Colored underlining without affecting vertical spacing

Question

I'm using the coloured underlining trick described in the ulem package manual (p.3). The underlining looks good, but interacts poorly with align-like environments, where (in contrast to \uline) it affects the height of the row:

It is possible to have a version of \reduline that, modulo colour, behaves as \uline?

\documentclass{article}
\usepackage{amsmath}
\usepackage{ulem}
\usepackage{xcolor}

\newcommand\reduline{\bgroup\markoverwith{\textcolor{red}{\rule[-0.5ex]{2pt}{0.4pt}}}\ULon}

\begin{document}

\begin{align*}
  \uline{ABCD} + EFGH \\
  \reduline{ABCD} + EFGH \\
  ABCD + EFGH
\end{align*}
\end{document}

The accents package is preferable to put accents under mathematical symbols and doing this would be easy (but not from the cellphone I'm typing this on) — JPi, Aug 21 '16 at 19:58

score 7 · Accepted Answer · answered Aug 21 '16 at 23:31

7

Well, this works....

\documentclass{article}
\usepackage{amsmath}
\usepackage{ulem}
\usepackage{xcolor}

\newcommand{\reduline}[1]{{\color{red}\uline{{\color{black}#1}}}}

\begin{document}

    \begin{align*}
    \uline{ABCD} + EFGH \\
    \reduline{ABCD} + EFGH \\
    ABCD + EFGH
    \end{align*}
\end{document}

answered Aug 21 '16 at 23:31

JPi

13,595

The trick seems doesn't allow line breaks in the inner text. (I'm using it in a normal text paragraph) – Yan King Yin Feb 22 '23 at 09:48
I needed to add \color{black} to the end of the \reduline command for it to switch back to black outside the command. – Toivo Säwén Sep 26 '23 at 14:36

score 1 · Answer 2 · edited Apr 13 '17 at 12:36

Example:

\documentclass{article}
\usepackage{amsmath}
\usepackage{xcolor}
\usepackage{accents}


\newcommand{\redlb}[1]{{\color{red}\underaccent{\bar}{\color{black}#1}}}

\begin{document}

\begin{align*}
  {A} + B \\
  \redlb{A} + B \\
  A + B
\end{align*}
\end{document}

Your red under-bar is wider than mine. The author of the accents package questions the wisdom of using wide bars, but if you want one of those then you can find out as an answer to a different question how to accomplish that. Strangely, wide tildes are easier.

EDIT

And here's how to get a wide tilde under accent:

\documentclass{article}
\usepackage{amsmath}
\usepackage{xcolor}
\usepackage{accents}
\DeclareMathAccent{\wtilde}{\mathord}{largesymbols}{"65}

\newcommand{\redlb}[1]{{\color{red}\underaccent{\bar}{\color{black}#1}}}
\newcommand{\redwt}[1]{{\color{red}\underaccent{\wtilde}{\color{black}#1}}}

\begin{document}

\begin{align*}
  A + B \\
  \redlb{A} + B \\
  \redwt{A} + B
\end{align*}
\end{document}

Thanks - however it's underlining that I need. Updated example code and PNG. — Roly, Aug 21 '16 at 23:22

Colored underlining without affecting vertical spacing

2 Answers2

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