Package 'RcppColors'

'C++' header files for conversion from some color spaces to hexadecimal.

Description

This package is mainly intended to be used with 'Rcpp', but it also provides some R functions for color conversion and color mappings.

Details

See README for a description of the available 'C++' functions and how to use the package.

Author(s)

Stéphane Laurent.

Maintainer: Stéphane Laurent <[email protected]>

---

Color mappings functions

Description

Functions mapping each complex number to a color.

Usage

colorMap1(
  Z,
  bkgcolor = "#15191e",
  nancolor = "#000000",
  reverse = c(FALSE, FALSE, FALSE),
  nthreads = 1L
)

colorMap2(
  Z,
  bkgcolor = "#15191e",
  nancolor = "#000000",
  reverse = c(FALSE, FALSE, FALSE),
  nthreads = 1L
)

colorMap3(
  Z,
  bkgcolor = "#15191e",
  nancolor = "#000000",
  s = 80,
  n = 5,
  nthreads = 1L
)

colorMap4(
  Z,
  bkgcolor = "#15191e",
  nancolor = "#000000",
  reverse = c(FALSE, FALSE, FALSE),
  nthreads = 1L
)

colorMap5(
  Z,
  bkgcolor = "#15191e",
  nancolor = "#000000",
  reverse = c(FALSE, FALSE, FALSE),
  nthreads = 1L
)

colorMap6(
  Z,
  bkgcolor = "#15191e",
  nancolor = "#000000",
  reverse = c(FALSE, FALSE, FALSE),
  nthreads = 1L
)

colorMap7(
  Z,
  bkgcolor = "#15191e",
  nancolor = "#000000",
  reverse = c(FALSE, FALSE, FALSE),
  nthreads = 1L
)

colorMap8(
  Z,
  bkgcolor = "#15191e",
  nancolor = "#000000",
  reverse = c(FALSE, FALSE, FALSE),
  nthreads = 1L
)

colorMap9(
  Z,
  bkgcolor = "#15191e",
  nancolor = "#000000",
  reverse = c(FALSE, FALSE, FALSE),
  nthreads = 1L
)

colorMap10(
  Z,
  bkgcolor = "#15191e",
  nancolor = "#000000",
  reverse = c(FALSE, FALSE, FALSE),
  nthreads = 1L
)

colorMap11(
  Z,
  bkgcolor = "#15191e",
  nancolor = "#000000",
  reverse = c(FALSE, FALSE, FALSE),
  nthreads = 1L
)

colorMap12(
  Z,
  bkgcolor = "#15191e",
  nancolor = "#000000",
  reverse = c(FALSE, FALSE, FALSE),
  nthreads = 1L
)

colorMap13(
  Z,
  bkgcolor = "#15191e",
  nancolor = "#000000",
  reverse = c(FALSE, FALSE, FALSE),
  nthreads = 1L
)

colorMap14(
  Z,
  bkgcolor = "#15191e",
  nancolor = "#000000",
  reverse = c(FALSE, FALSE, FALSE),
  nthreads = 1L
)

Arguments

Z	complex number, vector or matrix
bkgcolor	background color; it is applied for the NA values of Z
nancolor	color for infinite and NaN values
reverse	logical vector of length three; for each component of the color space (e.g. R, G, B or H, S, L), whether to reverse it (e.g. R -> 255-R)
nthreads	number of threads used for parallel computation
s	saturation, a number between 0 and 100
n	number of rays drawn in a cycle; it should be a positive integer but any non-zero numeric value is accepted

Value

A string or a character vector or a character matrix, having the same size as Z. Each entry is a color given by a hexadecimal string.

Examples

library(RcppColors)

iota <- function(z){
  (z + 1i) / (1i*z + 1)
}
f <- function(z){
  q <- exp(2i * pi * z)
  r <- q - 4*q^2 + 2*q^3 + 8*q^4 - 5*q^5 - 8*q^6 + 6*q^7 - 23*q^9
  r / Mod(r)
}
g <- function(z){
  ifelse(
    Mod(z) >= 1, 
    NA_complex_,
    f(iota(Conj(z)))
  )
}

x <- y <- seq(-1, 1, len = 1500)
W <- outer(y, x, function(x, y) complex(real = x, imaginary = y))
Z <- g(W)
image <- colorMap1(Z)

opar <- par(mar = c(0,0,0,0), bg = "#15191E")
plot(
  c(-100, 100), c(-100, 100), type = "n", 
  xlab = "", ylab = "", axes = FALSE, asp = 1
)
rasterImage(image, -100, -100, 100, 100)
par(opar)

---

HSI color specification

Description

Converts a color given in HSI coordinates to a hexadecimal string.

