color2blackwhite: Convert colors to contrasted gray level for black and white...

In spnet: Plotting (Social) Networks on Maps

Description

This function converts color codes (given in hexadecimal format) to constrasted gray levels. This is useful to enhance readability when printing in black and white. The conversion from color to gray levels is performed using the luminosity method (0.21R + 0.72G + 0.07B), then levels are linearly scaled to [contrast.min;contrast.max].

Usage

color2blackwhite(x, increase.contrast = TRUE, contrast.min = 0.02,
  contrast.max = 0.98)

Arguments

x	a character, the vector of color codes given in hexadecimal format (ex "#21AD5C").
increase.contrast	a logical, if TRUE the scaling is performed.
contrast.min	the minimal gray value to use in the scaling (0 = white, 1 = black).
contrast.max	the maximal gray value to use in the scaling (0 = white, 1 = black).

Examples

mycols = c("#BA364E", "#32BAA1", "#12AA91")
color2blackwhite(mycols)

barplot(1:3, axes=FALSE, col=mycols)
barplot(1:3, axes=FALSE, col=color2blackwhite(mycols, increase.contrast = FALSE))
barplot(1:3, axes=FALSE, col=color2blackwhite(mycols))
barplot(1:3, axes=FALSE, col=color2blackwhite(mycols, contrast.min = 0, contrast.max = 1))

spnet documentation built on May 2, 2019, 10:56 a.m.