R: Generate a transparent RGB color

Col {lava} | R Documentation

## Generate a transparent RGB color

### Description

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

### Usage

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

### Arguments

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

### Details

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

### Value

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').

### Author(s)

Klaus K. Holst

### Examples

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

[Package lava version 1.6.1 Index]