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Create a color object for workbook styling

Source: R/class-color.R
wb_color.Rd

wb_color() is a helper function used to define colors for fonts, fills, borders, and other styling elements. It creates a wbColour object that encapsulates color information in a format compatible with the OpenXML specification.

Usage

wb_color(
  name = NULL,
  auto = NULL,
  indexed = NULL,
  hex = NULL,
  theme = NULL,
  tint = NULL,
  format = c("ARGB", "RGBA")
)

Arguments

name

A character string. Can be a standard R color name (e.g., "red", "steelblue") or a hex value.

auto

A logical value. If TRUE, the spreadsheet application determines the color automatically (usually for text contrast).

indexed

An integer referencing a legacy indexed color value.

hex

A character string representing a hex color (e.g., "FF0000"). Leading "#" is optional.

theme

A zero-based integer index referencing a value in the workbook's theme (usually 0-11).

tint

A numeric value between -1.0 (darkest) and 1.0 (lightest) to modify the base color.

format

The alpha channel format for hex strings: "ARGB" (default) or "RGBA".

Value

A wbColour object (a named character vector).

Details

Colors in spreadsheets can be defined in several ways. This function standardizes those inputs into a single object.

Hex Color Formats: Hexadecimal colors represent the intensity of Red, Green, and Blue. A major point of confusion is the Alpha (transparency) channel:

  • ARGB (Default): Spreadsheet software expects the Alpha value before the RGB values (e.g., FFFF0000 for solid red).

  • RGBA: R functions like grDevices::adjustcolor() place the Alpha value after the RGB values (e.g., FF0000FF for solid red).

  • Use the format argument to tell wb_color() how to interpret your hex string if it includes transparency.

Theme Colors: Instead of hard-coding a hex value, you can use theme. These are indices (0-based) referencing the workbook's theme palette (e.g., "Text 1", "Accent 1"). Using theme colors allows the spreadsheet's appearance to change automatically if the user changes the workbook theme.

Tints: The tint parameter modifies a color's lightness. A value of -0.25 darkens the color by 25%, while 0.5 lightens it by 50%.

See also

wb_get_base_colors(), grDevices::colors()

Examples

# Using standard R colors
font_col <- wb_color("darkblue")

# Using Hex values with Alpha
bg_col <- wb_color(hex = "FFED7D31") # ARGB for orange

# Using Theme colors with a tint (4th accent color, 40% lighter)
theme_col <- wb_color(theme = 4, tint = 0.4)

# Converting R-style RGBA to spreadsheet-style ARGB
r_col <- adjustcolor("red", alpha.f = 0.5)
xlsx_col <- wb_color(hex = r_col, format = "RGBA")