\name{getI}
\alias{getI}
\title{
Which data that \code{panel.fun} is using
}
\description{
Which data that \code{panel.fun} is using
}
\usage{
getI(...)
}
\arguments{

  \item{...}{Invisible arguments that users do not need to care
}

}
\details{
The function should only be put inside \code{panel.fun} when using \code{\link{circos.genomicTrackPlotRegion}}.

If \code{stack} is set to \code{TRUE} in \code{\link{circos.genomicTrackPlotRegion}}, the returned value
indicates which stack the function will be applied to.

If \code{data} is a list of data frames, the value
indicates which data frame is being used. Please see the vignette to get a more clear explanation.
}
\examples{
# There is no example
NULL

}
