dompdf is an HTML to PDF converter included in Tiki
Since Tiki18, mPDF is the recommended PDF generator
Also: if you want to generate PDFs from a web-based slideshow, you should really upgrade to Tiki19 (the slideshow has been massively improved). dompdf has been completely removed.

dompdf

dompdf is an HTML to PDF converter
https://github.com/dompdf/dompdf

dompdf support was added in Tiki9 to export the Slideshow to PDF.

Collection of References on doc.tiki.org

• Print general info about printing
• PDF general overview about PDF creation in Tiki
• mPDF create PDFs from Tiki content (advanced library that works even on shared hosting). Recommended for Tiki18+
• PluginPDF alter default settings of mPDF per wiki page
• PluginPDFPageBreak add a page break for PDFs created with mPDF
• PluginMediaPlayer display PDF file from file gallery
• PDF.js viewer PDF.js from Mozilla
• ViewerJS: a script to view PDFs and ODFs, which bundles WebODF
• PluginArchiveBuilder Generate a zip file, including PDFs from wiki pages
• WeasyPrint A PDF generation option in Python
• wkhtmltopdf create PDFs from Tiki content (needs root installation)
• dompdf once used for PDF print of slideshows