Multiple gradient colour scales

Maps multiple aesthetics to multiple colour fill gradient scales. It takes in listed arguments for each aesthetic and disseminates these to ggplot2::continuous_scale().

Usage

scale_fill_multi(
  ...,
  colours,
  values = NULL,
  na.value = "transparent",
  guide = "colourbar",
  aesthetics = "fill",
  colors
)

scale_colour_multi(
  ...,
  colours,
  values = NULL,
  na.value = "transparent",
  guide = "colourbar",
  aesthetics = "colour",
  colors
)

Arguments

..., colours, values, na.value, guide, colors

listed arguments in scale_colour_gradientn() (e.g. colours = list(c("white", "red"), c("black", "blue"))).

aesthetics

a character vector with names of aesthetic mapping.

Value

A nested list-like structure of the class MultiScale.

Details

This function should only be called after all layers that this function affects are added to the plot.

The list elements of the listed arguments are assumed to follow the aesthetics order, i.e. the nth list element belongs to the nth aesthetic. When there are more list elements than n aesthetics, only the first nth list elements are taken. When there are more aesthetics than list elements, the first list element is used for the remaining aesthethics.

In contrast to other scale_*_continous-family functions, the guide argument is interpreted before adding it to the plot instead of at the time of plot building. This behaviour ensures that the available_aes argument of the guides are set correctly, but may interfere with the ggplot2::guides() function.

Examples

# Setup dummy data
df <- rbind(data.frame(x = 1:3, y = 1, v = NA, w = 1:3, z = NA),
            data.frame(x = 1:3, y = 2, v = 1:3, w = NA, z = NA),
            data.frame(x = 1:3, y = 3, v = NA, w = NA, z = 1:3))

ggplot(df, aes(x, y)) +
  geom_raster(aes(fill1 = v)) +
  geom_raster(aes(fill2 = w)) +
  geom_raster(aes(fill3 = z)) +
  scale_fill_multi(aesthetics = c("fill1", "fill2", "fill3"),
                   colours = list(c("white", "red"),
                                  c("black", "blue"),
                                  c("grey50", "green")))
#> Warning: Ignoring unknown aesthetics: fill1
#> Warning: Ignoring unknown aesthetics: fill2
#> Warning: Ignoring unknown aesthetics: fill3