choose_palette: Graphical User Interface for Choosing HCL Color Palettes

In colorspace: A Toolbox for Manipulating and Assessing Colors and Palettes

Graphical User Interface for Choosing HCL Color Palettes

Description

A graphical user interface (GUI) for viewing, manipulating, and choosing HCL color palettes.

Usage

choose_palette(pal = diverging_hcl, n = 7L, parent = NULL, gui = "tcltk", ...)

hclwizard(n = 7L, gui = "shiny", ...)

Arguments

pal	function; the initial palette, see ‘Value’ below. Only used if gui = "tcltk".
n	integer; the initial number of colors in the palette.
parent	tkwin; the GUI parent window. Only used if gui = "tcltk".
gui	character; GUI to use. Available options are tcltk and shiny, see ‘Details’ below.
...	used for development purposes only.

Details

Computes palettes based on the HCL (hue-chroma-luminance) color model (as implemented by polarLUV). The GUIs interface the palette functions qualitative_hcl for qualitative palettes, sequential_hcl for sequential palettes with a single or multiple hues, and diverging_hcl for diverging palettes (composed from two single-hue sequential palettes).

Two different GUIs are implemented and can be selected using the function input argument gui ("tcltk" or "shiny"). Both GUIs allows for interactive modification of the arguments of the respective palette-generating functions, i.e., starting/ending hue (wavelength, type of color), minimal/maximal chroma (colorfulness), minimal maximal luminance (brightness, amount of gray), and a power transformations that control how quickly/slowly chroma and/or luminance are changed through the palette. Subsets of the parameters may not be applicable depending on the type of palette chosen. See qualitative_hcl and Zeileis et al. (2009, 2019) for a more detailed explanation of the different arguments. Stauffer et al. (2015) provide more examples and guidance.

Optionally, active palette can be illustrated by using a range of examples such as a map, heatmap, scatter plot, perspective 3D surface etc.

To demonstrate different types of deficiencies, the active palette may be desaturated (emulating printing on a grayscale printer) and collapsed to emulate different types of color-blindness (without red-green or green-blue contrasts) using the simulate_cvd functions.

choose_palette by default starts the Tcl/Tk version of the GUI while hclwizard by default starts the shiny version. hcl_wizard is an alias for hclwizard.

Value

Returns a palette-generating function with the selected arguments. Thus, the returned function takes an integer argument and returns the corresponding number of HCL colors by traversing HCL space through interpolation of the specified hue/chroma/luminance/power values.

Author(s)

Jason C. Fisher, Reto Stauffer, Achim Zeileis

References

Zeileis A, Hornik K, Murrell P (2009). Escaping RGBland: Selecting Colors for Statistical Graphics. Computational Statistics & Data Analysis, 53, 3259–3270. doi: 10.1016/j.csda.2008.11.033 Preprint available from https://www.zeileis.org/papers/Zeileis+Hornik+Murrell-2009.pdf.

Stauffer R, Mayr GJ, Dabernig M, Zeileis A (2015). Somewhere over the Rainbow: How to Make Effective Use of Colors in Meteorological Visualizations. Bulletin of the American Meteorological Society, 96(2), 203–216. doi: 10.1175/BAMS-D-13-00155.1

Zeileis A, Fisher JC, Hornik K, Ihaka R, McWhite CD, Murrell P, Stauffer R, Wilke CO (2020). “colorspace: A Toolbox for Manipulating and Assessing Colors and Palettes.” Journal of Statistical Software, 96(1), 1–49. doi: 10.18637/jss.v096.i01

See Also

simulate_cvd, desaturate, qualitative_hcl.

Examples

if(interactive()) {
## Using tcltk GUI
pal <- choose_palette()
## or equivalently: hclwizard(gui = "tcltk")

## Using shiny GUI
pal <- hclwizard()
## or equivalently: choose_palette(gui = "shiny")

## use resulting palette function
filled.contour(volcano, color.palette = pal, asp = 1)
}

colorspace documentation built on Jan. 25, 2023, 3:12 p.m.