Pure-Ruby PDF generation library: vector drawing (lines, polygons, curves, ellipses); flowing text with inline formatting, builtin/embedded TrueType fonts, UTF-8, RTL, and fallback fonts; PNG/JPG image embedding; a basic grid layout system; encryption and password protection; repeatable headers/footers/page numbers; PDF outlines; and low-level PDF object access for extensions. Explicitly not an HTML-to-PDF generator, though it offers limited inline styling.