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Guide primitives: segments

Source: R/primitive-segments.R
primitive_segments.Rd

This function constructs a guide primitive.

Usage

primitive_segments(
  key = NULL,
  space = rel(10),
  vanish = FALSE,
  theme = NULL,
  position = waiver()
)

Arguments

key

A segment key specification. See more information in the linked topic. Alternatively, an object of class <hclust> that automatically invokes key_dendro().

space

Either a <unit> or <rel> object of length 1 determining the space allocated in the orthogonal direction. When the space argument is of class <rel> (default) the base size is taken from the tick length theme setting.

vanish

Only relevant when the guide is used in the secondary theta position: a <logical[1]> on whether the continue to draw the segments until they meed in the center (TRUE) or strictly observe the space setting (FALSE).

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 <PrimitiveSegments> primitive guide that can be used inside other guides.

Styling options

Below are the theme options that determine the style 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.ticks.{x/y}.{position} an <element_line> for display of the segments.

  • axis.ticks.length.{x/y}.{position} a <unit> for the base size of the segments in the orthogonal direction.

As a legend guide

  • legend.ticks an <element_line> for display of the segments.

  • legend.ticks.length a <unit> for the base size of the segments in the orthogonal direction.

See also

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

Examples

# Building a key
key <- key_segment_manual(
  value     = c(1.6, 1.6, 3.4, 5.2),
  value_end = c(7.0, 7.0, 3.4, 5.2),
  oppo      = c(1.0, 2.0, 0.0, 0.0),
  oppo_end  = c(1.0, 2.0, 3.0, 3.0)
)

# Using the primitive in a plot
ggplot(mpg, aes(displ, hwy)) +
  geom_point() +
  scale_x_continuous(
    guide = primitive_segments(key = key)
  )