R: Transform back from colors to values

col2value {circlize} | R Documentation

## Transform back from colors to values

### Description

Transform back from colors to values

### Usage

    col2value(r, g, b, col_fun)

### Arguments

`r` | red channel in `sRGB` color space, value should be between 0 and 1. The `r`, `g` and `b` argumentc can be wrapped into one variable which is either a three-column matrix or a vector of colors.
`g` | green channel in `sRGB` color space, value should be between 0 and 1.
`b` | blue channel in `sRGB` color space, value should be between 0 and 1.
`col_fun` | the color mapping function generated by `colorRamp2`.

### Details

`colorRamp2` transforms values to colors and this function does the reversed job. Note for some color spaces, it cannot transform back to the original value perfectly.

### Value

A vector of original numeric values.

### Author(s)

Zuguang Gu <z.gu@dkfz.de>

### Examples

    x = seq(0, 1, length = 11)
    col_fun = colorRamp2(c(0, 0.5, 1), c("blue", "white", "red"))
    col = col_fun(x)
    col2value(col, col_fun = col_fun)
    col2value("red", col_fun = col_fun)

    col_fun = colorRamp2(c(0, 0.5, 1), c("blue", "white", "red"), space = "sRGB")
    col = col_fun(x)
    col2value(col, col_fun = col_fun)

[Package circlize version 0.4.1 Index]