heplots (version 1.3-8)

trans.colors: Make Colors Transparent

Description

Takes a vector of colors (as color names or rgb hex values) and adds a specified alpha transparency to each.

Usage

trans.colors(col, alpha = 0.5, names = NULL)

Arguments

col

A character vector of colors, either as color names or rgb hex values

alpha

alpha transparency value(s) to apply to each color (0 means fully transparent and 1 means opaque)

names

optional character vector of names for the colors

Value

A vector of color values of the form "#rrggbbaa"

Details

Colors (col) and alpha need not be of the same length. The shorter one is replicated to make them of the same length.

See Also

col2rgb, rgb, adjustcolor,

Examples

# 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=""))

# }