rainbow_hcl
HCL and HSV Color Palettes
Color palettes based on the HCL and HSV color spaces.
- Keywords
- color
Usage
rainbow_hcl(n, c = 50, l = 70, start = 0, end = 360*(n-1)/n,
gamma = 2.4, fixup = TRUE, ...)sequential_hcl(n, h = 260, c. = c(80, 0), l = c(30, 90), power = 1.5,
gamma = 2.4, fixup = TRUE, ...)
heat_hcl(n, h = c(0, 90), c. = c(100, 30), l = c(50, 90), power = c(1/5, 1),
gamma = 2.4, fixup = TRUE, ...)
terrain_hcl(n, h = c(130, 0), c. = c(80, 0), l = c(60, 95), power = c(1/10, 1),
gamma = 2.4, fixup = TRUE, ...)
diverge_hcl(n, h = c(260, 0), c = 80, l = c(30, 90), power = 1.5,
gamma = 2.4, fixup = TRUE, ...)
diverge_hsv(n, h = c(240, 0), s = 1, v = 1, power = 1,
gamma = 2.4, fixup = TRUE, ...)
Arguments
- n
- the number of colors ($\ge 1$) to be in the palette.
- c, c.
- chroma value in the HCL color description.
- l
- luminance value in the HCL color description.
- start
- the hue at which the rainbow begins.
- end
- the hue at which the rainbow ends.
- h
- hue value in the HCL or HSV color description, has to be in [0, 360] for HCL and in [0, 1] for HSV colors.
- s
- saturation value in the HSV color description.
- v
- value value in the HSV color description.
- power
- control parameter determining how chroma and luminance should be increased (1 = linear, 2 = quadratic, etc.).
- gamma
- gamma value of the display.
- fixup
- logical. Should the color be corrected to a valid RGB value before correction?
- ...
- Other arguments passed to
hex
.
Details
All functions compute palettes based on either the HCL (polarLUV
)
or the HSV (HSV
) color space.
rainbow_hcl
computes a rainbow of colors (qualitative palette)
defined by different hues given a single value of each chroma and luminance.
It corresponds to rainbow
which computes a rainbow in
HSV space.
sequential_hcl
gives a sequential palette starting at the full
color HCL(h
, c[1]
, l[1]
) through to a light color
HCL(h
, c[2]
, l[2]
) by interpolation.
diverge_hcl
and diverge_hsv
, compute
a set of colors diverging from a neutral center (grey or white, without
color) to two different extreme colors (blue and red by default). This
is similar to cm.colors
. For the diverging HSV colors,
two hues h
are needed, a maximal saturation s
and a
fixed value v
. The saturation is then varied to obtain the
diverging colors. For the diverging HCL colors, again two hues h
are needed, a maximal chroma c
and two luminances l
.
The colors are then created by an interpolation between the
full color HCL(h[1]
, c
, l[1]
), a neutral color HCL(h
, 0, l[2]
)
and the other full color HCL(h[2]
, c
, l[1]
).
The palette heat_hcl
gives an implementation of heat.colors
in HCL space. By default, it goes from a red to a yellow hue, while
simultaneously going to lighter colors (i.e., increasing luminance)
and reducing the amount of color (i.e., decreasing chroma).
The terrain_hcl
palette simply calls heat_hcl
with different
parameters, providing colors similar in spirit to terrain.colors
.
The lighter colors are not strictly HCL colors, though.
Value
- A character vector with (s)RGB codings of the colors in the palette.
encoding
UTF-8
References
Zeileis A., Hornik K. and Murrell P. (2007),
Escaping RGBland: Selecting Colors for Statistical Graphics.
Report 61, Department of Statistics and Mathematics, Wirtschaftsuniversität Wien,
Research Report Series,
See Also
Examples
## convenience demo functions
wheel <- function(col, radius = 1, ...)
pie(rep(1, length(col)), col = col, radius = radius, ...)
pal <- function(col, border = "light gray")
{
n <- length(col)
plot(0, 0, type="n", xlim = c(0, 1), ylim = c(0, 1), axes = FALSE, xlab = "", ylab = "")
rect(0:(n-1)/n, 0, 1:n/n, 1, col = col, border = border)
}
## qualitative palette
wheel(rainbow_hcl(12))
## a few useful diverging HCL palettes
par(mar = rep(0, 4), mfrow = c(4, 1))
pal(diverge_hcl(7))
pal(diverge_hcl(7, h = c(246, 40), c = 96, l = c(65, 90)))
pal(diverge_hcl(7, h = c(130, 43), c = 100, l = c(70, 90)))
pal(diverge_hcl(7, h = c(180, 70), c = 70, l = c(90, 95)))
pal(diverge_hcl(7, h = c(180, 330), c = 59, l = c(75, 95)))
pal(diverge_hcl(7, h = c(128, 330), c = 98, l = c(65, 90)))
pal(diverge_hcl(7, h = c(255, 330), l = c(40, 90)))
pal(diverge_hcl(7, c = 100, l = c(50, 90), power = 1))
## sequential palettes
pal(sequential_hcl(12))
pal(heat_hcl(12, h = c(0, -100), l = c(75, 40), c = c(40, 80), power = 1))
pal(terrain_hcl(12, c = c(65, 0), l = c(45, 95), power = c(1/3, 1.5)))
pal(heat_hcl(12, c = c(80, 30), l = c(30, 90), power = c(1/5, 1.5)))
## compare base and vcd palettes
par(mfrow = c(2, 1))
wheel(rainbow(12)); wheel(rainbow_hcl(12))
pal(diverge_hcl(7, c = 100, l = c(50, 90))); pal(diverge_hsv(7))
pal(diverge_hcl(7, h = c(180, 330), c = 59, l = c(75, 95))); pal(cm.colors(7))
pal(heat_hcl(12)); pal(heat.colors(12))
pal(terrain_hcl(12)); pal(terrain.colors(12))