R: HCL and RGB color sequences

colSequence {VIM} | R Documentation

## HCL and RGB color sequences

### Description

Compute color sequences by linear interpolation based on a continuous color scheme between certain start and end colors. Color sequences may thereby be computed in the HCL or RGB color space.

### Usage

    colSequence(p, start, end, space = c("hcl", "rgb"), ...)

    colSequenceRGB(p, start, end, fixup = TRUE, ...)

    colSequenceHCL(p, start, end, fixup = TRUE, ...)

### Arguments

`p` | a numeric vector in [0,1] giving values to be used for interpolation between the start and end color (0 corresponds to the start color, 1 to the end color).
`start, end` | the start and end color, respectively. For HCL colors, each can be supplied as a vector of length three (hue, chroma, luminance) or an object of class "`polarLUV`". For RGB colors, each can be supplied as a character string, a vector of length three (red, green, blue) or an object of class "`RGB`".
`space` | character string; if `start` and `end` are both numeric, this determines whether they refer to HCL or RGB values. Possible values are `"hcl"` (for the HCL space) or `"rgb"` (for the RGB space).
`...` | for `colSequence`, additional arguments to be passed to `colSequenceHCL` or `colSequenceRGB`. For `colSequenceHCL` and `colSequenceRGB`, additional arguments to be passed to `hex`.
`fixup` | a logical indicating whether the colors should be corrected to valid RGB values (see `hex`).

### Value

A character vector containing hexadecimal strings of the form `"#RRGGBB"`.

### Author(s)

Andreas Alfons

### References

Zeileis, A., Hornik, K., Murrell, P. (2009) Escaping RGBland: Selecting colors for statistical graphics. Computational Statistics & Data Analysis, 53 (9), 1259–1270.

### See Also

`hex`, `sequential_hcl`

### Examples

    p <- c(0, 0.3, 0.55, 0.8, 1)

    ## HCL colors
    colSequence(p, c(0, 0, 100), c(0, 100, 50))
    colSequence(p, polarLUV(L=90, C=30, H=90), c(0, 100, 50))

    ## RGB colors
    colSequence(p, c(1, 1, 1), c(1, 0, 0), space="rgb")
    colSequence(p, RGB(1, 1, 0), "red")

[Package VIM version 5.1.1 Index]