morgenstemning (version 1.0)

isolum: Create a colorblind-safe vector of n isoluminent colors.

Description

Create a colorblind-safe vector of n isoluminent colors.

Usage

isolum(n = 256, mincolor = NULL, maxcolor = NULL, invert = FALSE, gamma = 1.8, alpha = 1)

Arguments

n

the number of colors to be in the palette.

mincolor

a color with which to replace the lower end of the scale.

maxcolor

a color with which to replace the upper end of the scale.

invert

logical indicating whether the palette should be inverted.

gamma

the exponent to use for each channel when converting to greyscale, such that grey = (red^gamma + green^gamma + blue^gamma) ^ (1/gamma).

alpha

the alpha transparency for the palette.

Value

A character vector of color names. This can be used either to create a user-defined color palette for subsequent graphics by palette(cv), a col = specification in graphics functions or in par.

Details

The colormap is isoluminent and perceived by those with a red-green color perception deficiency as a linear ramp between blue and yellow. However, the colormap has been enriched with a red control point for those with normal color vision, with the shade carefully chosen to avoid creating a non-linear ramp for those with red-green color perception deficiency. As the color map is isoluminent, it will appear as one shade of grey across the entire range when printed on a black & white printer.

See Also

palettes and colors.

Examples

require(graphics)
# A color wheel
pie(rep(1,12), col=isolum(12))