R: Text on a curve

geom_textcurve {geomtextpath}

R Documentation

Text on a curve

Description

geom_textcurve() and geom_labelcurve() draw text on curved lines. See the underlying grid::curveGrob() for the parameters that control the curve.

Usage

geom_textcurve(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  ...,
  curvature = 0.5,
  angle = 90,
  ncp = 5,
  arrow = NULL,
  lineend = "butt",
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

geom_labelcurve(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  ...,
  curvature = 0.5,
  angle = 90,
  ncp = 5,
  arrow = NULL,
  lineend = "butt",
  label.r = unit(0.15, "lines"),
  label.padding = unit(0.25, "lines"),
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

Arguments

`mapping`	Set of aesthetic mappings created by `aes()`. If specified and `inherit.aes = TRUE` (the default), it is combined with the default mapping at the top level of the plot. You must supply `mapping` if there is no plot mapping.
`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)`).
`stat`	The statistical transformation to use on the data for this layer, either as a `ggproto` `Geom` subclass or as a string naming the stat stripped of the `stat_` prefix (e.g. `"count"` rather than `"stat_count"`)
`position`	Position adjustment, either as a string naming the adjustment (e.g. `"jitter"` to use `position_jitter`), or the result of a call to a position adjustment function. Use the latter if you need to change the settings of the adjustment.
`...`	Other arguments passed on to `layer`. These are often aesthetics, used to set an aesthetic to a fixed value, like `colour = "red"` or `size = 3`. These can also be the following text-path parameters: `text_only` A `logical(1)` indicating whether the path part should be plotted along with the text (`FALSE`, the default). If `TRUE`, any parameters or aesthetics relating to the drawing of the path will be ignored. `gap` A `logical(1)` which if `TRUE`, breaks the path into two sections with a gap on either side of the label. If `FALSE`, the path is plotted as a whole. Alternatively, if `NA`, the path will be broken if the string has a `vjust` between 0 and 1, and not otherwise. The default for the label variant is `FALSE` and for the text variant is `NA`. `upright` A `logical(1)` which if `TRUE` (default), inverts any text where the majority of letters would upside down along the path, to improve legibility. If `FALSE`, the path decides the orientation of text. `halign` A `character(1)` describing how multi-line text should be justified. Can either be `"center"` (default), `"left"` or `"right"`. `offset` A `unit` object of length 1 to determine the offset of the text from the path. If this is `NULL` (default), the `vjust` parameter decides the offset. If not `NULL`, the `offset` argument overrules the `vjust` setting. `parse` A `logical(1)` which if `TRUE`, will coerce the labels into expressions, allowing for plotmath syntax to be used. `straight` A `logical(1)` which if `TRUE`, keeps the letters of a label on a straight baseline and if `FALSE` (default), lets individual letters follow the curve. This might be helpful for noisy paths. `padding` A `unit` object of length 1 to determine the padding between the text and the path when the `gap` parameter trims the path. `rich` A `logical(1)` whether to interpret the text as html/markdown formatted rich text. Default: `FALSE`. See also the rich text section of the details in `geom_textpath()`. `remove_long` if TRUE, labels that are longer than their associated path will be removed.
`curvature`	A numeric value giving the amount of curvature. Negative values produce left-hand curves, positive values produce right-hand curves, and zero produces a straight line.
`angle`	A numeric value between 0 and 180, giving an amount to skew the control points of the curve. Values less than 90 skew the curve towards the start point and values greater than 90 skew the curve towards the end point.
`ncp`	The number of control points used to draw the curve. More control points creates a smoother curve.
`arrow`	Arrow specification, as created by `grid::arrow()`.
`lineend`	Line end style (round, butt, square).
`na.rm`	If `FALSE`, the default, missing values are removed with a warning. If `TRUE`, missing values are silently removed.
`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.
`inherit.aes`	If `FALSE`, overrides the default aesthetics, rather than combining with them. This is most useful for helper functions that define both data and aesthetics and shouldn't inherit behaviour from the default plot specification, e.g. `borders()`.
`label.r`	Radius of rounded corners. Defaults to 0.15 lines.
`label.padding`	Amount of padding around label. Defaults to 0.25 lines.

Value

A Layer ggproto object that can be added to a plot.

Aesthetics

geom_textcurve() understands the following aesthetics (required aesthetics are in bold):

x
xend
y
yend
label
alpha
angle
colour
family
fontface
group
hjust
linecolour
lineheight
linetype
linewidth
size
spacing
textcolour
vjust

In addition to aforementioned aesthetics, geom_labelcurve() also understands:

boxcolour
boxlinetype
boxlinewidth
fill

The spacing aesthetic allows fine control of spacing of text, which is called 'tracking' in typography. The default is 0 and units are measured in 1/1000 em. Numbers greater than zero increase the spacing, whereas negative numbers decrease the spacing.

Learn more about setting these aesthetics in vignette("ggplot2-specs").

Examples

t <- seq(0, 2 * pi, length.out = 4)[-1]

df <- data.frame(
  x = cos(t),
  y = sin(t),
  xend = cos(t + 1.8),
  yend = sin(t + 1.8)
)

ggplot(df, aes(x, y, xend = xend, yend = yend)) +
  geom_textcurve(
    label = c(
      "A chicken lays an egg",
      "A chick becomes a chicken",
      "An egg hatches into a chick"
    ),
    curvature = 0.5, vjust = 2,
    arrow = arrow(ends = "first")
  ) +
  coord_equal(xlim = c(-1.1, 1.1), ylim = c(-1.1, 1.1))

[Package geomtextpath version 0.1.4 Index]