Package 'ltc'

Adjust Lightness of Palette Colors

Description

Darken or lighten an entire palette or specific colors within it. Uses the colorspace package for perceptually uniform adjustments.

Usage

adjust_ltc(palette_name, amount = 0, which = NULL)

Arguments

palette_name	Character or unquoted name. Name of the ltc palette to adjust.
amount	Numeric. Amount to adjust lightness (-100 to 100). Negative values darken, positive values lighten. Default is 0 (no change).
which	Integer vector. Which colors to adjust (e.g., c(1, 3) for 1st and 3rd). If NULL (default), adjusts all colors.

Value

A vector of adjusted hex color codes with class "ltc"

Examples

# Darken entire palette
adjust_ltc(alger, amount = -20)

# Lighten entire palette
adjust_ltc("maya", amount = 30)

# Darken only specific colors
adjust_ltc(remains, amount = -25, which = c(2, 4))

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Plot a Colour Palette as a Bird

Description

Visualizes a selected colour palette in the form of a bird drawing. Requires at least 5 colors in the palette.

Usage

bird(chrom)

Arguments

chrom

An ltc palette object

Value

A ggplot2 object showing a bird drawing using the selected colours.

Examples

# Create a bird visualization
pal <- ltc(paloma)
bird(pal)

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Create Custom Palette with Individual Color Adjustments

Description

Apply different lightness adjustments to each color in a palette.

Usage

custom_adjust_ltc(palette_name, adjustments)

Arguments

palette_name	Character or unquoted name. Name of the ltc palette.
adjustments	Numeric vector. Lightness adjustments for each color (-100 to 100). Length must match the palette length.

Value

A vector of adjusted hex color codes with class "ltc"

Examples

# Different adjustment for each color
custom_adjust_ltc(remains, c(-30, 0, 40, 0))

# Create gradient effect
custom_adjust_ltc("maya", c(-40, -20, 0, 20, 40))

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Desaturate Palette Colors

Description

Reduce color saturation (make colors more gray).

Usage

desaturate_ltc(palette_name, amount = 0.5, which = NULL)

Arguments

palette_name	Character or unquoted name. Name of the ltc palette.
amount	Numeric. Desaturation amount (0 to 1). 0 = no change, 1 = completely gray.
which	Integer vector. Which colors to desaturate. If NULL (default), affects all colors.

Value

A vector of desaturated hex color codes with class "ltc"

Examples

# Desaturate entire palette
desaturate_ltc(luminaries, amount = 0.5)

# Desaturate only specific colors
desaturate_ltc("heatmap2", amount = 0.7, which = c(1, 2))

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Information about the Colour Palettes

Description

This dataframe contains the backstory or inspiration behind each color palette.

Usage

info

Format

An object of class data.frame with 32 rows and 2 columns.

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List of colour palettes

Description

A list containing predefined colour palettes with artistic backstories.

This function provides the desired colour palette by name. You can call it with or without quotes: ltc(paloma) or ltc("paloma")

Usage

palettes

ltc(name, n, type = c("discrete", "continuous"))

Arguments

name	Character or unquoted name. The name of the desired palette.
n	Integer. The number of colors you want from the palette. If omitted, it uses all colors from the palette.
type	The type of palette. Either "discrete" or "continuous".

Format

An object of class list of length 32.

Details

ltc: A Collection of Art-inspired Colour Palettes

This package provides a collection of color palettes inspired by art, nature, and personal preferences. Each palette has a backstory, providing context and meaning to the colors.

Value

A vector of hex color codes with class "ltc"

Examples

# Load a palette (with or without quotes)
ltc(paloma)
ltc("maya")

# Select first 3 colors
ltc(maya, n = 3)

# Generate continuous palette
ltc(remains, n = 10, type = "continuous")

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Preview a Palette under Colour Vision Deficiency (CVD)

Description

Simulates how an ltc palette appears to viewers with the three main types of colour vision deficiency (colour blindness) and shows the result as rows of swatches. Useful for checking whether a palette stays distinguishable for colour-blind readers.

The simulation uses colorspace: deuteranopia (green-weak, the most common), protanopia (red-weak) and tritanopia (blue-weak).

