PLIB is a set of libraries to write games and other realtime interactive applications that are 100% portable across a wide range of hardware and operating systems. It's used by Majik3D, FlightGear, and others, and includes libraries for GUI widgets, sound replay, geometry, scene graph, joystick, and fonts/text.
pad sequential filenames so alphabetical order matches numerical order. It automatically determines the necessary integer field width, treats filenames with different prefixes or suffixes separately, removes redundant padding, and is reasonably efficient, even for thousands of names.
FreeImage is an Open Source library project for developers who would like to support popular graphics image formats in their software. The libraries are available in both binary and source distributions. FreeImage supports BMP, CUT, ICO, IFF, JBIG, JNG, JPEG, JFIF, KOALA, LBM, PCD, PBM, PGM, PNG, PPM, PSD, RAS, TARGA, TIFF, and WBMP.
pstoedit converts Postscript(TM) and PDF files to other vector graphic formats so that they can be edited graphically. The formats it can generate include tgif, fig, PDF, gnuplot, DXF, Java Applets, HPGL, WMF, EMF, LaTeX2e, SWF, and many others. pstoedit's framework can be used independantly by other programs.
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.
Kognition is an omnifont OCR software for KDE. It is the result of two diploma theses about omnifont optical character recognition which are included as documentation (in German). Due to the fact that each step of the OCR process can be visualized you can get a quick idea of how OCR works and where the problems lie. However the program may be of minor/no use for end users in its current state.