XLSXWriter::xlsCell PHP Method

    public static function xlsCell($row_number, $column_number)
    {
        $n = $column_number;
        for ($r = ""; $n >= 0; $n = intval($n / 26) - 1) {
            $r = chr($n % 26 + 0x41) . $r;
        }
        return $r . ($row_number + 1);
    }

 protected function initializeSheet($sheet_name)
 {
     //if already initialized
     if ($this->current_sheet == $sheet_name || isset($this->sheets[$sheet_name])) {
         return;
     }
     $sheet_filename = $this->tempFilename();
     $sheet_xmlname = 'sheet' . (count($this->sheets) + 1) . ".xml";
     $this->sheets[$sheet_name] = (object) array('filename' => $sheet_filename, 'sheetname' => $sheet_name, 'xmlname' => $sheet_xmlname, 'row_count' => 0, 'file_writer' => new XLSXWriter_BuffererWriter($sheet_filename), 'columns' => array(), 'merge_cells' => array(), 'max_cell_tag_start' => 0, 'max_cell_tag_end' => 0, 'finalized' => false);
     $sheet =& $this->sheets[$sheet_name];
     $tabselected = count($this->sheets) == 1 ? 'true' : 'false';
     //only first sheet is selected
     $max_cell = XLSXWriter::xlsCell(self::EXCEL_2007_MAX_ROW, self::EXCEL_2007_MAX_COL);
     //XFE1048577
     $sheet->file_writer->write('<?xml version="1.0" encoding="UTF-8" standalone="yes"?>' . "\n");
     $sheet->file_writer->write('<worksheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships">');
     $sheet->file_writer->write('<sheetPr filterMode="false">');
     $sheet->file_writer->write('<pageSetUpPr fitToPage="false"/>');
     $sheet->file_writer->write('</sheetPr>');
     $sheet->max_cell_tag_start = $sheet->file_writer->ftell();
     $sheet->file_writer->write('<dimension ref="A1:' . $max_cell . '"/>');
     $sheet->max_cell_tag_end = $sheet->file_writer->ftell();
     $sheet->file_writer->write('<sheetViews>');
     $sheet->file_writer->write('<sheetView colorId="64" defaultGridColor="true" rightToLeft="false" showFormulas="false" showGridLines="true" showOutlineSymbols="true" showRowColHeaders="true" showZeros="true" tabSelected="' . $tabselected . '" topLeftCell="A1" view="normal" windowProtection="false" workbookViewId="0" zoomScale="100" zoomScaleNormal="100" zoomScalePageLayoutView="100">');
     $sheet->file_writer->write('<selection activeCell="A1" activeCellId="0" pane="topLeft" sqref="A1"/>');
     $sheet->file_writer->write('</sheetView>');
     $sheet->file_writer->write('</sheetViews>');
     $sheet->file_writer->write('<cols>');
     $sheet->file_writer->write('<col collapsed="false" hidden="false" max="1025" min="1" style="0" width="11.5"/>');
     $sheet->file_writer->write('</cols>');
     $sheet->file_writer->write('<sheetData>');
 }