCell($sheet_name, $start_cell_row, $start_cell_column, $end_cell_row, $end_cell_column)
    {
        if (empty($sheet_name) || $this->sheets[$sheet_name]->finalized) {
            return;
        }
        self::initializeSheet($sheet_name);
        $sheet =& $this->sheets[$sheet_name];
        $startCell = self::xlsCell($start_cell_row, $start_cell_column);
        $endCell = self::xlsCell($end_cell_row, $end_cell_column);
        $sheet->merge_cells[] = $startCell . ":" . $endCell;
    }

<?php

include_once "xlsxwriter.class.php";
$header = array("string", "string", "string", "string", "string");
$row1 = array("Merge Cells Example");
$row2 = array(100, 200, 300, 400, 500);
$row3 = array(110, 210, 310, 410, 510);
$sheet_name = 'Sheet1';
$writer = new XLSXWriter();
$writer->writeSheetHeader($sheet_name, $header, $suppress_header_row = true);
$writer->writeSheetRow($sheet_name, $row1);
$writer->writeSheetRow($sheet_name, $row2);
$writer->writeSheetRow($sheet_name, $row3);
$writer->markMergedCell($sheet_name, $start_row = 0, $start_col = 0, $end_row = 0, $end_col = 4);
$writer->writeToFile('example.xlsx');