Asciidoctor PDF is a native PDF converter for AsciiDoc. It bypasses the requirement to generate an intermediary format such as DocBook, Apache FO, or LaTeX. Instead, you can use this extension to convert your documents directly from AsciiDoc to PDF. Its aim is to take the pain out of creating PDF documents from AsciiDoc.
It uses Prawn
https://prawnpdf.org/api-docs/2.3.0/ a pure Ruby PDF generation library that provides a lot of great functionality while trying to remain simple and reasonably performant.