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Manual axis

Source: R/guide_axis_manual.R
guide_axis_manual.Rd

[Questioning] This axis allows a greater degree of control than the default axes guides. In particular, this axis allows setting break positions and labels independently from the scale and is not bound by the same constraints as secondary axes. Additionally, label attributes may be set in parallel to the labels themselves, circumventing the unsupported vectorised input to element_text(). The function is questioned due to a possible migration of guide functions after ggplot2 releases a new guide system.

Usage

guide_axis_manual(
  title = waiver(),
  breaks = waiver(),
  labels = waiver(),
  label_family = NULL,
  label_face = NULL,
  label_colour = NULL,
  label_size = NULL,
  label_hjust = NULL,
  label_vjust = NULL,
  label_lineheight = NULL,
  label_color = NULL,
  label_margin = NULL,
  check.overlap = FALSE,
  angle = NULL,
  n.dodge = 1,
  order = 0,
  colour = NULL,
  color = NULL,
  trunc_lower = NULL,
  trunc_upper = NULL,
  position = waiver()
)

Arguments

title

A character string or expression indicating a title of guide. If NULL, the title is not shown. By default (waiver()), the name of the scale object or the name specified in labs() is used for the title.

breaks

One of the following ways to parametrise the tick and label positions:

  • NULL to draw no ticks and labels.

  • waiver() for the default breaks computed by the scale (default).

  • A numeric vector for continuous or discrete scales, or a character vector for discrete scales.

  • A function that takes the limits as input and returns breaks as output. Also accepts rlang lambda notation.

  • A unit vector for setting data-independent breaks.

labels

One of the following ways to dictate the labels:

  • NULL to draw no labels.

  • waiver() for the default labels computed by the scale on the breaks (default). Note that a scale with non-identity transformation is unlikely to graciously handle breaks defined in grid-units.

  • A character vector giving

  • A function that takes the breaks as input and returns labels as output. Also accepts rlang lambda notation.

label_family, label_face, label_colour, label_size, label_hjust, label_vjust, label_lineheight, label_color, label_margin

Arguments passed down to the label constructor. See element_text() arguments, which these arguments mirror with the label_-prefix. With the exception of label_margin, the other label_* arguments are assumed be parallel to (the result of) the labels argument and will be recycled with rep_len() as necessary. By default, these parameters are taken from the theme.

check.overlap

silently remove overlapping labels, (recursively) prioritizing the first, last, and middle labels.

angle

Compared to setting the angle in theme() / element_text(), this also uses some heuristics to automatically pick the hjust and vjust that you probably want. Can be one of the following:

  • NULL to take the angles and hjust/vjust directly from the theme.

  • waiver() to allow reasonable defaults in special cases.

  • A number representing the text angle in degrees.

n.dodge

The number of rows (for vertical axes) or columns (for horizontal axes) that should be used to render the labels. This is useful for displaying labels that would otherwise overlap.

order

A positive integer of length 1 that specifies the order of this guide among multiple guides. This controls in which order guides are merged if there are multiple guides for the same position. If 0 (default), the order is determined by a secret algorithm.

colour, color

A character(1) with a valid colour for colouring the axis text, axis ticks and axis line. Overrules the colour assigned by the theme.

trunc_lower, trunc_upper

The lower and upper range of the truncated axis:

  • NULL to not perform any truncation.

  • A function that takes the break positions as input and returns the lower or upper boundary. Note that also for discrete scales, positions are the mapped positions as numeric.

  • A numeric value in data units for the lower and upper boundaries.

  • A unit object.

position

Where this guide should be drawn: one of top, bottom, left, or right.

Value

An axis_manual guide class object.

See also

Other axis-guides: guide_axis_logticks(), guide_axis_minor(), guide_axis_nested(), guide_axis_scalebar(), guide_axis_truncated()

Examples

ggplot(iris, aes(Species, Sepal.Width)) +
  geom_boxplot(aes(fill = Species)) +
  guides(x = guide_axis_manual(
    label_colour = scales::hue_pal()(3),
    label_face = c("bold", "italic", "plain"),
    labels = toupper
  ))


# Using the manual axis to annotate some specific point
ggplot(pressure, aes(temperature, pressure)) +
  geom_point() +
  geom_hline(yintercept = 300, linetype = 2, colour = "blue") +
  guides(y.sec = guide_axis_manual(breaks = 300, labels = "some\nthreshold",
                                   label_colour = "blue"))