FluidTYPO3\Flux\Backend\Preview::renderPreview PHP Method

    public function renderPreview(&$headerContent, &$itemContent, array &$row, &$drawItem)
    {
        // every provider for tt_content will be asked to get a preview
        $fieldName = NULL;
        if ('shortcut' === $row['CType'] && FALSE === strpos($row['records'], ',')) {
            $itemContent = $this->createShortcutIcon($row) . $itemContent;
        } else {
            $itemContent = '<a name="c' . $row['uid'] . '"></a>' . $itemContent;
        }
        $providers = $this->configurationService->resolveConfigurationProviders('tt_content', $fieldName, $row);
        foreach ($providers as $provider) {
            /** @var ProviderInterface $provider */
            list($previewHeader, $previewContent, $continueDrawing) = $provider->getPreview($row);
            if (FALSE === empty($previewHeader)) {
                $headerContent = $previewHeader . (FALSE === empty($headerContent) ? ': ' . $headerContent : '');
                $drawItem = FALSE;
            }
            if (FALSE === empty($previewContent)) {
                $itemContent .= $previewContent;
                $drawItem = FALSE;
            }
            if (FALSE === $continueDrawing) {
                break;
            }
        }
        $this->attachAssets();
        return NULL;
    }