[Tex/LaTex] How to gradient shade the background of a beamer section/subsection in head/foot

beamershading

Here is a reduced example of my code. I am attempting to restyle the background of the section in head/foot and subsection in head/foot in the CambridgeUS theme to a gradient background colour.

Right now the gradient background works if I were to specify say beamer@frametitleshade in my pgf declaration. I can't find and can't guess the correct keywords to get this to affect the background of the section in head/foot nor the subsection in head/foot, I've tried things like sectioninheadfootshade and variants.

\documentclass[hyperref={pdftex}]{beamer}
\useoutertheme{shadow}
\definecolor {Burgandy}{HTML}{660033}
\definecolor {Crimson}{HTML}{990033}
\definecolor {Orange}{HTML}{ff9933}

\usetheme{CambridgeUS}

\colorlet{titleleft}{Burgandy}
\colorlet{titlemiddle}{Crimson}
\colorlet{titleright}{Orange}

\pgfdeclarehorizontalshading[titleleft,titlemiddle,titleright]
      {beamer@frametitleshade}{\paperheight}{
    color(0pt)=(titleleft);
    color(0.6\paperwidth)=(titlemiddle);
    color(\paperwidth)=(titleright)
  }

\title[Short Title]{Long title}
\subtitle{Sub title}
\date{\today}

\begin{document}
    \begin{titlepage}
    \end{titlepage}

    \begin{frame}{Slide 1}
          Content
    \end{frame}
\end{document}

Best Answer

You can redefine the elements to use the same colour gradient as the frametitle. Please compare the following redefinition of the footline with the original one from beamerouterthemeinfolines.sty to see the changes. You can use the same approach to modify the headline.

One trick: The background of the colours has to be set to empty.

\documentclass[hyperref={pdftex}]{beamer}
\useoutertheme{shadow}
\usetheme{CambridgeUS}

\colorlet{titleleft}{red}
\colorlet{titlemiddle}{orange}
\colorlet{titleright}{yellow}

\pgfdeclarehorizontalshading[titleleft,titlemiddle,titleright]
      {beamer@frametitleshade}{\paperheight}{
    color(0pt)=(titleleft);
    color(0.6\paperwidth)=(titlemiddle);
    color(\paperwidth)=(titleright)
  }

\title[Short Title]{Long title}
\subtitle{Sub title}
\date{\today}
\author{test}

\setbeamercolor{author in head/foot}{parent=palette primary,bg=}
\setbeamercolor{title in head/foot}{parent=palette secondary,bg=}
\setbeamercolor{date in head/foot}{parent=palette tertiary,bg=}

\makeatletter
\setbeamertemplate{footline}
{
    \leavevmode%
    \setbox\beamer@tempbox=\hbox{%
        \begin{beamercolorbox}[wd=.333333\paperwidth,ht=2.25ex,dp=1ex,center]{author in head/foot}%
            \usebeamerfont{author in head/foot}\insertshortauthor\expandafter\beamer@ifempty\expandafter{\beamer@shortinstitute}{}{~~(\insertshortinstitute)}
        \end{beamercolorbox}%
        \begin{beamercolorbox}[wd=.333333\paperwidth,ht=2.25ex,dp=1ex,center]{title in head/foot}%
            \usebeamerfont{title in head/foot}\insertshorttitle
        \end{beamercolorbox}%
        \begin{beamercolorbox}[wd=.333333\paperwidth,ht=2.25ex,dp=1ex,right]{date in head/foot}%
            \usebeamerfont{date in head/foot}\insertshortdate{}\hspace*{2em}
            \insertframenumber{} / \inserttotalframenumber\hspace*{2ex} 
        \end{beamercolorbox}%
        }%
        \beamer@tempdim=\ht\beamer@tempbox%
        \advance\beamer@tempdim by 4pt%
        \begin{pgfpicture}{0pt}{0pt}{\paperwidth}{20pt}
            \pgfpathrectangle{\pgfpointorigin}{\pgfpoint{\paperwidth}{\beamer@tempdim}}
            \pgfusepath{clip}
            \pgftext[left,base]{\pgfuseshading{beamer@frametitleshade}}
        \end{pgfpicture}
        \vskip-\beamer@tempdim%
        \box\beamer@tempbox%    
}%
\makeatother

\begin{document}
    \begin{titlepage}
    \end{titlepage}

\section{ble}
    \begin{frame}{Slide 1}
          Content
    \end{frame}
\end{document}

As the procrastination force is great in me, here also the headline

\documentclass[hyperref={pdftex}]{beamer}
\useoutertheme{shadow}
\usetheme{CambridgeUS}

\colorlet{titleleft}{red}
\colorlet{titlemiddle}{orange}
\colorlet{titleright}{yellow}

\pgfdeclarehorizontalshading[titleleft,titlemiddle,titleright]
      {beamer@frametitleshade}{\paperheight}{
    color(0pt)=(titleleft);
    color(0.6\paperwidth)=(titlemiddle);
    color(\paperwidth)=(titleright)
  }

\title[Short Title]{Long title}
\subtitle{Sub title}
\date{\today}
\author{test}

\setbeamercolor{author in head/foot}{parent=palette primary,bg=}
\setbeamercolor{title in head/foot}{parent=palette secondary,bg=}
\setbeamercolor{date in head/foot}{parent=palette tertiary,bg=}

\setbeamercolor{section in head/foot}{parent=palette primary,bg=}
\setbeamercolor{subsection in head/foot}{parent=palette secondary,bg=}

