Fast Multi-Page PDF Report Layout on the Graphics Device

A lightweight, dependency-free engine to build multi-page PDF reports quickly on top of R's built-in graphics device ('pdf'/'cairo_pdf'). Content is placed by a measured flow layout: every text block reports its real width and height via 'strwidth'/'strheight', the vertical cursor advances by measured height, and pages break automatically. This eliminates the text-overlap of dead-reckoned coordinate reports (such as the 'nmw' NONMEM diagnostic reports) and replaces slow '.Rmd'/'knitr'/'LaTeX' pipelines for fixed report generation: no external toolchain is started and the document is written in a single pass. Interactive AcroForm CRFs are out of scope.

simPDF

Multi-page PDF reports in a fraction of a second, in base R.

Why: speed

The usual way to produce a PDF report from R is .Rmd → knitr → pandoc → LaTeX. That chain starts three external programs, writes the document to disk three times, and lets TeX re-typeset the whole thing in several global passes. For a fixed-format report — the same layout, new numbers, run after run — you pay that cost every single time.

simPDF skips the chain. It draws straight onto R's built-in pdf() / cairo_pdf() device in one pass, so there is no toolchain to start and no intermediate format to convert.

The same report — 40 paragraphs, a 200-row table, one scatter plot — written both ways (R 4.6.1, Windows 11, median of three runs):

About 20× faster, and nothing outside R has to be installed: no pandoc, no TeX distribution, no .Rmd file. A batch of a hundred diagnostic reports takes seconds instead of minutes, which is what makes it practical to regenerate them on every model run.

And: no overlapping text

simPDF lays reports out with a measured flowing layout: every block reports its real width and height, the cursor advances by that measured height, and pages break automatically. Text, tables and matrices therefore never overlap, however many rows or parameters they contain — the failure mode of reports built from hand-computed coordinates.

Interactive fillable forms (AcroForm CRFs) are out of scope: simPDF is for reports and figures.

Installation

install.packages("simPDF")

# development version
# install.packages("remotes")
remotes::install_github("ksbae/simPDF")

Quick start

library(simPDF)

doc <- sp_new("report.pdf", paper = "letter")
frame_set(doc, top = doc$H - 45, bottom = 45, left = 45, right = doc$W - 45)

flow_run(doc, list(
  block_para("Summary", size = 16, font = 2),
  block_rule(),
  block_table(head(mtcars)),                       # measured columns, repeats header, splits pages
  block_para("Diagnostics", size = 12, font = 2),
  block_plot(plot(mpg ~ wt, mtcars), height = 220) # a plot, inline with the text
), footer = block_para("CONFIDENTIAL", size = 8, align = "center"))

sp_close(doc)

See vignette("simPDF") for the full guide.

Features

• Flow engine — sp_new(), frame_set(), flow_run(); blocks: block_para (wrapped/aligned text), block_pre (capture.output() dumps), block_table (auto column widths, repeating header, page-splitting), block_matrix (wide matrices split into column groups), block_plot (inline plots), sp_figure_page() (full-page multi-panel figures), block_image, block_keep, block_spacer, block_rule, running headers/footers.
• No overlap — AFM-exact measurement (sp_width/sp_height) drives every placement; sp_trace() / sp_overlaps() let you assert zero overlap in tests.
• Signatures — block_authorship() and block_signature() draw a prepared-by block and approval lines; sp_add_sig_fields() adds interactive Adobe Acrobat signature fields (/Sig) to the finished PDF via a pure base-R incremental update.
• Model flow diagrams — block_flow_diagram() renders a tree of nodes as measured boxes, scaled to fit the page.

Related packages

• nmw uses simPDF for its NONMEM diagnostic reports.

License

GPL-3. Author/maintainer: Kyun-Seop Bae [email protected].