Takes a vector of colors (as color names or rgb hex values) and adds a specified alpha transparency to each.
trans.colors(col, alpha = 0.5, names = NULL)
A character vector of colors, either as color names or rgb hex values
alpha transparency value(s) to apply to each color (0 means fully transparent and 1 means opaque)
optional character vector of names for the colors
A vector of color values of the form "#rrggbbaa"
Colors (col
) and alpha
need not be of the same length.
The shorter one is replicated to make them of the same length.
# NOT RUN { trans.colors(palette(), alpha=0.5) # alpha can be vectorized trans.colors(palette(), alpha=seq(0, 1, length=length(palette()))) # lengths need not match: shorter one is repeated as necessary trans.colors(palette(), alpha=c(.1, .2)) trans.colors(colors()[1:20]) # single color, with various alphas trans.colors("red", alpha=seq(0,1, length=5)) # assign names trans.colors("red", alpha=seq(0,1, length=5), names=paste("red", 1:5, sep="")) # }