SnapTeX is a lightweight, ultra-fast LaTeX previewer for Visual Studio Code. Unlike traditional previewers, it does not require a full TeX distribution (like TeXLive or MiKTeX) to function.
It combines a custom high‑speed regex parser with Markdown-It and KaTeX to deliver near‑instant structural and mathematical previews. The result is a lightweight engine featuring a text‑block splitter, diff checker, and fully local rendering.
SnapTeX also runs in the browser via vscode.dev or GitHub codespace, so you can use it from any device with an internet connection, making this ideal for tablets and other machines that don’t have a native VS Code install. Note that the SnapTeX preview itself is rendered entirely locally in the page, but you’ll need the ability to open the VS Code web site/Github codespace.
It is a demo based on the early conceptual proof, mume.parser for MPE.
Demo
| Bi-directional sync |
Auto scroll sync |
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| References, figures, tables, algorithms, and tooltips |
Fast local updates |
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What's New in 0.6.0
- Default virtual mode for long documents: SnapTeX now keeps lightweight block shells in the webview and mounts real block DOM only near the viewport, greatly reducing DOM, PDF, image, and TikZ memory pressure.
- On-demand block HTML loading: Large previews can send block metadata first and request HTML only when a block needs to render.
- Smoother synchronization: Editor-to-preview sync, preview-to-editor sync, reference jumps, and hover tooltips now work through virtualized blocks.
- Faster, sturdier TikZ previews: TikZJax is lazy-loaded, worker resources are bootstrapped safely inside VS Code webviews, unused libraries are pruned per picture, stale SVGs remain visible while rerendering, and compile failures are surfaced cleanly.
- Better PDF handling: PDF figures use webview-safe URI loading, viewport-near rendering, a blob module worker, and far-offscreen canvas release.
- Stronger rendering safety and maintainability: Generated HTML is protected explicitly, user-controlled HTML is escaped more consistently, and the renderer/webview code is split into clearer modules with broader tests.
SnapTeX Preview Quick Start Guide
Installation
Grab it from the Visual Studio Code Marketplace by searching for SnapTeX or visiting the extension page.
How to Open the Preview
- Via Command Palette: Open your
*.tex file, press Ctrl+Shift+p, search for "SnapTeX Preview: Start", and press Enter.
- Via Shortcut: Simply press the keyboard shortcut
Ctrl+k v to launch the preview immediately.
- Initial Load: The first time you open the preview, it may take several seconds to complete the full rendering.
- Real-Time Updates: Once initialized, updates are processed locally, providing instant, real-time rendering as you type.
- Virtual Mode:
snaptex.virtualMode is enabled by default. It keeps long previews responsive by mounting only viewport-near blocks while preserving scrollbar length with measured shell heights.
- Lazy Heavy Resources: PDF canvases and TikZ output are created only when their blocks are mounted near the viewport and can be released when far offscreen.
Features
Instant Math Rendering: Real-time rendering of inline math $ ... $ and complex display math environments (e.g., equation, align, gather) using KaTeX.
Intelligent Math Protection: Uses a proprietary protection layer to ensure LaTeX math syntax is not corrupted by the Markdown parser.
Structural Previews: Renders hierarchical headers (\section to \subsubsection), abstracts, and keywords with academic styling.
Low-Memory Long Document Preview: Uses block hashes, shell virtualization, on-demand HTML, and viewport-near resource mounting to keep large documents usable.
Smart Bi-Directional Sync:
- Forward Sync: Jump from the editor cursor to the exact location in the preview with
ctrl+alt+n.
- Reverse Sync: Double-click any element in the preview to jump to the corresponding line in the LaTeX source.
- Virtualized References and Tooltips: Reference jumps and hover tooltips mount offscreen target blocks on demand, including nearby context blocks.
Auto Scrolling:
snaptex.autoScrollSync: Enable cursor and scroll synchronization between editor and preview.snaptex.autoScrollDelay: Debounce/Throttle delay (in ms) for scroll synchronization events.
Macro Support: Real-time expansion of \newcommand, \def and \DeclareMathOperator definitions.
Advanced Environments Support (Basic demo works):
- Algorithms: Renders pseudocode with keyword bolding (If, For, Return) and preserved indentation.
- Tables: Converts standard
tabular and common tabularx environments into clean HTML tables with support for internal math rendering.
- Figures: Resolves local image paths and renders PDF/image figures through webview-safe resource URIs.
- TikZ: Supported by TikZJax with lazy runtime loading, per-picture library pruning, and smoother rerendering after edits.
Label Reference: Supports equation/section/figure/table/algorithm/theorem... labeling and cross-reference commands ref,label,eqref.
Citations: Support dynamic BibTeX bibliography rendering, with a simple style and rendering rule for snap preview.
User-defined Rules: under dev.
Requirements
SnapTeX is designed to be "zero-config." It works out of the box with no external dependencies.
- Simply open a
.tex file and run the preview command.
- For math rendering, it uses an internal bundled version of KaTeX.
Known Issues and update plan
- Planned: broaden package support by adopting techniques similar to those used for TikzJax, enabling more familiar LaTeX packages in the preview.
Dependence
Enjoy writing LaTeX with SnapTeX!
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