colAlpha: Add an alpha chanel to any color
In ajrominger/socorro: Helper functions for R

Description Usage Arguments Details Value Author(s) See Also Examples

View source: R/colAlpha.R

Make any color have transparancy by adding an alpha chanel

1	colAlpha(col, alpha = 1)

`col`	the color to be modified
`alpha`	the alpha level to be added

This function converts a color to red, blue, green components and then adds the desired alpha level

A character vector of the desired colors

Andy Rominger <ajrominger@gmail.com>

hsv, rgb, col2rgb

## demonstrates use of the alpha argument: we can specify simple colors and use them in plots
## along with semi-transparent versions of them
cols <- c('red', 'blue', 'green')
plot(1:3, col=cols, bg=colAlpha(cols, alpha=c(0.7, 0.4, 0.1)), pch=21, cex=2, lwd=2)