dichromat {dichromat}R Documentation

Remove red-green distinctions from colours

Description

Collapses red-green color distinctions to approximate the effect of the two common forms of red-green colour blindness, protanopia and deuteranopia.

Usage

dichromat(colours, type = c("deutan", "protan"))

Arguments

colours A vector of R colors, either color names or color hex strings
type Type of color-blindness to simulate

Details

Someone with the specified form of red-green colour blindness will find that the transformation has little effect on the appearance of colours. Colours that are indistinguishable after transformation were likely indistinguishable to them before transformation. About 10% of men (and almost no women) have some degree of red-green colour blindness.

Value

A vector of R colors

Author(s)

Thomas Lumley

References

T. Lumley (2006) Color-coding and color blindness in statistical graphics. Statistical Computing and Graphics Newsletter. http://www.amstat-online.org/sections/graphics/newsletter/Volumes/v172.pdf

F. Vienot, H. Brettel and J. D. Mollon (1999) Digital video colourmaps for checking the legibility of displays by dichromats. Color Research and Application 24, 243-252.

Examples

## from example(pie)
 par(mfrow=c(2,2))
 pie.sales <- c(0.12, 0.3, 0.26, 0.16, 0.04, 0.12)
 names(pie.sales) <- c("Blueberry", "Cherry",
         "Apple", "Boston Cream", "Other", "Vanilla Cream")
 pie(pie.sales) # default colours
 pie(pie.sales,
       col = c("purple", "violetred1", "green3", "cornsilk", "cyan", "white"))
 pie(pie.sales,col=dichromat( c("white", "lightblue", "mistyrose", "lightcyan", 
                "lavender", "cornsilk"))) # default colours
 pie(pie.sales,
       col =dichromat(c("purple", "violetred1", "green3", "cornsilk", "cyan", "white")))


## standard color schemes
pie(rep(1,10),col=heat.colors(10))
pie(rep(1,10),col=dichromat(heat.colors(10)))
pie(rep(1,8),col=palette())
pie(rep(1,8),col=dichromat(palette()))

pie(rep(1,15),col=topo.colors(15))
pie(rep(1,15),col=dichromat(topo.colors(15)))
pie(rep(1,15),col=terrain.colors(15))
pie(rep(1,15),col=dichromat(terrain.colors(15)))

pie(rep(1,15),col=cm.colors(15))
pie(rep(1,15),col=dichromat(cm.colors(15)))
bluescale<-colorRampPalette(c("#FFFFCC","#C7E9B4","#7FCDBB","#40B6C4","#2C7FB8" ,"#253494"))
pie(rep(1,15),col=bluescale(15))
pie(rep(1,15),col=dichromat(bluescale(15)))

par(mfrow=c(2,3))
x<-matrix(rnorm(10*10),10)
redgreen<-colorRampPalette(c("red","green3"))
image(1:10,1:10,x, col=bluescale(10),
main="blue-yellow scale")
image(1:10,1:10,x, col=dichromat(bluescale(10)), main="deutan")
image(1:10,1:10,x,col=dichromat(bluescale(10),"protan"), main="protan")

image(1:10,1:10,x, col=redgreen(10),
main="red-green scale")
image(1:10,1:10,x, col=dichromat(redgreen(10)), main="deutan")
image(1:10,1:10,x, col=dichromat(redgreen(10),"protan"), main="protan")


[Package dichromat version 1.2-3 Index]