Hi,
I needed to interpolate in the CIE XYZ color space, but the default
colorRamp function does not exploit the color spaces available in
colorConvert function. Please find below a few changes to colorRamp that
permits to extend the choice of color spaces.
Best,
Samuel
colorRamp <- function(
colors, bias = 1,
space = c("rgb","Lab", "XYZ", "Apple RGB", "CIE RGB", "Luv"),
interpolate = c("linear","spline"), alpha = FALSE)
{
if (bias <= 0) stop("'bias' must be positive")
if (!missing(space) && alpha)
stop("'alpha' must be false if 'space' is specified")
colors <- t(col2rgb(colors, alpha = alpha)/255)
space <- match.arg(space)
interpolate <- match.arg(interpolate)
if (space != "rgb")
colors <- convertColor(colors, from = "sRGB", to = space)
interpolate <- switch(interpolate,
linear = stats::approxfun,
spline = stats::splinefun)
if((nc <- nrow(colors)) == 1L) {
colors <- colors[c(1L, 1L) ,]
nc <- 2L
}
x <- seq.int(0, 1, length.out = nc)^bias
palette <- c(interpolate(x, colors[, 1L]),
interpolate(x, colors[, 2L]),
interpolate(x, colors[, 3L]),
if(alpha) interpolate(x, colors[, 4L]))
roundcolor <- function(rgb) ## careful to preserve matrix:
pmax(pmin(rgb, 1), 0)
if (space != "rgb")
function(x)
roundcolor(convertColor(cbind(palette[[1L]](x),
palette[[2L]](x),
palette[[3L]](x),
if(alpha) palette[[4L]](x)),
from = space, to = "sRGB"))*255
else
function(x)
roundcolor(cbind(palette[[1L]](x),
palette[[2L]](x),
palette[[3L]](x),
if(alpha) palette[[4L]](x)))*255
}
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide https://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
