Low-level PDF manipulation for F#

		     Daniel Beer <dlbeer@gmail.com>
			      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.