Type: Package
Title: Text Extraction, Rendering and Converting of PDF Documents
Version: 3.5.0
Description: Utilities based on 'libpoppler' https://poppler.freedesktop.org for extracting text, fonts, attachments and metadata from a PDF file. Also supports high quality rendering of PDF documents into PNG, JPEG, TIFF format, or into raw bitmap vectors for further processing in R.
License: MIT + file LICENSE
URL: https://ropensci.r-universe.dev/pdftools, https://docs.ropensci.org/pdftools/
BugReports: https://github.com/ropensci/pdftools/issues
SystemRequirements: Poppler C++ API: libpoppler-cpp-dev (deb) or poppler-cpp-devel (rpm), and poppler-data (rpm/deb) package.
Encoding: UTF-8
Imports: Rcpp (≥ 0.12.12), qpdf
LinkingTo: Rcpp
Suggests: png, webp, tesseract, testthat
RoxygenNote: 7.2.3
NeedsCompilation: yes
Packaged: 2025-03-03 13:55:55 UTC; jeroen
Author: Jeroen Ooms ORCID iD [aut, cre]
Maintainer: Jeroen Ooms <jeroenooms@gmail.com>
Repository: CRAN
Date/Publication: 2025-03-03 15:10:05 UTC

OCR text extraction

Description

Perform OCR text extraction. This requires you have the tesseract package.

Usage

pdf_ocr_text(
  pdf,
  pages = NULL,
  opw = "",
  upw = "",
  dpi = 600,
  language = "eng",
  options = NULL
)

pdf_ocr_data(
  pdf,
  pages = NULL,
  opw = "",
  upw = "",
  dpi = 600,
  language = "eng",
  options = NULL
)

Arguments

pdf

file path or raw vector with pdf data

pages

which pages of the pdf file to extract

opw

string with owner password to open pdf

upw

string with user password to open pdf

dpi

resolution to render image that is passed to pdf_convert.

language

passed to tesseract to specify the languge of the engine.

options

passed to tesseract to specify OCR parameters

See Also

Other pdftools: pdftools, qpdf, rendering

PDF utilities

Description

Utilities based on libpoppler for extracting text, fonts, attachments and metadata from a pdf file.

Usage

pdf_info(pdf, opw = "", upw = "")

pdf_text(pdf, opw = "", upw = "")

pdf_data(pdf, font_info = FALSE, opw = "", upw = "")

pdf_fonts(pdf, opw = "", upw = "")

pdf_attachments(pdf, opw = "", upw = "")

pdf_toc(pdf, opw = "", upw = "")

pdf_pagesize(pdf, opw = "", upw = "")

Arguments

pdf

file path or raw vector with pdf data

opw

string with owner password to open pdf

upw

string with user password to open pdf

font_info

if TRUE, extract font-data for each box. Be careful, this requires a very recent version of poppler and will error otherwise.

Details

The pdf_text function renders all textboxes on a text canvas and returns a character vector of equal length to the number of pages in the PDF file. On the other hand, pdf_data is more low level and returns one data frame per page, containing one row for each textbox in the PDF.

Note that pdf_data requires a recent version of libpoppler which might not be available on all Linux systems. When using pdf_data in R packages, condition use on poppler_config()$has_pdf_data which shows if this function can be used on the current system. For Ubuntu 16.04 (Xenial) and 18.04 (Bionic) you can use the PPA with backports of Poppler 0.74.0.

Poppler is pretty verbose when encountering minor errors in PDF files, in especially pdf_text. These messages are usually safe to ignore, use suppressMessages to hide them altogether.

See Also

Other pdftools: pdf_ocr_text(), qpdf, rendering

Examples

# Just a random pdf file
pdf_file <- file.path(R.home("doc"), "NEWS.pdf")
info <- pdf_info(pdf_file)
text <- pdf_text(pdf_file)
fonts <- pdf_fonts(pdf_file)
files <- pdf_attachments(pdf_file)

qpdf utilities

Description

These objects are imported from other packages. Follow the links below to see their documentation.

qpdf

pdf_combine, pdf_compress, pdf_length, pdf_split, pdf_subset

See Also

Other pdftools: pdf_ocr_text(), pdftools, rendering

Render / Convert PDF

Description

High quality conversion of pdf page(s) to png, jpeg or tiff format, or render into a raw bitmap array for further processing in R.

Usage

pdf_render_page(
  pdf,
  page = 1,
  dpi = 72,
  numeric = FALSE,
  antialias = TRUE,
  opw = "",
  upw = ""
)

pdf_convert(
  pdf,
  format = "png",
  pages = NULL,
  filenames = NULL,
  dpi = 72,
  antialias = TRUE,
  opw = "",
  upw = "",
  verbose = TRUE
)

poppler_config()

Arguments

pdf

file path or raw vector with pdf data

page

which page to render

dpi

resolution (dots per inch) to render

numeric

convert raw output to (0-1) real values

antialias

enable antialiasing. Must be "text" or "draw" or TRUE (both) or FALSE (neither).

opw

owner password

upw

user password

format

string with output format such as "png" or "jpeg". Must be equal to one of poppler_config()$supported_image_formats.

pages

vector with one-based page numbers to render. NULL means all pages.

filenames

vector of equal length to pages with output filenames. May also be a format string which is expanded using pages and format respectively.

verbose

print some progress info to stdout

See Also

Other pdftools: pdf_ocr_text(), pdftools, qpdf

Examples

# Rendering should be supported on all platforms now
# convert few pages to png
file.copy(file.path(Sys.getenv("R_DOC_DIR"), "NEWS.pdf"), "news.pdf")
pdf_convert("news.pdf", pages = 1:3)

# render into raw bitmap
bitmap <- pdf_render_page("news.pdf")

# save to bitmap formats
png::writePNG(bitmap, "page.png")
webp::write_webp(bitmap, "page.webp")

# Higher quality
bitmap <- pdf_render_page("news.pdf", page = 1, dpi = 300)
png::writePNG(bitmap, "page.png")

# slightly more efficient
bitmap_raw <- pdf_render_page("news.pdf", numeric = FALSE)
webp::write_webp(bitmap_raw, "page.webp")

# Cleanup
unlink(c('news.pdf', 'news_1.png', 'news_2.png', 'news_3.png',
 'page.jpeg', 'page.png', 'page.webp'))