Save a matched set of images, one per group

Splits data by a column, builds a table for each group with a function you supply, and writes one image per group. The images are padded to a common width so a posted series does not come out at ragged sizes.

Usage

gt_save_batch(
  data,
  group,
  fn,
  file,
  dir = ".",
  match_width = TRUE,
  bg = "white",
  whitespace = 50,
  zoom = 2,
  quiet = FALSE
)

Arguments

data

A data frame to split.

group

The column to split on.

fn

A function building one table. It is called as fn(df, group), where df is that group's rows and group is its value, and it must return a gt_tbl.

file

Character. A file name pattern containing {group}, which is replaced by the group value, as "net-{group}.png".

dir

Character. The directory to write into. Created if it does not exist. Defaults to ".".

match_width

Logical. Should every image be padded to the width of the widest one, so a posted series shares one width? Defaults to TRUE.

bg

Character. The background color of the padding. Defaults to "white".

whitespace

Numeric. Padding left around each table, in pixels. Defaults to 50.

zoom

Numeric. The rendering zoom factor. Defaults to 2.

quiet

Logical. Suppress the per-group progress message. Defaults to FALSE.

Value

Invisibly, a character vector of the files written.

Details

A group whose table fails to build does not abandon the run. The error is collected, the remaining groups are written, and a warning at the end names every group that failed.

Group values are used in file names with anything awkward replaced by a dash, so a group called "North / East" writes to north-east.

Without match_width, each image is trimmed to its own content, so a set posted together can come out at different widths. With it, every image is padded to the width of the widest before its border is added.

See also

gt_grid() for the same split composed into one image instead.

Examples

if (FALSE) { # \dontrun{
library(gt)

build <- function(df, group) {
  gt(df[c("mpg", "hp", "wt")]) %>%
    gt_theme_broadsheet() %>%
    tab_header(title = paste(group, "cylinders"))
}

gt_save_batch(mtcars, cyl, build, "cars-{group}.png", dir = "out")
} # }