Add (Hyper-)Links to PDFs

Adding links to PDFs , both internal and external, certainly only makes sense for digital copies of the file. Nevertheless, they still come in handy, for example for actual WWW-addresses or as direct reference inside a document.

Local references

As usual, you first need the package which handles the links:

\usepackage{hyperref}

This does the job for the moment. The package “hyperref” will automatically insert links wherever you place a citation or reference (\cite{}, \ref{}).

Global references

Referencing to URLs or local files can be done as follows:

\href{url}{text}

Try this:

\href{http://texblog.wordpress.com}{\bf{Blog on Latex Matters}}

Colour references

So far, the references were marked by a colour rectangle around them, which is not very appealing (unless you are using Apple Preview). Here is how you remove the border and if you wish define your own colours for references.

Either add this optional argument to the previous package:

\usepackage[colorlinks]{hyperref}

or use a new line and set the colour:

\usepackage{hyperref}
\hypersetup{colorlinks}

If you want to define your own colours, you will have to use the latter, as the colours are part of the argument of “hypersetup”. But in order to do so, you first need to define colours, which is why you will need the colour-package:

\usepackage{color}

Then you can define different colours you may want to use for your references, e.g.:

\definecolor{darkred}{rgb}{0.5,0,0}
\definecolor{darkgreen}{rgb}{0,0.5,0}
\definecolor{darkblue}{rgb}{0,0,0.5}

Latex uses the standard RGB (red/green/blue) colour model. The three values define the intensity for each channel within the interval (just because Latex looks nicer:-).

Now you are ready to use the defined colours, by extending the previously used command:

\hypersetup{ colorlinks,
linkcolor=darkblue,
filecolor=darkgreen,
urlcolor=darkred,
citecolor=darkblue }

Note: If your tex-distribution does not contain the hyperref-package, you can download it here (hyperref.zip), including the complete documentation.