Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Style/Alignment.php
public function setHorizontal($pValue)
    {
        if ($pValue == '') {
            $pValue = self::HORIZONTAL_GENERAL;
        }

        if ($this->isSupervisor) {
            $styleArray = $this->getStyleArray(['horizontal' => $pValue]);
            $this->getActiveSheet()->getStyle($this->getSelectedCells())->applyFromArray($styleArray);
        } else {
            $this->horizontal = $pValue;
        }

        return $this;
    }
public function setHorizontal($pValue)
    {
        if ($pValue == '') {
            $pValue = self::HORIZONTAL_GENERAL;
        }

        if ($this->isSupervisor) {
            $styleArray = $this->getStyleArray(['horizontal' => $pValue]);
            $this->getActiveSheet()->getStyle($this->getSelectedCells())->applyFromArray($styleArray);
        } else {
            $this->horizontal = $pValue;
        }

        return $this;
    }
Set Horizontal.

@param string $pValue see self::HORIZONTAL_*

@return Alignment