QuantLib is a cross-platform, quantitative finance C++ library for modeling, pricing, trading, and risk management in real-life. It is also wrapped as Python/Ruby/Scheme modules. Extensions for Excel, R, and Mathematica are available. Other such extensions are under consideration. QuantLib offers tools that are useful both for practical implementation and for advanced modeling. It features market conventions, yield curve models, solvers, PDEs, Monte Carlo (low-discrepancy included), exotic options, VAR, and so on.
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.
Canorus is a cross-platform music score editor. It supports an unlimited number and length of staffs, polyphony, MIDI playback of written notes, chord markings, lyrics, and a number of import and export filters to many formats like MIDI, MusicXML, ABC Music, MUP, PMX, MusiXTeX, and LilyPond. It features multiple viewports of the same score, scripting support, score source view, and a fast and intuitive UI. It is based on Qt4, uses CMake as a project management tool, swig for scripting/macros integration (primary script languages are Ruby and Python), and the cross platform rtmidi library for MIDI playback. It is the official successor to NoteEdit.
Open-RJ is an library that implements readers for the Record-Jar structured text file format. Mappings are provided to several languages and technologies, including C++, COM, D, Java, .NET, Python, Ruby, and STL. In addition to platform-independence, the library focuses on small runtime costs - memory and speed - and the classic UNIX attributes of discoverability and visibility.