Package 'colorRamp2'

Add transparency to colors

Description

Add transparency to colors

Usage

add_transparency(col, transparency = 0)

Arguments

col	A vector of colors.
transparency	Transparency, numeric value between 0 and 1.

Value

A vector of colors.

Examples

add_transparency("red", 0.5)
add_transparency(1, 0.5)
add_transparency("#FF000080", 0.2)

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Convert back from colors to values

Description

Convert back from colors to values

Usage

col2value(r, g, b, col_fun)

Arguments

r	Red channel in sRGB color space. Value should be between 0 and 1. The value can also be a character vector of colors or a three-column matrix with r, g, b as columns. In this case, g and b are ignored,
g	Green channel in sRGB color space. Value should be between 0 and 1.
b	Blue channel in sRGB color space. Value should be between 0 and 1.
col_fun	the color mapping function generated by colorRamp2.

Details

colorRamp2 maps values to colors and this function does the reversed job. Note for some color spaces, it cannot convert back to the original value perfectly.

Value

A vector of original numeric values.

Author(s)

Zuguang Gu <[email protected]>

Examples

x = seq(0, 1, length.out = 11)
col_fun = colorRamp2(c(0, 0.5, 1), c("blue", "white", "red"))
col = col_fun(x)
col2value(col, col_fun = col_fun)
col2value("red", col_fun = col_fun)

col_fun = colorRamp2(c(0, 0.5, 1), c("blue", "white", "red"), space = "sRGB")
col = col_fun(x)
col2value(col, col_fun = col_fun)

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Generate color mapping functions

Description

Generate color mapping functions

Usage

colorRamp2(breaks, colors, transparency = 0, space = "LAB",
    hcl_palette = NULL, reverse = FALSE)

Arguments

breaks	A vector of numeric break values.
colors	A vector of colors which correspond to values in breaks.
transparency	A single value in [0, 1]. 0 refers to no transparency and 1 refers to full transparency.
space	Color space in which colors are interpolated. Value should be one of "RGB", "LAB", "XYZ", "sRGB", "LUV", see color-class for details.
hcl_palette	Name of the HCL palette. Value should be supported in hcl.pals.
reverse	Whether should the colors in hcl_palette be reversed.

Details

Colors are linearly interpolated according to the break values and corresponding colors through a certain color space. Values exceeding breaks will be assigned with corresponding maximum or minimum colors.

Value

A function which accepts a vector of numeric values and returns interpolated colors.

See Also

col2value converts back to the original values by providing the color mapping function generated by colorRamp2.

Examples

col_fun = colorRamp2(c(-1, 0, 1), c("green", "white", "red"))
col_fun(c(-2, -1, -0.5, 0, 0.5, 1, 2))

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Generate random colors

Description

Generate random colors

Usage

rand_color(n, hue = NULL, luminosity = "random", transparency = 0, friendly = FALSE)

Arguments

n	Number of colors
hue	The hue of the generated color. You can use following default color name: red, orange, yellow, green, blue, purple, pink and monochrome. If the value is a hexidecimal color string such as #00FFFF, the function will extract its hue value and use that to generate colors.
luminosity	it controls the luminosity of the generated color. The value should be a string containing bright, light, dark and random.
transparency	Transparency, numeric value between 0 and 1.
friendly	If it is true, light random colors will not be generated.

Details

The code is adapted from randomColor.js (https://github.com/davidmerfield/randomColor ).

Author(s)

Zuguang Gu <[email protected]>

Examples

plot(NULL, xlim = c(1, 10), ylim = c(1, 8), axes = FALSE, ann = FALSE)
points(1:10, rep(1, 10), pch = 16, cex = 5, 
    col = rand_color(10))
points(1:10, rep(2, 10), pch = 16, cex = 5, 
    col = rand_color(10, luminosity = "bright"))
points(1:10, rep(3, 10), pch = 16, cex = 5, 
    col = rand_color(10, luminosity = "light"))
points(1:10, rep(4, 10), pch = 16, cex = 5, 
    col = rand_color(10, luminosity = "dark"))
points(1:10, rep(5, 10), pch = 16, cex = 5, 
    col = rand_color(10, hue = "red", luminosity = "bright"))
points(1:10, rep(6, 10), pch = 16, cex = 5, 
    col = rand_color(10, hue = "green", luminosity = "bright"))
points(1:10, rep(7, 10), pch = 16, cex = 5, 
    col = rand_color(10, hue = "blue", luminosity = "bright"))
points(1:10, rep(8, 10), pch = 16, cex = 5, 
    col = rand_color(10, hue = "monochrome", luminosity = "bright"))

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