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10. Miscelleanous questions

10.1 Why does KDE use Qt?

Qt is a very sophisticated toolkit that provides everything that is needed to build a modern user interface. Qt is written in C++, thus allowing object oriented development affording the necesary efficiency and reuse of code necessary for a project of the enormous size and scope of KDE. In our opinion there is no better toolkit available for Unix and that it would have been a grave mistake to try to build KDE on anything but the best.

Furthermore, all KDE developers agree that it would have not been possible to build KDE in equally short amount of time without the use of Qt.

10.2 Why does KDE not use gtk, xforms, xlib, whatever?

There are a number of toolkits available. To provide a consistent user interface and to keep used resources such as memory to a minimum, KDE can use only one of them. Qt was selected for the reasons mentioned above.

10.3 But Qt isn't free, is it?

That depends on your definiton of free. According to our definition it is free, since:

• The Qt libraries and source code are available for free and are readily available on many ftp site.
• You can run application written using Qt for free. No run time charges apply.
• You can develop application with Qt for free as long as you make the source code of your applications written in Qt readily available. Note -- you can even sell your application, however you must make its source code readily available if you wish to avoid buying a license for Qt.
• You can distribute Qt as well as application using Qt in any form -- be it on ftp sites or CDs. In particular all Linux distribution may press a copy of Qt and its source on their CD's free of charge.

As KDE was, and is, intented to be a noncommercial desktop environment for the X Window system, Qt fits our purposes.

Qt is constantly developed by Troll Tech's dedicated, professional staff. Troll Tech devotes all of its resources to improve Qt on a daily basis. Due to this fact Qt continues to develop at a rate unmatched by any L/GPL'ed toolkit, providing us with the best toolkit available under Unix and providing possible commercial developers for KDE with the quality and support they need.

10.4 Why not code a L/GPL'ed Qt clone?

Given the threat that Windows NT poses to Unix we feel a strong sense of urgency and believe it to be important to develop a great desktop for UNIX first, before we might even want to think about rebuilding the _tools_ we are using to build this desktop. Given the fact that our resources are limited KDE itself can not engage in a Qt cloning project at this point. However, if anyone feels that they would prefer a L/GPL'ed version of Qt we would like to encourage you to write such a L/GPL'ed clone. Keep in mind that Qt is only about 80.000 lines of code while KDE is already more than 500.000 lines and the number is rising daily so that a precise count is very difficult. This means writing a Qt clone is definitely feasable and it is only a matter of people who feel strongly enough about a L/GPL'ed version of Qt getting together and starting such a subproject.

Currently, there is a project called Harmony which started to implement a GPL'ed Qt-clone. If you dislike Qt's license, please consider joining this project.

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