ggpp (version 0.4.3)

geom_label_s: Linked Text

Description

Text geoms are most useful for labelling plots. `geom_text_s()` adds text to the plot and for nudged positions links the original location to the nudged text with a segment.

Usage

geom_label_s(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  ...,
  parse = FALSE,
  nudge_x = 0,
  nudge_y = 0,
  label.padding = grid::unit(0.25, "lines"),
  label.r = grid::unit(0.15, "lines"),
  label.size = 0.25,
  add.segments = TRUE,
  arrow = NULL,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)
geom_text_s(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  ...,
  parse = FALSE,
  nudge_x = 0,
  nudge_y = 0,
  add.segments = TRUE,
  arrow = NULL,
  check_overlap = FALSE,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

Arguments

mapping

Set of aesthetic mappings created by [ggplot2::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.

...

other arguments passed on to layer. There are three types of arguments you can use here:

• Aesthetics: to set an aesthetic to a fixed value, like colour = "red" or size = 3.

• Other arguments to the layer, for example you override the default stat associated with the layer.

• Other arguments passed on to the stat.

parse

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

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.

label.padding

Amount of padding around label. Defaults to 0.25 lines.

label.r

Radius of rounded corners. Defaults to 0.15 lines.

label.size

Size of label border, in mm.

add.segments

logical Display connecting segments or arrows between original positions and displaced ones if both are available.

arrow

specification for arrow heads, as created by arrow

na.rm

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

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.

check_overlap

If TRUE, text that overlaps previous text in the same layer will not be plotted. check_overlap takes place at draw time and in the order of the data, thus its action depends of the size at which the plot is drawn.

Value

A plot layer instance.

Under development

This is preliminary version of the geom. I plan to add features like padding around text and points. I aim to make use of the new features of 'grid' in R >= 4.1.0 to keep the implementation as fast and simple as possible. Currently this geom does all drawing using at most two vectorized calls to 'grid' functions. As a temporary replacement of padding around text one can use 'slightly out-of-range' numeric values for justification as shown in the examples. Aesthetics `segment.colour` and `segment.alpha` are implemented, but `segment.linetype` not yet.

Alignment

You can modify text alignment with the `vjust` and `hjust` aesthetics. These can either be a number between 0 (right/bottom) and 1 (top/left) or a character (`"left"`, `"middle"`, `"right"`, `"bottom"`, `"center"`, `"top"`). There several two special alignments: `"inward"` and `"outward"`. Inward always aligns text towards the center of the plotting area, and outward aligns it away from the center of the plotting area. It tagged with `_mean` or `_median` the mean or median of the data in the panel along the corresponding axis is used as center.

Details

Note that when you change the scale limits for x and/or y of a plot, text labels stay the same size, as determined by the size aesthetic. The actual size as seen in the plotted output is decided during the rendering of the plot to a graphics device. Limits are expanded only to include the anchor point of the labels because the "width" and "height" of a text element are 0 (as seen by ggplot2). For the same reason, stacking and dodging text will not work as they take place within 'ggplot2' before the rendered size of text is known. Text labels do have height and width, but in grid units, not data units.

By default this geom uses position_nudge_center which is backwards compatible with position_nudge but provides additional control on the direction of the nudging. In contrast to position_nudge, position_nudge_center and all other position functions defined in packages 'ggpp' and 'ggrepel' keep the original coordinates thus allowing the plotting of connecting segments and arrows.

Examples

# NOT RUN {
my.cars <- mtcars[c(TRUE, FALSE, FALSE, FALSE), ]
my.cars$name <- rownames(my.cars)
p <- ggplot(my.cars, aes(wt, mpg, label = name))

# default behavior is as for geon_text()
p + geom_text_s()
# Avoid overlaps
p + geom_text_s(check_overlap = TRUE)
# Change size of the label
p + geom_text_s(size = 2.5)

# default behavior is as for geon_label()
p + geom_label_s()
# Change size of the label
p + geom_label_s(size = 2.5)

# Use nudging
p +
  geom_point() +
  geom_text_s(hjust = -0.04, nudge_x = 0.12) +
  expand_limits(x = 6.2)
p +
  geom_point() +
  geom_text_s(hjust = -0.04, nudge_x = 0.12,
  arrow = arrow(length = grid::unit(1.5, "mm"))) +
  expand_limits(x = 6.2)
p +
  geom_point() +
  geom_text_s(vjust = -0.5, nudge_y = 0.5)
p +
  geom_point() +
  geom_text_s(angle = 90,
              hjust = -0.04, nudge_y = 1,
              arrow = arrow(length = grid::unit(1.5, "mm")),
              segment.colour = "red") +
  expand_limits(y = 30)

p +
  geom_point() +
  geom_label_s(hjust = 0, nudge_x = 0.12) +
  expand_limits(x = 6.2)

# Add aesthetic mappings and adjust arrows
p +
  geom_point() +
  geom_text_s(aes(colour = factor(cyl)),
              segment.colour = "black",
              angle = 90,
              hjust = -0.04, nudge_y = 1,
              arrow = arrow(angle = 20,
                            length = grid::unit(1.5, "mm"),
                            ends = "first",
                            type = "closed"),
              show.legend = FALSE) +
  scale_colour_discrete(l = 40) + # luminance, make colours darker
  expand_limits(y = 40)

# Add aesthetic mappings and adjust arrows
p +
  geom_point() +
  geom_label_s(aes(colour = factor(cyl)),
              hjust = 0, nudge_x = 0.3,
              arrow = arrow(angle = 20,
                            length = grid::unit(2/3, "lines"))) +
  scale_colour_discrete(l = 40) + # luminance, make colours darker
  expand_limits(x = 7)

# Scale height of text, rather than sqrt(height)
p +
  geom_point() +
  geom_text_s(aes(size = wt), nudge_x = -0.1, hjust = "right") +
  scale_radius(range = c(3,6)) + # override scale_area()
    expand_limits(x = c(1.8, 5.5))

# }