A Node.js web application that allows LaTeX math equations to be entered and converted to PNG/JPG/SVG images.

For each conversion, an isolated Docker container with a LaTeX installation is started; it compiles the generated .tex file and converts it to an SVG vector image. If required, the SVG file is then converted to a raster image format for PNG/JPG using sharp.

Bootstrap and jQuery are used in the web interface, with AJAX calls made to the conversion API endpoint.

Generate image on the fly

   example: /latex?latexInput=a_{n%2B1}%3Da_n%2Bk&outputFormat=PNG&outputScale=200%25&color=ff0000
           
   let latex = "a_{n+1}=a_n+k"
   `/latex?latexInput=${encodeURIComponent(latex)}&outputFormat=PNG&outputScale=200%25&color=ffff00`

The application is accessible at https://latex2image.joeraut.com

I made use of Ubuntu 18.04. Other Linux distributions should work without problems.

Docker CE with non-root user support.

Docker image containing the required LaTeX packages preinstalled.

Pull the image:

docker pull blang/latex:ubuntu

I made use of v10.14.2, anything newer should be fine.

After cloning or downloading this project, run the following to install local dependencies from npm:

cd latex2image-web/
npm install

To run:

node app.js

The web interface will be accessible at http://localhost:3001 by default. The port and HTTP URL can be modified inside app.js.

Enter a LaTeX equation, for example \frac{a}{b}, and press Convert. The result will be displayed below the button.

LaTeX is powerful, with the reading and writing of external files and execution of terminal commands possible. It was decided that a new isolated Docker container be launched for every conversion.

The container is only able to access the local temp/<id>/ directory and has no network access.

Additionally, the compilation process will be killed after 5 seconds if not complete; this is to safeguard against infinite loops and other troublesome LaTeX quirks.

• latex - Converts .tex source file to .dvi intermediate
• dvisvgm - Converts .dvi file to .svg vector image

We use sharp to convert the SVG file to PNG and JPG images where required.

• The directories temp/ and output/ will be generated automatically inside the latex2image-web/ directory upon first launch.
• temp/ stores temporary .tex, .dvi, and .svg files during compilation in an inner temp/<id>/ directory, which is deleted upon completion of the conversion.
• Final output images are stored in output/, and are never deleted.

• Joseph Rautenbach - joeraut

For any issues or bugs, please submit an issue or pull request.

This project is licensed under the MIT License - see the LICENSE file for details.