GISTools (version 1.0-2)

Create Transparency: Add transparency to a hex-defined colour

Description

Takes a colour defined in hex format as #XXXXXX and adds a two transparency bytes XX based on a number from 0 to 1. Its main use is to make RColorBrewer palettes transparent.

Usage

add.alpha(hex.color.list,alpha)

Value

A list of strings defining transparent colours in eight byte format.

Arguments

hex.color.list

A list of strings defining solid colors in six byte format.

alpha

A value (or list of values) from 0 to 1 specifying transparency.

Author

Chris Brunsdon

Examples

# Make a list of semi-transparent RColorBrewer colours,  based on Brewer's Red palette with 5 shades
require(RColorBrewer)
add.alpha(brewer.pal(5,'Reds'),0.5)