Manual legend

This is a guide that displays user-defined keys independent of scales. It should only be used as a last resort when struggling to format a conventional legend.

Usage

guide_legend_manual(
  labels,
  ...,
  layers = list(geom_point()),
  title = NULL,
  legend_args = list()
)

Arguments

labels

Labels to display next to the keys. Can be a <character> or <expression> vector to set labels, or NULL to draw no labels.

...

Arguments interpreted as aesthetics. For example: colour = "red". The aesthetics must have the same size as the labels argument, or have size 1. These aesthetics may be overruled by fixed aesthetics set in the layers argument.

layers

A <list> of layers (<LayerInstance> objects) created by the geom_*() or stat_*() family of functions. These layers are used for their key_glyph drawing functions, as well as to populate default aesthetics. Any fixed aesthetics provided to these layers overrule aesthetics passed to the ... argument.

title

One of the following to indicate the title of the guide:

• A <character[1]> or <expression[1]> to set a custom title.

• NULL to not display any title.

legend_args

A <list> of arguments passed on to guide_legend_base().

Value

A <GuideCustom> object.

Details

Because this guide is not tied to a scale, it can be given an arbitrary name in guides(); as long as it doesn't clash with other aesthetics.

See also

Other standalone guides: guide_axis_base(), guide_axis_dendro(), guide_axis_nested(), guide_axis_plot(), guide_circles(), guide_colbar(), guide_colring(), guide_colsteps(), guide_legend_base(), guide_legend_cross(), guide_legend_group()

Other legend guides: guide_legend_base(), guide_legend_cross(), guide_legend_group()

Examples

# A standard plot
p <- ggplot(mtcars, aes(disp, mpg)) +
  geom_point()

# Typical usage: set `label` and some aesthetics
p + guides(
  some_name = guide_legend_manual(
    label  = c("foo", "bar"),
    colour = c(NA, "black"),
    fill   = c("grey40", NA),
    layers = geom_col()
  )
)


# Alternative: use `layers` to set aesthetics
p + guides(
  some_name = guide_legend_manual(
    label = c("foo", "bar"),
    layers = geom_col(
      # Must match length of `label`
      colour = c(NA, "black"),
      fill = c("grey40", NA)
    )
  )
)


# You can use >1 layer
p + guides(
  some_name = guide_legend_manual(
    label = c("foo", "bar"),
    colour = c("tomato", "dodgerblue"),
    fill = NA,
    layers = list(geom_col(), geom_point())
  )
)