Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Writer/Xls/Worksheet.php
public function setOutline($visible = true, $symbols_below = true, $symbols_right = true, $auto_style = false)
    {
        $this->outlineOn = $visible;
        $this->outlineBelow = $symbols_below;
        $this->outlineRight = $symbols_right;
        $this->outlineStyle = $auto_style;

        // Ensure this is a boolean vale for Window2
        if ($this->outlineOn) {
            $this->outlineOn = 1;
        }
    }
public function setOutline($visible = true, $symbols_below = true, $symbols_right = true, $auto_style = false)
    {
        $this->outlineOn = $visible;
        $this->outlineBelow = $symbols_below;
        $this->outlineRight = $symbols_right;
        $this->outlineStyle = $auto_style;

        // Ensure this is a boolean vale for Window2
        if ($this->outlineOn) {
            $this->outlineOn = 1;
        }
    }
This method sets the properties for outlining and grouping. The defaults
correspond to Excel's defaults.

@param bool $visible
@param bool $symbols_below
@param bool $symbols_right
@param bool $auto_style