HexaPDF is a pure Ruby library with an accompanying application for working with PDF files. In short, it allows

• creating new PDF files,
• manipulating existing PDF files,
• merging multiple PDF files into one,
• extracting meta information, text, images and files from PDF files,
• securing PDF files by encrypting them and
• optimizing PDF files for smaller file size or other criteria.

HexaPDF was designed with ease of use and performance in mind. It uses lazy loading and lazy computing when possible and tries to produce small PDF files by default.

The HexaPDF distribution provides the library as well as the hexapdf application. The application can be used to perform common tasks like merging PDF files, decrypting or encrypting PDF files and so on.

When HexaPDF is used as a library, it can be used to do all the task that the command line application does and much more. Here is a "Hello World" example that shows how to create a simple PDF file:

require 'hexapdf'

doc = HexaPDF::Document.new
canvas = doc.pages.add.canvas
canvas.font('Helvetica', size: 100)
canvas.text("Hello World!", at: [20, 400])
doc.write("hello-world.pdf")

For detailed information have a look at the HexaPDF website where you will the API documentation, example code and more.

It is recommend to use the HTML API documentation provided by the HexaPDF website as it is enhanced with example graphics and PDF files and tightly integrated into the rest of the website.

Since HexaPDF is written in Ruby, a working Ruby installation is needed - see the official installation documentation for details. Note that you need Ruby version 2.4 or higher as prior versions are not supported!

Apart from Ruby itself the HexaPDF library has only one external dependency geom2d which is written and provided by the HexaPDF authors. The hexapdf application has an additional dependency on cmdparse, a command line parsing library.

HexaPDF itself is distributed via Rubygems and therefore easily installable via gem install hexapdf.

The main difference between HexaPDF and Prawn is that HexaPDF is a full PDF library whereas Prawn is a library for generating content.

To be more specific, it is easily possible to read an existing PDF with HexaPDF and modify parts of it before writing it out again. The modifications can be to the PDF object structure like removing superfluous annotations or the the content itself.

Prawn has no such functionality. There is basic support for using a PDF as a template using the pdf-reader and prawn-template gems but support is very limited. However, Prawn has a very featureful API when it comes to creating content, for individual pages as well as across pages.

Such functionality will be incorporated into HexaPDF in the near future. The main functionality for providing such a feature is already available in HexaPDF (the page canvas API). Additionally, laying out text inside a box with line wrapping and such is also supported. What's missing (and this is still quite a big chunk) is support for advanced features like tables, page breaking and so on.

So why use HexaPDF?

• The architecture of HexaPDF is based on the object model of the PDF standard. This makes extending HexaPDF very easy and allows for reading PDF files for templating purposes.

• HexaPDF will provide a high level layer for composing a document of individual elements that are automatically layouted. Such elements can be headers, paragraphs, code blocks, ... or links, emphasized text and so on. These elements can be customized and additional element types easily added.

• In addition to being usable as a library, HexaPDF also comes with a command line tool for manipulating PDFs. This tool is intended to be a replacement for tools like pdftk and the various Poppler-based tools like pdfinfo, pdfimages, ...

Clone the repository and then run rake dev:setup. This will install the needed Rubygem dependencies as well as make sure that all applications needed for the tests are available.

AGPL - see the LICENSE file for licensing details. Commercial licenses are available at https://gettalong.at/hexapdf/.

Some included files have a different license:

• For the license of the included AFM files in the data/hexapdf/afm directory, see the file data/hexapdf/afm/MustRead.html.

• The files test/data/encoding/{glyphlist.txt,zapfdingbats.txt} are licensed under the Apache License V2.0.

• The file test/data/fonts/Ubuntu-Title.ttf is licensed under the SIL Open Font License.

• The AES test vector files in test/data/aes-test-vectors have been created using the test vector file available from http://csrc.nist.gov/groups/STM/cavp/block-ciphers.html#test-vectors.

See http://hexapdf.gettalong.org/contributing.html for more information.

Thomas Leitner, http://gettalong.org