Libavg
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Libavg is a high-level development platform for media-centric applications. It allows programmers, media artists and designers to quickly develop media applications, uses python as scripting language and is written in high-speed C++.
libavg is great for multitouch development. It supports Win7 Touch, Linux Drivers, TUIO and even the Apple Multitouch Trackpad - in short, all major driver models. It also includes it's own tracker for optical FTIR and DI devices. The libavg event system is fully multitouch-enabled and makes building even complex multitouch applications easy.