GraphicsMagick is a robust collection of tools and libraries which support reading, writing, and manipulating an image in over 90 major formats including popular formats like DPX, DICOM, BMP, GIF, JPEG, JPEG-2000, PDF, PNG, PNM, SVG, and TIFF. A high-quality 2D renderer is included, which provides a subset of SVG capabilities. C, C++, Perl, Tcl, and Ruby are supported. Originally based on ImageMagick, GraphicsMagick focuses on performance, minimizing bugs, and providing stable APIs and ABIs. It runs on all modern variants of Unix, Windows, and Mac OS X.
Mathomatic is a portable, general-purpose computer algebra system (CAS) that can solve, differentiate, simplify, combine, and compare algebraic equations, perform standard, complex number, modular, and polynomial arithmetic, etc. It does some calculus and is very easy to compile/install, learn, and use. The symbolic math application with a simple command-line interface is designed to be a colorful algebra calculator that is reliable, responsive, and convenient to use. The symbolic math library is lightweight and easy to include in other software, due to being written entirely in C with no additional dependencies.
GNU libmicrohttpd is a small C library for embedding HTTP server functionality into other applications. It is reentrant, fast, supports HTTP 1.1, and permits listening on multiple ports. The API is simple and still powerful enough to allow programmers to use the entire HTTP feature set. SSL/TLS support is available as an option.
album is a free HTML/XHTML photo album and gallery generator that supports themes/skins. You can choose different themes or write your own to get different layouts and styles. It creates all your thumbnails (including directory thumbnails) and descends into directories so you can organize your photos. See the home page for more examples. album is also multi-lingual, with many languages being added all the time. N.B.: The purchase link is provided for donations; the software does not cost anything.
KDevelop is an integrated development environment which makes the creation and development of applications an easy task even for beginners. Highlights of the current release are: an application wizard for easy creation of KDE 4, Qt4, GNOME, and terminal C/C++ projects, full project management, a syntax-highlighting editor, code completion, an integrated dialog editor for the Qt/KDE GUI libraries, an internal debugger, a full-featured class browser with class tools, CVS and SVN support, an integrated HTML-based help system offering manuals and class-references, and extensive search mechanisms to browse sources and documentation.
strongSwan is a complete IPsec implementation for the Linux, Android, Maemo, FreeBSD, and Mac OS X operating systems. It interoperates with with most other IPsec-based VPN products via the IKEv2 or IKEv1 key exchange protocols. The focus of the strongSwan project is on strong authentication mechanisms using X.509 public key certificates and optional secure storage of private keys on smartcards through a standardized PKCS#11 interface. A rich choice of modular plugins adds additional features like Trusted Network Connect or advanced cryptographical algorithms.
Simple Groupware is a complete enterprise application offering email, calendaring, contacts, tasks, document management, synchronization with cell phones and Outlook, full-text search, and much more. Simple Groupware combines standards like RSS, iCalendar, vCard, IMAP, POP3, SMTP, CIFS, CSV, WebDAV, LDAP, and SyncML under one platform. Unlike other groupware software, Simple Groupware contains the programming language sgsML to enable the quick customization and creation of powerful Web applications.