Text (Last Only) Repel

Source: R/geom_text_lastonly_repel.R

Label only the last point(s) on a plot. geom_text_lastonly_repel() can be used instead of ggplot2::geom_text() when only the last point(s) should be labeled. This is accomplished by identifying the maximum value of x in data and applying a filter to omit records where x is less than the maximum.

geom_text_lastonly_repel(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = NULL,
  parse = FALSE,
  box.padding = 0.25,
  point.padding = 1e-06,
  min.segment.length = 0.5,
  arrow = NULL,
  force = 1,
  force_pull = 1,
  max.time = 0.5,
  max.iter = 10000,
  max.overlaps = getOption("ggrepel.max.overlaps", default = 10),
  nudge_x = 0.4,
  nudge_y = 0,
  xlim = c(NA, NA),
  ylim = c(NA, NA),
  na.rm = FALSE,
  check_overlap = FALSE,
  direction = c("y", "x", "both"),
  seed = NA,
  verbose = FALSE,
  show.legend = FALSE,
  inherit.aes = TRUE,
  add_points = FALSE,
  text_aes = NULL,
  point_aes = NULL,
  ...
)

Arguments

mapping

Set of aesthetic mappings created by aes or aes_. If specified and inherit.aes = TRUE (the default), is combined with the default mapping at the top level of the plot. You only need to supply mapping if there isn't a mapping defined for the plot.

data

A data frame. If specified, overrides the default data frame defined at the top level of the plot.

stat

The statistical transformation to use on the data for this layer, as a string.

position

Position adjustment, either as a string, or the result of a call to a position adjustment function.

parse

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

box.padding

Amount of padding around bounding box, as unit or number. Defaults to 0.25. (Default unit is lines, but other units can be specified by passing unit(x, "units")).

point.padding

Amount of padding around labeled point, as unit or number. Defaults to 0. (Default unit is lines, but other units can be specified by passing unit(x, "units")).

min.segment.length

Skip drawing segments shorter than this, as unit or number. Defaults to 0.5. (Default unit is lines, but other units can be specified by passing unit(x, "units")).

arrow

specification for arrow heads, as created by arrow

force

Force of repulsion between overlapping text labels. Defaults to 1.

force_pull

Force of attraction between a text label and its corresponding data point. Defaults to 1.

max.time

Maximum number of seconds to try to resolve overlaps. Defaults to 0.5.

max.iter

Maximum number of iterations to try to resolve overlaps. Defaults to 10000.

max.overlaps

Exclude text labels when they overlap too many other things. For each text label, we count how many other text labels or other data points it overlaps, and exclude the text label if it has too many overlaps. Defaults to 10.

nudge_x, nudge_y

Horizontal and vertical adjustments to nudge the starting position of each text label. The units for nudge_x and nudge_y are the same as for the data units on the x-axis and y-axis.

xlim, ylim

Limits for the x and y axes. Text labels will be constrained to these limits. By default, text labels are constrained to the entire plot area.

na.rm

If FALSE (the default), removes missing values with a warning. If TRUE silently removes missing values.

direction

"both", "x", or "y" – direction in which to adjust position of labels

seed

Random seed passed to set.seed. Defaults to NA, which means that set.seed will not be called.

verbose

If TRUE, some diagnostics of the repel algorithm are printed

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.

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.

add_points

If TRUE, points will be added to the plot (for the labeled data only). Default size=2, color will match line color.

text_aes, point_aes

Named list, additional aesthetics to send to the text and point geoms, respectively.

...

Additional aesthetics to send to BOTH the point and text geoms. Note that if add_points = FALSE, additional parameters can be passed to the text geom here, rather than in text_aes, without breaking.

Details

Labels are placed by default to the right of the final point, and may be partially cut off by the plot limits. There are two known ways to address this:

  1. Turn off panel clipping, e.g. with coord_cartesian(clip = "off"). Substitute the correct coordinate system for your plot–all have a clip argument available. Note that this will allow all geoms in the plot to draw outside the panel area, which may have unintended consequences.

  2. Manually expand the x scale, e.g. with scale_x_continuous(expand=expand_scale(mult=0.10)) or coord_cartesian(xlim = c(min, max)).

Code was mostly copied from the source of ggrepel::geom_text_repel() and ggplot2::geom_point().

Examples


library(tidyverse)
#> ── Attaching core tidyverse packages ──────────────────────── tidyverse 2.0.0 ──
#> ✔ dplyr     1.1.4     ✔ readr     2.1.5
#> ✔ forcats   1.0.0     ✔ stringr   1.5.1
#> ✔ lubridate 1.9.4     ✔ tibble    3.2.1
#> ✔ purrr     1.0.4     ✔ tidyr     1.3.1
#> ── Conflicts ────────────────────────────────────────── tidyverse_conflicts() ──
#> ✖ dplyr::filter() masks stats::filter()
#> ✖ dplyr::lag()    masks stats::lag()
#> ℹ Use the conflicted package (<http://conflicted.r-lib.org/>) to force all conflicts to become errors

df <- transit_ridership %>%
  filter(system != "pace_ada") %>%
 mutate(system = recode_factor(system,
                               cta_bus = "CTA bus",
                              cta_rail = "CTA rail",
                               metra = "Metra",
                               pace = "Pace"))

# Without points, label formatting or x-axis expansion
ggplot(df, aes(x = year, y = ridership, color = system)) +
 geom_line() +
 labs(title = "Annual Transit Ridership") +
 scale_y_continuous("Ridership (Millions)") +
 scale_x_continuous("Year") +
 geom_text_lastonly()