How to color delimiters

Question

I have some special delimiters that I want to add to a glossary, those get hyperlinks and colors etc. However when i want to use those delimiters, using \left, \right and \middle becomes impossible. I think with the following question fixed I can create my hyperlinked delimiters:

How to color delimiters:

As a minimal working example I have:

$\left\textcolor{red}{(}a\right)$

What i would like to have is (Created without \left \right):

This gets the error: ! Missing delimiter (. inserted).

---

Trying this :

$\textcolor{red}{\left(}a\right)$

results in ! Extra }, or forgotten \right.

Who can help me?

Answer 1

use it this way:

$\color{red}\left(\normalcolor a\right)$

or

$\textcolor{red}{\big(} a\big)$

There a \big, \bigg, \Big, and \Bigg

Answer 2

Here is macro that can easily be extended to different styles of brackets:

Notes:

• As egreg pointed out one should use adjust the horizontal spacing via nulldelimiterspace. More details on this are at How to compute exact width added by \left. \right.

Code:

\documentclass{article}
\usepackage{xcolor}

\newcommand{\BracKern}{\kern-\nulldelimiterspace}
\makeatletter
    \newcommand{\@Brac}[3]{% #1,#3 = left/right bracket type           
        \mathopen{\color{red}\left#1\vphantom{#2}\BracKern\right.}% left bracket
        #2%  content
        \mathclose{\left.\BracKern\vphantom{#2}\right#3}% right bracket
    }
    \newcommand{\bracr}[1]{\@Brac{(}{#1}{)}}%
    \newcommand{\bracs}[1]{\@Brac{[}{#1}{]}}%
    \newcommand{\bracc}[1]{\@Brac{\{}{#1}{\}}}%
\makeatother


\begin{document}
    $\bracr{a}$  $\displaystyle\bracr{\frac{1}{2}}$
    $\bracs{a}$  $\displaystyle\bracs{\frac{1}{2}}$
    $\bracc{a}$  $\displaystyle\bracc{\frac{1}{2}}$
\end{document}