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Color Theme Scales for ggplot2 Graphics

Source: R/scale_color_theme.R
scale_color_theme.Rd

scale_color_theme() and its family of functions provide a unified interface to apply custom color themes to the colour and fill aesthetics of "ggplot" objects.

Usage

scale_color_theme(
  theme,
  ...,
  discrete = NULL,
  middle = 0,
  aesthetics = "colour"
)

scale_colour_theme(
  theme,
  ...,
  discrete = NULL,
  middle = 0,
  aesthetics = "colour"
)

scale_fill_theme(theme, ..., discrete = NULL, middle = 0, aesthetics = "fill")

Arguments

theme

a color theme name (e.g., "Viridis"), a character vector of color names, or a palette/ramp function. See ?color.theme for more details.

...

optional arguments to be passed to ggplot2::continuous_scale() or ggplot2::discrete_scale().

discrete

logical. If TRUE, a discrete scale is used regardless of the theme type.

middle

a numeric value specifying the middle point for the diverging color themes.

aesthetics

the aesthetic to be scaled. Can be "colour", "color", or "fill".

Value

scale_color_theme() returns a ggplot2 scale object (either a "ScaleContinuous" or "ScaleDiscrete" object) that can be added to a "ggplot" object.

Details

This function automatically determines the appropriate ggplot2 scale based on the theme's type. If the theme is "qualitative", a discrete scale is used by default to assign distinct colors to categorical data. The discrete argument is automatically set to TRUE if not specified. If the theme is "sequential" or "diverging", a continuous scale is used by default. The "diverging" themes are handled by scales::rescale_mid() to correctly center the gradient around the middle value.

See also

color.theme

Examples

data(txhousing, package = "ggplot2")
cities <- c("Houston", "Fort Worth", "San Antonio", "Dallas", "Austin")
df <- subset(txhousing, city %in% cities)
d <- ggplot2::ggplot(data = df, ggplot2::aes(x = sales, y = median)) +
  ggplot2::geom_point(ggplot2::aes(colour = city))

# Plot with a qualitative theme
d + scale_color_theme("Set 1")


# Use a sequential theme as a discrete scale
d + scale_color_theme("SunsetDark", discrete = TRUE)


data(faithfuld, package = "ggplot2")
v <- ggplot2::ggplot(faithfuld) +
  ggplot2::geom_tile(ggplot2::aes(waiting, eruptions, fill = density))

# Plot with continuous themes
v + scale_fill_theme("Plasma")


# Use a diverging theme with a specified midpoint
v + scale_fill_theme("midr", middle = 0.017)