Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Writer/Xlsx/StringTable.php
public function writeRichTextForCharts(XMLWriter $objWriter, $pRichText = null, $prefix = null)
    {
        if (!$pRichText instanceof RichText) {
            $textRun = $pRichText;
            $pRichText = new RichText();
            $pRichText->createTextRun($textRun);
        }

        if ($prefix !== null) {
            $prefix .= ':';
        }

        // Loop through rich text elements
        $elements = $pRichText->getRichTextElements();
        foreach ($elements as $element) {
            // r
            $objWriter->startElement($prefix . 'r');

            // rPr
            $objWriter->startElement($prefix . 'rPr');

            // Bold
            $objWriter->writeAttribute('b', ($element->getFont()->getBold() ? 1 : 0));
            // Italic
            $objWriter->writeAttribute('i', ($element->getFont()->getItalic() ? 1 : 0));
            // Underline
            $underlineType = $element->getFont()->getUnderline();
            switch ($underlineType) {
                case 'single':
                    $underlineType = 'sng';

                    break;
                case 'double':
                    $underlineType = 'dbl';

                    break;
            }
            $objWriter->writeAttribute('u', $underlineType);
            // Strikethrough
            $objWriter->writeAttribute('strike', ($element->getFont()->getStrikethrough() ? 'sngStrike' : 'noStrike'));

            // rFont
            $objWriter->startElement($prefix . 'latin');
            $objWriter->writeAttribute('typeface', $element->getFont()->getName());
            $objWriter->endElement();

            $objWriter->endElement();

            // t
            $objWriter->startElement($prefix . 't');
            $objWriter->writeRawData(StringHelper::controlCharacterPHP2OOXML($element->getText()));
            $objWriter->endElement();

            $objWriter->endElement();
        }
    }
public function writeRichTextForCharts(XMLWriter $objWriter, $pRichText = null, $prefix = null)
    {
        if (!$pRichText instanceof RichText) {
            $textRun = $pRichText;
            $pRichText = new RichText();
            $pRichText->createTextRun($textRun);
        }

        if ($prefix !== null) {
            $prefix .= ':';
        }

        // Loop through rich text elements
        $elements = $pRichText->getRichTextElements();
        foreach ($elements as $element) {
            // r
            $objWriter->startElement($prefix . 'r');

            // rPr
            $objWriter->startElement($prefix . 'rPr');

            // Bold
            $objWriter->writeAttribute('b', ($element->getFont()->getBold() ? 1 : 0));
            // Italic
            $objWriter->writeAttribute('i', ($element->getFont()->getItalic() ? 1 : 0));
            // Underline
            $underlineType = $element->getFont()->getUnderline();
            switch ($underlineType) {
                case 'single':
                    $underlineType = 'sng';

                    break;
                case 'double':
                    $underlineType = 'dbl';

                    break;
            }
            $objWriter->writeAttribute('u', $underlineType);
            // Strikethrough
            $objWriter->writeAttribute('strike', ($element->getFont()->getStrikethrough() ? 'sngStrike' : 'noStrike'));

            // rFont
            $objWriter->startElement($prefix . 'latin');
            $objWriter->writeAttribute('typeface', $element->getFont()->getName());
            $objWriter->endElement();

            $objWriter->endElement();

            // t
            $objWriter->startElement($prefix . 't');
            $objWriter->writeRawData(StringHelper::controlCharacterPHP2OOXML($element->getText()));
            $objWriter->endElement();

            $objWriter->endElement();
        }
    }
Write Rich Text.

@param XMLWriter $objWriter XML Writer
@param RichText|string $pRichText text string or Rich text
@param string $prefix Optional Namespace prefix