geom_text_sciname: Text
In Jtrachsel/ggscinames: Geoms for Scientific Names

Description Usage Arguments Details 'geom_label' Alignment Examples

'geom_text' adds text directly to the plot. 'geom_label' draws a rectangle behind the text, making it easier to read.

geom_text_sciname(mapping = NULL, data = NULL, stat = "identity",
  position = "identity", ..., parse = TRUE, nudge_x = 0, nudge_y = 0,
  check_overlap = FALSE, na.rm = FALSE, show.legend = NA,
  inherit.aes = TRUE)

`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.
`check_overlap`	If 'TRUE', text that overlaps previous text in the same layer will not be plotted.

Note the 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 that 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' and 'geom_label' both add a label for each row in the data, even if coordinates x, y are set to single values in the call to 'geom_label' or 'geom_text'. To add labels at specified points use [annotate()] with 'annotate(geom = "text", ...)' or 'annotate(geom = "label", ...)'

Currently 'geom_label' does not support the 'rot' parameter and is considerably slower than 'geom_text'. The 'fill' aesthetic controls the background colour of the label.

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

p <- ggplot(mtcars, aes(wt, mpg, label = rownames(mtcars)))

p + geom_text()
# Avoid overlaps
p + geom_text(check_overlap = TRUE)
# Labels with background
p + geom_label()
# Change size of the label
p + geom_text(size = 10)

# Set aesthetics to fixed value
p + geom_point() + geom_text(hjust = 0, nudge_x = 0.05)
p + geom_point() + geom_text(vjust = 0, nudge_y = 0.5)
p + geom_point() + geom_text(angle = 45)
## Not run: 
# Doesn't work on all systems
p + geom_text(family = "Times New Roman")

## End(Not run)

# Add aesthetic mappings
p + geom_text(aes(colour = factor(cyl)))
p + geom_text(aes(colour = factor(cyl))) +
  scale_colour_discrete(l = 40)
p + geom_label(aes(fill = factor(cyl)), colour = "white", fontface = "bold")

p + geom_text(aes(size = wt))
# Scale height of text, rather than sqrt(height)
p + geom_text(aes(size = wt)) + scale_radius(range = c(3,6))

# You can display expressions by setting parse = TRUE.  The
# details of the display are described in ?plotmath, but note that
# geom_text uses strings, not expressions.
p + geom_text(aes(label = paste(wt, "^(", cyl, ")", sep = "")),
  parse = TRUE)

# Add a text annotation
p +
  geom_text() +
  annotate("text", label = "plot mpg vs. wt", x = 2, y = 15, size = 8, colour = "red")


# Aligning labels and bars --------------------------------------------------
df <- data.frame(
  x = factor(c(1, 1, 2, 2)),
  y = c(1, 3, 2, 1),
  grp = c("a", "b", "a", "b")
)

# ggplot2 doesn't know you want to give the labels the same virtual width
# as the bars:
ggplot(data = df, aes(x, y, group = grp)) +
  geom_col(aes(fill = grp), position = "dodge") +
  geom_text(aes(label = y), position = "dodge")
# So tell it:
ggplot(data = df, aes(x, y, group = grp)) +
  geom_col(aes(fill = grp), position = "dodge") +
  geom_text(aes(label = y), position = position_dodge(0.9))
# Use you can't nudge and dodge text, so instead adjust the y postion
ggplot(data = df, aes(x, y, group = grp)) +
  geom_col(aes(fill = grp), position = "dodge") +
  geom_text(
    aes(label = y, y = y + 0.05),
    position = position_dodge(0.9),
    vjust = 0
  )

# To place text in the middle of each bar in a stacked barplot, you
# need to set the vjust parameter of position_stack()
ggplot(data = df, aes(x, y, group = grp)) +
 geom_col(aes(fill = grp)) +
 geom_text(aes(label = y), position = position_stack(vjust = 0.5))

# Justification -------------------------------------------------------------
df <- data.frame(
  x = c(1, 1, 2, 2, 1.5),
  y = c(1, 2, 1, 2, 1.5),
  text = c("bottom-left", "bottom-right", "top-left", "top-right", "center")
)
ggplot(df, aes(x, y)) +
  geom_text(aes(label = text))
ggplot(df, aes(x, y)) +
  geom_text(aes(label = text), vjust = "inward", hjust = "inward")