OpenImageIO is a library for reading and writing images, and a bunch of related classes, utilities, and applications.

CrissCross is a small open source cross platform C++ library for console and file I/O, CPU identification (CPUID), hashing (MD2, MD4, MD5, SHA-1, SHA-256, SHA-512, Tiger), sockets (TCP and UDP only currently), and data structures (LList, DArray, RedBlackTree, AVLTree, SplayTree, etc)....

Free implementation of Heroes of the Might and Magic II engine.,

YahooPOPs! is an application which emulates a POP3 mail server and provides free POP3 access to Yahoo! It does not depend on Yahoo's POP3 mail server. You can use a POP3 mail client of your choice. This application emulates a POP3 server and enables popular email clients like Outlook, Netscape, Eudora, Mozilla, and Calypso to download email from Yahoo! accounts....

Google Gadgets for Linux provides a platform for running desktop gadgets under Linux, catering to the unique needs of Linux users. We are compatible with the gadgets written for Google Desktop for Windows as well as the Universal Gadgets on iGoogle. Following Linux norms, this project is open-sourced under the Apache License....

A compiler infrastructure to build source-to-source program transformation and analysis tools.

sbf, a shortcut for SConsBuildFrameWork is a build system construct using SCons.,

Referencer is a Gnome application to organise documents or references, and ultimately generate a BibTeX bibliography file. Referencer includes a number of features to make this process easier:

• Automatic metadata retrieval (using DOI code or ArXiV ID)...

That project aims at providing a clean API, and the corresponding C++ implementation, for choosing one item among a set of travel solutions, given demand-related characteristics (e.g., Willingness-To-Pay, preferred airline, preferred cabin, etc.).

Editor for manipulating PDF documents.
GUI version + commandline interface.
Scripting is used to a great extent in editor and almost anything can be scripted, it is possible to create own scripts or plugins.