Qt is a comprehensive application and UI framework for developing Mac applications that can also be deployed across many other desktop and embedded operating systems without rewriting the source code. Use the code from one single code-base and rebuild for all supported Windows versions and other platforms.
Qt includes a set of integrated development tools to speed development on the Mac platform.
Qt Creator is a complete Cross-platform IDE included in the Qt SDK. The IDE allows programmers to create, build, debug and run Qt applications accross all supported platforms.
The Qt class library includes all the functionality needed to build advanced GUI applications.
Qt is written without making assumptions about the number representation, endianness or architecture of the underlying processor. To support Intel hardware on the Apple platforms, Qt customers simply need to recompile their apps.
Additional Cross-Platform and Platform-Specific Development information.
Note: Qt also provides support for 64-bit applications on top of Cocoa APIs.