| % File src/library/grDevices/man/densCols.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2014 R Core Team |
| % Distributed under GPL 2 or later |
| |
| |
| \name{densCols} |
| \alias{densCols} |
| \alias{blues9} |
| \title{Colors for Smooth Density Plots} |
| \description{ |
| \code{densCols} produces a vector containing colors which encode the |
| local densities at each point in a scatterplot. |
| } |
| \usage{ |
| densCols(x, y = NULL, nbin = 128, bandwidth, |
| colramp = colorRampPalette(blues9[-(1:3)])) |
| blues9 |
| } |
| \arguments{ |
| \item{x, y}{the \code{x} and \code{y} arguments provide the x and y |
| coordinates of the points. Any reasonable way of defining the |
| coordinates is acceptable. See the function \code{\link{xy.coords}} |
| for details. If supplied separately, they must be of the same length.} |
| \item{nbin}{numeric vector of length one (for both directions) or two |
| (for x and y separately) specifying the number of equally spaced |
| grid points for the density estimation; directly used as |
| \code{gridsize} in \code{\link[KernSmooth]{bkde2D}()}.} |
| \item{bandwidth}{numeric vector (length 1 or 2) of smoothing bandwidth(s). |
| If missing, a more or less useful default is used. \code{bandwidth} |
| is subsequently passed to function \code{\link[KernSmooth]{bkde2D}}.} |
| \item{colramp}{function accepting an integer \code{n} as an argument and |
| returning \code{n} colors.} |
| } |
| |
| \details{ |
| \code{densCols} computes and returns the set of colors that will be |
| used in plotting, calling \code{\link[KernSmooth]{bkde2D}(*, |
| bandwidth, gridsize = nbin, ..)} from package \CRANpkg{KernSmooth}. |
| |
| \code{blues9} is a set of 9 color shades of blue used as the default in |
| plotting. |
| } |
| |
| \value{ |
| \code{densCols} returns a vector of length \code{nrow(x)} that |
| contains colors to be used in a subsequent scatterplot. Each color |
| represents the local density around the corresponding point. |
| } |
| \seealso{ |
| \code{\link[KernSmooth]{bkde2D}} from package \CRANpkg{KernSmooth}; |
| further, \code{\link{smoothScatter}()} (package \pkg{graphics}) which |
| builds on the same computations as \code{densCols}. |
| } |
| \author{Florian Hahne at FHCRC, originally} |
| \examples{\donttest{ |
| x1 <- matrix(rnorm(1e3), ncol = 2) |
| x2 <- matrix(rnorm(1e3, mean = 3, sd = 1.5), ncol = 2) |
| x <- rbind(x1, x2) |
| |
| dcols <- densCols(x) |
| graphics::plot(x, col = dcols, pch = 20, main = "n = 1000") |
| }} |
| \keyword{dplot} |