R: Convert Colors to Grey/Grayscale

ColToGrey {DescTools} | R Documentation

## Convert Colors to Grey/Grayscale

### Description

Convert colors to grey/grayscale so that you can see how your plot will look after photocopying or printing to a non-color printer.

### Usage

    ColToGrey(col)
    ColToGray(col)

### Arguments

`col` | vector of any of the three kind of R colors, i.e., either a color name (an element of colors()), a hexadecimal string of the form "#rrggbb" or "#rrggbbaa" (see rgb), or an integer i meaning palette()[i]. Non-string values are coerced to integer.

### Details

Converts colors to greyscale using the formula grey = 0.3*red + 0.59*green + 0.11*blue. This allows you to see how your color plot will approximately look when printed on a non-color printer or photocopied.

### Value

A vector of colors (greys) corresponding to the input colors.

### Note

These function was previously published as `Col2Grey()` in the TeachingDemos package and has been integrated here without logical changes.

### Author(s)

Greg Snow <greg.snow@imail.org>

### See Also

`grey`, `ColToRgb`, dichromat package

### Examples

    par(mfcol=c(2,2))
    tmp <- 1:3
    names(tmp) <- c('red','green','blue')

    barplot(tmp, col=c('red','green','blue'))
    barplot(tmp, col=ColToGrey(c('red','green','blue')))

    barplot(tmp, col=c('red','#008100','#3636ff'))
    barplot(tmp, col=ColToGrey(c('red','#008100','#3636ff')))

[Package DescTools version 0.99.32 Index]