Daniel Beer

# Low-level PDF manipulation for F#

13 Mar 2017

The code contained here consists of a module for manipulating PDF objects (pdf.fs), and a very simple parser for Adobe Font Metrics files and glyph-lists (afm.fs).

Things it can do:

• Create arbitrary PDF documents.

• Read objects from PDF documents (although it does not support parsing or decompression of content streams -- you need to implement this yourself).

• Deep-copy objects from one PDF document to another (e.g. to use a page of one document as an image or background in another).

• Calculate text sizes given a string, a point size, and an Adobe Font Metrics file.

PDFs of arbitrary complexity can be created, but you may find it useful to wrap the module in something higher-level and more specific to your needs.

Included is an example program (example.fs), which takes as arguments the name of an input and an output PDF file. Page 1 of the input file is extracted, and then a single-page output file is created which shows page 1 of the input file scaled down and centered in the middle of the page, with a blue border and a centered caption above it.

## Building the example

The included code should be able to be run on nearly any system. It has no dependencies outside the .NET standard library. If you're on a Linux system with mono and the F# compiler installed, type "make" to build.

If you're building manually, select all F# files for building, with example.fs last in the list. You will also need to include glyphlist.txt and Times-Roman.afm as assembly resources. The names of these resources should be the same as their filenames.