\HeaderA{simpleTheme}{Function to generate a simple theme}{simpleTheme}
\keyword{dplot}{simpleTheme}
\begin{Description}\relax
Simple interface to generate a list appropriate as a theme, typically
used as the \code{par.settings} argument in a high level call
\end{Description}
\begin{Usage}
\begin{verbatim}
simpleTheme(col, alpha, 
            cex, pch, lty, lwd, font, fill, border,
            col.points, col.line, 
            alpha.points, alpha.line)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{col, col.points, col.line}] A color specification.  \code{col} is used for components
\code{plot.symbol}, \code{plot.line}, \code{plot.polygon},
\code{superpose.symbol}, \code{superpose.line}, and
\code{superpose.polygon}.  \code{col.points} overrides \code{col},
and is used only for \code{plot.symbol} and
\code{superpose.symbol}.  Similarly, \code{col.lines} overrides
\code{col} for \code{plot.line} and \code{superpose.line}.  The
arguments can be vectors, but only the first component is used for
scalar targets (i.e., the ones without \code{"superpose"} in their
name).

\item[\code{alpha, alpha.points, alpha.line}] A numeric alpha transparency specification.  The same rules as
\code{col}, etc., apply.

\item[\code{cex, pch, font}] Parameters for points.  Applicable for
components \code{plot.symbol} (for which only the first component is
used) and \code{superpose.symbol} (for which the arguments can be
vectors).

\item[\code{lty, lwd}] Parameters for lines.  Applicable for
components \code{plot.line} (for which only the first component is
used) and \code{superpose.line} (for which the arguments can be
vectors).

\item[\code{fill}] fill color, applicable for components \code{plot.symbol},
\code{plot.polygon}, \code{superpose.symbol}, and
\code{superpose.polygon}.  
\item[\code{border}] border color, applicable for components
\code{plot.polygon} and \code{superpose.polygon}.  
\end{ldescription}
\end{Arguments}
\begin{Details}\relax
The appearance of a lattice display depends partly on the
\dQuote{theme} active when the display is plotted (see
\code{\LinkA{trellis.device}{trellis.device}} for details).  This theme is used to
obtain defaults for various graphical parameters, and in particular,
the \code{auto.key} argument works on the premise that the same source
is used for both the actual graphical encoding and the legend.  The
easiest way to specify custom settings for a particular display is to
use the \code{par.settings} argument, which is usually tedious to
construct as it is a nested list.  The \code{simpleKey} function can
be used in such situations as a wrapper that generates a suitable list
given parameters in simple \code{name=value} form, with the nesting
made implicit.  This is less flexible, but straightforward and
sufficient in most situations.
\end{Details}
\begin{Value}
A list that would work as the \code{theme} argument to
\code{\LinkA{trellis.device}{trellis.device}} and \code{\LinkA{trellis.par.set}{trellis.par.set}}, or
as the \code{par.settings} argument to any high level lattice function
such as \code{\LinkA{xyplot}{xyplot}}.
\end{Value}
\begin{Author}\relax
Deepayan Sarkar \email{Deepayan.Sarkar@R-project.org}, based on a
suggestion from John Maindonald.
\end{Author}
\begin{SeeAlso}\relax
\code{\LinkA{trellis.device}{trellis.device}}, \code{\LinkA{xyplot}{xyplot}},
\code{\LinkA{Lattice}{Lattice}}
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}

str(simpleTheme(pch = 16))

dotplot(variety ~ yield | site, data = barley, groups = year,
        auto.key = list(space = "right"),
        par.settings = simpleTheme(pch = 16),
        xlab = "Barley Yield (bushels/acre) ",
        aspect=0.5, layout = c(1,6))

\end{ExampleCode}
\end{Examples}

