Beamer customization II: footline with multiple lines

This is part II of a series of posts on customizing the beamer default theme and circles around the aspect of configuring a footline that displays the title, author, institute, date and slide number in two lines. The beamer themes (see the previous post) provide footlines that display this information in parts. Unfortunatley I found them to be inadequate for my case, because of the length of the information to be displayed. For a nice formatting, I need a two-line footline and none of the currently available themes offers this. The normal approach in this case is to configure a new beamer template with the \setbeamertemplate command:

\setbeamertemplate{footline}{
   \unilogo
   \dsglogo
   \begin{beamercolorbox}[ht=4ex,leftskip=1.4cm,rightskip=.3cm]{author in head/foot}
    \usebeamercolor{UniBlue}
    \hrule
    \vspace{0.1cm}
    \insertdate \hfill \inserttitle \newline 
    \insertshortauthor \ - \insertshortinstitute \hfill \insertframenumber
   \end{beamercolorbox}
   \vspace*{0.1cm}
} 

This overwrites the default template for the footline with custom configuration. The commands in line 2 and 3 display logos and will be explained in a following post. So let me focus on the beamercolorbox. This is the standard way to display colored text and in various themes, the footline consists of several beamercolorboxes positioned next to each other. When using multiple boxes, it is problematic to display lengthy text (in my case the institute) that crosses the borders of a box. Using a single box and layouting all text in it was a convenient way to solve this problem. As for the options:

• ht marks the height of the footline which is set to 4 times the height of the character “x”
• leftskip and rightskip mark the distance of the footline to the page borders

The parameter author in head/foot determines the font used in the box. In the content of the box, first the color of the font is overwritten to a custom color (line 5, for its definition, see the previous post). Then, a horizontal rule is drawn to seperate the footline from the main text of the slide (line 6). The following vertical space (line 7) produces some free space between the vertical rule and the following text. Without this command, the rule would reside directly on top of the text. The \insert commands insert meta information which needs to be specified somewhere else in the preamble (\title, \author, \institute and \date) and are omitted here. The inserted meta information is formatted in two lines using \newline and \hfill to align them to the left and right side of the box with an empty space inbetween that depends on the actual size of the date, title, etc. strings. The seconds line also contains a dash and a freespace (produced by \) between the dash and \insertshortauthor. Without the freespace the dash would be directly appended to the text produced by \insertshortauthor.

Finally, there is a vertical space after the box. Without this space, the footline would directly sit on the lower page border, which is not very pretty. All in all, a sample footline (with some meta information set) looks as follows:

sample footline