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Add a column of text to a ggplot

Source: R/add_text_column.R
add_text_column.Rd

Adds a column of text to a ggplot object, overlaying the text at specified coordinates with customizable transformation, font size, and alignment.

Usage

add_text_column(
  p,
  x,
  y,
  trans = "identity",
  text,
  coord = c(0.05, 0.95),
  skip = 0.06,
  font_size = 4.2,
  hjust = 0,
  vjust = 0.5,
  ...
)

Arguments

p

ggplot object. Plot to have text overlaid onto.

x, y

numeric vector. The min and max of these vectors specify the range of the plot.

trans

character or trans object. Specifies the (visual) transformation applied to the y-axis. Internally passed to get_trans. Default is "identity". Note that this transformation is NOT applied to the y-axis (the assumption is that it already has been or will be).

text

character vector. Each element specifies a line of text. Subsequent elements are plotted underneath (assuming skip >= 0).

coord

numeric vector of length two. The elements specify the x- and y-coordinates, respectively, for the first line of text (i.e. the first element) of text. c(0, 0) means the bottom-left corner and c(1, 1) the top-right. There is no problem with specifying values outside [0, 1], however. Default is c(0.05, 0.95) (i.e. towards top-left corner).

skip

numeric. Proportion of y-axis length to skip between rows. Default is 0.06.

font_size

numeric. Font size. Default is 4.2 (roughly size 12).

hjust, vjust

numeric. Passed to hjust and vjust parameters of geom_text. Defaults are 0 and 0.5, respectively.

...

Additional parameters passed to geom_text.

Value

A ggplot object with the added text.

Examples

data_mod <- data.frame(x = rnorm(10))
data_mod$y <- data_mod$x * 3 + rnorm(10, sd = 0.5)
fit <- lm(y ~ x, data = data_mod)
coef_tbl <- coefficients(summary(fit))
results_vec <- c(
  paste0(
    "Intercept: ", signif(coef_tbl[1, "Estimate"][[1]], 2), " (",
    signif(coef_tbl[1, 1][[1]] - 2 * coef_tbl[1, 2][[1]], 3), ", ",
    signif(coef_tbl[1, 1][[1]] + 2 * coef_tbl[1, 2][[1]], 3), "; p = ",
    signif(coef_tbl[1, 4][[1]], 3), ")"
  ),
  paste0(
    "Slope: ", signif(coef_tbl[2, "Estimate"][[1]], 2), " (",
    signif(coef_tbl[2, 1][[1]] - 2 * coef_tbl[2, 2][[1]], 3), ", ",
    signif(coef_tbl[2, 1][[1]] + 2 * coef_tbl[2, 2][[1]], 3), "; p = ",
    signif(coef_tbl[2, 4][[1]], 3), ")"
  )
)
library(ggplot2)
library(UtilsGGSV)
p <- ggplot(data_mod, aes(x = x, y = y)) + geom_point()
add_text_column(
  p = p,
  x = data_mod$x,
  y = data_mod$y,
  text = results_vec
)


# Works even if y-axis is transformed
p <- p + scale_y_continuous(trans = get_trans("asinh"))
add_text_column(
  p = p,
  x = data_mod$x,
  y = data_mod$y,
  text = results_vec,
  trans = "asinh"
)