# How to edit Beamer theme CambridgeUS

I have been using the beamer document class with the theme- cambridgeUS in lyx. The following code is the preamble. Now, I want to insert a hyperlink to a pdf file in all the pages by adding them in the header or the footer. The footer at present has the author, title and page number. How do I add the fourth? Or how can it be done with the header?

%\usecolortheme[named=Brown]{structure}
\usetheme{CambridgeUS}
%\usecolortheme{seahorse}
\setbeamertemplate{items}[ball]
\setbeamercolor{title}{bg=red!65!black, fg=white}
\usepackage{hyperref}
%% Macro for inserting Page number in Warsaw theme
%\newcommand*\oldmacro{}%
%\let\oldmacro\insertshorttitle%
%\renewcommand*\insertshorttitle{%
%  \oldmacro\hfill%

\usepackage{ragged2e}\title{TE TM Hybrid Modes}
\author[Dr. James]{Dr. James}
\pgfdeclareimage[height=1cm]{iitmlogo}{/home/melvinp/Dropbox/NPTEL/Lecture2/IITMLogo.pdf}
\logo{\pgfuseimage{iitmlogo}}

\date{}

\AtBeginDocument{\setlength{\abovedisplayskip}{0pt}}

%\AtBeginSubsection[]
%{
%  \begin{frame}<beamer>
%   \frametitle{Layout}
%  \tableofcontents[currentsection,currentsubsection]
% \end{frame}
%}
%\justifying{


Thank You

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The CambridgeUS theme uses the outer theme infolines. You can download the original file from CTAN and use it as a basis to make your own outer theme with an external link.

In this example the footer contains a fourth field with a link to the beamer user guide:

\mode<presentation>

% colors for the external link field

{
\leavevmode%
\hbox{%
\end{beamercolorbox}%
\end{beamercolorbox}%
\end{beamercolorbox}%
% this is a new field with an external link
\end{beamercolorbox}}%
\vskip0pt%
}

{
\leavevmode%
\hbox{%
\end{beamercolorbox}%
\end{beamercolorbox}}%
\vskip0pt%
}

\setbeamersize{text margin left=1em,text margin right=1em}

\mode
<all>


Save this as beamerouterthemewithlink.sty and put it in your project folder or the local tex-mf tree. Then you can use it by adding this line in your tex file:

\useoutertheme{withlink}


Similarly, you could also modify the header by adding another beamercolorbox. Just make sure that the total width of all beamercolorboxes is equal to \textwidth.

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Wonderful!!! Thank you very much!!! –  Melvin Paul Aug 14 '12 at 6:30

Here's a solution that adds a link to a web ressource immediatly above the navigation symbols. This is done by modifying the sidebar right template. (Additions to the footer are also possible, but may be more appropriate for additional titling information.)

\documentclass{beamer}

\usetheme{CambridgeUS}
\setbeamercolor{title}{bg=red!65!black,fg=white}

\setbeamertemplate{sidebar right}
{
\vfill%
\llap{\insertlogo\hskip0.1cm}%
\vskip2pt%
\vskip3pt% NEW
\vskip2pt%
}

\begin{document}

\title{TE TM Hybrid Modes}
\author{Dr. James}
\date{}
\maketitle

\end{document}


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