Col function

Generate a transparent RGB color

This function transforms a standard color (e.g. "red") into an transparent RGB-color (i.e. alpha-blend<1).

Col(col, alpha = 0.2, locate = 0)

Arguments

• col: Color (numeric or character)
• alpha: Degree of transparency (0,1)
• locate: Choose colour (with mouse)

Returns

A character vector with elements of 7 or 9 characters, # followed by the red, blue, green and optionally alpha values in hexadecimal (after rescaling to '0 ... 255').

Details

This only works for certain graphics devices (Cairo-X11 (x11 as of R>=2.7), quartz, pdf, ...).

Examples

plot(runif(1000),cex=runif(1000,0,4),col=Col(c("darkblue","orange"),0.5),pch=16)

Author(s)

Klaus K. Holst