Vertically centering text in powerdot, taking baseline into account

Question

I have a powerdot style that includes the following slide definition:

\pddefinetemplate[slide]{blackslide}{
  titlepos={.05\slidewidth,.93\slideheight},
  titlewidth=.9\slidewidth,
  titlefont=\bfseries\Large\color{pdcolor3}\raggedright,
  textpos={.05\slidewidth,.90\slideheight},
  textwidth=.9\slidewidth,
  textheight=.85\slideheight,
  textfont=\Huge\color{white}\centering,
}{%
  \psframe[linestyle=none,linewidth=0pt,fillstyle=solid,fillcolor=black](0,0)(\slidewidth,\slideheight)%
}

This style essentially gives me large text within a slide, horizontally centered. This isn't quite enough, however, and I would like to occasionally vertically center text. I put a command together to do this:

\newcommand\bigslide[1]{%
\begin{blackslide}{}
  \par\vspace*{\stretch{1}}%
  #1
  \vspace*{\stretch{1}}%
  \par
\end{blackslide}
}

This was based on the code for the vplace environment from the memoir class.

Unfortunately, this doesn't quite do the job -- text is vertically aligned, but it will ignore descenders. As a minimal example:

\bigslide{This is some text}
\bigslide{Text that happens to have descenders}

The text for the second slide is marginally higher than the text for the first, because the spacing is against the box rather than the baseline.

So my question: how can I get the text to vertically align sensibly, whether or not there are any descenders, and however many lines it has?

Answer 1

I do not really understand what exactly you want. However, try it this way:

\documentclass{powerdot}
\pddefinetemplate[slide]{blackslide}{
  titlepos={.05\slidewidth,.93\slideheight},
  titlewidth=.9\slidewidth,
  titlefont=\bfseries\Large\color{pdcolor3}\raggedright,
  textpos={.05\slidewidth,.90\slideheight},
  textwidth=.9\slidewidth,
  textheight=.85\slideheight,
  textfont=\Huge\color{white}\centering,
}{%
  \psframe[linestyle=none,linewidth=0pt,fillstyle=solid,fillcolor=black](0,0)(\slidewidth,\slideheight)%
}
\newcommand\bigslide[1]{%
\begin{blackslide}{}
\rput(0,-0.5\textheight){\parbox{\textwidth}{\centering#1}}
\end{blackslide}}
\begin{document}
\bigslide{This is some text}
\bigslide{Text that happens to have descenders}
\end{document}