Qt Project

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

Qt Project
Qt logo 2015.svg
Founded21 October 2011; 7 years ago (2011-10-21)
FocusFree software
ProductsQt, Qt Creator
MethodDevelopment and documentation
WebsiteThe Qt Company

The Qt Project is a project to co-ordinate the development of the Qt software framework. The project was founded by Nokia,[1] and has been now led by Digia’s subsidiary The Qt Company since it acquired Qt software technologies, trademarks, and personnel from Nokia.[2]


KDE mascot Konqi showing its Qt heart.

Haavard Nord and Eirik Chambe-Eng (the original developers of Qt and the CEO and President, respectively, of Trolltech) began development of "Qt" in 1991, three years before the company was incorporated as Quasar Technologies, then changed the name to Troll Tech and then to Trolltech.[3]

Until version 1.45, source code for Qt was released under the Qt Free Edition License.[4] This was viewed as not compliant with the open source principle by the Open Source Initiative and the free software definition by Free Software Foundation because, while the source was available, it did not allow the redistribution of modified versions.

Controversy arose around 1998 when it became clear that KDE’s K Desktop Environment was going to become one of the leading desktop environments for Linux. As it was based on Qt, many people in the free software movement worried that an essential piece of one of their major operating systems would be proprietary.

With the release of version 2.0 of the toolkit, the license was changed to the Q Public License (QPL), a free software license but one regarded by the Free Software Foundation as incompatible with the GPL. Compromises were sought between KDE and Trolltech whereby Qt would not be able to fall under a more restrictive license than the QPL, even if Trolltech was bought out or went bankrupt. This led to the creation of the KDE Free Qt Foundation which guarantees that Qt would fall under a BSD-style license should no free/open source version of Qt be released during 12 months.[5]

In 2000, Qt 2.2 was released under the GPL v2, ending all controversy regarding GPL compatibility.[6]

On 28 January 2008 Nokia announced to acquire Trolltech.[7][8]

On 14 January 2009 Qt version 4.5 was relicensed, adding LGPL as licensing option.[9]

The Qt Project was founded on 21 October 2011.[1][10] In August 2012 Digia announced to acquire all rights to Qt and take Nokia’s role within the Qt Project.[2]


The Qt Project is not a separate legal entity or organization; Digia retains all trademarks around Qt.[11][12]

Qt's Open Governance is modelled after WebKit's.[13][14]

Decision-making takes place in a process the project describes as "lazy consensus".[15]

The project facilitates online communication among its developers and community members through public forums,[16] mailing lists,[17] and wiki pages.[18]

Participating organizations[edit]

Distribution of non-Digia Qt contributors (2013, Week 18)

Aside from the project leader Digia and various individuals, a number of other organizations participate in the Qt Project.[19] Second-largest Qt contributor is KDAB, a Swedish Qt consulting company.[20] KDAB is involved in many areas, including maintenance of several components.[21][22] KDAB together with RIM/BlackBerry are maintaining the QNX and BlackBerry 10 ports of Qt.[19][23]

Another big participator is Intel, contributing for example Wayland support.[24] AudioCodes maintains IBM ClearCase support in Qt Creator.[25]

Various individuals from KDE implement features from KDE Frameworks in Qt.[26]

See also[edit]

External links[edit]


  1. ^ a b Lydia Pintscher (21 October 2011). "KDE Applauds Qt's Move to Open Governance". KDE.News. Retrieved 2013-05-08.
  2. ^ a b "Digia to acquire Qt from Nokia". Digia.com. Archived from the original on 5 March 2013. Retrieved 19 March 2013.
  3. ^ "A Brief History of Qt". Retrieved 20 December 2007.
  4. ^ "Qt Free Edition License". Trolltech. 1992. Archived from the original on 14 October 2016. Retrieved 14 October 2016.
  5. ^ "Free Qt Foundation". KDE. Retrieved 2013-05-08.
  6. ^ "Trolltech to Release Qt Under GPL - Decision Alters Linux GUI Landscape - Reports". LinuxPlanet. 2000-09-04. Retrieved 2013-05-08.
  7. ^ "Nokia to acquire Trolltech to accelerate software strategy". 28 January 2008. Retrieved 28 January 2008.
  8. ^ Paul, Ryan (2008-01-28). "Nokia to buy Trolltech, will become a patron of KDE". Ars Technica. Retrieved 2013-05-08.
  9. ^ "Qt Everywhere: 4.5 To Be Relicensed As LGPL". Retrieved 2013-05-08.
  10. ^ Meyer, David (2011-10-24). "Nokia gives Qt open-source governance". ZDNet. Retrieved 2013-05-08.
  11. ^ "About us - Digia Plc". Qt.digia.com. 13 September 2011. Archived from the original on 30 May 2013. Retrieved 8 May 2013.
  12. ^ "Qt Project". Qt Project. Retrieved 2013-05-08.
  13. ^ "Nokia: Qt 5 soll im April 2012 erscheinen" (in German). Golem.de. 2011-06-16. Retrieved 2013-05-08.
  14. ^ Anita Klingler (2011-10-24). "Nokia startet Qt-Projekt mit unabhängiger Infrastruktur" (in German). Zdnet.de. Retrieved 2013-05-08.
  15. ^ "The_Qt_Governance_Model | Qt Wiki". Qt Project. 2012-09-25. Retrieved 2013-05-08.
  16. ^ "forums". Qt Project. Retrieved 2013-05-08.
  17. ^ "Mailing Lists". Lists.qt-project.org. Retrieved 2013-05-08.
  18. ^ "index | Qt Wiki". Qt Project. 2013-03-29. Retrieved 2013-05-08.
  19. ^ a b Macieira, Thiago. "Qt Project Statistics". Thiago Macieira's blog. Macieira.org. Retrieved 2013-05-08.
  20. ^ "contributions to Qt 5.0 (part 1)". KDAB. 2012-12-20. Retrieved 2013-05-08.
  21. ^ "contributions to Qt 5.0 (part 2)". KDAB. 2012-12-21. Retrieved 2013-05-08.
  22. ^ "Maintaining Qt3D". KDAB. 2012-12-21. Retrieved 2013-05-08.
  23. ^ "Qt5 on the QNX operating system". KDAB. 2012-04-19. Retrieved 2013-05-08.
  24. ^ "[Phoronix] Qt Is Now Drawing On Wayland". Phoronix.com. 2010-09-21. Retrieved 2013-05-08.
  25. ^ "Maintainers | Qt Wiki". Qt Project. 2013-04-12. Retrieved 2013-05-08.
  26. ^ "Frameworks/Epics/Contributions to Qt5". KDE Community Wiki. Retrieved 2015-04-27.