Haru Free PDF Library

A very cool PDF generation library for developers. From the website:
HARU is a free, cross platform, open-sourced software library for generating PDF. It supports the following features.

1. Generating PDF files with lines, text, images.
2. Outline, text annotation, link annotation.
3. Compressing document with deflate-decode.
4. Embedding PNG, Jpeg images.
5. Embedding Type1 font and TrueType font.
6. Creating encrypted PDF files.
7. Using various character set (ISO8859-1~16, MSCP1250~8, KOI-8R).
8. Supporting CJK fonts and encodings.

You can add the feature of PDF creation by using HARU without understanding complicated internal structure of PDF.

HARU is distributed under the ZLIB/LIBPNG License. Because ZLIB/LIBPNG License is one of the freest licenses, You can use Haru for various purposes.

C/C++ as well as bindings for Ruby and Delphi/Free Pascal and C#.

The website offers some great examples.

http://libharu.sourceforge.net/examples.html