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Change pdf paper size

Source: R/pdf_change_paper.R
pdf_change_paper.Rd

pdf_change_paper() changes the paper size of a pdf, centering the original contents on the new paper size. pdf_pad_paper() is an alias semantically intended for padding an undersized pdf document to a normal paper size (e.g. padding a pdf smaller than letter to letter size).

Usage

pdf_change_paper(
  input,
  output = NULL,
  ...,
  paper = getOption("papersize", "letter")
)

pdf_pad_paper(
  input,
  output = NULL,
  ...,
  paper = getOption("papersize", "letter")
)

Arguments

input

Input pdf filename.

output

Output pdf filename. NULL defaults to tempfile(fileext = ".pdf").

...

Passed to pdf_apply().

paper

Paper size. Usually either "letter" or "a4" but in certain circumstances can be one of "letter", "a4", "poker", "bridge", "legal", "a5", "a3", "special".

Value

output pdf file name invisibly. As a side effect creates a pdf with the new paper size.

Details

By default these function do not scale the original contents (but you can pass on a scale argument in the ... to pdf_apply()).

To convert a document between A4 and letter paper without losing any of its original safe zone, scale by the ratio of the binding dimension (the dimension that shrinks) rather than leaving scale at its default of 1:

A4 to letter

Height is the binding dimension (letter is shorter than A4), so use scale = 11 / (297 / 25.4) (about 0.94).

Letter to A4

Width is the binding dimension (A4 is narrower than letter), so use scale = (210 / 25.4) / 8.5 (about 0.97).

Examples

# Some PnP files' size is the intersection of A4/letter page sizes
# i.e. shorter than A4 and narrower than letter.
# We usually want pad to full A4 or letter page size.
input <- tempfile(fileext = ".pdf")
grDevices::pdf(input, width = 8.3, height = 11, bg = "blue")
grid::grid.text("")
invisible(grDevices::dev.off())

pdf_width(input)
#> [1] 8.29166666666667inches
pdf_height(input)
#> [1] 11inches

output <- pdf_change_paper(input, paper = "letter")
pdf_width(output)
#> [1] 8.5inches
pdf_height(output)
#> [1] 11inches
unlink(output)

output_a4 <- pdf_pad_paper(input, paper = "a4")
pdf_width(output_a4)
#> [1] 8.26777777777778inches
pdf_height(output_a4)
#> [1] 11.6929166666667inches
unlink(output_a4)

unlink(input)

# Convert an A4 document to letter, preserving its safe zone
input_a4 <- pdf_create_blank(paper = "a4", bg = "blue")
output_letter <- pdf_change_paper(
  input_a4,
  paper = "letter",
  scale = 11 / (297 / 25.4)
)
pdf_width(output_letter)
#> [1] 8.5inches
pdf_height(output_letter)
#> [1] 11inches
unlink(input_a4)
unlink(output_letter)

# Convert a letter document to A4, preserving its safe zone
input_letter <- pdf_create_blank(paper = "letter", bg = "blue")
output_a4_safe <- pdf_change_paper(
  input_letter,
  paper = "a4",
  scale = (210 / 25.4) / 8.5
)
pdf_width(output_a4_safe)
#> [1] 8.26777777777778inches
pdf_height(output_a4_safe)
#> [1] 11.6929166666667inches
unlink(input_letter)
unlink(output_a4_safe)