#*********************************************
#*********************************************
#' Returns a color vector of heat colors.
#'
#' @param x is a numeric object to which rainbow colors combined with lightening and darkening should be matched.
#' @param h is the value hue at the end point of the heat color vector, defaulted to 1/6 to move from red to yellow.
#' @param v is the value (lightness) of the colors.
#' @param start and 'end' are the start and end colors, given as values in [0,1].
#' @param breakpoint is the breakpoint between 0 and 1 where the color vector turns at white.
#' @param flip is true if the color scale should be reversed.
#' @param alpha is the transparency.
#' @param ... methods passed on to sub-functions (not used, but allowing for unused arguments).
#'
#' @return
#'
#' @examples
#' \dontrun{
#' x=runif(1000)
#' pp(1,2)
#' plot(x, pch=".", cex=30, col=heat.colorsx(x))
#' plot(x, pch=".", cex=30, col=heat.colorsx(x, flip=TRUE))
#' }
#'
#' @importFrom TSD dim_all NAs setrange
#' @importFrom grDevices hsv
#'
#' @export
#' @rdname heat.colorsx
#'
heat.colorsx<-function(x, h=1/6, v=1, start=0, end=1, clamp=NULL, breakpoint=0.75, flip=FALSE, alpha=1, ...){
############### LOG: ###############
# Start: 2013-09-12 - Clean version.
##################################################
##################################################
##### Preparation #####
if(length(breakpoint)==0){
breakpoint=0.75
}
fit1breakpoint<-function(z,breakpoint,zlow,zhigh,y){
out = NAs(dim_all(z))
out[zlow] = y[1] + 1/breakpoint * z[zlow] * (y[2]-y[1])
out[zhigh] = y[3] + (1/(1-breakpoint)) * (z[zhigh]-breakpoint) * (y[4]-y[3])
out
}
# Identify NAs, and discard these from the calculation of colors:
notna = !is.na(x)
x = setrange(x,if(flip) c(end,start) else c(start,end), clamp=clamp)
xlow = which(x[notna] < breakpoint)
xhigh = which(x[notna] >= breakpoint)
##### Execution #####
# The hue and saturation are adopted from heat.colors():
h = c(0,h,h,h)
h = fit1breakpoint(x[notna],breakpoint,xlow,xhigh,h)
s = c(1,1,1,0)
s = fit1breakpoint(x[notna],breakpoint,xlow,xhigh,s)
##### Output #####
out = NAs(dim_all(x))
out[notna] = hsv(h=h, s=s, v=v, alpha=alpha)
out
##################################################
##################################################
}
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