\Header{polygonChrom}{Functions to plot circular chromosomes informations}
\alias{chromPos2angle}{polygonChrom}
\alias{cPlotCircle}{polygonChrom}
\keyword{hplot}{polygonChrom}
\keyword{dplot}{polygonChrom}
\begin{Description}\relax
Functions to plot circular chromosomes informations\end{Description}
\begin{Usage}
\begin{verbatim}
cPlotCircle(radius=1, xlim=c(-2, 2), ylim=xlim, edges=300, main=NULL,
            main.inside, ...)

chromPos2angle(pos, len.chrom, rot=pi/2, clockwise=TRUE)

polygonChrom(begin, end, len.chrom, radius.in, radius.out,
             total.edges = 300,
             edges = max(round(abs(end - begin)/len.chrom *
                     total.edges), 2, na.rm = TRUE),
             rot = pi/2, clockwise = TRUE, ...)

ecoli.len
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{radius}] radius
\item[\code{xlim, ylim}] range for the plot. Can be used to zoom-in a
particular region.
\item[\code{pos}] position (nucleic base coordinate)
\item[\code{begin}] begining of the segment (nucleic base number). 
\item[\code{end}] end of the segment (nucleic base number). 
\item[\code{len.chrom}] length of the chromosome in base pairs 
\item[\code{radius.in}] inner radius 
\item[\code{radius.out}] outer radius 
\item[\code{total.edges}] total number of edges for the chromosome
\item[\code{edges}] number of edges for the specific segment(s) 
\item[\code{rot}] rotation (default is \code{pi / 2}, bringing the angle
zero at 12 o'clock)
\item[\code{clockwise}] rotate clockwise. Default to \code{TRUE}.  
\item[\code{main, main.inside}] main titles for the plot
\item[\code{...}] optional graphical parameters 
\end{ldescription}
\end{Arguments}
\begin{Details}\relax
The function \code{chromPos2angle} is a convenience function.
The variable ecoli.len contains the size of the Escheria coli genome
considered (K12).\end{Details}
\begin{Value}
Except \code{chromPos2angle}, the function are solely used for their
border effects.\end{Value}
\begin{Author}\relax
laurent <laurent@cbs.dtu.dk>\end{Author}
\begin{SeeAlso}\relax
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}

data(ecoligenomeSYMBOL2AFFY)
data(ecoligenomeCHRLOC)

## find the operon lactose ("lac*" genes)
lac.i <- grep("^lac", ls(ecoligenomeSYMBOL2AFFY))
lac.symbol <- ls(ecoligenomeSYMBOL2AFFY)[lac.i]
lac.affy <- unlist(lapply(lac.symbol, get, envir=ecoligenomeSYMBOL2AFFY))

beg.end <- lapply(lac.affy, get, envir=ecoligenomeCHRLOC)
beg.end <- matrix(unlist(beg.end), nc=2, byrow=TRUE)

lac.o <- order(beg.end[, 1])

lac.i <- lac.i[lac.o]
lac.symbol <- lac.symbol[lac.o]
lac.affy <- lac.affy[lac.o]
beg.end <- beg.end[lac.o, ]

lac.col <- rainbow(length(lac.affy))

par(mfrow=c(2,2))

## plot

cPlotCircle(main="lac genes")
polygonChrom(beg.end[, 1], beg.end[, 2], ecoli.len, 1, 1.2, col=lac.col)
rect(0, 0, 1.1, 1.1, border="red")

cPlotCircle(xlim=c(0, 1.2), ylim=c(0, 1.1))
polygonChrom(beg.end[, 1], beg.end[, 2], ecoli.len, 1, 1.1, col=lac.col)
rect(0.4, 0.8, 0.7, 1.1, border="red")

cPlotCircle(xlim=c(.45, .5), ylim=c(.85, 1.0))
polygonChrom(beg.end[, 1], beg.end[, 2], ecoli.len, 1, 1.03, col=lac.col)

mid.genes <- apply(beg.end, 1, mean)
mid.angles <- chromPos2angle(mid.genes, ecoli.len)
xy <- polar2xy(1.03, mid.angles)
xy.labels <- data.frame(x = seq(0.45, 0.5, length=4), y = seq(0.95, 1.0, length=4))
segments(xy$x, xy$y, xy.labels$x, xy.labels$y, col=lac.col)
text(xy.labels$x, xy.labels$y, lac.symbol, col=lac.col)

\end{ExampleCode}
\end{Examples}

