ggpmisc (version 0.3.2)

geom_label_npc: Text with Normalised Parent Coordinates

Description

`geom_text_npc()` adds text directly to the plot. `geom_label_npc()` draws a rectangle behind the text, making it easier to read. The difference is that x and y mappings are expected to be given in `npc` graphic units. They are intended to be used for positioning text relative to the physical dimensions of a plot. This can be achieved with `annotate()` except when facetting is used.

Usage

geom_label_npc(mapping = NULL, data = NULL, stat = "identity",
  position = "identity", ..., parse = FALSE, nudge_x = 0,
  nudge_y = 0, label.padding = unit(0.25, "lines"),
  label.r = unit(0.15, "lines"), label.size = 0.25, na.rm = FALSE,
  show.legend = FALSE, inherit.aes = FALSE)
geom_text_npc(mapping = NULL, data = NULL, stat = "identity",
  position = "identity", ..., parse = FALSE, nudge_x = 0,
  nudge_y = 0, check_overlap = FALSE, na.rm = FALSE,
  show.legend = FALSE, inherit.aes = FALSE)

Arguments

mapping

The aesthetic mapping, usually constructed with aes or aes_. Only needs to be set at the layer level if you are overriding the plot defaults.

data

A layer specific dataset - only needed if you want to override the plot defaults.

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. This can include aesthetics whose values you want to set, not map. See layer for more details.

parse

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

nudge_x, nudge_y

Horizontal and vertical adjustment to nudge labels by. Useful for offsetting text from points, particularly on discrete scales.

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.

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.

`geom_label_npc()`

Currently `geom_label_npc()` does not support the `angle` aesthetic and is considerably slower than `geom_text_npc()`. The `fill` aesthetic controls the background colour of the label.

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 are two special alignments: `"inward"` and `"outward"`. Inward always aligns text towards the center, and outward aligns it away from the center. When using textual positions a shift is added based on grouping, however unsused levels are not dropped. In plots with faceting so that not all groups appear in each panel, gaps will appear in between labels. To solve this pass numeric values for the npc coordinates of each label instead of character strings.

Details

Note that the "width" and "height" of a text element are 0, so stacking and dodging text will not work by default, and axis limits are not automatically expanded to include all text. Obviously, labels do have height and width, but they are physical units, not data units. The amount of space they occupy on the plot is not constant in data units: when you resize a plot, labels stay the same size, but the size of the axes changes.

`geom_text_npc()` and `geom_label_npc()` add labels for each row in the data, even if coordinates x, y are set to single values in the call to `geom_label_npc()` or `geom_text_npc()`. To add labels at specified points use [annotate()] with `annotate(geom = "text_npc", ...)` or `annotate(geom = "label_npc", ...)`.

See Also

geom_text

Examples

# NOT RUN {
df <- data.frame(
  x = c(0, 0, 1, 1, 0.5),
  x.chr = c("left", "left", "right", "right", "center"),
  y = c(0, 1, 0, 1, 0.5),
  y.chr = c("bottom", "top", "bottom", "top", "middle"),
  text = c("bottom-left", "top-left", "bottom-right", "top-right", "center-middle")
)
ggplot(df) +
  geom_text_npc(aes(npcx = x, npcy = y, label = text))

ggplot(df) +
  geom_text_npc(aes(npcx = x.chr, npcy = y.chr, label = text))

ggplot(data = mtcars, mapping = aes(wt, mpg)) +
  geom_point() +
  geom_text_npc(data = df, aes(npcx = x, npcy = y, label = text))

ggplot(data = mtcars, mapping = aes(wt, mpg)) +
  geom_point() +
  geom_text_npc(data = df, aes(npcx = x, npcy = y, label = text)) +
  expand_limits(y = 40, x = 6)

ggplot(data = mtcars) +
  geom_point(mapping = aes(wt, mpg)) +
  geom_label_npc(data = df, aes(npcx = x, npcy = y, label = text))

# }