spal: Create sequential color palettes using the HCL color space

In michaelmalick/r-chroma: chroma

Description

spal creates sequential color palettes using the HCL color space. Sequential color palettes are composed of a gradient of colors where the gradient can include a range of hues, luminance values, or chroma values. Sequential color palettes are suitable for encoding continuous variables where either low or high values are of importance, but not both.

Usage

spal(n, hue.start = 235, hue.end = NULL, luminance = c(30, 85),
  chroma = c(90, 100), power = 1, alpha = 1, fixup = TRUE)

Arguments

n	number of colors to create
hue.start	starting hue value, should be in the interval [0, 360]
hue.end	ending hue value, should be in the interval [0, 360].
luminance	vector of length 2 giving the start and end bounds for the range of luminance values
chroma	vector of length 2 giving the start and end bounds for the range of chroma values
power	parameter to control how chroma and luminance increase/decrease
alpha	transparency level defined on the interval [0, 1] where 0 = transparent and 1 = opaque
fixup	logical, should RGB value be corrected (see hcl

Value

spal returns a vector of hex colors

Author(s)

Michael Malick

See Also

hcl qpal dpal

Examples

plotpal(spal(140))
plotpal(spal(140, luminance = c(20, 80)))
plotpal(spal(140, hue.start = 235, hue.end = 70))
plotpal(spal(140, hue.start = 235, hue.end = 70, luminance = c(20, 80)))

image(t(volcano)[ncol(volcano):1,], col = spal(100))
image(t(volcano)[ncol(volcano):1,], col = spal(100, hue.end = 70))

plotpal(spal(140, power = 0.8))
plotpal(spal(140, power = 1))
plotpal(spal(140, power = 1.3))
plotpal(spal(140, power = 1.5))

plotpal(spal(140, hue.start = 260, chroma = c(80, 0),
    luminance = c(30, 90), power = 1.5))

michaelmalick/r-chroma documentation built on May 22, 2019, 9:51 p.m.