Turn a folder of images into a corpus measure() can take

Builds a tibble of one row per file, with the columns the rest of the package expects. id keys the results and the audit joins, image is the path measure() reads, and bytes is a size covariate.

Nothing is decoded. bytes comes from file.size(), which needs no image reader and no system library.

Usage

prepare_image(paths, id = NULL)

Arguments

paths

A character vector of file paths.

id

A character vector of identifiers, one per path. Defaults to the file name without its extension, which is what a corpus of scanned pages usually keys on.

Value

A tibble with id, image, bytes, exists and ext.

Missing files

A path that does not resolve comes back with exists = FALSE and bytes as NA rather than being silently removed, because a corpus that quietly lost four documents is the failure this exists to prevent. Filter on exists after reading the count.

See also

measure(), which reads the image column.

Examples

f <- tempfile(fileext = ".png")
grDevices::png(f, width = 8, height = 8)
graphics::par(mar = c(0, 0, 0, 0))
graphics::plot.new()
grDevices::dev.off()
#> agg_record_107ad7e455355 
#>                        2 

prepare_image(f)
#> # A tibble: 1 × 5
#>   id                image                                     bytes exists ext  
#>   <chr>             <chr>                                     <dbl> <lgl>  <chr>
#> 1 file107ad1dceb57c /var/folders/0d/6_y1swz50c7gy3g7v86g9324…  1197 TRUE   png