colorRamp
Ramp/Interpolate Colors

### Description

Generates functions that interpolate the given colors to create new color ramps and palettes.

### Usage

    colorRamp(colors, bias = 1, space = c("rgb", "Lab"),
        interpolate = c("linear", "spline"))
    colorRampPalette(colors, ...)

### Arguments

colors | a vector of color names, or an "##rrggbb"/"##rrggbbaa" format string representing colors, or integers representing the color index of the palette table.
bias | a positive number. The interpolating function places the input color values at positions seq(0, 1, length.out=length(colors)) ^ bias on the x axis. When bias is 1 (the default), the input colors are equally spaced.
space | a character string specifying the interpolation in an sRGB or Lab color space. This argument is currently ignored: the interpolation is always done in an sRGB color space.
interpolate | a character string specifying the "linear" or "spline" interpolation method.
... | all remaining arguments to colorRampPalette are passed to colorRamp to control how the colors are interpolated.

### Details

approxfun or splinefun is used for the "linear" or "spline" interpolation method.
Value

colorRamp | returns a function that maps the values between 0 and 1 to a 3- (or 4- if alpha is TRUE) column matrix of numbers between 0 and 255, specifying the values of the red, green, and blue components of the interpolated color (and the opacity value if alpha is TRUE). There is one row per input color.
colorRampPalette | returns a function that maps a positive integer, n, to a n-long character vector specifying n colors that interpolate between the input colors. The returned colors are in the hexadecimal color format "#RRGGBB" (or "RRGGBBAA" if alpha is TRUE).

See Also
rgb, col2rgb, colors.
Examples

    colorRamp(c("green", "yellow", "red"))(0:4/4)
    colorRampPalette(c("green", "yellow", "red"))(5)
    colorRamp(c("#00ff0000", "#ffff00af", "#ff0000ff"), alpha=TRUE, interp="spline")((0:10)/10)
    colorRamp(c("red", "yellow", "green", "cyan"), bias=1/3)((0:10)/10)

Package grDevices version 6.1.5-18
Package Index