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Formula interface to geom_text() and geom_label()

Source: R/gf_functions.R
gf_text.Rd

Text geoms are useful for labeling plots. They can be used by themselves as scatterplots or in combination with other geoms, for example, for labeling points or for annotating the height of bars. geom_text() adds only text to the plot. geom_label() draws a rectangle behind the text, making it easier to read.

Usage

gf_text(
  object = NULL,
  gformula = NULL,
  data = NULL,
  ...,
  label,
  alpha,
  angle,
  color,
  family,
  fontface,
  group,
  hjust,
  lineheight,
  size,
  vjust,
  parse = FALSE,
  nudge_x = 0,
  nudge_y = 0,
  check_overlap = FALSE,
  xlab,
  ylab,
  title,
  subtitle,
  caption,
  geom = "text",
  stat = "identity",
  position = "nudge",
  show.legend = NA,
  show.help = NULL,
  inherit = TRUE,
  environment = parent.frame()
)

gf_label(
  object = NULL,
  gformula = NULL,
  data = NULL,
  ...,
  label,
  alpha,
  angle,
  color,
  family,
  fontface,
  group,
  hjust,
  vjust,
  size,
  parse,
  nudge_x = 0,
  nudge_y = 0,
  label.padding = unit(0.25, "lines"),
  label.r = unit(0.15, "lines"),
  xlab,
  ylab,
  title,
  subtitle,
  caption,
  stat = "identity",
  position = "nudge",
  show.legend = NA,
  show.help = NULL,
  inherit = TRUE,
  environment = parent.frame()
)

Arguments

object

When chaining, this holds an object produced in the earlier portions of the chain. Most users can safely ignore this argument. See details and examples.

gformula

A formula with shape y ~ x. Faceting can be achieved by including | in the formula.

data

The data to be displayed in this layer. There are three options:

If NULL, the default, the data is inherited from the plot data as specified in the call to ggplot().

A data.frame, or other object, will override the plot data. All objects will be fortified to produce a data frame. See fortify() for which variables will be created.

A function will be called with a single argument, the plot data. The return value must be a data.frame, and will be used as the layer data. A function can be created from a formula (e.g. ~ head(.x, 10)).

...

Additional arguments. Typically these are (a) ggplot2 aesthetics to be set with attribute = value, (b) ggplot2 aesthetics to be mapped with attribute = ~ expression, or (c) attributes of the layer as a whole, which are set with attribute = value.

label

The text to be displayed.

alpha

Opacity (0 = invisible, 1 = opaque).

angle

An angle for rotating the text.

color

A color or a formula used for mapping color.

family

A font family.

fontface

One of "plain", "bold", "italic", or "bold italic".

group

Used for grouping.

hjust, vjust

Numbers between 0 and 1 indicating how to justify text relative the the specified location.

lineheight

Line height.

size

A numeric size or a formula used for mapping size.

parse

If TRUE, the labels will be parsed into expressions and displayed as described in ?plotmath.

nudge_x, nudge_y

Passed to ggplot2::position_nudge() to nudge text or labels horizontally or vertically.

check_overlap

If TRUE, text that overlaps previous text in the same layer will not be plotted. check_overlap happens at draw time and in the order of the data. Therefore data should be arranged by the label column before calling geom_text(). Note that this argument is not supported by geom_label().

xlab

Label for x-axis. See also gf_labs().

ylab

Label for y-axis. See also gf_labs().

title, subtitle, caption

Title, sub-title, and caption for the plot. See also gf_labs().

geom

A character string naming the geom used to make the layer.

stat

The statistical transformation to use on the data for this layer. When using a geom_*() function to construct a layer, the stat argument can be used to override the default coupling between geoms and stats. The stat argument accepts the following:

  • A Stat ggproto subclass, for example StatCount.

  • A string naming the stat. To give the stat as a string, strip the function name of the stat_ prefix. For example, to use stat_count(), give the stat as "count".

  • For more information and other ways to specify the stat, see the layer stat documentation.

position

A position adjustment to use on the data for this layer. This can be used in various ways, including to prevent overplotting and improving the display. The position argument accepts the following:

  • The result of calling a position function, such as position_jitter(). This method allows for passing extra arguments to the position.

  • A string naming the position adjustment. To give the position as a string, strip the function name of the position_ prefix. For example, to use position_jitter(), give the position as "jitter".

  • For more information and other ways to specify the position, see the layer position documentation.

show.legend

logical. Should this layer be included in the legends? NA, the default, includes if any aesthetics are mapped. FALSE never includes, and TRUE always includes. It can also be a named logical vector to finely select the aesthetics to display. To include legend keys for all levels, even when no data exists, use TRUE. If NA, all levels are shown in legend, but unobserved levels are omitted.

show.help

If TRUE, display some minimal help.

inherit

A logical indicating whether default attributes are inherited.

environment

An environment in which to look for variables not found in data.

label.padding

Amount of padding around label. Defaults to 0.25 lines.

label.r

Radius of rounded corners. Defaults to 0.15 lines.

Value

a gg object

Specifying plot attributes

Positional attributes (a.k.a, aesthetics) are specified using the formula in gformula. Setting and mapping of additional attributes can be done through the use of additional arguments. Attributes can be set can be set using arguments of the form attribute = value or mapped using arguments of the form attribute = ~ expression.

In formulas of the form A | B, B will be used to form facets using ggplot2::facet_wrap() or ggplot2::facet_grid(). This provides an alternative to gf_facet_wrap() and gf_facet_grid() that is terser and may feel more familiar to users of lattice.

Evaluation

Evaluation of the ggplot2 code occurs in the environment of gformula. This will typically do the right thing when formulas are created on the fly, but might not be the right thing if formulas created in one environment are used to create plots in another.

See also

ggplot2::geom_text()

Examples

data(penguins, package = "palmerpenguins")
gf_text(bill_length_mm ~ bill_depth_mm,
  data = penguins,
  label = ~species, color = ~species, size = 2, angle = 30
)
#> Warning: Removed 2 rows containing missing values or values outside the scale range
#> (`geom_text()`).

penguins |>
gf_point(bill_length_mm ~ bill_depth_mm, color = ~species, alpha = 0.5) |>
  gf_text(bill_length_mm ~ bill_depth_mm,
    label = ~species, color = ~species,
    size = 2, angle = 0, hjust = 0, nudge_x = 0.1, nudge_y = 0.1
  )
#> Warning: Removed 2 rows containing missing values or values outside the scale range
#> (`geom_point()`).
#> Warning: Removed 2 rows containing missing values or values outside the scale range
#> (`geom_text()`).

if (require(dplyr)) {
  data(penguins, package = "palmerpenguins")
  penguins_means <-
    penguins |>
    group_by(species) |>
    summarise(bill_length_mm = mean(bill_length_mm), bill_depth_mm = mean(bill_depth_mm))
  gf_point(bill_length_mm ~ bill_depth_mm, data = penguins, color = ~species) |>
    gf_label(bill_length_mm ~ bill_depth_mm,
      data = penguins_means,
      label = ~species, color = ~species, size = 2, alpha = 0.7
    )
}
#> Warning: Removed 2 rows containing missing values or values outside the scale range
#> (`geom_point()`).
#> Warning: Removed 2 rows containing missing values or values outside the scale range
#> (`geom_label()`).