Functions for working with colour scales or palettes

Description

The getColourScale function can be used to obtain a standard or customised colour scale for use in the package's image visualisation functions. A graded palette of colours between two or more key colours can be obtained using interpolatePalette.

Usage

interpolatePalette(colours, n, ...)

getColourScale(n)

Arguments

Details

Colour scales can be specified in any of three ways. Firstly, by a single number, representing a predefined colour scale. Currently valid values are 1 (greyscale, black background), 2 (red to yellow heat scale, red background), 3 (blue to red rainbow scale, blue background), 4 (blue to white to red diverging scale, white background), 5 (white to red, white background) and 6 (white to blue, white background). Secondly, a single colour name can be given (see colours); in this case the background will be black. This is useful for binary images. Thirdly and most flexibly, a list with two named elements can be given: colours, a vector of colours representing the colour scale, perhaps created using rgb; and background, a single colour representing the background.

Value

For getColourScale, a list with elements

colours

A character-mode vector representing the colours in the scale, usually of length 100. This can be passed as a colour scale to R's plotting functions.

background

A single character string representing the background colour.

The interpolatePalette function returns a character-mode vector representing the colours in the interpolated scale.

Author(s)

Jon Clayden

References

Please cite the following reference when using TractoR in your work:

J.D. Clayden, S. Muñoz Maniega, A.J. Storkey, M.D. King, M.E. Bastin & C.A. Clark (2011). TractoR: Magnetic resonance imaging and tractography with R. Journal of Statistical Software 44(8):1-18. http://www.jstatsoft.org/v44/i08/.

See Also

colours, rgb, colorRamp

Examples

getColourScale(1)

interpolatePalette(c("red","yellow"), 10)