Where can I see architecture of QT framework ?

[Ganesha]

Is Qt developer written some wrapper over mfc and other libraries?

[Chris Kawa]

Hi, welcome to devnet.

No, Qt is not a wrapper around MFC or any other library. It is a "cross-platform library":http://qt-project.org/doc/qt-5/supported-platforms.html so MFC wouldn't do you any good on for example blackberry or embedded linux.
The topic is vast and complicated but to simplify Qt implements its own drawing mechanism, event delivery system, threads, networking and communication via signal/slots.
All this is implemented using "a thin abstraction over the underlying platform":http://qt-project.org/doc/qt-5/qpa.html. The most fundamental things (platform dependent thread primitives, blitting to a window, native events and handles) are placed in platform plugins and kept separated from the main classes. On each platform these plugins are implemented using whatever low-level API the platform provides eg. WinAPI on Windows, Cocoa on OSX etc.

Saying that Qt is not a wrapper for another library does not mean that it doesn't use 3rd party libraries for some of the features. Notable examples here would be WebKit for web layout, OpenSSL for encryption or ANGLE for emulating OpenGL on DirectX drivers.

There are also platform specific modules that provide additional functionality eg. COM and WDDM access on Windows.

[Ganesha]

Thanks Chris Kawa .

[IamSumit]

Hi.
In order to see the architecture of Qt
"Go":http://lmgtfy.com/?q=Qt+architecture+images

Hope this helps.