Realtime TeX Live Preview

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A live LaTeX preview for VS Code that keeps up with your typing. It is built on realtime-tex (rtex), which keeps LuaTeX running and re-typesets only the paragraph you are editing, in about a millisecond. Page breaks, references and bibliographies follow from a full compile in the background.

1. Open a folder with a LaTeX project. Linux, macOS and Windows are supported.
2. Open a .tex file and click the preview icon in the editor title bar, or press Ctrl+Alt+V (Cmd+Alt+V on Mac).
3. Start typing.

On first use, the preview walks you through anything that is missing:

• rtex is not installed. Click Install rtex. It downloads the prebuilt engine of the latest realtime-tex release for your platform (a few MB) and checks its SHA-256. Prefer to build it yourself? Build from Source clones realtime-tex main and builds it with Rust's cargo (a few minutes; on Windows it also needs Git for Windows and the Visual Studio C++ Build Tools that rustup asks for). The realtimeTex.installFrom setting picks which one Install rtex does.
• LuaLaTeX was not found. Choose your TeX Live bin folder, or let the extension install a minimal TeX Live 2026.

Realtime TeX: Check Setup in the command palette checks everything and offers a fix for each problem.

The extension keeps the rtex it installed up to date, the way it was installed: a downloaded rtex updates to the latest release, one built from source pulls realtime-tex main and rebuilds it. It checks once a day and offers Update Now; Realtime TeX: Update rtex Engine updates on demand and restarts the engine. The realtimeTex.updateCheck setting controls this.

The main file is found automatically. The extension looks for, in order:

1. a % !TEX root = main.tex comment;
2. the file with \documentclass;
3. the file that \inputs or \includes the one you are editing.

If it is ambiguous, the preview asks you to choose. The choice is saved in realtimeTex.mainFile.

Body text, inline and display math, \ref/\eqref/\cite (with the numbers from the last full compile), lists, theorems, figures and tables (content), and headings all update with each keystroke. Everything else updates with the next full compile, typically a second or two later:

• preamble changes;
• TikZ;
• moved floats;
• footnote text at the bottom of the page;
• new page breaks.

The pill says when this is happening. See rtex's live editing guide for details.

For the fastest updates, use TFM fonts (the default, lmodern, …) or OpenType fonts loaded with Renderer=Basic. fontspec's default node mode works, but each keystroke takes longer.

The preview draws rtex's display lists itself, so a keystroke repaints a single paragraph without a PDF round trip. It supports:

• OpenType/TrueType fonts, by glyph index;
• Type1 fonts, such as Computer Modern math and lmodern, found through TeX's pdftex.map;
• colors, rules, PNG/JPEG/PDF images and graphicx scaling.

Some pages cannot be drawn this way, for example TikZ drawings or \specials. Those are shown from the background PDF, marked with a small from PDF badge, and edits on them still appear live on top.

All commands are under Realtime TeX: in the command palette:

• Open Live Preview to the Side
• Export PDF
• Recompile Whole Document
• Show Cursor Position in Preview
• Restart Engine
• Stop Engine
• Show Log
• Open Debug Folder
• Check Setup
• Install rtex
• Install rtex (Build from Source)
• Update rtex Engine
• Locate rtex Binary…
• Choose Main File…
• Get Started

npm install
npm run build        # dist/extension.js, dist/webview.js
npm test             # unit tests (node:test)
npm run typecheck
npm run package      # .vsix

Press F5 in VS Code to start an Extension Development Host.

The integration suite drives a real VS Code with the real engine. It needs a built rtex and TeX Live:

RTEX_E2E_SERVER=/path/to/realtime-tex/target/release/rtex \
RTEX_E2E_TEXLIVE_BIN=/path/to/texlive/2026/bin/x86_64-linux \
xvfb-run -a npm run test:e2e

On macOS and Windows, run npm run test:e2e without xvfb-run. The E2E workflow runs the suite on Linux, macOS and Windows against the latest realtime-tex.

Set version in package.json and add a ## <version> section to CHANGELOG.md, then push a matching tag:

git tag v0.0.1 && git push origin v0.0.1

The Release workflow builds the .vsix, checks that the tag matches package.json, and creates the GitHub release with the changelog section as notes and the .vsix (plus its SHA-256) attached. Publishing a release in the GitHub UI, or running the workflow by hand with a tag, attaches the .vsix to an existing release.

MIT