KDE software is based on the Qt framework.

Qt ( " cute ", or unofficially as Q-T cue-tee ) is a cross-platform application framework that is widely used for developing application software with a graphical user interface ( GUI ) ( in which cases Qt is classified as a widget toolkit ), and also used for developing non-GUI programs such as command-line tools and consoles for servers.

Distributed under the terms of the GNU Lesser General Public License ( among others ), Qt is free and open source software.

Qt is developed by an open source project, the Qt Project, involving developers as individuals and from firms working to advance Qt, such as Nokia, Digia, and others.

Qt is to replace Nokia's Avkon as the supported UI SDK for developing Symbian applications.

Qt is available under the following copyright licenses:

Qt Development Frameworks ( formerly known as Qt Software, Trolltech and as Quasar Technologies ) is an Oslo, Norway-based software company best known for its Qt toolkit and application framework.

Qt Development Frameworks is a wholly owned subsidiary of Nokia Corporation.

Its flagship product is Qt, a multi-platform Graphical User Interface ( GUI ) framework written in C ++.

Qt is popular with application developers using C ++ but is supported by bindings for other programming languages too, such as Python.

In 2001 Trolltech introduced Qtopia which is based on Qt.

* Symbian, which is moving towards Qt as the main development framework.

The Q Public License ( QPL ) is a non-copyleft license, created by Trolltech for its free edition of the Qt.

KDE, a desktop environment for Linux, is based on Qt.

* As most libraries based in C ++ ( MFC, wxWidgets, Qt ), C ++ language requires a learning curve.

The appearance and behaviour of buttons in Linux ( and other Unix-like ) operating systems is defined primarily by which widget toolkit is being employed, the most popular being GTK and Qt, though other toolkits are used.

In particular, most clients use libraries such as Xaw, Motif, GTK +, or Qt which in turn use Xlib for interacting with the server.

* die Kurve, an open source implementation of die Kurve on Qt, hence available on most of the platforms.

Examples of the use of this prefix in names of Python applications or libraries include Pygame, a binding of SDL to Python ( commonly used to create games ); PyS60, an implementation for the Symbian S60 operating system ; PyQt and PyGTK, which bind Qt and GTK, respectively, to Python ; and PyPy, a Python implementation written in Python.

Qt can also be used in several other programming languages via language bindings.

It was used until Qt 3. 0, as Trolltech toolkit version 4. 0 was released under GPL version 2.

As KDE grew in popularity, the free software community urged Trolltech to put Qt under a license ( the QPL ) that would assure that it would remain free software forever and could be used and developed by commercial third-parties.

Commonly used GUIs are gMplayer and Gnome MPlayer written in GTK +, KMPlayer written in Qt, MPlayer OS X Extended and MPlayerX for Mac OS X and MPUI-hcb for Windows.

The QPL license that Qt used was free only if the program was not sold for profit and if its source code was freely available.

" This was shortly followed by the SL-5500 ; both used ' Embedix ' - an embedded version of the Linux operating system developed by Lineo-combined with Qtopia, the Qt toolkit-based embedded application environment developed by Trolltech.

For example, it can be used instead of GStreamer as a backend for the Phonon media framework used by KDE and Qt.

In addition to the Javadoc syntax, Doxygen supports the documentation tags used in the Qt toolkit and can generate output in HyperText Markup Language ( HTML ) as well as in Microsoft Compiled HTML Help ( CHM ), Rich Text Format ( RTF ), Portable Document Format ( PDF ), LaTeX, PostScript or man pages.

Porten took part in the development of Qt a GUI toolkit used by Windows, Mac OS X, and X11 developers.

The Norwegian company Trolltech, who develop the Qt Development Frameworks, used this " encheferization " for a more serious purpose – although the friendly rivalry between Norwegians and Swedes perhaps was its inspiration.

The Qt port of WebKit is also available to be used in Konqueror in KDE 4. 1.

The word signal is used instead of the word dataflow in documentation of such libraries as Qt, GTK + and libsigc ++.

* Meta Object Compiler, used by the Qt development framework

The Rockbox Utility is a free computer application, available for Linux, Mac OS X, and Microsoft Windows, built using Nokia Qt platform, that is used to install and manage Rockbox on DAPs.

Toolkits developed more recently include Qt ( 1991-, used by KDE ), GTK + ( 1997-, used by GNOME ), wxWidgets ( 1992-), FLTK ( 1998-), FOX ( 1997-) and fpGUI ( 2005-current ).

Qt has only been used in Kernel 2. 6.

WebKit has also been ported to several toolkits that support multiple platforms, such as the GTK + toolkit, Qt framework, Adobe Integrated Runtime, Enlightenment Foundation Libraries ( EFL ), and the Clutter toolkit.

* The Phonon multimedia API for Qt and KDE applications can optionally use VLC as a backend.

* Clementine ( software ), a music player based on Qt 4

Other programmers quickly started developing KDE / Qt applications, and by early 1997, a few applications were being released.

This cost in supporting operating systems diversity can be avoided by instead writing applications against software platforms like Java or Qt.

Before the launch of the Qt Project, it was produced by Nokia's Qt Development Frameworks division, which came into being after Nokia's acquisition of the Norwegian company Trolltech, the original producer of Qt.

Only the personal edition of Qt was covered by the QPL ; the commercial edition, which is functionally equal, is under a pay-per-use license and could not be freely distributed.

As usual, the profit maximizing output ( Qt ) is determined by the intersection of the marginal cost curve ( MC ) with the marginal revenue curve for the total market ( MRt ).

KSVG was first developed in 2001 by Nikolas Zimmermann and Rob Buis ; however, by 2003, it was decided to fork the then-current KSVG implementation into two new projects: KDOM / KSVG2 ( to improve the state of DOM rendering in KHTML underneath a more formidable SVG 1. 0 render state ) and Kcanvas ( to abstract any rendering done within khtml / ksvg2 in a single shared library, with multiple backends for it, e. g., Cairo / Qt, etc.

* The GNU project, an essay by Richard Stallman, telling the story of Qt, Harmony, and GNOME

Much of the development efforts concentrated on increasing the emulator's portability, by rewriting assembly code in C and C ++, including a new GUI using Qt.

CLX was based on Qt by Nokia.

It was developed by Qt Software, a subsidiary of Nokia.