R: Add and set alpha channel for RGB color

col.alpha {MESS} | R Documentation

## Add and set alpha channel for RGB color

### Description

Add and set alpha channel

### Usage

    col.alpha(col, alpha = 1)

### Arguments

`col` | a vector of RGB color(s)
`alpha` | numeric value between 0 and 1. Zero results fully transparent and 1 means full opacity

### Details

This function adds and set an alpha channel to a RGB color

### Author(s)

Claus Ekstrom claus@rprimer.dk

### References

Ekstrom, CT (2011) The R Primer.

### Examples

    newcol <- col.alpha("blue", .5)

[Package MESS version 0.5.6 Index]