[Tex/LaTex] Specific colour in equation links

colorhyperref

In hyperref package, is it possible to specify a specific color for equation links different than other link colors ?

Following are present color specifications that I am using for hyperref package

colorlinks=true,       % false: boxed links; true: colored links
linkcolor=red,          % color of internal links
citecolor=blue,        % color of links to bibliography
filecolor=magenta,      % color of file links
urlcolor=cyan

(Is it possible to do it with \cref ?)

Thanks.

Best Answer

You can define your own link command for equations and change the (border) color for links locally.

LaTeX with `\ref`

\documentclass[a5paper]{article}

\usepackage{xcolor}
\colorlet{linkequation}{blue}
\usepackage[colorlinks]{hyperref}

\newcommand*{\refeq}[1]{%
  \begingroup
    \hypersetup{
      linkcolor=linkequation,
      linkbordercolor=linkequation,
    }%
    \ref{#1}%
  \endgroup
}

\begin{document}
\tableofcontents
\section{Example}\label{sec:example}
\begin{equation}
\label{eq:einstein}
E=mc^2
\end{equation}
See section \ref{sec:example} and equation \refeq{eq:einstein}.
\end{document}

$Result \refeq$

Package `amsmath` and `\eqref`

And an example for the redefinition of \eqref from package amsmath:

\documentclass[a5paper]{article}

\usepackage{amsmath}

\usepackage{xcolor}
\colorlet{linkequation}{blue}
\usepackage[colorlinks]{hyperref}

\newcommand*{\SavedEqref}{}
\let\SavedEqref\eqref
\renewcommand*{\eqref}[1]{%
  \begingroup
    \hypersetup{
      linkcolor=linkequation,
      linkbordercolor=linkequation,
    }%
    \SavedEqref{#1}%
  \endgroup
}

\begin{document}
\tableofcontents
\section{Example}\label{sec:example}
\begin{equation}
\label{eq:einstein}
E=mc^2
\end{equation}
See section \ref{sec:example} and equation \eqref{eq:einstein}.
\end{document}

$Result \eqref$

Package `cleveref` and `\cref`

\documentclass[a5paper]{article}

\usepackage{xcolor}
\colorlet{linkequation}{blue}
\usepackage[colorlinks]{hyperref}
\usepackage{cleveref}

\makeatletter
\creflabelformat{equation}{%
  \textup{%
    \hypersetup{
      linkcolor=linkequation,
      linkbordercolor=linkequation,
    }%
    (#2#1#3)%
  }%
}
\makeatother

\begin{document}
\tableofcontents
\section{Example}\label{sec:example}
\begin{equation}
\label{eq:einstein}
E=mc^2
\end{equation}
See section \ref{sec:example} and \cref{eq:einstein}.
\end{document}

$Result \cref$

Manual

You deactivate the colorlinks option so that hyperref sets the link border:

\hypersetup{%
  colorlinks=false,% hyperlinks will be black
  linkbordercolor=red,% hyperlink borders will be red
  pdfborderstyle={/S/U/W 1}% border style will be underline of width 1pt
}

and typeset the text manually using \color{<color>}. For example:

...
\begin{document}
  \section{To See}\label{tosee}
  \hyperref[tosee]{\color{green}just to see}
\end{document}

Colorlinks=false with manual colour setting of link

Note that this is virtually the same as what hyperref does internally, since the text colour is modified and will typeset this way even if the hyperlink is removed via printing to PDF (or flattening).

The advantage behind this approach (motivating to include it here) is that you can specify different colours for each hyperlink, if you so wish.

Automatic

You activate the colorlinks option so that hyperref sets the link colour in the text

\hypersetup{%
  colorlinks=true,% hyperlinks will be coloured
  linkcolor=green,% hyperlink text will be green
  linkbordercolor=red,% hyperlink border will be red
}

and then add the following after the above \hypersetup{...}:

\makeatletter
\Hy@AtBeginDocument{%
  \def\@pdfborder{0 0 1}% Overrides border definition set with colorlinks=true
  \def\@pdfborderstyle{/S/U/W 1}% Overrides border style set with colorlinks=true
                                % Hyperlink border style will be underline of width 1pt
}
\makeatother

Colorlinks=true with linkborder active

Here is the pdfborderstyle specification from Adobe:

PDF border specification

[Tex/LaTex] Color Options for Appearance of Links in Hyperref

Once you load the xcolor package, you have access to all the color specifications this package allows; in particular, you can use the hundredths of predefined colors it provides, to the ! modifier for mixing colors, to the - for complements, etc.; using \definecolor{<name>}{<model>}{<specification>} you can build your own colors in the desired modes and then use <name> in the hyperref setup (please refer to the package documentation for further details).

A little example showing some of the possibilities:

\documentclass{article} 
\usepackage[dvipsnames]{xcolor}
\usepackage{hyperref}

\definecolor{mycolor}{HTML}{F7F8E0}
\definecolor{myorange}{RGB}{245,156,74}

\hypersetup{
  colorlinks=true,
  urlcolor=red
}

\begin{document}

\href{www.tex.stackexchange.com}{TeX.sx}

\hypersetup{
  colorlinks=true,
  urlcolor=cyan!50
}
\href{www.tex.stackexchange.com}{TeX.sx}

\hypersetup{
  colorlinks=true,
  urlcolor=ForestGreen% required dvipsnames optioon for xcolor
}
\href{www.tex.stackexchange.com}{TeX.sx}

\hypersetup{
  colorlinks=true,
  urlcolor=myorange
}
\href{www.tex.stackexchange.com}{TeX.sx}

\hypersetup{
  colorlinks=true,
  urlcolor=-myorange
}
\href{www.tex.stackexchange.com}{TeX.sx}

\hypersetup{
  colorlinks=true,
  urlcolor=mycolor!75!black
}
\href{www.tex.stackexchange.com}{TeX.sx}

\end{document}

Best Answer

LaTeX with \ref

Package amsmath and \eqref

Package cleveref and \cref

Related Solutions

[Tex/LaTex] How to have colored and underlined links with hyperref