realtime-tex Henry Yang

rtex is a typesetting engine for editors. When you type, it re-typesets only the paragraph being edited through a LuaLaTeX process that has already loaded your preamble, and hands the editor the new lines to draw. A full background compile takes care of what really is global: page breaks, floats, the table of contents, references and bibliographies. The result is exactly what LuaLaTeX produces — the same line breaks and the same glyphs at the same positions to 1/65536 pt — because rtex uses an unmodified LuaTeX from TeX Live and exported PDFs are identical to a normal LuaLaTeX build. Time from keystroke to updated paragraph is about a millisecond and does not depend on document length. The archive contains the `rtex` command, the C library and header, and rtex TeX support files.