How to highlight text with an arbitrary color

Question

Okay so I have the command

\newcommand{\hlc}[2][yellow]{{\sethlcolor{#1}\hl{#2}}}

in my preamble (after the inclusion of soul and xcolor packages), and colors that are already defined work perfectly well.

\hlc[pink]{hello}

gives me hello highlighted in pink. However, colour combinations don't output anything for me.

\hlc[cyan!50]{hello}

would output just

hello

without any colour.

I want a command that's completely generic (ie. let's me highlight with any colour combination I want). Is there any nice way to do that? I don't want to repeatedly use the command \setcolor either. I want to be able to input the colors right in the command.

Answer 1

The \sethlcolor macro does not understand the colour specifiction of x!y!z etc, it can work with named colors being defined with \definecolor only.

However, using xcolor there is a trick to support the colour definition:

\colorlet{foo}{x!y!z!} defines and transforms the specification into a colour named foo (this will overwrite an existing definition of the colour named foo, however.

Basically, it is similar to the macro \let\foo\foobar statement. Since all happens in a group (by definition of \hlc), the new colour foo is not known outside.

\documentclass{article}

\usepackage{xcolor}
\usepackage{soul}

\newcommand{\hlc}[2][yellow]{{%
    \colorlet{foo}{#1}%
    \sethlcolor{foo}\hl{#2}}%
}



\begin{document}

\hlc[pink]{hello}

\hlc[cyan!50]{hello}

\end{document}