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http://www.gtkmm.org/ - http://www.gtkmm.org/
The official C++ interface for the popular GUI library GTK+. Highlights include typesafe callbacks, and a comprehensive set of widgets that are easily extensible via inheritance. |
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Windows Template Library (WTL) - http://wtl.sourceforge.net/
A C++ library for developing Windows applications and UI components. It extends ATL (Active Template Library) and provides a set of classes for controls, dialogs, frame windows, GDI objects. [Open Source] |
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FOX Toolkit - http://www.fox-toolkit.org
A free, cross-platform C++ GUI library. It features an event messaging and targeting scheme with a very clean, factored, OS-abstracted design. [Open Source, LGPL] |
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Ultimate++ - http://www.ultimatepp.org/
A C++ cross-platform rapid application development suite. It includes a set of libraries (GUI, SQL, etc..), and an integrated development environment with GUI designer, debugger, etc. |
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http://www.ivtools.org/ivtools/etplusplus.html - http://www.ivtools.org/ivtools/etplusplus.html
Another application framework upon which layers of value-added frameworks have been built. Provides a few links to further information. |