Usage

hsi(h = 360, s = 100, i = 100, alpha = NULL)

Arguments

h	the hue, a number between 0 and 360
s	the saturation, a number between 0 and 100
i	the intensity, a number between 0 and 100
alpha	opacity, a number between 0 and 1, or NULL

Value

The hsi function returns a hexadecimal string representing the corresponding color.

Examples

saturation <- 100
f <- Vectorize(
  function(x, y){
    z <- complex(real = x, imaginary = y)
    modulus <- Mod(z)
    if(modulus > 1){
      return("#ffffff")
    }
    radians <- Arg(z)
    if(radians < 0){
      radians <- radians + 2*pi
    }
    degrees <- 360 * radians / 2 / pi
    hsi(h = degrees, s = saturation, i = 100*modulus)
  }
)

x <- y <- seq(-1, 1, length.out = 200L)
image <- outer(x, y, f)

opar <- par(mar = c(0, 0, 0, 0))
plot(NULL, xlim = c(-1, 1), ylim = c(-1, 1), asp = 1)
rasterImage(image, -1, -1, 1, 1)
par(opar)

---

HSL color specification

Description

Converts a color given in HSL coordinates to a hexadecimal string.

Usage

hsl(h = 360, s = 100, l = 100, alpha = NULL)

Arguments

h	the hue, a number between 0 and 360
s	the saturation, a number between 0 and 100
l	the lightness, a number between 0 and 100
alpha	opacity, a number between 0 and 1, or NULL

Value

The hsl function returns a hexadecimal string representing the corresponding color.

Examples

saturation <- 100
f <- Vectorize(
  function(x, y){
    z <- complex(real = x, imaginary = y)
    modulus <- Mod(z)
    if(modulus > 1){
      return("#ffffff")
    }
    radians <- Arg(z)
    if(radians < 0){
      radians <- radians + 2*pi
    }
    degrees <- 360 * radians / 2 / pi
    hsl(h = degrees, s = saturation, l = 100*modulus)
  }
)

x <- y <- seq(-1, 1, length.out = 200L)
image <- outer(x, y, f)

opar <- par(mar = c(0, 0, 0, 0))
plot(NULL, xlim = c(-1, 1), ylim = c(-1, 1), asp = 1)
rasterImage(image, -1, -1, 1, 1)
par(opar)

---

HSLuv color specification

Description

Converts a color given in HSLuv coordinates to a hexadecimal string or a RGB color specification.

Usage

hsluv(h = 360, s = 100, l = 100, alpha = NULL)

hsluv2rgb(h = 360, s = 100, l = 100)

Arguments

h	the hue, a number between 0 and 360
s	the saturation, a number between 0 and 100
l	the lightness, a number between 0 and 100
alpha	opacity, a number between 0 and 1, or NULL

Value

The hsluv function returns a hexadecimal string representing a color, and the hsluv2rgb returns the RGB coordinates of this color, a named vector of three integers between 0 and 255.

Examples

saturation <- 100
f <- Vectorize(
  function(x, y){
    z <- complex(real = x, imaginary = y)
    modulus <- Mod(z)
    if(modulus > 1){
      return("#ffffff")
    }
    radians <- Arg(z)
    if(radians < 0){
      radians <- radians + 2*pi
    }
    degrees <- 360 * radians / 2 / pi
    hsluv(h = degrees, s = saturation, l = 100*modulus)
  }
)

x <- y <- seq(-1, 1, length.out = 200L)
image <- outer(x, y, f)

opar <- par(mar = c(0, 0, 0, 0))
plot(NULL, xlim = c(-1, 1), ylim = c(-1, 1), asp = 1)
rasterImage(image, -1, -1, 1, 1)
par(opar)

---

RGB permutation

Description

Permutes the R-G-B components of a color.

Usage

permuteRGB(hexcolor, permutation = "gbr")

Arguments

hexcolor	vector or matrix or array of hexadecimal colors
permutation	a character string with three letters "r", "g" and "b"

Value

The colors after applying the permutation.

Examples

library(RcppColors)
x <- y <- seq(-1.7, 1.7, length.out = 512L)
zarray <- outer(y, x, function(x, y) {
  z <- x + 1i*y
  (1 + 1i) * log(sin((z^3 - 1)))
})
# image
img1 <- colorMap1(zarray)
# r -> b, g -> r, b -> g
img2 <- permuteRGB(img1, "brg")
# plot
opar <- par(mar = c(0,0,0,0), mfrow = c(1, 2), bg = "#002240")
plot(
  c(0, 1), c(0, 1), type = "n", asp = 1,
  xlab = NA, ylab = NA, axes = FALSE
)
rasterImage(img1, 0, 0, 1, 1, interpolate = TRUE)
plot(
  c(0, 1), c(0, 1), type = "n", asp = 1,
  xlab = NA, ylab = NA, axes = FALSE
)
rasterImage(img2, 0, 0, 1, 1, interpolate = TRUE)
par(opar)

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