\HeaderA{plotExpressionGraph}{A function to plot a graph colored by expression data}{plotExpressionGraph}
\aliasA{defMapFun}{plotExpressionGraph}{defMapFun}
\aliasA{getPlotExpressionColors}{plotExpressionGraph}{getPlotExpressionColors}
\keyword{utilities}{plotExpressionGraph}
\keyword{graphs}{plotExpressionGraph}
\keyword{hplot}{plotExpressionGraph}
\begin{Description}\relax
Given a graph and expression data for one entity, will plot the graph
with the nodes colored according to the expression levels provided.
\end{Description}
\begin{Usage}
\begin{verbatim}
plotExpressionGraph(graph, nodeLLmap, exprs, LOCUSIDenvir, mapFun, log = FALSE, nodeAttrs = list(), ...)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{graph}] The graph to plot
\item[\code{nodeLLmap}] A list with element names being node names and the
elements being LocusLink IDs corresponding to those node names.
\item[\code{exprs}] A vector of expression data, with names being Affymetrix
IDs and values being the expression level.
\item[\code{LOCUSIDenvir}] An environment mapping Affymetrix IDs to LocusLink
IDs, such as the ones provided in the xxx2LOCUSID environments from
the Bioconductor data packages (where xxx) is a data package)
\item[\code{mapFun}] A function to map expression levels to colors
\item[\code{log}] Whether or not the expression data 
\item[\code{nodeAttrs}] A list of node attributes, as per \code{plot.graph}
\item[\code{...}] Any extra arguments to be passed to \code{plot.graph} 
\end{ldescription}
\end{Arguments}
\begin{Details}\relax
This function can be used to plot a graph and have the nodes colored
according to expression levels provided by the user.  The
\code{graph} parameter is a \code{graph} object from the \code{graph}
package.

The \code{nodeLLmap} parameter is a list that maps the nodes of the
graphs to LocusLink IDs.  An example of this is the
\code{IMCALocusLink} object in the
\code{integrinMediatedCellAdhesion} data set in the
\code{graph} package.

The \code{exprs} argument is a vector mapping expression levels to
Affymetrix IDs.  One way to generate an appropriate vector is to
extract a single column from an \code{exprSet}.

The \code{LOCUSIDenvir} environment maps Affymetrix IDs to LocusLink
IDs.  The simplest way to provide this argument is to load the
preferred Bioconductor data package (e.g. \code{hgu95av2}) and pass in
that package's \code{xxx2LOCUSID}, where \code{xxx} is the name of the
package.

The \code{mapFun} function defaults to the function \code{defMapFun},
which maps nodes to be either blue, green or red depending for
expression ranges of 0-100, 101-500, and 501+.  In the case where
\code{log} is \code{TRUE} these ranges are modified with
\code{\LinkA{log2}{log2}}.  Custom versions of this function can be supplied
by the user - it must take two parameters, first the expression vector
and a boolean value (\code{log}) specifying if the data has had a
\code{log2} applied to it.  The function must return a vector with the
same names as the expression vector, but the values of the vector will
be color strings.

The \code{nodeAttrs} list can be specified if any other node
attributes are desired to be set by the user.  Please see the
\code{\LinkA{plot.graph}{plot.graph}} man page for more information on this.  The
other attribute list (\code{attrs} and \code{edgeAttrs}) can be passed
in via the \code{...} parameter.
\end{Details}
\begin{Author}\relax
Jeff Gentry
\end{Author}
\begin{SeeAlso}\relax
\code{\LinkA{plot.graph}{plot.graph}}, \code{integrinMediatedCellAdhesion}
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
   if ((require("Rgraphviz")) && (require("hgu95av2")) &&
        (require("fibroEset")) && (interactive())) {     
            data(integrinMediatedCellAdhesion)
            data(fibroEset)
            attrs=getDefaultAttrs()
            attrs$graph$rankdir <- "LR"
            plotExpressionGraph(IMCAGraph, IMCALocusLink,
                                exprs(fibroEset)[,1],
                                hgu95av2LOCUSID, attrs=attrs)
   }
\end{ExampleCode}
\end{Examples}