\makeatletter
\setbeamertemplate{footline}
{
    \leavevmode%
    \setbox\beamer@tempbox=\hbox{%
        \begin{beamercolorbox}[wd=.333333\paperwidth,ht=2.25ex,dp=1ex,center]{author in head/foot}%
            \usebeamerfont{author in head/foot}\insertshortauthor\expandafter\beamer@ifempty\expandafter{\beamer@shortinstitute}{}{~~(\insertshortinstitute)}
        \end{beamercolorbox}%
        \begin{beamercolorbox}[wd=.333333\paperwidth,ht=2.25ex,dp=1ex,center]{title in head/foot}%
            \usebeamerfont{title in head/foot}\insertshorttitle
        \end{beamercolorbox}%
        \begin{beamercolorbox}[wd=.333333\paperwidth,ht=2.25ex,dp=1ex,right]{date in head/foot}%
            \usebeamerfont{date in head/foot}\insertshortdate{}\hspace*{2em}
            \insertframenumber{} / \inserttotalframenumber\hspace*{2ex} 
        \end{beamercolorbox}%
        }%
        \beamer@tempdim=\ht\beamer@tempbox%
        \advance\beamer@tempdim by 4pt%
        \begin{pgfpicture}{0pt}{0pt}{\paperwidth}{20pt}
            \pgfpathrectangle{\pgfpointorigin}{\pgfpoint{\paperwidth}{\beamer@tempdim}}
            \pgfusepath{clip}
            \pgftext[left,base]{\pgfuseshading{beamer@frametitleshade}}
        \end{pgfpicture}
        \vskip-\beamer@tempdim%
        \box\beamer@tempbox%    
}%

\setbeamertemplate{headline}
{
    \leavevmode%
    \setbox\beamer@tempbox=\hbox{%
        \begin{beamercolorbox}[wd=.5\paperwidth,ht=2.65ex,dp=1.5ex,right]{section in head/foot}%
            \usebeamerfont{section in head/foot}\insertsectionhead\hspace*{2ex}
        \end{beamercolorbox}%
        \begin{beamercolorbox}[wd=.5\paperwidth,ht=2.65ex,dp=1.5ex,left]{subsection in head/foot}%
            \usebeamerfont{subsection in head/foot}\hspace*{2ex}\insertsubsectionhead
        \end{beamercolorbox}%
        }%
        \beamer@tempdim=\ht\beamer@tempbox%
        \advance\beamer@tempdim by 4pt%
        \vskip-\beamer@tempdim%
        \begin{pgfpicture}{0pt}{0pt}{\paperwidth}{20pt}
            \pgfpathrectangle{\pgfpointorigin}{\pgfpoint{\paperwidth}{\beamer@tempdim}}
            \pgfusepath{clip}
            \pgftext[left,base]{\pgfuseshading{beamer@frametitleshade}}
        \end{pgfpicture}
        \vskip-\beamer@tempdim%
        \box\beamer@tempbox%    
        \vskip0pt%
}
\makeatother

\begin{document}
    \begin{titlepage}
    \end{titlepage}

\section{ble}
\subsection{bla}
    \begin{frame}{Slide 1}
          Content
    \end{frame}
\end{document}

1. Changing all the used (content) colors in a certain area to gray

For all code and packages that rely on xcolor to produce colored output, you can use \selectcolor{gray} in a group (i. e. wrapped in curly braces). Make sure to also issue \color{black} at the beginning of the group so that previous color changes are reverted. At the end of that group, the old color model will be restored automatically so that you're able to produce colorful output again:

\documentclass{beamer}
\begin{document}
\begin{frame}
\color{red} This is red text with {\color{blue} blue}, but {\selectcolormodel{gray}\color{black} from now on {\color{blue} all} \color{green} is grey.} Now it's colourful (red) again!
\end{frame}
\end{document}

output of the example code, showing how to change the content color of a certain area to gray

Note that this won't work for packages which have some color management of their own, e.g. directly setting the respective PDF properties.

2. Changing the background color of a certain area to white

This can be done in a number of ways, the easiest of which is probably wrapping the content of the area in a beamercolorbox:

\documentclass{beamer}
\setbeamercolor{normal text}{bg=gray!40}
\begin{document}
\begin{frame}
\setbeamercolor{whitebox}{bg=white}
\begin{beamercolorbox}[sep=2mm]{whitebox}
    This text is in a box with white backgound.
\end{beamercolorbox}
\end{frame}
\end{document}

output of the example code: a text in a white box

The size of the box can be controlled with the optional argument of beamercolorbox - in the example, a margin of 2mm is added to each side.

[Tex/LaTex] How to position title, frametitle, navigation bar and contents in arbitrary absolute positions

To customize a theme take a look at the .sty files of the default themes of beamer. This will give you an idea.

Look for\defbeamertemplate{title page}, \defbeamertemplate{footline}, \setbeamertemplate{sidebar right},etc.. Those let you position and customize the regions on the page.
The elements that you put on the title page for example are called by commands like \inserttitle, \insertauthor, \insertframetitle. Again look for them in the defualt .sty files. There are a lot of resources online where you can read the theme files in your browser.
Here is a list with different "beamer colors" that are used in themes. You should make use of those when setting or defining a template.

Best Answer

Related Solutions

[Tex/LaTex] how can I shade an area in a beamer frame

1. Changing all the used (content) colors in a certain area to gray

2. Changing the background color of a certain area to white

[Tex/LaTex] How to position title, frametitle, navigation bar and contents in arbitrary absolute positions

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