The bbox extension defines a new macro for adding background colors, borders, and padding to your math expressions.


puts a bounding box around math using the provided options. The options can be one of the following:

  1. A color name used for the background color.
  2. A dimension (e.g., 2px) to be used as a padding around the mathematics (on all sides).
  3. Style attributes to be applied to the mathematics (e.g., border: 1px solid red).
  4. A combination of these separated by commas.

Here are some examples:

\bbox[red]{x+y}      % a red box behind x+y
\bbox[2pt]{x+1}      % an invisible box around x+y with 2pt of extra space
\bbox[red,2pt]{x+1}  % a red box around x+y with 2pt of extra space
\bbox[5px, border: 2px solid red]
                     % a 2px red border around the math 5px away

This extension is loaded automatically when the autoload extension is used. To load the bbox extension explicitly, add '[tex]/bbox' to the load array of the loader block of your MathJax configuration, and add 'bbox' to the packages array of the tex block.

window.MathJax = {
  loader: {load: ['[tex]/bbox']},
  tex: {packages: {'[+]': ['bbox']}}

Alternatively, use \require{bbox} in a TeX expression to load it dynamically from within the math on the page, if the require extension is loaded.

bbox Commands

The bbox extension implements the following macros: \bbox