QuickJax

中文

Zero-dependency MathJax v4 SVG renderer for Python, powered by QuickJS.

QuickJax lets you convert LaTeX math expressions to self-contained SVG strings entirely within your Python process — no Node.js, no subprocess calls, no network requests.

Features

• Pure in-process rendering — MathJax v4 runs inside an embedded QuickJS engine via the quickjs Python library.
• Self-contained SVG output — Every rendered SVG carries its own font glyphs (fontCache: "local"); no external CSS or fonts required.
• 23 TeX extensions included out of the box: AMS, physics, mhchem, mathtools, braket, cancel, color, and more.
• Display & inline modes supported.
• Python 3.8+ compatible.

Installation

pip install quickjax

The only runtime dependency is the quickjs package (a C extension embedding the QuickJS engine, about 2 MB in size). No Node.js installation is needed.

Quick Start

from quickjax import render

# Display mode (default)
svg = render(r"E = mc^2")

# Inline mode
svg = render(r"\alpha + \beta", display=False)

# Write to file
with open("equation.svg", "w") as f:
    f.write(svg)

Using the Renderer Class

For batch rendering, instantiate MathJaxRenderer once to amortize the JS context creation (~0.3 s):

from quickjax import MathJaxRenderer

renderer = MathJaxRenderer()

expressions = [
    r"\int_0^\infty e^{-x}\,dx = 1",
    r"\nabla \times \mathbf{E} = -\frac{\partial \mathbf{B}}{\partial t}",
    r"\mathbb{R}^n",
]

for i, expr in enumerate(expressions):
    svg = renderer.render(expr)
    with open(f"eq_{i}.svg", "w") as f:
        f.write(svg)

API Reference

render(latex, *, display=True) -> str

Module-level convenience function. Creates a shared MathJaxRenderer lazily on first call.

Returns: A self-contained <svg>…</svg> string.

Raises: MathJaxRenderError if the expression cannot be rendered.

class MathJaxRenderer

Supports use as a context manager (with MathJaxRenderer() as r: …).

class MathJaxRenderError

Subclass of Exception. Raised when MathJax cannot parse or render the given LaTeX input.

Supported TeX Extensions

ams · newcommand · boldsymbol · braket · cancel · color · enclose · extpfeil · html · mhchem · noerrors · noundefined · physics · mathtools · amscd · action · bbox · unicode · verb · textmacros · textcomp · cases

Development

Prerequisites

• Python 3.8+
• Node.js (build-time only, for bundling MathJax)
• esbuild (installed automatically via npm)

Building the JS Bundle

bash build_bundle.sh

This runs npm install in renderer_src/ and produces quickjax/js/mathjax_bundle.js (~4.1 MB minified).

Running Tests

pip install pytest
pytest tests/ -v

How It Works

1. Build time — esbuild bundles MathJax v4 (mathjax-full@4.0.0-beta.7) plus all 26 dynamic font files from mathjax-modern-font into a single IIFE JavaScript file.
2. Runtime — MathJaxRenderer.__init__() creates a QuickJS context (4 MB stack / 128 MB heap) and evaluates the bundle once.
3. Render — Each render() call invokes globalThis.render(latex) inside that context. MathJax's liteAdaptor provides a virtual DOM; the SVG output is extracted and returned as a pure <svg> string.

License

MIT