Guide primitive: line

This function constructs a line guide primitive.

Usage

primitive_line(key = NULL, cap = "none", theme = NULL, position = waiver())

Arguments

key

A standard key specification. See more information in the linked topic.

cap

A method to cap the axes. One of the following:

• A <character[1]> with one of the following:

  • "none" to perform no capping.

  • "both" to cap the line at both ends at the most extreme breaks.

  • "upper" to cap the line at the upper extreme break.

  • "lower" to cap the line at the lower extreme break.

• A <logical>[1], where TRUE is equivalent to "both" and FALSE is equivalent to "none" in the options above.

• A sorted <numeric>[2n] with an even number of members. The lines will be drawn between every odd-even pair.

• A <function> that takes the scale's breaks as the first argument, the scale's limits as the second argument and returns a <numeric>[2n] as described above.

theme

A <theme> object to style the guide individually or differently from the plot's theme settings. The theme argument in the guide overrides and is combined with the plot's theme.

position

A <character[1]> giving the location of the guide. Can be one of "top", "bottom", "left" or "right".

Value

A PrimitiveLine primitive guide that can be used inside other guides.

Styling options

Below are the theme options that determine the styling of this guide, which may differ depending on whether the guide is used in an axis or in a legend context.

As an axis guide

• axis.line.{x/y}.{position} an <element_line> for the line style.

As a legend guide

• legend.axis.line an <element_line> for the line style.

See also

Other primitives: primitive_box(), primitive_bracket(), primitive_fence(), primitive_labels(), primitive_segments(), primitive_spacer(), primitive_ticks(), primitive_title()

Examples

# A standard plot
p <- ggplot(mpg, aes(displ, hwy)) +
  geom_point() +
  theme(axis.line = element_line())

# Adding as secondary guides
p + guides(
  x.sec = primitive_line(),
  y.sec = primitive_line(cap = "both")
)