math-katex Plugin

A reveal.js plugin that renders mathematical formulas inside slides using KaTeX.

Lightweight rendering, thanks to KaTeX
Marks syntax errors on the slide
Renders all formulas when presentation loads (no re-rendering when slide changes)

Plugin setup

Download the latest release (tar.gz or zip) and extract it into the plugin directory of your reveal.js presentation.

Tell reveal.js to use the plugin:

Reveal.initialize({
    // … other configuration …

    dependencies: [
        { src: 'plugin/math-katex/math-katex.js', async: true }
    ]
});

A build of KaTeX is included with the plugin.

Usage

TL;DR: See the example.

There are two usage modes:

TeX-style, wrapped in $…$ or $$…$$. Works in Markdown, too
Wrapped in HTML elements with class formula or math. (Don’t also use dollar syntax when using a class.)

The rendered TeX-style formulas also get a class formula added so that you can style them. $…$ formulas in addition get class inline, $$…$$ class display.

TeX style (dollars)

Use $$…$$ for display-style (block) formulas: $$\frac{1}{1 + e^{-x}}$$
Use $…$ for in-line formulas: e.g. $P(A \mid B)$

Escape literal dollar characters with \$.

As an alternative: If you have many slides that use literal dollar characters, it may be easier to explicitly activate formula rendering per slide: Set math.enableGlobally to false and then activate formula replacements on each slide (<section>) by setting the data-math attribute (no value required).

Wrapped in an element

Wrap the formula in an element with class formula (or math):

<div class="formula display"> \frac{1}{1 + e^{-x}} </div>

Display mode is in-line by default, add class display if needed.

Exclude elements

You can exclude elements from formula rendering by:

Adding the class math-ignored to an element or its (direct) parent
Adding the element type to the math.ignoredElements array on the configuration object (default: pre, code)

Optional configuration

Reveal.initialize({
    // … presentation configuration …

    // `math-katex` plugin:

    // *Optional* configuration:
    math: {
        // Uncomment to disable syntax error notifications
        // notificationsEnabled: false   // default: true

        // Elements to ignore for math rendering (defaults shown):
        // ignoredElements: [ 'pre', 'code' ]

        // Set `enableGlobally` to `false` to avoid excessive
        // escaping of dollar characters. You will then need to
        // activate `$…$`-style replacements per slide with a
        // `data-math` attribute (formulas wrapped in elements
        // are still activated everywhere).
        //
        // enableGlobally: false

        // In case you need to load KaTeX from a different
        // location (relative or absolute URL):
        // katexScript:     'path/to/katex/katex.min.js',
        // katexStylesheet: 'path/to/katex/katex.min.css'
    },

    // Specify the plugin as a dependency:
    dependencies: [
        { src: 'plugin/math-katex/math-katex.js', async: true }
    ]
});

Example

To run the example in your browser, clone or download this repository and install reveal.js using npm (Node.js required):

From the repository root directory: $ npm install reveal.js

If you don't have Node.js installed: Download reveal.js and copy it into a new directory named node_modules.

Tests

Run tests (requires Node.js): $ npm install && npm test

Tests use Mocha + Chai via mocha-phantomjs.

j13z / reveal.js-math-katex-plugin