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Headers and Footers

Source: vignettes/headers_footers.Rmd
headers_footers.Rmd

A core feature of {docorator} is flexible header and footer options via the header and footer arguments in the as_docorator() function. These are made possible via the underlying fancyhdr latex library. This makes it possible to have multiple lines of headers and/or footers, as well as multiple positions of text within each.

Specifying headers

The header argument accepts a fancyhead object. The fancyhead object accepts a series of fancyrow objects. These correspond to each line of text in the header. Within a fancyrow, you can optionally specify the left, center, and right text (NA indicates a blank position). Some examples are below.

One line header 

fancyhead(
  fancyrow(left = "My Study", center = NA, right = NA)
)

Multi-line header 

fancyhead(
  fancyrow(left = "My Study", center = NA, right = "Date as of today"),
  fancyrow(left = "My Population", center = NA, right = NA),
  fancyrow(left = NA, center = "My Table", right = NA)
)

Specifying footers

The footer argument of as_docorator() accepts a fancyfoot object. This behaves identically to fancyhead above by accepting a series of fancyrow objects for each line of the footer.

fancyfoot(
  fancyrow(left = "Date as of today", center = NA, right = NA)
)
fancyfoot(
  fancyrow(left = "General footer for the table", center = NA, right = NA),
  fancyrow(left = "Date as of today", center = NA, right = "path/to/docname.pdf")
)

Available utilities for standard or automated information

There are several functions available for features like page numbering and time stamps. These are prefixed with doc_*().

Add automatic page numbering in upper left 

fancyhead(
  fancyrow(left = "My study", center = NA, right = doc_pagenum())
)

Add file path in bottom left and datetime in bottom right 

fancyfoot(
  fancyrow(left = doc_path(), center = NA, right = doc_datetime())
)

Putting it all together 

gt::gtcars |>
  dplyr::slice_head(n = 10) |>
  dplyr::select(mfr, model, year, msrp) |>
  gt::gt(groupname_col = "mfr",
         row_group_as_column = TRUE) |> 
  as_docorator( 
    display_name = "mytbl",
    header = fancyhead(
      fancyrow(left = "My Study", center = NA, right = doc_pagenum()),
      fancyrow(left = "My Population", center = NA, right = NA),
      fancyrow(left = NA, center = "My Table", right = NA)
    ),
    footer = fancyfoot(
      fancyrow(left = "path/mytbl.pdf", center = NA, right = "Data as of 2025-01-01")
    ) 
  ) |> 
  render_pdf()

Note about sizing

{docorator} will automatically adjust the allowed height for headers and footers according to the lines of text required. If many lines of headers and/or footers are specified, this cuts down on the available height for the table/figure. Additionally, {docorator} does not auto-wrap long lines of text, so it is recommended you keep your left, right, and center text as brief as possible.

Please file an issue if you discover unexpected results or problems related to headers and footers.