# How to get larger item symbols for some lists in a Beamer presentation?

I am writing a Beamer presentation that mixes normal-size font for some slides, and large-size font for other slides. When I use the itemize environment with a large font, the item symbol (a small ball) does not become larger, and the result is not aesthetically pleasant.

How can I make itemized lists with large item symbols, but only for those which have large text, not for the entire presentation (i.e., without globally changing the beamer template)?

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itemize symbols have font size hardcoded in definition (look at beamerthemedefault.sty or beamerbaseauxtemplates.sty).

% Itemize items, circle

\defbeamertemplate{itemize item}{circle}{\small\raise0.5pt\hbox{\textbullet}}
\defbeamertemplate{itemize subitem}{circle}{\footnotesize\raise0.5pt\hbox{\textbullet}}
\defbeamertemplate{itemize subsubitem}{circle}{\footnotesize\raise0.5pt\hbox{\textbullet}}


Section 16.3 "Changing the Templates Used for Different Elements of a Presentation" form beamer manual explain how to change it. It seems that would be possible to define a template with an option for font size. I don't know how to do it but a fast solution could be redeclare itemize symbols with new hardcoded size, something like

\documentclass{beamer}

\begin{document}
\begin{frame}[t]{Frame title}
\begin{itemize}
\item First item
\item Second item
\end{itemize}
\bigskip
{\setbeamertemplate{itemize item}{\small\raise1.25pt\hbox{\donotcoloroutermaths$\blaktriangleright$}}
\begin{itemize}
\item Second first item
\item Second second item
\end{itemize}
}
\bigskip
\begin{itemize}
\item Third first item
\item Third second item
\end{itemize}
\end{frame}
\end{document}


EDIT: Changing balls for Madrid Theme.

Madrid Theme (beamerthemeMadrid.sty) uses \useinnertheme[shadow]{rounded} which declares \setbeamertemplate{items}[ball]. So we need to look for ball in beamerbaseauxtemplates.sty. To do it short, in this file some 'spheres' are defined and used. You can make your own definition,

\documentclass{beamer}

\makeatletter
{color(0cm)=(bg!15);
color(0.15cm)=(bg!75);
color(0.3cm)=(bg!70!black);
color(0.301cm)=(parent.bg)}

\defbeamertemplate{itemize item}{myball}%
{\raise-0.2cm\beamer@usesphere{item projected}{mysphere}}
\makeatother

\begin{document}
\begin{frame}[t]{Frame title}
\begin{itemize}
\item First item
\begin{itemize}
\item first subitem
\item second subitem
\end{itemize}
\item Second item
\end{itemize}
\bigskip
{\setbeamertemplate{itemize item}[myball]
\begin{itemize}
\item Third first item
\item Third second item
\end{itemize}
}
\end{frame}
\end{document}


The result is

I think sphere sizes are related with font size because they are declared using ex units but I'm not able to change its size with just a fontsize declaration. May be somebody else can help us.

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Thanks! But can you do the same with spheres (like in the Mardid theme)? – Little Bobby Tables Jul 19 '11 at 7:19
I edited my answer with a new partial solution for Madrid theme. – Ignasi Jul 19 '11 at 9:22
Thanks a million! The results still need a bit of fine-tuning, depending on usage, but this is a pointer in the right direction. – Little Bobby Tables Jul 19 '11 at 9:59

Unfortunately the @Ignasi solution for change of the ball size is lacking in aliasing so the spheres have rough edges as you can see in the screenshot. To solve the problem, I modified the original definition in beamerbaseauxtemplates.sty by adding to preamble the following code:

% * original ball definition in beamerbaseauxtemplates.sty
%{%
%  color(0cm)=(bg!15);
%  color(0.1643835ex)=(bg!75);
%  color(0.3287671ex)=(bg!70!black);
%  color(0.4520547ex)=(bg!50!black);
%  color(0.53ex)=(parent.bg)}

% modified by 1.4x multiplication factor
{%
color(0cm)=(bg!15);
color(0.2301369ex)=(bg!75);
color(0.4602739ex)=(bg!70!black);
color(0.6328766ex)=(bg!50!black);
color(0.742ex)=(parent.bg)}

\defbeamertemplate{itemize item}{myball}{\raise0.2pt\beamer@usesphere{item projected}{bigsphere}}

\setbeamertemplate{itemize item}[myball]


Now all item bullet balls are 1.4 times bigger then in default template and they have smooth edges.

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