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)
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.