Usage

ltc_cvd(name, severity = 1, labels = TRUE)

Arguments

name	Character or unquoted palette name (e.g. dora or "dora"), or a character vector of hex colours.
severity	Numeric in ⁠[0, 1]⁠. Strength of the deficiency, where 1 is the full dichromatic simulation (the default) and lower values give milder anomalous-trichromacy simulations.
labels	Logical. If TRUE (default) the hex codes are printed on the swatches.

Value

A ggplot2 object: one row of swatches per vision type (Normal, Deuteranopia, Protanopia, Tritanopia).

Examples

ltc_cvd(dora)
ltc_cvd("expevo", severity = 0.6)

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Build a Palette Function from an ltc Palette

Description

Returns a function of n that gives n colours from the named palette, which is the form ggplot2 scales expect. Like the rest of the package, the name may be quoted, bare, or held in a variable.

If more colours are asked for than the palette holds, the palette is interpolated to that length rather than failing, so a scale never breaks on a data set with more groups than expected.

Usage

ltc_pal(name, direction = 1)

Arguments

name	Character or unquoted name. The name of the desired palette.
direction	1 keeps the palette order, -1 reverses it.

Value

A function taking n and returning a character vector of n hex colour codes.

Examples

pal <- ltc_pal(maya)
pal(3)

ltc_pal("expevo", direction = -1)(5)

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Plot a Colour Palette

Description

Visualizes a selected colour palette as a bar of colours.

Usage

## S3 method for class 'ltc'
plot(x, ...)

Arguments

x	An ltc palette object
...	Additional arguments (currently unused).

Value

A ggplot2 object showing the selected colours.

Examples

# Create and plot a palette
pal <- ltc(paloma)
plot(pal)

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Print Method for ltc Objects

Description

Custom print method that displays the palette name followed by hex color codes with actual colors visible in the console.

Usage

## S3 method for class 'ltc'
print(x, ...)

Arguments

x	An ltc palette object
...	Additional arguments (currently unused)

Value

Invisibly returns the palette object

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ggplot2 Colour Scale from an ltc Palette

Description

Colours the colour aesthetic with an ltc palette, the way scale_colour_viridis() does. Set discrete = FALSE for a continuous scale. scale_color_ltc() is the same function under the US spelling.

Usage

scale_colour_ltc(name, discrete = TRUE, direction = 1, ...)

scale_color_ltc(name, discrete = TRUE, direction = 1, ...)

Arguments

name	Character or unquoted name. The name of the desired palette.
discrete	TRUE for a discrete scale, FALSE for a continuous one.
direction	1 keeps the palette order, -1 reverses it.
...	Passed on to ggplot2::discrete_scale() when discrete = TRUE, or to ggplot2::scale_colour_gradientn() when discrete = FALSE.

Value

A ggplot2 scale, to add to a plot.

Examples

library(ggplot2)

ggplot(mtcars, aes(wt, mpg, colour = factor(cyl))) +
  geom_point(size = 3) +
  scale_colour_ltc(alger)

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ggplot2 Fill Scale from an ltc Palette

Description

Colours the fill aesthetic with an ltc palette, the way scale_fill_viridis() does. Set discrete = FALSE for a continuous scale.

Usage

scale_fill_ltc(name, discrete = TRUE, direction = 1, ...)

Arguments

name	Character or unquoted name. The name of the desired palette.
discrete	TRUE for a discrete scale, FALSE for a continuous one.
direction	1 keeps the palette order, -1 reverses it.
...	Passed on to ggplot2::discrete_scale() when discrete = TRUE, or to ggplot2::scale_fill_gradientn() when discrete = FALSE.

Value

A ggplot2 scale, to add to a plot.

Examples

library(ggplot2)

# discrete
ggplot(mtcars, aes(factor(cyl), mpg, fill = factor(cyl))) +
  geom_boxplot() +
  scale_fill_ltc(maya)

# continuous
ggplot(faithfuld, aes(waiting, eruptions, fill = density)) +
  geom_raster() +
  scale_fill_ltc(heatmap0, discrete = FALSE)

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