alpha_channel {colorplane} | R Documentation |
extract the alpha channel
alpha_channel(x, ...)
## S4 method for signature 'HexColorPlane'
alpha_channel(x, normalize = TRUE)
## S4 method for signature 'ConstantColorPlane'
alpha_channel(x, normalize = TRUE)
## S4 method for signature 'RGBColorPlane'
alpha_channel(x, normalize = TRUE)
x |
the object to extract alpha channel from |
... |
extra args |
normalize |
divide by 255 |
a numeric vector of alpha channel values
cp <- IntensityColorPlane(seq(1,5), cols=rainbow(25))
cl <- map_colors(cp, irange=c(0,50))
stopifnot(length(alpha_channel(cl)) == 5)